diff --git a/run.bash b/run.bash
index 06346d0..80f5336 100644
--- a/run.bash
+++ b/run.bash
@@ -1,17 +1,17 @@
-#!/bin/bash
-
-set -e  # exit if any command fails
-
-# Ensure QPP/database directory exists
-mkdir -p src/database
-
-python -m venv venv
-source venv/bin/activate
-
-pip install --upgrade pip
-pip install -r requirements.txt
-
-export FLASK_APP=src.app
-export FLASK_ENV=production
-
-flask run --host=0.0.0.0 --port=5000
+u!/bin/bash
+
+set -e  # exit if any command fails
+
+# Ensure QPP/database directory exists
+mkdir -p src/database
+
+python -m venv venv
+source venv/bin/activate
+
+pip install --upgrade pip
+pip install -r requirements.txt
+
+export FLASK_APP=src.app
+export FLASK_ENV=production
+
+flask run --host=0.0.0.0 --port=5000
diff --git a/run.bat b/run.bat
new file mode 100644
index 0000000..ba180fe
--- /dev/null
+++ b/run.bat
@@ -0,0 +1 @@
+python -m flask --app .\src\app.py run --host=0.0.0.0 --port=5000
\ No newline at end of file
diff --git a/src/static/index.css b/src/static/index.css
index fad9bcb..0ebf5fa 100644
--- a/src/static/index.css
+++ b/src/static/index.css
@@ -1,207 +1,326 @@
-:root {
-    --bg: #f6f8fb;
-    --card: #fff;
-    --muted: #6b7280;
-    --accent: #2563eb;
-    --shadow: 0 4px 12px rgba(16, 24, 40, 0.06);
-    --radius: 8px;
-    --mono: 'JetBrains Mono', monospace;
-}
-* { box-sizing: border-box; margin: 0; padding: 0; }
-html, body {
-    height: 100%;
-}
-body {
-    font-family: Inter, sans-serif;
-    background: var(--bg);
-    color: #0f172a;
-    padding: 16px;
-    display: flex;
-    justify-content: center;
-    align-items: center;
-}
-.wrap {
-    width: 100%;
-    max-width: 1100px;
-}
-header {
-    margin-bottom: 14px;
-}
-header h1 {
-    text-align: center;
-    font-size: 1.6rem;
-    color: #111827;
-}
-header p {
-    color: var(--muted);
-    font-size: 0.9rem;
-}
-.content {
-    display: grid;
-    grid-template-columns: 1fr 1fr;
-    gap: 12px;
-}
-.content.single-column {
-    grid-template-columns: 1fr;
-}
-.card {
-    background: var(--card);
-    border-radius: var(--radius);
-    box-shadow: var(--shadow);
-    padding: 12px;
-}
-/* Search/filter controls */
-.search-controls {
-    margin-bottom: 12px;
-    display: flex;
-    gap: 8px;
-}
-.search-input {
-    flex: 1;
-    padding: 6px 10px;
-    border: 1px solid #e5e7eb;
-    border-radius: 4px;
-    font-size: 0.9rem;
-}
-.filter-select {
-    padding: 6px 8px;
-    border: 1px solid #e5e7eb;
-    border-radius: 4px;
-    font-size: 0.9rem;
-    background: white;
-}
-/* Problems list */
-.problems-list .problem-item {
-    padding: 8px;
-    border-bottom: 1px solid #e5e7eb;
-    display: flex;
-    justify-content: space-between;
-    align-items: center;
-}
-.problem-item:last-child {
-    border-bottom: none;
-}
-.problem-item a {
-    text-decoration: none;
-    color: #0077ff;
-    font-weight: 600;
-}
-/* Difficulty badge */
-.difficulty {
-    display: inline-flex;
-    align-items: center;
-    padding: 0.25em 0.6em;
-    border-radius: 10px;
-    font-size: 0.85em;
-    font-weight: bold;
-    text-transform: uppercase;
-    color: white;
-    white-space: nowrap;
-}
-.difficulty[data-difficulty="easy"] {
-    background-color: #4CAF50; /* Green */
-}
-.difficulty[data-difficulty="medium"] {
-    background-color: #FFC107; /* Amber */
-    color: #333;
-}
-.difficulty[data-difficulty="hard"] {
-    background-color: #F44336; /* Red */
-}
-/* Leaderboard */
-.leaderboard-head {
-    display: flex;
-    justify-content: space-between;
-    align-items: center;
-    margin-bottom: 6px;
-}
-.leaderboard-controls {
-    display: flex;
-    gap: 8px;
-    margin-bottom: 12px;
-}
-.leaderboard-table {
-    width: 100%;
-    border-collapse: collapse;
-    font-size: 0.9rem;
-}
-.leaderboard-table th,
-.leaderboard-table td {
-    padding: 6px 8px;
-    border-bottom: 1px solid #e5e7eb;
-    text-align: left;
-}
-.leaderboard-table th {
-    background: #f9fafb;
-    font-weight: 600;
-    color: var(--muted);
-}
-.leaderboard-table tr:hover {
-    background: #f3f4f6;
-}
-/* Sort indicators */
-.sortable {
-    cursor: pointer;
-    position: relative;
-    padding-right: 16px;
-}
-.sortable::after {
-    content: "↕";
-    position: absolute;
-    right: 4px;
-    top: 50%;
-    transform: translateY(-50%);
-    font-size: 0.8em;
-    opacity: 0.5;
-}
-.sort-asc::after {
-    content: "↑";
-    opacity: 1;
-}
-.sort-desc::after {
-    content: "↓";
-    opacity: 1;
-}
-/* Toggle button */
-.btn {
-    border: none;
-    background: transparent;
-    cursor: pointer;
-    color: var(--accent);
-    font-size: 0.85rem;
-    padding: 4px 6px;
-    border-radius: 4px;
-}
-.btn:hover {
-    background: rgba(37, 99, 235, 0.08);
-}
-.btn.active {
-    background: rgba(37, 99, 235, 0.15);
-}
-@media (max-width: 800px) {
-    .content { grid-template-columns: 1fr; }
-    .leaderboard-controls {
-        flex-direction: column;
-    }
-}
-
-/* Leaderboard horizontal collapse */
-#leaderboardSection {
-  transition: max-width 0.35s ease, opacity 0.25s ease;
-  overflow: hidden;
-  max-width: 100%;
-}
-
-#leaderboardSection.hidden {
-  max-width: 0;
-  opacity: 0;
-  pointer-events: none;
-}
-
-#leaderboardSection.visible {
-  max-width: 100%; /* take full available space in grid column */
-  opacity: 1;
-}
-#rankingExplanation {
-    transition: all 0.35s ease;
-}
+:root {
+    --bg: #f6f8fb;
+    --card: #fff;
+    --text: #0f172a;
+    --muted: #6b7280;
+    --accent: #2563eb;
+    --border: #e5e7eb;
+    --hover: #f3f4f6;
+    --shadow: 0 4px 12px rgba(16, 24, 40, 0.06);
+    --radius: 8px;
+    --mono: "JetBrains Mono", monospace;
+}
+
+/* Dark mode variables */
+html.dark {
+    --bg: #0f172a;
+    --card: #1e293b;
+    --text: #f1f5f9;
+    --muted: #94a3b8;
+    --accent: #3b82f6;
+    --border: #334155;
+    --hover: #334155;
+    --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
+}
+* {
+    box-sizing: border-box;
+    margin: 0;
+    padding: 0;
+}
+html,
+body {
+    height: 100%;
+}
+body {
+    font-family: Inter, sans-serif;
+    background: var(--bg);
+    color: var(--text);
+    padding: 16px;
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    transition:
+        background-color 0.3s ease,
+        color 0.3s ease;
+}
+.wrap {
+    width: 100%;
+    max-width: 1100px;
+}
+header {
+    margin-bottom: 14px;
+}
+.header-content {
+    display: flex;
+    justify-content: center;
+    align-items: center;
+    position: relative;
+}
+header h1 {
+    text-align: center;
+    font-size: 1.6rem;
+    color: var(--text);
+}
+header p {
+    color: var(--muted);
+    font-size: 0.9rem;
+}
+.dark-mode-toggle {
+    position: absolute;
+    right: 0;
+    background: none;
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    padding: 6px 10px;
+    cursor: pointer;
+    color: var(--text);
+    font-size: 1.2rem;
+    transition: all 0.3s ease;
+}
+.dark-mode-toggle:hover {
+    background: var(--hover);
+    transform: scale(1.05);
+}
+html.dark .dark-mode-icon::before {
+    content: "☀︎️";
+}
+html:not(.dark) .dark-mode-icon::before {
+    content: "⏾";
+}
+.dark-mode-icon {
+    display: inline-block;
+}
+.dark-mode-icon::before {
+    font-size: 1em;
+}
+.content {
+    display: grid;
+    grid-template-columns: 1fr 1fr;
+    gap: 12px;
+}
+.content.single-column {
+    grid-template-columns: 1fr;
+}
+.card {
+    background: var(--card);
+    border-radius: var(--radius);
+    box-shadow: var(--shadow);
+    padding: 12px;
+}
+/* Search/filter controls */
+.search-controls {
+    margin-bottom: 12px;
+    display: flex;
+    gap: 8px;
+}
+.search-input {
+    flex: 1;
+    padding: 6px 10px;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    font-size: 0.9rem;
+    background: var(--card);
+    color: var(--text);
+    transition: border-color 0.3s ease;
+}
+.search-input:focus {
+    outline: none;
+    border-color: var(--accent);
+}
+.filter-select {
+    padding: 6px 8px;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    font-size: 0.9rem;
+    background: var(--card);
+    color: var(--text);
+    transition: border-color 0.3s ease;
+}
+.filter-select:focus {
+    outline: none;
+    border-color: var(--accent);
+}
+/* Problems list */
+.problems-list .problem-item {
+    padding: 8px;
+    border-bottom: 1px solid var(--border);
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    transition: background-color 0.3s ease;
+}
+.problem-item:hover {
+    background: var(--hover);
+}
+.problem-item:last-child {
+    border-bottom: none;
+}
+.problem-item a {
+    text-decoration: none;
+    color: var(--accent);
+    font-weight: 600;
+    transition: color 0.3s ease;
+}
+.problem-item a:hover {
+    text-decoration: underline;
+}
+/* Difficulty badge */
+.difficulty {
+    display: inline-flex;
+    align-items: center;
+    padding: 0.25em 0.6em;
+    border-radius: 10px;
+    font-size: 0.85em;
+    font-weight: bold;
+    text-transform: uppercase;
+    color: white;
+    white-space: nowrap;
+}
+.difficulty[data-difficulty="easy"] {
+    background-color: #4caf50; /* Green */
+}
+.difficulty[data-difficulty="medium"] {
+    background-color: #ffc107; /* Amber */
+    color: #333;
+}
+.difficulty[data-difficulty="hard"] {
+    background-color: #f44336; /* Red */
+}
+/* Leaderboard */
+.leaderboard-head {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-bottom: 6px;
+}
+.leaderboard-controls {
+    display: flex;
+    gap: 8px;
+    margin-bottom: 12px;
+}
+.leaderboard-table {
+    width: 100%;
+    border-collapse: collapse;
+    font-size: 0.9rem;
+}
+.leaderboard-table th,
+.leaderboard-table td {
+    padding: 6px 8px;
+    border-bottom: 1px solid var(--border);
+    text-align: left;
+}
+.leaderboard-table th {
+    background: var(--hover);
