diff --git a/src/app.py b/src/app.py
index 05d9c5d..317f07e 100644
--- a/src/app.py
+++ b/src/app.py
@@ -37,7 +37,7 @@ def script():
 
 @app.route('/favicon.ico')
 def favicon():
-    return send_from_directory("templates", "favicon", "favicon.ico")
+    return send_from_directory("templates", "favicon.ico")
 
 @app.route('/')
 def index():
diff --git a/src/problems/Palindrome/description.md b/src/problems/Palindrome/description.md
new file mode 100644
index 0000000..fcdad34
--- /dev/null
+++ b/src/problems/Palindrome/description.md
@@ -0,0 +1,60 @@
+## Problem: Check if a String is a Palindrome
+
+Given a string `s`, determine whether it reads the same forward and backward.
+Return `True` if it is a palindrome, otherwise return `False`.
+
+A **palindrome** is a sequence of characters that is identical when reversed.
+Comparison is **case-sensitive** and should consider all characters, including spaces and punctuation.
+
+---
+
+### Example 1
+
+**Input:**
+
+```
+s = "racecar"
+```
+
+**Output:**
+
+```
+True
+```
+
+**Explanation:**
+Reversing `"racecar"` results in `"racecar"`, which is the same as the original string.
+
+---
+
+### Example 2
+
+**Input:**
+
+```
+s = "hello"
+```
+
+**Output:**
+
+```
+False
+```
+
+**Explanation:**
+Reversing `"hello"` results in `"olleh"`, which is different from the original string.
+
+---
+
+### Constraints
+
+* `0 <= len(s) <= 10^5`
+* `s` may contain letters, digits, symbols, and spaces.
+
+---
+
+### Function Signature (Python)
+
+```python
+def palindrome(s: str) -> bool:
+```
diff --git a/src/problems/Palindrome/manifest.json b/src/problems/Palindrome/manifest.json
new file mode 100644
index 0000000..4d1c6c4
--- /dev/null
+++ b/src/problems/Palindrome/manifest.json
@@ -0,0 +1,7 @@
+{
+    "title": "Palindrome",
+    "description": "Find out wether or not a String is a Palindrome",
+    "description_md": "problems/Palindrome/description.md",
+    "test_code": "problems/Palindrome/test.py",
+    "difficulty": "medium"
+}
\ No newline at end of file
diff --git a/src/problems/Palindrome/test.py b/src/problems/Palindrome/test.py
new file mode 100644
index 0000000..324bbf8
--- /dev/null
+++ b/src/problems/Palindrome/test.py
@@ -0,0 +1,32 @@
+import unittest
+
+#<!-- User expected Function -->
+## def palindrome(s:str) -> bool:
+    ## return s == s[::-1]
+
+class TestSolution(unittest.TestCase):
+    def test_palindrome(self):
+        test_cases = [
+            ("racecar", True),          # Simple palindrome
+            ("hello", False),           # Not a palindrome
+            ("", True),                 # Empty string
+            ("a", True),                # Single character
+            ("madam", True),            # Palindrome word
+            ("Madam", False),           # Case-sensitive check
+            ("12321", True),            # Numeric string palindrome
+            ("123456", False),          # Numeric string non-palindrome
+        ]
+        print("\nFUNCTION OUTPUT TEST RESULTS")
+
+        for input_val, expected in test_cases:
+            try:
+                actual = palindrome(input_val)  # pyright: ignore[reportUndefinedVariable]
+                status = "✓ PASS" if actual == expected else "✗ FAIL"
+                print(f"{status} | Input: '{input_val}' -> Got: {actual} | Expected: {expected}")
+                self.assertEqual(actual, expected)
+            except Exception as e:
+                print(f"✗ ERROR | Input: '{input_val}' -> Exception: {e}")
+                raise
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)
diff --git a/src/templates/favicon/favicon.ico b/src/static/favicon.ico
similarity index 100%
rename from src/templates/favicon/favicon.ico
rename to src/static/favicon.ico
diff --git a/src/static/index.css b/src/static/index.css
index 96f1dbb..fad9bcb 100644
--- a/src/static/index.css
+++ b/src/static/index.css
@@ -28,6 +28,7 @@ header {
     margin-bottom: 14px;
 }
 header h1 {
+    text-align: center;
     font-size: 1.6rem;
     color: #111827;
 }
@@ -183,3 +184,24 @@ header p {
         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;
+}
diff --git a/src/static/problem.css b/src/static/problem.css
new file mode 100644
index 0000000..73572da
--- /dev/null
+++ b/src/static/problem.css
@@ -0,0 +1,212 @@
+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
diff --git a/src/templates/index.html b/src/templates/index.html
index 7d241c2..f722b1b 100644
--- a/src/templates/index.html
+++ b/src/templates/index.html
@@ -4,10 +4,17 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width,initial-scale=1" />
   <title>Quick Problem Platform</title>
-  <!--<link rel="favicon" href="/favicon/favicon.ico">-->
-  <script src="script.js" async defer></script>
-  <link rel="stylesheet" href="/static/index.css">
-
+  <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>
+    /* Minimal inline CSS to support full-width explanation and popout */
+    #rankingExplanation { 
+        display:none; 
+        grid-column: 1 / span 2; 
+        transition: all 0.35s ease; 
+    }
+    #rankInfoBtn.active { color: #2563eb; }
+  </style>
 </head>
 <body>
 <div class="wrap">
@@ -16,47 +23,30 @@
   </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>
+    <section class="card problems-list">
+      <div class="search-controls">
+        <input type="text" class="search-input" id="problemSearch" placeholder="Search problems..." />
       </div>
-    {% else %}
-      <div class="problem-item">No problems yet.</div>
-    {% endfor %}
-  </div>
-</section>