+    font-weight: 600;
+    color: var(--muted);
+}
+.leaderboard-table tr:hover {
+    background: var(--hover);
+}
+/* Sort indicators */
+.sortable {
+    cursor: pointer;
+    position: relative;
+    padding-right: 16px;
+}
+.sortable::after {
+    content: "↕";
+    position: absolute;
+    right: 4px;
+    top: 50%;
+    transform: translateY(-50%);
+    font-size: 0.8em;
+    opacity: 0.5;
+}
+.sort-asc::after {
+    content: "↑";
+    opacity: 1;
+}
+.sort-desc::after {
+    content: "↓";
+    opacity: 1;
+}
+/* Toggle button */
+.btn {
+    border: none;
+    background: transparent;
+    cursor: pointer;
+    color: var(--accent);
+    font-size: 0.85rem;
+    padding: 4px 6px;
+    border-radius: 4px;
+}
+.btn:hover {
+    background: rgba(37, 99, 235, 0.08);
+}
+.btn.active {
+    background: rgba(37, 99, 235, 0.15);
+}
+@media (max-width: 800px) {
+    .content {
+        grid-template-columns: 1fr;
+    }
+    .leaderboard-controls {
+        flex-direction: column;
+    }
+}
+
+/* Leaderboard horizontal collapse */
+#leaderboardSection {
+    transition:
+        max-width 0.35s ease,
+        opacity 0.25s ease;
+    overflow: hidden;
+    max-width: 100%;
+}
+
+#leaderboardSection.hidden {
+    max-width: 0;
+    opacity: 0;
+    pointer-events: none;
+}
+
+#leaderboardSection.visible {
+    max-width: 100%; /* take full available space in grid column */
+    opacity: 1;
+}
+#rankingExplanation {
+    transition: all 0.35s ease;
+}
+
+/* Pagination Controls */
+.pagination-controls {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-top: 12px;
+    padding-top: 12px;
+    border-top: 1px solid var(--border);
+}
+.pagination-btn {
+    background: var(--card);
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    padding: 6px 12px;
+    cursor: pointer;
+    color: var(--text);
+    font-size: 0.9rem;
+    transition: all 0.3s ease;
+}
+.pagination-btn:hover:not(:disabled) {
+    background: var(--hover);
+    border-color: var(--accent);
+}
+.pagination-btn:disabled {
+    opacity: 0.5;
+    cursor: not-allowed;
+}
+.pagination-info {
+    color: var(--muted);
+    font-size: 0.9rem;
+}
+
+/* Hide pagination when not needed */
+.pagination-controls.hidden {
+    display: none;
+}
diff --git a/src/static/problem.css b/src/static/problem.css
index 73572da..83037b4 100644
--- a/src/static/problem.css
+++ b/src/static/problem.css
@@ -1,212 +1,296 @@
-body {
-    font-family: 'Inter', sans-serif;
-    margin: 0;
-    padding: 0;
-    background-color: #f9f9f9;
-    color: #333;
-    min-height: 100vh; /* allow content to grow */
-    overflow-y: auto;  /* allow vertical scroll */
-    box-sizing: border-box;
-}
-
-*, *::before, *::after {
-    box-sizing: inherit;
-}
-
-.main-container {
-    display: flex;
-    flex-wrap: wrap; /* wrap on small screens */
-    min-height: 100vh;
-    width: 100vw;
-}
-
-.problem-panel {
-    flex: 1 1 400px; /* grow/shrink with base 400px */
-    min-width: 300px;
-    background: white;
-    overflow-y: auto;
-    padding: 20px;
-    border-right: 1px solid #eaeaea;
-    max-height: 100vh;
-}
-
-.editor-container {
-    flex: 1 1 400px;
-    min-width: 300px;
-    display: flex;
-    flex-direction: column;
-    background: white;
-    max-height: 100vh;
-    overflow: hidden; /* internal scroll handling */
-}
-
-.editor-header {
-    padding: 15px 20px;
-    border-bottom: 1px solid #eaeaea;
-    flex-shrink: 0;
-}
-
-.editor-wrapper {
-    flex: 1 1 auto;
-    display: flex;
-    flex-direction: column;
-    min-height: 0;
-    padding: 0 20px;
-    overflow-y: auto;
-}
-
-.problem-header {
-    display: flex;
-    align-items: center;
-    margin-bottom: 20px;
-}
-
-.back-btn {
-    background: none;
-    border: none;
-    cursor: pointer;
-    font-size: 16px;
-    color: #666;
-    margin-right: 15px;
-    padding: 5px;
-}
-
-.back-btn:hover {
-    color: #000;
-}
-
-h1 {
-    font-size: 22px;
-    font-weight: 600;
-    margin: 0;
-    color: #1a1a1a;
-}
-
-.problem-desc {
-    line-height: 1.6;
-    font-size: 15px;
-    overflow-wrap: break-word;
-}
-
-.problem-desc pre {
-    background: #f6f8fa;
-    padding: 12px;
-    border-radius: 4px;
-    overflow-x: auto;
-    font-family: 'JetBrains Mono', monospace;
-    font-size: 14px;
-}
-
-.problem-desc code {
-    background: #f6f8fa;
-    padding: 2px 4px;
-    border-radius: 3px;
-    font-family: 'JetBrains Mono', monospace;
-    font-size: 14px;
-}
-
-.editor-actions {
-    padding: 15px 0;
-    display: flex;
-    justify-content: flex-end;
-    flex-shrink: 0;
-}
-
-.editor-actions button {
-    background-color: #007bff;
-    color: white;
-    border: none;
-    padding: 8px 16px;
-    border-radius: 4px;
-    cursor: pointer;
-    font-weight: 500;
-    font-size: 14px;
-}
-
-.editor-actions button:hover {
-    background-color: #0069d9;
-}
-
-#editor {
-    flex: 1 1 auto;
-    min-height: 300px;
-    border: 1px solid #ddd;
-    border-radius: 4px;
-    overflow: auto;
-    max-height: 60vh;
-}
-
-.result-panel {
-    margin-top: 20px;
-    padding: 15px;
-    background: #f8f9fa;
-    border-radius: 4px;
-    margin-bottom: 20px;
-    min-height: 120px;
-    overflow-y: auto;
-    max-height: 30vh;
-}
-
-.result-panel h3 {
-    margin-top: 0;
-    font-size: 16px;
-    margin-bottom: 10px;
-}
-
-.result-panel pre {
-    background: #f6f8fa;
-    padding: 12px;
-    border-radius: 4px;
-    overflow-x: auto;
-    white-space: pre-wrap;
-    font-family: 'JetBrains Mono', monospace;
-    font-size: 14px;
-    margin: 5px 0;
-}
-
-.placeholder {
-    color: #999;
-    font-style: italic;
-    text-align: center;
-    padding: 20px;
-}
-
-label {
-    display: block;
-    margin-bottom: 5px;
-    font-size: 14px;
-    color: #666;
-}
-
-input[type="text"] {
-    width: 100%;
-    padding: 8px;
-    border: 1px solid #ddd;
-    border-radius: 4px;
-    margin-bottom: 15px;
-    font-family: 'Inter', sans-serif;
-}
-
-/* Responsive adjustments */
-@media (max-width: 768px) {
-    .main-container {
-        flex-direction: column;
-        height: auto;
-        overflow-y: visible;
-    }
-    .problem-panel, .editor-container {
-        flex: none;
-        width: 100%;
-        min-width: auto;
-        max-height: none;
-        border-right: none;
-        border-bottom: 1px solid #eaeaea;
-    }
-    #editor {
-        min-height: 400px;
-        max-height: none;
-    }
-    .result-panel {
-        max-height: none;
-    }
-}
\ No newline at end of file
+:root {
+    --bg: #f9f9f9;
+    --card: #fff;
+    --text: #333;
+    --muted: #666;
+    --accent: #007bff;
+    --accent-hover: #0069d9;
+    --border: #eaeaea;
+    --hover: #f8f9fa;
+    --code-bg: #f6f8fa;
+    --editor-border: #ddd;
+}
+
+html.dark {
+    --bg: #0f172a;
+    --card: #1e293b;
+    --text: #f1f5f9;
+    --muted: #94a3b8;
+    --accent: #3b82f6;
+    --accent-hover: #2563eb;
+    --border: #334155;
+    --hover: #334155;
+    --code-bg: #1e293b;
+    --editor-border: #475569;
+}
+
+body {
+    font-family: "Inter", sans-serif;
+    margin: 0;
+    padding: 0;
+    background-color: var(--bg);
+    color: var(--text);
+    min-height: 100vh; /* allow content to grow */
+    overflow-y: auto; /* allow vertical scroll */
+    box-sizing: border-box;
+    transition:
+        background-color 0.3s ease,
+        color 0.3s ease;
+}
+
+*,
+*::before,
+*::after {
+    box-sizing: inherit;
+}
+
+.main-container {
+    display: flex;
+    flex-wrap: wrap; /* wrap on small screens */
+    min-height: 100vh;
+    width: 100vw;
+}
+
+.problem-panel {
+    flex: 1 1 400px; /* grow/shrink with base 400px */
+    min-width: 300px;
+    background: var(--card);
+    overflow-y: auto;
+    padding: 20px;
+    border-right: 1px solid var(--border);
+    max-height: 100vh;
+    transition: background-color 0.3s ease;
+}
+
+.editor-container {
+    flex: 1 1 400px;
+    min-width: 300px;
+    display: flex;
+    flex-direction: column;
+    background: var(--card);
+    max-height: 100vh;
+    overflow: hidden; /* internal scroll handling */
+    transition: background-color 0.3s ease;
+}
+
+.editor-header {
+    padding: 15px 20px;
+    border-bottom: 1px solid var(--border);
+    flex-shrink: 0;
+}
+
+.editor-wrapper {
+    flex: 1 1 auto;
+    display: flex;
+    flex-direction: column;
+    min-height: 0;
+    padding: 0 20px;
+    overflow-y: auto;
+}
+
+.problem-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    margin-bottom: 20px;
+}
+
+.back-btn {
+    background: none;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    cursor: pointer;
+    font-size: 16px;
+    color: var(--muted);
+    margin-right: 15px;
+    padding: 6px 10px;
+    transition: all 0.3s ease;
+}
+
+.back-btn:hover {
+    color: var(--text);
+    background: var(--hover);
+}
+
+.dark-mode-toggle {
+    background: none;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    padding: 6px 10px;
+    cursor: pointer;
+    color: var(--text);
+    font-size: 1.2rem;
+    transition: all 0.3s ease;
+}
+
+.dark-mode-toggle:hover {
+    background: var(--hover);
+    transform: scale(1.05);
+}
+
+html.dark .dark-mode-icon::before {
+    content: "☀";
+}
+
+html:not(.dark) .dark-mode-icon::before {
+    content: "⏾";
+}
+
+.dark-mode-icon {
+    display: inline-block;
+}
+
+.dark-mode-icon::before {
+    font-size: 1em;
+}
+
+h1 {
+    font-size: 22px;
+    font-weight: 600;
+    margin: 0;
+    color: var(--text);
+    flex: 1;
+}
+
+.problem-desc {
+    line-height: 1.6;
+    font-size: 15px;
+    overflow-wrap: break-word;
+}
+
+.problem-desc pre {
+    background: var(--code-bg);
+    padding: 12px;
+    border-radius: 4px;
+    overflow-x: auto;
+    font-family: "JetBrains Mono", monospace;
+    font-size: 14px;
+    border: 1px solid var(--border);
+}
+
+.problem-desc code {
+    background: var(--code-bg);
+    padding: 2px 4px;
+    border-radius: 3px;
+    font-family: "JetBrains Mono", monospace;
+    font-size: 14px;
+}
+
+.editor-actions {
+    padding: 15px 0;
+    display: flex;
+    justify-content: flex-end;
+    flex-shrink: 0;
+}
+
+.editor-actions button {
+    background-color: var(--accent);
+    color: white;
+    border: none;
+    padding: 8px 16px;
+    border-radius: 4px;
+    cursor: pointer;
+    font-weight: 500;
+    font-size: 14px;
+    transition: background-color 0.3s ease;
+}
+
+.editor-actions button:hover {
+    background-color: var(--accent-hover);
+}
+
+#editor {
+    flex: 1 1 auto;
+    min-height: 300px;
+    border: 1px solid var(--editor-border);
+    border-radius: 4px;
+    overflow: auto;
+    max-height: 60vh;
+}
+
+.result-panel {
+    margin-top: 20px;
+    padding: 15px;
+    background: var(--hover);
+    border-radius: 4px;
+    margin-bottom: 20px;
+    min-height: 120px;
+    overflow-y: auto;
+    max-height: 30vh;
+    border: 1px solid var(--border);
+    transition: background-color 0.3s ease;
+}
+
+.result-panel h3 {
+    margin-top: 0;
+    font-size: 16px;
+    margin-bottom: 10px;
+}
+
+.result-panel pre {
+    background: var(--code-bg);
+    padding: 12px;
+    border-radius: 4px;
+    overflow-x: auto;
+    white-space: pre-wrap;
+    font-family: "JetBrains Mono", monospace;
+    font-size: 14px;
+    margin: 5px 0;
+    border: 1px solid var(--border);
+}
+
+.placeholder {
+    color: var(--muted);
+    font-style: italic;
+    text-align: center;
+    padding: 20px;
+}
+
+label {
+    display: block;
+    margin-bottom: 5px;
+    font-size: 14px;
+    color: var(--muted);
+}
+
+input[type="text"] {
+    width: 100%;
+    padding: 8px;
+    border: 1px solid var(--border);
+    border-radius: 4px;
+    margin-bottom: 15px;
+    font-family: "Inter", sans-serif;
+    background: var(--card);
+    color: var(--text);
+    transition: border-color 0.3s ease;
+}
+
+input[type="text"]:focus {
+    outline: none;
+    border-color: var(--accent);
+}
+
+/* Responsive adjustments */
+@media (max-width: 768px) {
+    .main-container {
+        flex-direction: column;
+        height: auto;
+        overflow-y: visible;
+    }
+    .problem-panel,
+    .editor-container {
+        flex: none;
+        width: 100%;
+        min-width: auto;
+        max-height: none;
+        border-right: none;
+        border-bottom: 1px solid var(--border);
+    }
+    #editor {
+        min-height: 400px;
+        max-height: none;
+    }
+    .result-panel {
+        max-height: none;
+    }
+}
diff --git a/src/static/script.js b/src/static/script.js
new file mode 100644
index 0000000..38d271f
--- /dev/null
+++ b/src/static/script.js
@@ -0,0 +1,403 @@
+document.addEventListener("DOMContentLoaded", () => {
+  // Dark mode functionality
+  const darkModeToggle = document.getElementById("darkModeToggle");
+  const html = document.documentElement;
+
+  // Load saved dark mode preference
+  const savedDarkMode = localStorage.getItem("darkMode");
+  if (
+    savedDarkMode === "true" ||
+    (savedDarkMode === null &&
+      // detect if the user already has a dark mode enabled in the system settings ( works for all systems )
+      window.matchMedia("(prefers-color-scheme: dark)").matches)
+  ) {
+    html.classList.add("dark");
+  }
+
+  darkModeToggle?.addEventListener("click", () => {
+    html.classList.toggle("dark");
+    localStorage.setItem("darkMode", html.classList.contains("dark"));
+  });
+
+  // Problem search and pagination
+  const problemSearch = document.getElementById("problemSearch");
+  const problemsContainer = document.getElementById("problemsContainer");
+  const problemsPagination = document.getElementById("problemsPagination");
+  const problemsPrevBtn = document.getElementById("problemsPrevBtn");
+  const problemsNextBtn = document.getElementById("problemsNextBtn");
+  const problemsPaginationInfo = document.getElementById(
+    "problemsPaginationInfo",
+  );
+
+  let allProblemItems = [];
+  let filteredProblemItems = [];
+  let currentPage = 1;
+  const itemsPerPage = 5;
+
+  // Initialize problem items
+  function initializeProblemItems() {
+    allProblemItems = Array.from(
+      problemsContainer?.querySelectorAll(".problem-item") || [],
+    );
+    filteredProblemItems = [...allProblemItems];
+    updatePagination();
+  }
+
+  function updatePagination() {
+    const totalPages = Math.ceil(filteredProblemItems.length / itemsPerPage);
+    const startIndex = (currentPage - 1) * itemsPerPage;
+    const endIndex = startIndex + itemsPerPage;
+
+    // Hide all items first
+    allProblemItems.forEach((item) => {
+      item.style.display = "none";
+    });
+
+    // Show current page items
+    filteredProblemItems.slice(startIndex, endIndex).forEach((item) => {
+      item.style.display = "";
+    });
+
+    // Update pagination controls
+    if (problemsPrevBtn) problemsPrevBtn.disabled = currentPage <= 1;
+    if (problemsNextBtn) problemsNextBtn.disabled = currentPage >= totalPages;
+    if (problemsPaginationInfo) {
+      problemsPaginationInfo.textContent =
+        totalPages > 0
+          ? `Page ${currentPage} of ${totalPages}`
+          : "No problems found";
+    }
+
+    // Hide pagination if not needed
+    if (problemsPagination) {
+      problemsPagination.classList.toggle("hidden", totalPages <= 1);
+    }
+  }
+
+  function filterProblems() {
+    const term = problemSearch?.value.toLowerCase().trim() || "";
+    filteredProblemItems = allProblemItems.filter((item) => {
+      const name = item.dataset.name?.toLowerCase() || "";
+      const desc = item.dataset.desc?.toLowerCase() || "";
+      return !term || name.includes(term) || desc.includes(term);
+    });
+    currentPage = 1;
+    updatePagination();
+  }
+
+  // Event listeners for pagination
+  problemsPrevBtn?.addEventListener("click", () => {
+    if (currentPage > 1) {
+      currentPage--;
+      updatePagination();
+    }
+  });
+
+  problemsNextBtn?.addEventListener("click", () => {
+    const totalPages = Math.ceil(filteredProblemItems.length / itemsPerPage);
+    if (currentPage < totalPages) {
+      currentPage++;
+      updatePagination();
+    }
+  });
+
+  problemSearch?.addEventListener("input", filterProblems);
+
+  // Initialize problems pagination
+  if (problemsContainer) {
+    initializeProblemItems();
+  }
+
+  // Leaderboard functionality
+  const problemFilter = document.getElementById("problemFilter");
+  const runtimeFilter = document.getElementById("runtimeFilter");
+  const leaderboardBody = document.getElementById("leaderboardBody");
+  const sortableHeaders = document.querySelectorAll(".sortable");
+
+  let currentSort = { column: "rank", direction: "asc" };
+  let allRows = [];
+
+  // Initialize rows array
+  function initializeRows() {
+    allRows = Array.from(leaderboardBody.querySelectorAll("tr")).map((row) => {
+      return {
+        element: row,
+        user: row.dataset.user || "",
+        problem: row.dataset.problem || "",
+        runtime: parseFloat(row.dataset.runtime) || 0,
+        memory: parseFloat(row.dataset.memory) || 0,
+        timestamp: new Date(row.dataset.timestamp || Date.now()).getTime(),
+        language: row.dataset.language || "",
+        originalIndex: Array.from(leaderboardBody.children).indexOf(row),
+      };
+    });
+  }
+
+  function updateRankClasses() {
+    const visibleRows = allRows.filter(
+      (row) => row.element.style.display !== "none",
+    );
+    visibleRows.forEach((rowData, index) => {
+      const rank = index + 1;
+      const row = rowData.element;
+
+      // Update rank cell
+      const rankCell = row.cells[0];
+      if (rankCell) rankCell.textContent = rank;
+
+      // Update rank classes
+      row.className = row.className.replace(/\brank-\d+\b/g, "");
+      if (rank === 1) row.classList.add("rank-1");
+      else if (rank <= 3) row.classList.add("rank-top3");
+    });
+  }
+
+  function calculateOverallRanking() {
+    const visibleRows = allRows.filter(
+      (row) => row.element.style.display !== "none",
+    );
+
+    if (visibleRows.length === 0) return;
+
+    // Group submissions by problem to find the best performance for each
+    const problemBests = {};
+
+    visibleRows.forEach((rowData) => {
+      const problem = rowData.problem;
+      if (!problemBests[problem]) {
+        problemBests[problem] = {
+          bestRuntime: Infinity,
+          bestMemory: Infinity,
+        };
+      }
+
+      problemBests[problem].bestRuntime = Math.min(
+        problemBests[problem].bestRuntime,
+        rowData.runtime,
+      );
+      problemBests[problem].bestMemory = Math.min(
+        problemBests[problem].bestMemory,
+        rowData.memory,
+      );
+    });
+
+    // Calculate normalized scores for each submission
+    visibleRows.forEach((rowData) => {
+      const problemBest = problemBests[rowData.problem];
+
+      // Prevent division by zero
+      const runtimeScore =
+        problemBest.bestRuntime > 0
+          ? rowData.runtime / problemBest.bestRuntime
+          : 1;
+      const memoryScore =
+        problemBest.bestMemory > 0
+          ? rowData.memory / problemBest.bestMemory
+          : 1;
+
+      // Weighted overall score (70% runtime, 30% memory)
+      rowData.overallScore = runtimeScore * 0.7 + memoryScore * 0.3;
+    });
+
+    // Sort by overall score (lower is better), then by timestamp (earlier is better for ties)
+    visibleRows.sort((a, b) => {
+      const scoreDiff = a.overallScore - b.overallScore;
+      if (Math.abs(scoreDiff) > 0.000001) return scoreDiff; // Use small epsilon for float comparison
+
+      // If scores are essentially equal, prefer earlier submission
+      return a.timestamp - b.timestamp;