+      <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</h2>
-        <button class="btn" id="toggleLeaderboard">Hide</button>
       </div>
       <div class="leaderboard-controls">
-        <input 
-          type="text" 
-          class="search-input" 
-          id="userSearch" 
-          placeholder="Filter by user..." 
-        />
-        <input 
-          type="text" 
-          class="search-input" 
-          id="problemFilter" 
-          placeholder="Filter by problem..." 
-        />
+        <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>
@@ -67,7 +57,7 @@
         <table class="leaderboard-table">
           <thead>
             <tr>
-              <th class="sortable" data-sort="rank">Rank</th>
+              <th class="sortable" data-sort="rank">Rank <span id="rankInfoBtn" title="How ranking works" style="cursor:pointer;">ℹ️</span></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>
@@ -83,7 +73,14 @@
                 data-timestamp="{{ entry[5] }}">
               <td>{{ loop.index }}</td>
               <td>{{ entry[0] }}</td>
-              <td>{{ problem_titles.get(entry[1], 'Unknown') }}</td>
+              <td>
+                <a href="/problem/{{ problem_titles.get(entry[1], 'Unknown') }}"
+                  style="color: #0077ff; 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>
@@ -96,7 +93,150 @@
         </table>
       </div>
     </section>
+
+    <!-- Ranking explanation popout -->
+    <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.
+        It considers multiple metrics for each submission:
+      </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>Each metric is normalized against the best in the leaderboard, and the 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 two scores are equal, the earlier submission ranks higher.</p>
+    </section>
   </div>
 </div>
+
+<!-- Inline JS -->
+<script>
+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();
+    problemItems.forEach(item => {
+      const name = item.dataset.name.toLowerCase();
+      const desc = item.dataset.desc?.toLowerCase() || '';
+      item.style.display = (name.includes(term) || desc.includes(term)) ? '' : 'none';
+    });
+  });
+
+  // Leaderboard
+  const problemFilter = document.getElementById('problemFilter');
+  const runtimeFilter = document.getElementById('runtimeFilter');
+  const leaderboardBody = document.getElementById('leaderboardBody');
+  const leaderboardRows = Array.from(leaderboardBody.querySelectorAll('tr'));
+  const sortableHeaders = document.querySelectorAll('.sortable');
+
+  let currentSort = { column: null, direction: 'asc' };
+
+  function filterLeaderboard() {
+    const problemTerm = problemFilter.value.toLowerCase();
+    const runtimeType = runtimeFilter.value;
+
+    leaderboardRows.forEach(row => {
+      const problem = row.dataset.problem.toLowerCase();
+      const runtime = parseFloat(row.dataset.runtime);
+      const showProblem = problem.includes(problemTerm);
+
+      let showRuntime = true;
+      if(runtimeType === 'best') {
+        const userProblemRows = leaderboardRows.filter(r => r.dataset.user === row.dataset.user && r.dataset.problem === row.dataset.problem);
+        const best = Math.min(...userProblemRows.map(r=>parseFloat(r.dataset.runtime)));
+        showRuntime = runtime === best;
+      } else if(runtimeType === 'worst') {
+        const userProblemRows = leaderboardRows.filter(r => r.dataset.user === row.dataset.user && r.dataset.problem === row.dataset.problem);
+        const worst = Math.max(...userProblemRows.map(r=>parseFloat(r.dataset.runtime)));
+        showRuntime = runtime === worst;
+      }
+
+      row.style.display = (showProblem && showRuntime) ? '' : 'none';
+    });
+  }
+
+  problemFilter?.addEventListener('input', filterLeaderboard);
+  runtimeFilter?.addEventListener('change', filterLeaderboard);
+
+  function getCellValue(row, column) {
+    const index = Array.from(document.querySelectorAll('th')).findIndex(th => th.dataset.sort===column);
+    let val = row.cells[index].textContent.trim();
+    if(['runtime','memory','rank'].includes(column)) return parseFloat(val)||0;
+    if(column==='timestamp') return new Date(val).getTime();
+    return val.toLowerCase();
+  }
+
+  function compareValues(a,b,direction) {
+    if(typeof a==='number' && typeof b==='number') return direction==='asc'?a-b:b-a;
+    if(a<b) return direction==='asc'?-1:1;
+    if(a>b) return direction==='asc'?1:-1;
+    return 0;
+  }
+
+  function calculateOverallRank() {
+    const rows = Array.from(leaderboardBody.querySelectorAll('tr'));
+    const runtimes = rows.map(r=>parseFloat(r.dataset.runtime)||Infinity);
+    const memories = rows.map(r=>parseFloat(r.dataset.memory)||Infinity);
+    const minRuntime = Math.min(...runtimes);
+    const minMemory = Math.min(...memories);
+
+    rows.forEach(row=>{
+      const runtimeScore = (parseFloat(row.dataset.runtime)||Infinity)/minRuntime;
+      const memoryScore = (parseFloat(row.dataset.memory)||Infinity)/minMemory;
+      const score = runtimeScore*0.7 + memoryScore*0.3;
+      row.dataset.overallScore = score;
+    });
+  }
+
+  function sortLeaderboard(column,direction) {
+    let rows = Array.from(leaderboardBody.querySelectorAll('tr'));
+    if(column==='rank') {
+      calculateOverallRank();
+      rows.sort((a,b)=>parseFloat(a.dataset.overallScore)-parseFloat(b.dataset.overallScore));
+      rows.forEach((row,index)=>row.cells[0].textContent = index+1);
+    } else {
+      rows.sort((a,b)=>compareValues(getCellValue(a,column),getCellValue(b,column),direction));