+    });
+
+    // Reorder DOM elements and update ranks
+    visibleRows.forEach((rowData, index) => {
+      leaderboardBody.appendChild(rowData.element);
+    });
+
+    updateRankClasses();
+  }
+
+  function filterLeaderboard() {
+    const problemTerm = (problemFilter?.value || "").toLowerCase().trim();
+    const runtimeType = runtimeFilter?.value || "all";
+
+    // Reset all rows to visible first
+    allRows.forEach((rowData) => {
+      rowData.element.style.display = "";
+    });
+
+    // Apply problem filter
+    if (problemTerm) {
+      allRows.forEach((rowData) => {
+        const problemMatch = rowData.problem
+          .toLowerCase()
+          .includes(problemTerm);
+        if (!problemMatch) {
+          rowData.element.style.display = "none";
+        }
+      });
+    }
+
+    // Apply runtime filter (best/worst per user per problem)
+    if (runtimeType === "best" || runtimeType === "worst") {
+      const userProblemGroups = {};
+
+      // Group by user + problem combination
+      allRows.forEach((rowData) => {
+        if (rowData.element.style.display === "none") return;
+
+        const key = `${rowData.user}::${rowData.problem}`;
+        if (!userProblemGroups[key]) {
+          userProblemGroups[key] = [];
+        }
+        userProblemGroups[key].push(rowData);
+      });
+
+      // Hide all except best/worst for each user-problem combination
+      Object.values(userProblemGroups).forEach((group) => {
+        if (group.length <= 1) return;
+
+        // Sort by runtime
+        group.sort((a, b) => a.runtime - b.runtime);
+
+        const keepIndex = runtimeType === "best" ? 0 : group.length - 1;
+        group.forEach((rowData, index) => {
+          if (index !== keepIndex) {
+            rowData.element.style.display = "none";
+          }
+        });
+      });
+    }
+
+    calculateOverallRanking();
+  }
+
+  function getCellValue(rowData, column) {
+    switch (column) {
+      case "rank":
+        return parseInt(rowData.element.cells[0]?.textContent) || 0;
+      case "user":
+        return rowData.user.toLowerCase();
+      case "problem":
+        return rowData.problem.toLowerCase();
+      case "runtime":
+        return rowData.runtime;
+      case "memory":
+        return rowData.memory;
+      case "timestamp":
+        return rowData.timestamp;
+      case "language":
+        return rowData.language.toLowerCase();
+      default:
+        return "";
+    }
+  }
+
+  function sortLeaderboard(column, direction) {
+    if (column === "rank") {
+      calculateOverallRanking();
+      return;
+    }
+
+    const visibleRows = allRows.filter(
+      (row) => row.element.style.display !== "none",
+    );
+
+    visibleRows.sort((a, b) => {
+      const valueA = getCellValue(a, column);
+      const valueB = getCellValue(b, column);
+
+      let comparison = 0;
+      if (typeof valueA === "number" && typeof valueB === "number") {
+        comparison = valueA - valueB;
+      } else {
+        comparison = valueA < valueB ? -1 : valueA > valueB ? 1 : 0;
+      }
+
+      return direction === "asc" ? comparison : -comparison;
+    });
+
+    // Reorder DOM elements
+    visibleRows.forEach((rowData) => {
+      leaderboardBody.appendChild(rowData.element);
+    });
+
+    updateRankClasses();
+  }
+
+  // Event listeners for sorting
+  sortableHeaders.forEach((header) => {
+    header.addEventListener("click", () => {
+      const column = header.dataset.sort;
+      if (!column) return;
+
+      // Remove sorting classes from all headers
+      sortableHeaders.forEach((h) =>
+        h.classList.remove("sort-asc", "sort-desc"),
+      );
+
+      // Toggle sort direction
+      if (currentSort.column === column) {
+        currentSort.direction =
+          currentSort.direction === "asc" ? "desc" : "asc";
+      } else {
+        currentSort.column = column;
+        currentSort.direction = "asc";
+      }
+
+      // Add sorting class to current header
+      header.classList.add(`sort-${currentSort.direction}`);
+
+      sortLeaderboard(column, currentSort.direction);
+    });
+  });
+
+  // Filter event listeners
+  problemFilter?.addEventListener("input", filterLeaderboard);
+  runtimeFilter?.addEventListener("change", filterLeaderboard);
+
+  // Rank info popout
+  const rankInfoBtn = document.getElementById("rankInfoBtn");
+  const rankingExplanation = document.getElementById("rankingExplanation");
+
+  rankInfoBtn?.addEventListener("click", (e) => {
+    e.preventDefault();
+    rankingExplanation?.classList.toggle("active");
+    rankInfoBtn?.classList.toggle("active");
+  });
+
+  // Close ranking explanation when clicking outside
+  document.addEventListener("click", (e) => {
+    if (
+      rankingExplanation?.classList.contains("active") &&
+      !rankingExplanation.contains(e.target) &&
+      !rankInfoBtn?.contains(e.target)
+    ) {
+      rankingExplanation.classList.remove("active");
+      rankInfoBtn?.classList.remove("active");
+    }
+  });
+
+  // Initialize everything
+  if (leaderboardBody && leaderboardBody.children.length > 0) {
+    initializeRows();
+    calculateOverallRanking();
+
+    // Set initial sort indicator
+    const defaultHeader = document.querySelector('[data-sort="rank"]');
+    if (defaultHeader) {
+      defaultHeader.classList.add("sort-asc");
+    }
+  }
+
+  // Apply dark mode to dynamically created elements
+  function applyDarkModeToElements() {
+    const isDark = html.classList.contains("dark");
+    // Any additional dark mode styling for dynamically created elements can go here
+  }
+
+  // Watch for dark mode changes
+  new MutationObserver(applyDarkModeToElements).observe(html, {
+    attributes: true,
+    attributeFilter: ["class"],
+  });
+});
diff --git a/src/static/style.css b/src/static/style.css
index b576b4a..2724ba5 100644
--- a/src/static/style.css
+++ b/src/static/style.css
@@ -1,260 +1,317 @@
-/* Reset and base styles */
-* {
-    margin: 0;
-    padding: 0;
-    box-sizing: border-box;
-}
-
-body {
-    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
-    line-height: 1.6;
-    color: #333;
-    background-color: #f8f9fa;
-    padding: 20px;
-    max-width: 1200px;
-    margin: 0 auto;
-}
-
-/* Main heading */
-h1 {
-    color: #2c3e50;
-    margin-bottom: -10px;
-    padding-bottom: 3px;
-    border-bottom: 3px solid #3498db;
-    font-size: 2.2em;
-}
-
-h2 {
-    color: #34495e;
-    margin: 30px 0 20px 0;
-    font-size: 1.5em;
-}
-
-h3 {
-    color: #34495e;
-    margin: 25px 0 15px 0;
-    font-size: 1.3em;
-}
-
-/* Links and buttons */
-a {
-    color: #3498db;
-    text-decoration: none;
-    padding: 8px 16px;
-    border-radius: 5px;
-    transition: background-color 0.3s ease;
-}
-
-a:hover {
-    background-color: #e3f2fd;
-    text-decoration: none;
-}
-
-/* Primary action link (Submit New Problem) */
-a[href="/problem/new"] {
-    background-color: #3498db;
-    color: white;
-    font-weight: 600;
-    margin-bottom: 30px;
-    display: inline-block;
-    padding: 12px 24px;
-    border-radius: 8px;
-}
-
-a[href="/problem/new"]:hover {
-    background-color: #2980b9;
-}
-
-/* Problem list */
-ul {
-    list-style: none;
-    background: white;
-    border-radius: 8px;
-    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
-    padding: 25px;
-    margin: 20px 0;
-}
-
-li {
-    padding: 15px 0;
-    border-bottom: 1px solid #eee;
-}
-
-li:last-child {
-    border-bottom: none;
-}
-
-li a {
-    display: block;
-    padding: 12px 20px;
-    margin: -12px -20px;
-    border-radius: 6px;
-    font-size: 1.1em;
-}
-
-li a:hover {
-    background-color: #f8f9fa;
-    transform: translateX(5px);
-    transition: all 0.2s ease;
-}
-
-/* Problem page specific styles */
-.problem-header {
-    display: flex;
-    align-items: center;
-    margin-bottom: 30px;
-    gap: 20px;
-}
-
-.back-btn {
-    background-color: #95a5a6;
-    color: white;
-    border: none;
-    padding: 10px 20px;
-    border-radius: 6px;
-    cursor: pointer;
-    font-size: 14px;
-    font-weight: 500;
-    transition: background-color 0.3s ease;
-}
-
-.back-btn:hover {
-    background-color: #7f8c8d;
-}
-
-.problem-desc {
-    background: white;
-    padding: 30px;
-    border-radius: 8px;
-    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
-    margin-bottom: 30px;
-    font-size: 1.1em;
-    line-height: 1.7;
-}
-
-/* Editor section */
-.editor-section {
-    background: white;
-    padding: 30px;
-    border-radius: 8px;
-    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
-    margin-bottom: 30px;
-}
-
-#editor {
-    border: 2px solid #ddd;
-    border-radius: 8px;
-    margin: 20px 0;
-    height: 400px;
-    overflow: hidden;
-}
-
-.editor-actions {
-    margin-top: 20px;
-    text-align: right;
-}
-
-form button[type="submit"] {
-    background-color: #27ae60;
-    color: white;
-    border: none;
-    padding: 12px 30px;
-    border-radius: 8px;
-    cursor: pointer;
-    font-size: 16px;
-    font-weight: 600;
-    transition: background-color 0.3s ease;
-}
-
-form button[type="submit"]:hover {
-    background-color: #229954;
-}
-
-/* Results section */
-b {
-    color: #2c3e50;
-    display: inline-block;
-    margin: 10px 0 5px 0;
-}
-
-pre {
-    background-color: #f4f4f4;
-    padding: 20px;
-    border-radius: 6px;
-    border-left: 4px solid #3498db;
-    margin: 10px 0 20px 0;
-    overflow-x: auto;
-    font-family: 'JetBrains Mono', 'Courier New', monospace;
-    font-size: 14px;
-    line-height: 1.4;
-}
-
-pre[style*="color:red"] {
-    border-left-color: #e74c3c;
-    background-color: #fdf2f2;
-}
-
-/* Status messages */
-p[style*="color:green"] {
-    background-color: #d4edda;
-    color: #155724;
-    padding: 15px 20px;
-    border-radius: 6px;
-    border-left: 4px solid #27ae60;
-    margin: 20px 0;
-    font-weight: 600;
-}
-
-p[style*="color:red"] {
-    background-color: #f8d7da;
-    color: #721c24;
-    padding: 15px 20px;
-    border-radius: 6px;
-    border-left: 4px solid #e74c3c;
-    margin: 20px 0;
-    font-weight: 600;
-}
-
-/* Back to Problems link */
-a[href="/"] {
-    display: inline-block;
-    margin-top: 30px;
-    background-color: #6c757d;
-    color: white;
-    padding: 10px 20px;
-    border-radius: 6px;
-    font-weight: 500;
-}
-
-a[href="/"]:hover {
-    background-color: #5a6268;
-}
-
-/* Responsive design */
-@media (max-width: 768px) {
-    body {
-        padding: 15px;
-    }
-    
-    .problem-header {
-        flex-direction: column;
-        align-items: flex-start;
-        gap: 15px;
-    }
-    
-    h1 {
-        font-size: 1.8em;
-    }
-    
-    .problem-desc, .editor-section, ul {
-        padding: 20px;
-    }
-    
-    #editor {
-        height: 300px;
-    }
-    
-    .editor-actions {
-        text-align: center;
-    }
-}
+:root {
+    --bg: #f8f9fa;
+    --card: #fff;
+    --text: #333;
+    --heading: #2c3e50;
+    --heading-secondary: #34495e;
+    --accent: #3498db;
+    --accent-hover: #2980b9;
+    --success: #27ae60;
+    --success-hover: #229954;
+    --error: #e74c3c;
+    --muted: #6c757d;
+    --muted-hover: #5a6268;
+    --border: #ddd;
+    --code-bg: #f4f4f4;
+    --success-bg: #d4edda;
+    --success-text: #155724;
+    --error-bg: #f8d7da;
+    --error-text: #721c24;
+    --hover-bg: #e3f2fd;
+    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
+}
+
+html.dark {
+    --bg: #0f172a;
+    --card: #1e293b;
+    --text: #f1f5f9;
+    --heading: #3b82f6;
+    --heading-secondary: #94a3b8;
+    --accent: #3b82f6;
+    --accent-hover: #2563eb;
+    --success: #22c55e;
+    --success-hover: #16a34a;
+    --error: #ef4444;
+    --muted: #64748b;
+    --muted-hover: #475569;
+    --border: #334155;
+    --code-bg: #1e293b;
+    --success-bg: #065f46;
+    --success-text: #d1fae5;
+    --error-bg: #7f1d1d;
+    --error-text: #fecaca;
+    --hover-bg: #1e40af;
+    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
+}
+
+/* Reset and base styles */
+* {
+    margin: 0;
+    padding: 0;
+    box-sizing: border-box;
+}
+
+body {
+    font-family:
+        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
+    line-height: 1.6;
+    color: var(--text);
+    background-color: var(--bg);
+    padding: 20px;
+    max-width: 1200px;
+    margin: 0 auto;
+    transition:
+        background-color 0.3s ease,
+        color 0.3s ease;
+}
+
+/* Main heading */
+h1 {
+    color: var(--heading);
+    margin-bottom: -10px;
+    padding-bottom: 3px;
+    border-bottom: 3px solid var(--accent);
+    font-size: 2.2em;
+}
+
+h2 {
+    color: var(--heading-secondary);
+    margin: 30px 0 20px 0;
+    font-size: 1.5em;
+}
+
+h3 {
+    color: var(--heading-secondary);
+    margin: 25px 0 15px 0;
+    font-size: 1.3em;
+}
+
+/* Links and buttons */
+a {
+    color: var(--accent);
+    text-decoration: none;
+    padding: 8px 16px;
+    border-radius: 5px;
+    transition: background-color 0.3s ease;
+}
+
+a:hover {
+    background-color: var(--hover-bg);
+    text-decoration: none;
+}
+
+/* Primary action link (Submit New Problem) */
+a[href="/problem/new"] {
+    background-color: var(--accent);
+    color: white;
+    font-weight: 600;
+    margin-bottom: 30px;
+    display: inline-block;
+    padding: 12px 24px;
+    border-radius: 8px;
+}
+
+a[href="/problem/new"]:hover {
+    background-color: var(--accent-hover);
+}
+
+/* Problem list */
+ul {
+    list-style: none;
+    background: var(--card);
+    border-radius: 8px;
+    box-shadow: var(--shadow);
+    padding: 25px;
+    margin: 20px 0;
+    transition: background-color 0.3s ease;
+}
+
+li {
+    padding: 15px 0;
+    border-bottom: 1px solid var(--border);
+}
+
+li:last-child {
+    border-bottom: none;
+}
+
+li a {
+    display: block;
+    padding: 12px 20px;
+    margin: -12px -20px;
+    border-radius: 6px;
+    font-size: 1.1em;
+}
+
+li a:hover {
+    background-color: var(--hover-bg);
+    transform: translateX(5px);
+    transition: all 0.2s ease;
+}
+
+/* Problem page specific styles */
+.problem-header {
+    display: flex;
+    align-items: center;
+    margin-bottom: 30px;
+    gap: 20px;
+}
+
+.back-btn {
+    background-color: var(--muted);
+    color: white;
+    border: none;
+    padding: 10px 20px;
+    border-radius: 6px;
+    cursor: pointer;
+    font-size: 14px;
+    font-weight: 500;
+    transition: background-color 0.3s ease;
+}
+
+.back-btn:hover {
+    background-color: var(--muted-hover);
+}
+
+.problem-desc {
+    background: var(--card);
+    padding: 30px;
+    border-radius: 8px;
+    box-shadow: var(--shadow);
+    margin-bottom: 30px;
+    font-size: 1.1em;
+    line-height: 1.7;
+    transition: background-color 0.3s ease;
+}
+
+/* Editor section */
+.editor-section {
+    background: var(--card);
+    padding: 30px;
+    border-radius: 8px;
+    box-shadow: var(--shadow);
+    margin-bottom: 30px;
+    transition: background-color 0.3s ease;
+}
+
+#editor {
+    border: 2px solid var(--border);
+    border-radius: 8px;
+    margin: 20px 0;
+    height: 400px;
+    overflow: hidden;
+}
+
+.editor-actions {
+    margin-top: 20px;
+    text-align: right;
+}
+
+form button[type="submit"] {
+    background-color: var(--success);
+    color: white;
+    border: none;
+    padding: 12px 30px;
+    border-radius: 8px;
+    cursor: pointer;
+    font-size: 16px;
+    font-weight: 600;
+    transition: background-color 0.3s ease;
+}
+
+form button[type="submit"]:hover {
+    background-color: var(--success-hover);
+}
+
+/* Results section */
+b {
+    color: var(--heading);
+    display: inline-block;
+    margin: 10px 0 5px 0;
+}
+
+pre {
+    background-color: var(--code-bg);
+    padding: 20px;
+    border-radius: 6px;
+    border-left: 4px solid var(--accent);
+    margin: 10px 0 20px 0;
+    overflow-x: auto;
+    font-family: "JetBrains Mono", "Courier New", monospace;
+    font-size: 14px;
+    line-height: 1.4;
+    border: 1px solid var(--border);
+    transition: background-color 0.3s ease;
+}
+
+pre[style*="color:red"] {
+    border-left-color: var(--error);
+    background-color: var(--error-bg);
+}
+
+/* Status messages */
+p[style*="color:green"] {
+    background-color: var(--success-bg);
+    color: var(--success-text);
+    padding: 15px 20px;
+    border-radius: 6px;
+    border-left: 4px solid var(--success);
+    margin: 20px 0;
+    font-weight: 600;
+}
+
+p[style*="color:red"] {
+    background-color: var(--error-bg);
+    color: var(--error-text);
+    padding: 15px 20px;
+    border-radius: 6px;
+    border-left: 4px solid var(--error);
+    margin: 20px 0;
+    font-weight: 600;
+}
+
+/* Back to Problems link */
+a[href="/"] {
+    display: inline-block;
+    margin-top: 30px;
+    background-color: var(--muted);
+    color: white;
+    padding: 10px 20px;
+    border-radius: 6px;
+    font-weight: 500;
+}
+
+a[href="/"]:hover {
+    background-color: var(--muted-hover);
+}
+
+/* Responsive design */
+@media (max-width: 768px) {
+    body {
+        padding: 15px;
+    }
+
+    .problem-header {
+        flex-direction: column;
+        align-items: flex-start;
+        gap: 15px;
+    }
+
+    h1 {
+        font-size: 1.8em;
+    }
+
+    .problem-desc,
+    .editor-section,
+    ul {
+        padding: 20px;
+    }
+
+    #editor {
+        height: 300px;
+    }
+
+    .editor-actions {
+        text-align: center;
+    }
+}
diff --git a/src/templates/index.html b/src/templates/index.html
index 14dec25..744137b 100644
--- a/src/templates/index.html
+++ b/src/templates/index.html
@@ -1,136 +1,146 @@
-<!doctype html>
-<html lang="en">
-<head>
-<meta charset="utf-8" />
-<meta name="viewport" content="width=device-width,initial-scale=1" />
-<title>Quick Problem Platform</title>
-<link rel="icon" type="image/x-icon" href="{{ url_for('static', filename='favicon.ico') }}">
-<link rel="stylesheet" href="{{ url_for('static', filename='index.css') }}">
-<style>
-/* Popout explanation */
-#rankingExplanation {
-  grid-column: 1 / span 2;
-  max-height: 0;
-  opacity: 0;
-  overflow: hidden;
-  transition: max-height 0.5s ease, opacity 0.4s ease, padding 0.4s ease;
-  padding: 0 12px;
-}
-#rankingExplanation.active {
-  max-height: 800px;
-  opacity: 1;
-  padding: 12px;
-}
-#rankInfoBtn.active { color: #2563eb; cursor:pointer; transition: transform 0.3s ease; }
-#rankInfoBtn.active { transform: rotate(90deg); }
-
-/* Highlight top rank */
-.rank-1 { background-color: #f0fff0; }
-.rank-1 td:first-child { font-weight: bold; color: #2e7d32; }
-.sort-asc::after { content: " ↑"; }
-.sort-desc::after { content: " ↓"; }
-</style>
-</head>
-<body>
-<div class="wrap">
-  <header>
-    <h1>Quick Problem Platform</h1>
-  </header>
-  <div class="content" id="contentContainer">
-    <!-- Problems -->
-    <section class="card problems-list">
-      <div class="search-controls">
-        <input type="text" class="search-input" id="problemSearch" placeholder="Search problems..." />
-      </div>
-      <h2 style="margin-bottom:6px;font-size:1.1rem">Problems</h2>
-      <div id="problemsContainer">
-        {% for folder, description, test_code, difficulty in problems %}
-          <div class="problem-item" data-name="{{ folder.replace('_',' ').title() }}" data-desc="{{ description }}">
-            <a href="/problem/{{ folder }}">{{ folder.replace('_',' ').title() }}</a>
-            <span class="difficulty" data-difficulty="{{ difficulty|lower }}">{{ difficulty }}</span>
-          </div>
-        {% else %}
-          <div class="problem-item">No problems yet.</div>
-        {% endfor %}
-      </div>
-    </section>
-
-    <!-- Leaderboard -->