+    }
+    rows.forEach(row=>leaderboardBody.appendChild(row));
+  }
+
+  sortableHeaders.forEach(header=>{
+    header.addEventListener('click',()=>{
+      const column = header.dataset.sort;
+      sortableHeaders.forEach(h=>h.classList.remove('sort-asc','sort-desc'));
+      if(currentSort.column===column) currentSort.direction = currentSort.direction==='asc'?'desc':'asc';
+      else { currentSort.column=column; currentSort.direction='asc'; }
+      header.classList.add(`sort-${currentSort.direction}`);
+      sortLeaderboard(column,currentSort.direction);
+    });
+  });
+
+  // Rank info popout
+  const rankInfoBtn = document.getElementById('rankInfoBtn');
+  const rankingExplanation = document.getElementById('rankingExplanation');
+  rankInfoBtn?.addEventListener('click',()=>{
+    if(rankingExplanation.style.display==='none' || rankingExplanation.style.display==='') {
+      rankingExplanation.style.display='block';
+      rankInfoBtn.classList.add('active');
+    } else {
+      rankingExplanation.style.display='none';
+      rankInfoBtn.classList.remove('active');
+    }
+  });
+});
+</script>
 </body>
 </html>
diff --git a/src/templates/problem.html b/src/templates/problem.html
index 80aea3a..20b0068 100644
--- a/src/templates/problem.html
+++ b/src/templates/problem.html
@@ -5,222 +5,11 @@
     <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">
-    <style>
-        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;
-    }
-}
-
-    </style>
 </head>
 <body>
     <div class="main-container">
diff --git a/src/templates/ranking.html b/src/templates/ranking.html
new file mode 100644
index 0000000..c63cae3
--- /dev/null
+++ b/src/templates/ranking.html
@@ -0,0 +1,101 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="UTF-8">
+<title>Leaderboard Ranking System</title>
+<style>
+    body {
+        font-family: Arial, sans-serif;
+        max-width: 800px;
+        margin: 2rem auto;
+        line-height: 1.6;
+        color: #333;
+    }
+    h1, h2 {
+        color: #222;
+    }
+    code {
+        background: #f4f4f4;
+        padding: 2px 4px;
+        border-radius: 4px;
+    }
+    ul {
+        margin-top: 0.5rem;
+    }
+    .example {
+        background: #f9f9f9;
+        border-left: 4px solid #007acc;
+        padding: 1rem;
+        margin: 1rem 0;
+        font-size: 0.95rem;
+    }
+</style>
+</head>
+<body>
+
+<h1>Leaderboard Ranking System</h1>
+
+<p>
+The leaderboard uses a <strong>weighted scoring system</strong> to determine who ranks first.
+Rather than simply sorting by a single column, the system considers multiple performance metrics:
+</p>
+
+<h2>Metrics Used</h2>
+<ul>
+    <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>
+
+<h2>Score Calculation</h2>
+<p>
+Each metric is normalized against the best result in the leaderboard.  
+The formula for the score is:
+</p>
+
+<div class="example">
+<code>
+runtimeScore = (yourRuntime / bestRuntime)<br>
+memoryScore  = (yourMemory / bestMemory)<br>
+overallScore = runtimeScore × 0.7 + memoryScore × 0.3
+</code>
+</div>
+
+<ul>
+    <li>Lower scores are better.</li>
+    <li><code>0.7</code> means runtime is worth 70% of your score.</li>
+    <li><code>0.3</code> means memory usage is worth 30% of your score.</li>
+</ul>
+
+<h2>Ranking Rules</h2>
+<ol>
+    <li>Players are sorted by <strong>overallScore</strong> (lowest first).</li>
+    <li>If two players have the same score, ties are broken by <strong>earlier timestamp</strong> (who submitted first).</li>
+    <li>Ranks are updated dynamically when you click the "Rank" column header.</li>
+</ol>
+
+<h2>Example</h2>
+<div class="example">
+<b>Best Runtime:</b> 1.000s  
+<b>Best Memory:</b> 50MB  
+
+Player A: Runtime = 1.200s, Memory = 60MB  
+runtimeScore = 1.200 / 1.000 = 1.20  
+memoryScore = 60 / 50 = 1.20  
+overallScore = (1.20 × 0.7) + (1.20 × 0.3) = 1.20  
+
+Player B: Runtime = 1.100s, Memory = 70MB  
+runtimeScore = 1.100 / 1.000 = 1.10  
+memoryScore = 70 / 50 = 1.40  
+overallScore = (1.10 × 0.7) + (1.40 × 0.3) = 1.19  
+
+<b>Winner:</b> Player B (score 1.19 is better than 1.20)
+</div>
+
+<h2>Why This Method?</h2>
+<p>
+This ranking system prevents a player with an extremely low runtime but huge memory usage (or vice versa) from automatically winning.  
+It rewards balanced solutions while still prioritizing speed.
+</p>
+
+</body>
+</html>
diff --git a/src/templates/script.js b/src/templates/script.js
index 9e45856..c021281 100644
--- a/src/templates/script.js
+++ b/src/templates/script.js
@@ -1,39 +1,22 @@
-// Toggle leaderboard visibility
-const toggleBtn = document.getElementById('toggleLeaderboard');
-const leaderboardSection = document.getElementById('leaderboardSection');
-const contentContainer = document.getElementById('contentContainer');
-
-toggleBtn.addEventListener('click', () => {
-if (leaderboardSection.style.display === 'none') {
-    leaderboardSection.style.display = '';
-    toggleBtn.textContent = 'Hide';
-    contentContainer.classList.remove('single-column');
-} else {
-    leaderboardSection.style.display = 'none';
-    toggleBtn.textContent = 'Show';
-    contentContainer.classList.add('single-column');
-}
-});
-
-// Problem search functionality
+// =======================
+// Problem search
+// =======================
 const problemSearch = document.getElementById('problemSearch');
 const problemsContainer = document.getElementById('problemsContainer');
 const problemItems = problemsContainer.querySelectorAll('.problem-item');
 