-    <section class="card" id="leaderboardSection">
-      <div class="leaderboard-head">
-        <h2 style="font-size:1.1rem;margin:0">Leaderboard
-          <span id="rankInfoBtn" title="How ranking works">ℹ️</span>
-        </h2>
-      </div>
-      <div class="leaderboard-controls">
-        <input type="text" class="search-input" id="problemFilter" placeholder="Filter by problem..." />
-        <select class="filter-select" id="runtimeFilter">
-          <option value="">All runtimes</option>
-          <option value="best">Best runtime</option>
-          <option value="worst">Worst runtime</option>
-        </select>
-      </div>
-      <div id="leaderboardContainer">
-        <table class="leaderboard-table">
-          <thead>
-            <tr>
-              <th class="sortable" data-sort="rank">Rank</th>
-              <th class="sortable" data-sort="user">User</th>
-              <th class="sortable" data-sort="problem">Problem</th>
-              <th class="sortable" data-sort="runtime">Runtime (s)</th>
-              <th class="sortable" data-sort="memory">Memory (KB)</th>
-              <th>Line</th>
-              <th class="sortable" data-sort="timestamp">Timestamp</th>
-            </tr>
-          </thead>
-          <tbody id="leaderboardBody">
-            {% for entry in leaderboard %}
-            <tr data-user="{{ entry[0] }}" data-problem="{{ problem_titles.get(entry[1], 'Unknown') }}"
-                data-runtime="{{ '%.4f'|format(entry[2]) }}" data-memory="{{ entry[3] }}"
-                data-timestamp="{{ entry[5] }}">
-              <td>{{ loop.index }}</td>
-              <td>{{ entry[0] }}</td>
-              <td>
-                <a href="/problem/{{ problem_titles.get(entry[1], 'Unknown') }}"
-                  style="color:#2563eb; text-decoration: none;"
-                  onmouseover="this.style.textDecoration='underline';"
-                  onmouseout="this.style.textDecoration='none';">
-                  {{ problem_titles.get(entry[1], 'Unknown') }}
-                </a>
-              </td>
-              <td>{{ '%.4f'|format(entry[2]) }}</td>
-              <td>{{ entry[3] }}</td>
-              <td>{{ entry[4] if entry[4] else '-' }}</td>
-              <td>{{ entry[5] }}</td>
-            </tr>
-            {% else %}
-            <tr><td colspan="7">No leaderboard entries yet.</td></tr>
-            {% endfor %}
-          </tbody>
-        </table>
-      </div>
-    </section>
-
-    <!-- Ranking explanation -->
-    <section class="card" id="rankingExplanation">
-      <h2 style="font-size:1.1rem;margin-bottom:6px">How Ranking Works</h2>
-      <p>The leaderboard uses a <strong>weighted scoring system</strong> to determine overall rank:</p>
-      <ul style="margin-left: 15px;">
-        <li><strong>Runtime:</strong> How fast the solution runs (lower is better).</li>
-        <li><strong>Memory Usage:</strong> How much memory the solution uses (lower is better).</li>
-      </ul>
-      <p>Overall score is calculated as:</p>
-      <div style="background:#f9f9f9; border-left:4px solid #007acc; padding:1rem; margin:1rem 0;">
-        <code>
-          runtimeScore = yourRuntime / bestRuntime<br>
-          memoryScore  = yourMemory / bestMemory<br>
-          overallScore = runtimeScore × 0.7 + memoryScore × 0.3
-        </code>
-      </div>
-      <p>Lower overall scores are better. If scores are equal, earlier submission ranks higher.</p>
-    </section>
-  </div>
-</div>
-<script src="./script.js"></script>
-</body>
-</html>
\ No newline at end of file
+<!doctype html>
+<html lang="en" class="">
+<head>
+<meta charset="utf-8" />
+<meta name="viewport" content="width=device-width,initial-scale=1" />
+<title>Quick Problem Platform</title>
+<link rel="icon" type="image/x-icon" href="{{ url_for('static', filename='favicon.ico') }}">
+<link rel="stylesheet" href="{{ url_for('static', filename='index.css') }}">
+</head>
+<style>
+/* Popout explanation */
+#rankingExplanation {
+  grid-column: 1 / span 2;
+  max-height: 0;
+  opacity: 0;
+  overflow: hidden;
+  transition: max-height 0.5s ease, opacity 0.4s ease, padding 0.4s ease;
+  padding: 0 12px;
+}
+#rankingExplanation.active {
+  max-height: 800px;
+  opacity: 1;
+  padding: 12px;
+}
+#rankInfoBtn.active { color: #2563eb; cursor:pointer; transition: transform 0.3s ease; }
+#rankInfoBtn.active { transform: rotate(90deg); }
+
+/* Highlight top rank */
+.rank-1 td:first-child { font-weight: bold; }
+.sort-asc::after { content: " ↑"; }
+.sort-desc::after { content: " ↓"; }
+</style>
+</head>
+<body>
+<div class="wrap">
+  <header>
+    <div class="header-content">
+      <h1>Quick Problem Platform</h1>
+      <button id="darkModeToggle" class="dark-mode-toggle" title="Toggle dark mode">
+        <span class="dark-mode-icon"></span>
+      </button>
+    </div>
+  </header>
+  <div class="content" id="contentContainer">
+    <!-- Problems -->
+    <section class="card problems-list">
+      <div class="search-controls">
+        <input type="text" class="search-input" id="problemSearch" placeholder="Search problems..." />
+      </div>
+      <h2 style="margin-bottom:6px;font-size:1.1rem">Problems</h2>
+      <div id="problemsContainer">
+        {% for folder, description, test_code, difficulty in problems %}
+          <div class="problem-item" data-name="{{ folder.replace('_',' ').title() }}" data-desc="{{ description }}" data-difficulty="{{ difficulty|lower }}">
+            <a href="/problem/{{ folder }}">{{ folder.replace('_',' ').title() }}</a>
+            <span class="difficulty" data-difficulty="{{ difficulty|lower }}">{{ difficulty }}</span>
+          </div>
+        {% else %}
+          <div class="problem-item">No problems yet.</div>
+        {% endfor %}
+      </div>
+      <div class="pagination-controls" id="problemsPagination">
+        <button class="pagination-btn" id="problemsPrevBtn" disabled>← Previous</button>
+        <span class="pagination-info" id="problemsPaginationInfo">Page 1 of 1</span>
+        <button class="pagination-btn" id="problemsNextBtn" disabled>Next →</button>
+      </div>
+    </section>
+
+    <!-- Leaderboard -->
+    <section class="card" id="leaderboardSection">
+      <div class="leaderboard-head">
+        <h2 style="font-size:1.1rem;margin:0">Leaderboard
+          <span id="rankInfoBtn" title="How ranking works">ℹ️</span>
+        </h2>
+      </div>
+      <div class="leaderboard-controls">
+        <input type="text" class="search-input" id="problemFilter" placeholder="Filter by problem..." />
+        <select class="filter-select" id="runtimeFilter">
+          <option value="">All runtimes</option>
+          <option value="best">Best runtime</option>
+          <option value="worst">Worst runtime</option>
+        </select>
+      </div>
+      <div id="leaderboardContainer">
+        <table class="leaderboard-table">
+          <thead>
+            <tr>
+              <th class="sortable" data-sort="rank">Rank</th>
+              <th class="sortable" data-sort="user">User</th>
+              <th class="sortable" data-sort="problem">Problem</th>
+              <th class="sortable" data-sort="runtime">Runtime (s)</th>
+              <th class="sortable" data-sort="memory">Memory (KB)</th>
+              <th>Line</th>
+              <th class="sortable" data-sort="timestamp">Timestamp</th>
+            </tr>
+          </thead>
+          <tbody id="leaderboardBody">
+            {% for entry in leaderboard %}
+            <tr data-user="{{ entry[0] }}" data-problem="{{ problem_titles.get(entry[1], 'Unknown') }}"
+                data-runtime="{{ '%.4f'|format(entry[2]) }}" data-memory="{{ entry[3] }}"
+                data-timestamp="{{ entry[5] }}">
+              <td>{{ loop.index }}</td>
+              <td>{{ entry[0] }}</td>
+              <td>
+                <a href="/problem/{{ problem_titles.get(entry[1], 'Unknown') }}"
+                  style="color:#2563eb; text-decoration: none;"
+                  onmouseover="this.style.textDecoration='underline';"
+                  onmouseout="this.style.textDecoration='none';">
+                  {{ problem_titles.get(entry[1], 'Unknown') }}
+                </a>
+              </td>
+              <td>{{ '%.4f'|format(entry[2]) }}</td>
+              <td>{{ entry[3] }}</td>
+              <td>{{ entry[4] if entry[4] else '-' }}</td>
+              <td>{{ entry[5] }}</td>
+            </tr>
+            {% else %}
+            <tr><td colspan="7">No leaderboard entries yet.</td></tr>
+            {% endfor %}
+          </tbody>
+        </table>
+      </div>
+    </section>
+
+    <!-- Ranking explanation -->
+    <section class="card" id="rankingExplanation">
+      <h2 style="font-size:1.1rem;margin-bottom:6px">How Ranking Works</h2>
+      <p>The leaderboard uses a <strong>weighted scoring system</strong> to determine overall rank:</p>
+      <ul style="margin-left: 15px;">
+        <li><strong>Runtime:</strong> How fast the solution runs (lower is better).</li>
+        <li><strong>Memory Usage:</strong> How much memory the solution uses (lower is better).</li>
+      </ul>
+      <p>Overall score is calculated as:</p>
+      <div style="background:#f9f9f9; border-left:4px solid #007acc; padding:1rem; margin:1rem 0;">
+        <code>
+          runtimeScore = yourRuntime / bestRuntime<br>
+          memoryScore  = yourMemory / bestMemory<br>
+          overallScore = runtimeScore × 0.7 + memoryScore × 0.3
+        </code>
+      </div>
+      <p>Lower overall scores are better. If scores are equal, earlier submission ranks higher.</p>
+    </section>
+  </div>
+</div>
+<script src="{{ url_for('static', filename='script.js') }}"></script>
+</body>
+</html>
diff --git a/src/templates/problem.html b/src/templates/problem.html
index 20b0068..46d79ca 100644