 problemSearch.addEventListener('input', () => {
-const searchTerm = problemSearch.value.toLowerCase();
-problemItems.forEach(item => {
-    const name = item.dataset.name.toLowerCase();
-    const desc = item.dataset.desc?.toLowerCase() || '';
-    if (name.includes(searchTerm) || desc.includes(searchTerm)) {
-    item.style.display = '';
-    } else {
-    item.style.display = 'none';
-    }
-});
+    const searchTerm = problemSearch.value.toLowerCase();
+    problemItems.forEach(item => {
+        const name = item.dataset.name.toLowerCase();
+        const desc = item.dataset.desc?.toLowerCase() || '';
+        item.style.display = (name.includes(searchTerm) || desc.includes(searchTerm)) ? '' : 'none';
+    });
 });
 
-// Leaderboard filtering and sorting
+// =======================
+// Leaderboard filtering
+// =======================
 const userSearch = document.getElementById('userSearch');
 const problemFilter = document.getElementById('problemFilter');
 const runtimeFilter = document.getElementById('runtimeFilter');
@@ -41,112 +24,141 @@ const leaderboardBody = document.getElementById('leaderboardBody');
 const leaderboardRows = Array.from(leaderboardBody.querySelectorAll('tr'));
 const sortableHeaders = document.querySelectorAll('.sortable');
 
-// Current sort state
-let currentSort = {
-column: null,
-direction: 'asc'
-};
+let currentSort = { column: null, direction: 'asc' };
 
-// Filter leaderboard
 function filterLeaderboard() {
-const userTerm = userSearch.value.toLowerCase();
-const problemTerm = problemFilter.value.toLowerCase();
-const runtimeType = runtimeFilter.value;
+    const userTerm = userSearch.value.toLowerCase();
+    const problemTerm = problemFilter.value.toLowerCase();
+    const runtimeType = runtimeFilter.value;
 
-leaderboardRows.forEach(row => {
-    const user = row.dataset.user.toLowerCase();
-    const problem = row.dataset.problem.toLowerCase();
-    const runtime = parseFloat(row.dataset.runtime);
-    const showUser = user.includes(userTerm);
-    const showProblem = problem.includes(problemTerm);
-    
-    let showRuntime = true;
-    if (runtimeType === 'best') {
-    // Find if this is the best runtime for this user+problem combo
-    const userProblemRows = leaderboardRows.filter(r => 
-        r.dataset.user === row.dataset.user && 
-        r.dataset.problem === row.dataset.problem
-    );
-    const bestRuntime = Math.min(...userProblemRows.map(r => parseFloat(r.dataset.runtime)));
-    showRuntime = runtime === bestRuntime;
-    } else if (runtimeType === 'worst') {
-    // Find if this is the worst runtime for this user+problem combo
-    const userProblemRows = leaderboardRows.filter(r => 
-        r.dataset.user === row.dataset.user && 
-        r.dataset.problem === row.dataset.problem
-    );
-    const worstRuntime = Math.max(...userProblemRows.map(r => parseFloat(r.dataset.runtime)));
-    showRuntime = runtime === worstRuntime;
-    }
+    leaderboardRows.forEach(row => {
+        const user = row.dataset.user.toLowerCase();
+        const problem = row.dataset.problem.toLowerCase();
+        const runtime = parseFloat(row.dataset.runtime);
 
-    if (showUser && showProblem && showRuntime) {
-    row.style.display = '';
-    } else {
-    row.style.display = 'none';
-    }
-});
+        const showUser = user.includes(userTerm);
+        const showProblem = problem.includes(problemTerm);
+
+        let showRuntime = true;
+        if (runtimeType === 'best') {
+            const userProblemRows = leaderboardRows.filter(r =>
+                r.dataset.user === row.dataset.user &&
+                r.dataset.problem === row.dataset.problem
+            );
+            const bestRuntime = Math.min(...userProblemRows.map(r => parseFloat(r.dataset.runtime)));
+            showRuntime = runtime === bestRuntime;
+        } else if (runtimeType === 'worst') {
+            const userProblemRows = leaderboardRows.filter(r =>
+                r.dataset.user === row.dataset.user &&
+                r.dataset.problem === row.dataset.problem
+            );
+            const worstRuntime = Math.max(...userProblemRows.map(r => parseFloat(r.dataset.runtime)));
+            showRuntime = runtime === worstRuntime;
+        }
+
+        row.style.display = (showUser && showProblem && showRuntime) ? '' : 'none';
+    });
 }
 
-// Sort leaderboard
-function sortLeaderboard(column, direction) {
-const rows = Array.from(leaderboardBody.querySelectorAll('tr'));
-const index = Array.from(document.querySelectorAll('th')).findIndex(th => th.dataset.sort === column);
+// =======================
+// Helper: Get cell value
+// =======================
+function getCellValue(row, column) {
+    const index = Array.from(document.querySelectorAll('th')).findIndex(th => th.dataset.sort === column);
+    let val = row.cells[index].textContent.trim();
 
-rows.sort((a, b) => {
-    let aValue = a.cells[index].textContent;
-    let bValue = b.cells[index].textContent;
-    
-    // Special handling for numeric columns
-    if (column === 'runtime' || column === 'memory' || column === 'rank') {
-    aValue = parseFloat(aValue) || 0;
-    bValue = parseFloat(bValue) || 0;
-    return direction === 'asc' ? aValue - bValue : bValue - aValue;
+    if (['runtime', 'memory', 'rank'].includes(column)) return parseFloat(val) || 0;
+    if (column === 'timestamp') return new Date(val).getTime();
+    return val.toLowerCase();
+}
+
+function compareValues(a, b, direction) {
+    if (typeof a === 'number' && typeof b === 'number') {
+        return direction === 'asc' ? a - b : b - a;
     }
-    
-    // Special handling for timestamps
-    if (column === 'timestamp') {
-    aValue = new Date(aValue).getTime();
-    bValue = new Date(bValue).getTime();
-    return direction === 'asc' ? aValue - bValue : bValue - aValue;
-    }
-    
-    // Default string comparison
-    aValue = aValue.toLowerCase();
-    bValue = bValue.toLowerCase();
-    if (aValue < bValue) return direction === 'asc' ? -1 : 1;
-    if (aValue > bValue) return direction === 'asc' ? 1 : -1;
+    if (a < b) return direction === 'asc' ? -1 : 1;
+    if (a > b) return direction === 'asc' ? 1 : -1;
     return 0;
-});
-
-// Re-append rows in sorted order
-rows.forEach(row => leaderboardBody.appendChild(row));
 }
 