--- a/src/templates/problem.html
+++ b/src/templates/problem.html
@@ -1,85 +1,158 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>{{ problem.title }} - Coding Problem</title>
-    <link rel="stylesheet" href="/static/style.css">
-    <link rel="stylesheet" href="/static/problem.css">
-    <!-- this is stoopid fucking html link for favicon. just cause of flask-->
-    <link rel="icon" type="image/x-icon" href="{{ url_for('static', filename='favicon.ico') }}">
-    <link href="https://fonts.cdnfonts.com/css/jetbrains-mono" rel="stylesheet">
-    <link href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap" rel="stylesheet">
-</head>
-<body>
-    <div class="main-container">
-        <div class="problem-panel">
-            <div class="problem-header">
-                <button class="back-btn" onclick="window.location.href='/'">← Back</button>
-                <h1>{{ problem.title }}</h1>
-            </div>
-            <div class="problem-desc">{{ problem.description | safe | markdown }}</div>
-        </div>
-
-        <div class="editor-container">
-            <div class="editor-header">
-                <h2 style="margin:0;font-size:18px;">Submit Your Solution (Python)</h2>
-            </div>
-            <div class="editor-wrapper">
-                <form method="post">
-                    <label for="username">Username (optional):</label>
-                    <input type="text" name="username" id="username" placeholder="Anonymous">
-                    <div id="editor"></div>
-                    <textarea name="user_code" id="user_code" style="display:none;"></textarea>
-                    <div class="editor-actions">
-                        <button type="submit">Run & Submit</button>
-                    </div>
-                </form>
-
-                <div class="result-panel">
-                    <h3>Result</h3>
-                    {% if result %}
-                        <p><b>Runtime:</b> {{ '%.4f'|format(result.runtime) }} seconds</p>
-                        <p><b>Output:</b></p>
-                        <pre>{{ result.output }}</pre>
-                        {% if result.error %}
-                            <p><b>Error:</b></p>
-                            <pre>{{ result.error }}</pre>
-                        {% endif %}
-                    {% else %}
-                        <div class="placeholder">
-                            Your code execution results will appear here
-                        </div>
-                    {% endif %}
-                </div>
-            </div>
-        </div>
-    </div>
-
-    <script src="https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs/loader.js"></script>
-    <script>
-      require.config({ paths: { 'vs': 'https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs' } });
-      require(['vs/editor/editor.main'], function() {
-        var editor = monaco.editor.create(document.getElementById('editor'), {
-          value: '',
-          language: 'python',
-          theme: 'vs-light',
-          fontFamily: 'JetBrains Mono, monospace',
-          fontLigatures: true,
-          automaticLayout: true,
-          fontSize: 16,
-          minimap: { enabled: false }
-        });
-        document.querySelector('form').addEventListener('submit', function(e) {
-          var code = editor.getValue();
-          if (!code.trim()) {
-            alert('Please enter your code before submitting.');
-            e.preventDefault();
-            return false;
-          }
-          document.getElementById('user_code').value = code;
-        });
-      });
-    </script>
-</body>
-</html>
\ No newline at end of file
+<!doctype html>
+<html lang="en" class="">
+    <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+        <title>{{ problem.title }} - Coding Problem</title>
+        <link rel="stylesheet" href="/static/style.css" />
+        <link rel="stylesheet" href="/static/problem.css" />
+        <!-- this is stoopid fucking html link for favicon. just cause of flask-->
+        <link
+            rel="icon"
+            type="image/x-icon"
+            href="{{ url_for('static', filename='favicon.ico') }}"
+        />
+        <link
+            href="https://fonts.cdnfonts.com/css/jetbrains-mono"
+            rel="stylesheet"
+        />
+        <link
+            href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap"
+            rel="stylesheet"
+        />
+    </head>
+    <body>
+        <div class="main-container">
+            <div class="problem-panel">
+                <div class="problem-header">
+                    <button class="back-btn" onclick="window.location.href='/'">
+                        ← Back
+                    </button>
+                    <h1>{{ problem.title }}</h1>
+                    <button
+                        id="darkModeToggle"
+                        class="dark-mode-toggle"
+                        title="Toggle dark mode"
+                    >
+                        <span class="dark-mode-icon"></span>
+                    </button>
+                </div>
+                <div class="problem-desc">
+                    {{ problem.description | safe | markdown }}
+                </div>
+            </div>
+
+            <div class="editor-container">
+                <div class="editor-header">
+                    <h2 style="margin: 0; font-size: 18px">
+                        Submit Your Solution (Python)
+                    </h2>
+                </div>
+                <div class="editor-wrapper">
+                    <form method="post">
+                        <label for="username">Username (optional):</label>
+                        <input
+                            type="text"
+                            name="username"
+                            id="username"
+                            placeholder="Anonymous"
+                        />
+                        <div id="editor"></div>
+                        <textarea
+                            name="user_code"
+                            id="user_code"
+                            style="display: none"
+                        ></textarea>
+                        <div class="editor-actions">
+                            <button type="submit">Run & Submit</button>
+                        </div>
+                    </form>
+
+                    <div class="result-panel">
+                        <h3>Result</h3>
+                        {% if result %}
+                        <p>
+                            <b>Runtime:</b> {{ '%.4f'|format(result.runtime) }}
+                            seconds
+                        </p>
+                        <p><b>Output:</b></p>
+                        <pre>{{ result.output }}</pre>
+                        {% if result.error %}
+                        <p><b>Error:</b></p>
+                        <pre>{{ result.error }}</pre>
+                        {% endif %} {% else %}
+                        <div class="placeholder">
+                            Your code execution results will appear here
+                        </div>
+                        {% endif %}
+                    </div>
+                </div>
+            </div>
+        </div>
+
+        <script src="https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs/loader.js"></script>
+        <script>
+            // Dark mode functionality
+            const darkModeToggle = document.getElementById("darkModeToggle");
+            const html = document.documentElement;
+
+            // Load saved dark mode preference
+            const savedDarkMode = localStorage.getItem("darkMode");
+            if (
+                savedDarkMode === "true" ||
+                (savedDarkMode === null &&
+                    window.matchMedia("(prefers-color-scheme: dark)").matches)
+            ) {
+                html.classList.add("dark");
+            }
+
+            darkModeToggle.addEventListener("click", () => {
+                html.classList.toggle("dark");
+                localStorage.setItem(
+                    "darkMode",
+                    html.classList.contains("dark"),
+                );
+                // Update Monaco editor theme
+                if (window.monacoEditor) {
+                    const isDark = html.classList.contains("dark");
+                    window.monacoEditor.updateOptions({
+                        theme: isDark ? "vs-dark" : "vs-light",
+                    });
+                }
+            });
+
+            require.config({
+                paths: {
+                    vs: "https://cdn.jsdelivr.net/npm/monaco-editor@0.45.0/min/vs",
+                },
+            });
+            require(["vs/editor/editor.main"], function () {
+                const isDark = html.classList.contains("dark");
+                window.monacoEditor = monaco.editor.create(
+                    document.getElementById("editor"),
+                    {
+                        value: "",
+                        language: "python",
+                        theme: isDark ? "vs-dark" : "vs-light",
+                        fontFamily: "JetBrains Mono, monospace",
+                        fontLigatures: true,
+                        automaticLayout: true,
+                        fontSize: 16,
+                        minimap: { enabled: false },
+                    },
+                );
+                document
+                    .querySelector("form")
+                    .addEventListener("submit", function (e) {
+                        var code = window.monacoEditor.getValue();
+                        if (!code.trim()) {
+                            alert("Please enter your code before submitting.");
+                            e.preventDefault();