-// Set up event listeners
+// =======================
+// Calculate "Overall" score
+// =======================
+function calculateOverallRank() {
+    const rows = Array.from(leaderboardBody.querySelectorAll('tr'));
+    const runtimes = rows.map(r => parseFloat(r.dataset.runtime) || Infinity);
+    const memories = rows.map(r => parseFloat(r.dataset.memory) || Infinity);
+
+    const minRuntime = Math.min(...runtimes);
+    const minMemory = Math.min(...memories);
+
+    rows.forEach(row => {
+        const runtimeScore = (parseFloat(row.dataset.runtime) || Infinity) / minRuntime;
+        const memoryScore = (parseFloat(row.dataset.memory) || Infinity) / minMemory;
+        // Weighted score: runtime 70%, memory 30%
+        const score = runtimeScore * 0.7 + memoryScore * 0.3;
+        row.dataset.overallScore = score;
+    });
+}
+
+// =======================
+// Sorting
+// =======================
+function sortLeaderboard(column, direction) {
+    let rows = Array.from(leaderboardBody.querySelectorAll('tr'));
+
+    if (column === 'rank') {
+        calculateOverallRank();
+        rows.sort((a, b) => parseFloat(a.dataset.overallScore) - parseFloat(b.dataset.overallScore));
+        // Update displayed rank
+        rows.forEach((row, index) => {
+            row.cells[0].textContent = index + 1;
+        });
+    } else {
+        rows.sort((rowA, rowB) => {
+            const valA = getCellValue(rowA, column);
+            const valB = getCellValue(rowB, column);
+            return compareValues(valA, valB, direction);
+        });
+    }
+
+    rows.forEach(row => leaderboardBody.appendChild(row));
+}
+
+// =======================
+// Event listeners
+// =======================
 userSearch.addEventListener('input', filterLeaderboard);
 problemFilter.addEventListener('input', filterLeaderboard);
 runtimeFilter.addEventListener('change', filterLeaderboard);
 
-// Set up sorting
 sortableHeaders.forEach(header => {
-header.addEventListener('click', () => {
-    const column = header.dataset.sort;
-    
-    // Reset all sort indicators
-    sortableHeaders.forEach(h => {
-    h.classList.remove('sort-asc', 'sort-desc');
+    header.addEventListener('click', () => {
+        const column = header.dataset.sort;
+
+        sortableHeaders.forEach(h => h.classList.remove('sort-asc', 'sort-desc'));
+
+        if (currentSort.column === column) {
+            currentSort.direction = currentSort.direction === 'asc' ? 'desc' : 'asc';
+        } else {
+            currentSort.column = column;
+            currentSort.direction = 'asc';
+        }
+
+        header.classList.add(`sort-${currentSort.direction}`);
+        sortLeaderboard(column, currentSort.direction);
     });
-    
-    // Determine new sort direction
-    if (currentSort.column === column) {
-    currentSort.direction = currentSort.direction === 'asc' ? 'desc' : 'asc';
-    } else {
-    currentSort.column = column;
-    currentSort.direction = 'asc';
-    }
-    
-    // Apply new sort
-    header.classList.add(`sort-${currentSort.direction}`);
-    sortLeaderboard(column, currentSort.direction);
 });
-});
\ No newline at end of file
+
+const rankInfoBtn = document.getElementById('rankInfoBtn');
+const rankingExplanation = document.getElementById('rankingExplanation');
+
+rankInfoBtn.addEventListener('click', () => {
+    if (rankingExplanation.style.display === 'none' || rankingExplanation.style.display === '') {
+        rankingExplanation.style.display = 'block';
+        rankInfoBtn.classList.add('active');
+    } else {
+        rankingExplanation.style.display = 'none';
+        rankInfoBtn.classList.remove('active');
+    }
+});
diff --git a/src/utils.py b/src/utils.py
index cf20dc8..581e43b 100644
--- a/src/utils.py
+++ b/src/utils.py
@@ -5,8 +5,127 @@ import io
 import tempfile
 import subprocess
 import os
+import re
+import ast
 