+                            return false;
+                        }
+                        document.getElementById("user_code").value = code;
+                    });
+            });
+        </script>
+    </body>
+</html>
diff --git a/src/templates/script.js b/src/templates/script.js
deleted file mode 100644
index 6106ca8..0000000
--- a/src/templates/script.js
+++ /dev/null
@@ -1,274 +0,0 @@
-document.addEventListener('DOMContentLoaded', () => {
-  // Problem search
-  const problemSearch = document.getElementById('problemSearch');
-  const problemsContainer = document.getElementById('problemsContainer');
-  const problemItems = problemsContainer?.querySelectorAll('.problem-item') || [];
-  
-  problemSearch?.addEventListener('input', () => {
-    const term = problemSearch.value.toLowerCase().trim();
-    problemItems.forEach(item => {
-      const name = item.dataset.name?.toLowerCase() || '';
-      const desc = item.dataset.desc?.toLowerCase() || '';
-      const shouldShow = !term || name.includes(term) || desc.includes(term);
-      item.style.display = shouldShow ? '' : 'none';
-    });
-  });
-
-  // Leaderboard functionality
-  const problemFilter = document.getElementById('problemFilter');
-  const runtimeFilter = document.getElementById('runtimeFilter');
-  const leaderboardBody = document.getElementById('leaderboardBody');
-  const sortableHeaders = document.querySelectorAll('.sortable');
-  
-  let currentSort = { column: 'rank', direction: 'asc' };
-  let allRows = [];
-
-  // Initialize rows array
-  function initializeRows() {
-    allRows = Array.from(leaderboardBody.querySelectorAll('tr')).map(row => {
-      return {
-        element: row,
-        user: row.dataset.user || '',
-        problem: row.dataset.problem || '',
-        runtime: parseFloat(row.dataset.runtime) || 0,
-        memory: parseFloat(row.dataset.memory) || 0,
-        timestamp: new Date(row.dataset.timestamp || Date.now()).getTime(),
-        language: row.dataset.language || '',
-        originalIndex: Array.from(leaderboardBody.children).indexOf(row)
-      };
-    });
-  }
-
-  function updateRankClasses() {
-    const visibleRows = allRows.filter(row => row.element.style.display !== 'none');
-    visibleRows.forEach((rowData, index) => {
-      const rank = index + 1;
-      const row = rowData.element;
-      
-      // Update rank cell
-      const rankCell = row.cells[0];
-      if (rankCell) rankCell.textContent = rank;
-      
-      // Update rank classes
-      row.className = row.className.replace(/\brank-\d+\b/g, '');
-      if (rank === 1) row.classList.add('rank-1');
-      else if (rank <= 3) row.classList.add('rank-top3');
-    });
-  }
-
-  function calculateOverallRanking() {
-    const visibleRows = allRows.filter(row => row.element.style.display !== 'none');
-    
-    if (visibleRows.length === 0) return;
-
-    // Group submissions by problem to find the best performance for each
-    const problemBests = {};
-    
-    visibleRows.forEach(rowData => {
-      const problem = rowData.problem;
-      if (!problemBests[problem]) {
-        problemBests[problem] = {
-          bestRuntime: Infinity,
-          bestMemory: Infinity
-        };
-      }
-      
-      problemBests[problem].bestRuntime = Math.min(problemBests[problem].bestRuntime, rowData.runtime);
-      problemBests[problem].bestMemory = Math.min(problemBests[problem].bestMemory, rowData.memory);
-    });
-
-    // Calculate normalized scores for each submission
-    visibleRows.forEach(rowData => {
-      const problemBest = problemBests[rowData.problem];
-      
-      // Prevent division by zero
-      const runtimeScore = problemBest.bestRuntime > 0 ? 
-        rowData.runtime / problemBest.bestRuntime : 1;
-      const memoryScore = problemBest.bestMemory > 0 ? 
-        rowData.memory / problemBest.bestMemory : 1;
-      
-      // Weighted overall score (70% runtime, 30% memory)
-      rowData.overallScore = runtimeScore * 0.7 + memoryScore * 0.3;
-    });
-
-    // Sort by overall score (lower is better), then by timestamp (earlier is better for ties)
-    visibleRows.sort((a, b) => {
-      const scoreDiff = a.overallScore - b.overallScore;
-      if (Math.abs(scoreDiff) > 0.000001) return scoreDiff; // Use small epsilon for float comparison
-      
-      // If scores are essentially equal, prefer earlier submission
-      return a.timestamp - b.timestamp;
-    });
-
-    // Reorder DOM elements and update ranks
-    visibleRows.forEach((rowData, index) => {
-      leaderboardBody.appendChild(rowData.element);
-    });
-    
-    updateRankClasses();
-  }
-
-  function filterLeaderboard() {
-    const problemTerm = (problemFilter?.value || '').toLowerCase().trim();
-    const runtimeType = runtimeFilter?.value || 'all';
-    
-    // Reset all rows to visible first
-    allRows.forEach(rowData => {
-      rowData.element.style.display = '';
-    });
-    
-    // Apply problem filter
-    if (problemTerm) {
-      allRows.forEach(rowData => {
-        const problemMatch = rowData.problem.toLowerCase().includes(problemTerm);
-        if (!problemMatch) {
-          rowData.element.style.display = 'none';
-        }
-      });
-    }
-    
-    // Apply runtime filter (best/worst per user per problem)
-    if (runtimeType === 'best' || runtimeType === 'worst') {
-      const userProblemGroups = {};
-      
-      // Group by user + problem combination
-      allRows.forEach(rowData => {
-        if (rowData.element.style.display === 'none') return;
-        
-        const key = `${rowData.user}::${rowData.problem}`;
-        if (!userProblemGroups[key]) {
-          userProblemGroups[key] = [];
-        }
-        userProblemGroups[key].push(rowData);
-      });
-      
-      // Hide all except best/worst for each user-problem combination
-      Object.values(userProblemGroups).forEach(group => {
-        if (group.length <= 1) return;
-        
-        // Sort by runtime
-        group.sort((a, b) => a.runtime - b.runtime);
-        
-        const keepIndex = runtimeType === 'best' ? 0 : group.length - 1;
-        group.forEach((rowData, index) => {
-          if (index !== keepIndex) {
-            rowData.element.style.display = 'none';
-          }
-        });
-      });
-    }
-    
-    calculateOverallRanking();
-  }
-
-  function getCellValue(rowData, column) {
-    switch (column) {
-      case 'rank':
-        return parseInt(rowData.element.cells[0]?.textContent) || 0;
-      case 'user':
-        return rowData.user.toLowerCase();
-      case 'problem':
-        return rowData.problem.toLowerCase();
-      case 'runtime':
-        return rowData.runtime;
-      case 'memory':
-        return rowData.memory;
-      case 'timestamp':
-        return rowData.timestamp;
-      case 'language':
-        return rowData.language.toLowerCase();
-      default:
-        return '';
-    }
-  }
-
-  function sortLeaderboard(column, direction) {
-    if (column === 'rank') {
-      calculateOverallRanking();
-      return;
-    }
-    
-    const visibleRows = allRows.filter(row => row.element.style.display !== 'none');
-    
-    visibleRows.sort((a, b) => {
-      const valueA = getCellValue(a, column);
-      const valueB = getCellValue(b, column);
-      
-      let comparison = 0;
-      if (typeof valueA === 'number' && typeof valueB === 'number') {
-        comparison = valueA - valueB;
-      } else {
-        comparison = valueA < valueB ? -1 : valueA > valueB ? 1 : 0;
-      }
-      
-      return direction === 'asc' ? comparison : -comparison;
-    });
-
-    // Reorder DOM elements
-    visibleRows.forEach(rowData => {
-      leaderboardBody.appendChild(rowData.element);
-    });
-    
-    updateRankClasses();
-  }
-
-  // Event listeners for sorting
-  sortableHeaders.forEach(header => {
-    header.addEventListener('click', () => {
-      const column = header.dataset.sort;
-      if (!column) return;
-      
-      // Remove sorting classes from all headers
-      sortableHeaders.forEach(h => h.classList.remove('sort-asc', 'sort-desc'));
-      
-      // Toggle sort direction
-      if (currentSort.column === column) {
-        currentSort.direction = currentSort.direction === 'asc' ? 'desc' : 'asc';
-      } else {
-        currentSort.column = column;
-        currentSort.direction = 'asc';
-      }
-      
-      // Add sorting class to current header
-      header.classList.add(`sort-${currentSort.direction}`);
-      
-      sortLeaderboard(column, currentSort.direction);
-    });
-  });
-
-  // Filter event listeners
-  problemFilter?.addEventListener('input', filterLeaderboard);
-  runtimeFilter?.addEventListener('change', filterLeaderboard);
-
-  // Rank info popout
-  const rankInfoBtn = document.getElementById('rankInfoBtn');
-  const rankingExplanation = document.getElementById('rankingExplanation');
-  
-  rankInfoBtn?.addEventListener('click', (e) => {
-    e.preventDefault();
-    rankingExplanation?.classList.toggle('active');
-    rankInfoBtn?.classList.toggle('active');
-  });
-
-  // Close ranking explanation when clicking outside
-  document.addEventListener('click', (e) => {
-    if (rankingExplanation?.classList.contains('active') && 
-        !rankingExplanation.contains(e.target) && 
-        !rankInfoBtn?.contains(e.target)) {
-      rankingExplanation.classList.remove('active');
-      rankInfoBtn?.classList.remove('active');
-    }
-  });
-
-  // Initialize everything
-  if (leaderboardBody && leaderboardBody.children.length > 0) {
-    initializeRows();
-    calculateOverallRanking();
-    
-    // Set initial sort indicator
-    const defaultHeader = document.querySelector('[data-sort="rank"]');
-    if (defaultHeader) {
-      defaultHeader.classList.add('sort-asc');
-    }
-  }
-});
\ No newline at end of file