-def run_code_against_tests(user_code, test_code):
+# Security configuration
+ALLOWED_IMPORTS = {
+    'math', 'random', 'datetime', 'json', 'collections', 'itertools',
+    'functools', 'operator', 'copy', 'unittest', 're', 'string'
+}
+
+DANGEROUS_PATTERNS = [
+    r'import\s+os(?:\s|$|\.)',
+    r'from\s+os\s+import',
+    r'import\s+subprocess(?:\s|$|\.)',
+    r'from\s+subprocess\s+import',
+    r'import\s+sys(?:\s|$|\.)',
+    r'from\s+sys\s+import',
+    r'import\s+shutil(?:\s|$|\.)',
+    r'from\s+shutil\s+import',
+    r'import\s+pathlib(?:\s|$|\.)',
+    r'from\s+pathlib\s+import',
+    r'__import__\s*\(',
+    r'exec\s*\(',
+    r'eval\s*\(',
+    r'compile\s*\(',
+    r'open\s*\(',
+    r'file\s*\(',
+    r'input\s*\(',
+    r'raw_input\s*\(',
+    r'\.unlink\s*\(',
+    r'\.remove\s*\(',
+    r'\.rmdir\s*\(',
+    r'\.rmtree\s*\(',
+    r'\.delete\s*\(',
+    r'\.kill\s*\(',
+    r'\.terminate\s*\(',
+]
+
+def validate_code_security(code):
+    """
+    Validates code for security issues.
+    Returns (is_safe, error_message)
+    """
+    # Check for dangerous patterns
+    for pattern in DANGEROUS_PATTERNS:
+        if re.search(pattern, code, re.IGNORECASE):
+            return False, f"Dangerous operation detected: {pattern}"
+    
+    # Parse AST to check imports
+    try:
+        tree = ast.parse(code)
+        for node in ast.walk(tree):
+            if isinstance(node, ast.Import):
+                for alias in node.names:
+                    module_name = alias.name.split('.')[0]
+                    if module_name not in ALLOWED_IMPORTS:
+                        return False, f"Import not allowed: {module_name}"
+            elif isinstance(node, ast.ImportFrom):
+                if node.module:
+                    module_name = node.module.split('.')[0]
+                    if module_name not in ALLOWED_IMPORTS:
+                        return False, f"Import not allowed: {module_name}"
+    except SyntaxError as e:
+        return False, f"Syntax error in code: {str(e)}"
+    
+    return True, None
+
+def create_restricted_globals():
+    """Create a restricted global namespace for code execution."""
+    safe_builtins = {
+        'abs', 'all', 'any', 'bin', 'bool', 'chr', 'dict', 'dir', 
+        'divmod', 'enumerate', 'filter', 'float', 'format', 'frozenset',
+        'hex', 'id', 'int', 'isinstance', 'issubclass', 'iter', 'len',
+        'list', 'map', 'max', 'min', 'next', 'oct', 'ord', 'pow',
+        'print', 'range', 'repr', 'reversed', 'round', 'set', 'slice',
+        'sorted', 'str', 'sum', 'tuple', 'type', 'zip'
+    }
+    
+    restricted_globals = {
+        '__builtins__': {name: __builtins__[name] for name in safe_builtins if name in __builtins__}
+    }
+    
+    # Add allowed modules
+    for module in ALLOWED_IMPORTS:
+        try:
+            restricted_globals[module] = __import__(module)
+        except ImportError:
+            pass  # Module not available
+    
+    return restricted_globals
+
+def run_code_against_tests(user_code, test_code, max_execution_time=5):
+    """
+    Securely run user code against test code with safety restrictions.
+    
+    Args:
+        user_code: The user's solution code
+        test_code: The test code to validate the solution
+        max_execution_time: Maximum execution time in seconds (default: 5)
+    
+    Returns:
+        dict: Result containing passed, output, runtime, and error information
+    """
+    # Validate security for both user code and test code
+    user_safe, user_error = validate_code_security(user_code)
+    if not user_safe:
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': f"Security violation in user code: {user_error}"
+        }
+    
+    test_safe, test_error = validate_code_security(test_code)
+    if not test_safe:
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': f"Security violation in test code: {test_error}"
+        }
+    
     local_ns = {}
     output = ''
     start = time.perf_counter()
@@ -17,60 +136,83 @@ def run_code_against_tests(user_code, test_code):
     try:
         # Check if unittest is used in test_code
         if 'unittest' in test_code:
-            # Write user code + test code to a temp file
-            with tempfile.NamedTemporaryFile('w+', suffix='.py', delete=False, encoding='utf-8') as f:
-                combined_code = f"{user_code}\n\n{test_code}"
-                f.write(combined_code)
-                f.flush()
-                temp_file = f.name
-            
-            # Run the file as a subprocess
+            # Create temp file in a secure temporary directory
+            temp_dir = tempfile.mkdtemp(prefix='secure_code_')
             try:
-                proc = subprocess.run(
-                    [sys.executable, temp_file], 
-                    capture_output=True, 
-                    text=True, 
-                    timeout=10,
-                    encoding='utf-8'
-                )
-                output = proc.stdout
-                if proc.stderr:
-                    output += f"\n{proc.stderr}"
+                temp_file = os.path.join(temp_dir, 'test_code.py')
+                combined_code = f"{user_code}\n\n{test_code}"
                 
-                passed = proc.returncode == 0
-                if not passed:
-                    error = f"Tests failed. Return code: {proc.returncode}\n{output}"
-                else:
-                    # For successful unittest runs, the stderr contains the test results
-                    if proc.stderr and "OK" in proc.stderr:
-                        output = proc.stderr  # Use stderr as the main output for unittest
+                # Write to temp file with restricted permissions
+                with open(temp_file, 'w', encoding='utf-8') as f:
+                    f.write(combined_code)
+                os.chmod(temp_file, 0o600)  # Read/write for owner only
+                
+                # Run the file as a subprocess with additional security
+                try:
+                    proc = subprocess.run(
+                        [sys.executable, temp_file],
+                        capture_output=True,
+                        text=True,
+                        timeout=max_execution_time,
+                        encoding='utf-8',
+                        cwd=temp_dir,  # Run in the temporary directory
+                        env={'PYTHONPATH': ''}  # Restrict Python path
+                    )
                     
-            except subprocess.TimeoutExpired:
-                passed = False
-                error = "Code execution timed out after 10 seconds"
-                output = "Execution timed out"
-                
+                    # Combine both stdout and stderr to capture all output
+                    combined_output = ""
+                    if proc.stdout:
+                        combined_output += proc.stdout
+                    if proc.stderr:
+                        if combined_output:
+                            combined_output += "\n" + proc.stderr
+                        else:
+                            combined_output = proc.stderr
+                    
+                    output = combined_output
+                    passed = proc.returncode == 0
+                    
+                    if not passed:
+                        error = f"Tests failed. Return code: {proc.returncode}\n{output}"
+                            
+                except subprocess.TimeoutExpired:
+                    passed = False
+                    error = f"Code execution timed out after {max_execution_time} seconds"
+                    output = "Execution timed out"
+                    
+            finally:
+                # Secure cleanup of temporary directory and files
+                try:
+                    if temp_file and os.path.exists(temp_file):
+                        os.chmod(temp_file, 0o600)  # Ensure we can delete
+                        os.unlink(temp_file)
+                    if os.path.exists(temp_dir):
+                        os.rmdir(temp_dir)
+                except Exception as cleanup_error:
+                    print(f"Warning: Could not clean up temp files: {cleanup_error}")
         else:
-            # Capture stdout
+            # Direct execution with restricted globals
             old_stdout = sys.stdout
             captured_output = io.StringIO()
             sys.stdout = captured_output
             
             try:
-                # Execute user code
-                exec(user_code, {}, local_ns)
+                # Create restricted execution environment
+                restricted_globals = create_restricted_globals()
+                
+                # Execute user code in restricted environment
+                exec(user_code, restricted_globals, local_ns)
+                
                 # Execute test code (should raise AssertionError if fail)
-                exec(test_code, local_ns, local_ns)
+                exec(test_code, {**restricted_globals, **local_ns}, local_ns)
                 passed = True
                 
             except AssertionError as e:
                 passed = False
                 error = f"Assertion failed: {str(e)}"
-                
             except Exception as e:
                 passed = False
                 error = f"Runtime error: {traceback.format_exc()}"
-                
             finally:
                 output = captured_output.getvalue()
                 sys.stdout = old_stdout
@@ -78,17 +220,14 @@ def run_code_against_tests(user_code, test_code):
     except Exception as e:
         passed = False
         error = f"Execution error: {traceback.format_exc()}"
-        
-    finally:
-        # Clean up temporary file
-        if temp_file and os.path.exists(temp_file):
-            try:
-                os.unlink(temp_file)
-            except Exception as e:
-                print(f"Warning: Could not delete temp file {temp_file}: {e}")
     
     runtime = time.perf_counter() - start
     
+    # Limit output size to prevent memory issues
+    max_output_size = 10000  # 10KB limit
+    if len(output) > max_output_size:
+        output = output[:max_output_size] + "\n... (output truncated)"
+    
     result = {
         'passed': passed,
         'output': output.strip() if output else '',
@@ -97,3 +236,27 @@ def run_code_against_tests(user_code, test_code):
     }
     
     return result
+
+# Example usage with additional safety wrapper
+def safe_code_runner(user_code, test_code):
+    """
+    Additional wrapper for extra safety checks.
+    """
+    # Additional length checks
+    if len(user_code) > 50000:  # 50KB limit
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': "User code too large (maximum 50KB allowed)"
+        }
+    
+    if len(test_code) > 10000:  # 10KB limit for test code
+        return {
+            'passed': False,
+            'output': '',
+            'runtime': 0,
+            'error': "Test code too large (maximum 10KB allowed)"
+        }
+    
+    return run_code_against_tests(user_code, test_code)
\ No newline at end of file