diff --git a/src/static/home.html b/src/static/home.html
index 576097d..bba1ebe 100644
--- a/src/static/home.html
+++ b/src/static/home.html
@@ -3,7 +3,7 @@
 <head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <title>Python Editor</title>
+  <title>LED Editor</title>
   <link rel="icon" href="data:,">
   <style>
     * { box-sizing: border-box; }
@@ -182,7 +182,7 @@
 </head>
 <body>
   <main class="home-card">
-    <h1>Python Editor</h1>
+    <h1>LED Editor</h1>
     <div id="auth-nav" class="nav">
       <span id="auth-greeting" class="hidden"></span>
       <a class="btn btn-ghost hidden" id="link-login" href="/login">Sign in</a>
diff --git a/src/static/index.html b/src/static/index.html
index 000b63a..fd99601 100644
--- a/src/static/index.html
+++ b/src/static/index.html
@@ -2,14 +2,16 @@
 <html lang="en">
 <head>
   <meta charset="UTF-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <title>Python Editor</title>
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">
+  <meta name="theme-color" content="#2d3748">
+  <title>LED Editor</title>
   <link rel="icon" href="data:,">
-  <link rel="stylesheet" href="/static/styles.css?v=12">
+  <link rel="stylesheet" href="/static/styles.css?v=13">
 </head>
 <body>
   <div class="container">
-    <div class="sidebar">
+    <div class="sidebar-backdrop" id="sidebar-backdrop" hidden></div>
+    <div class="sidebar" id="sidebar">
       <div class="sidebar-header">
         <h3>Files</h3>
         <div class="sidebar-actions">
@@ -26,6 +28,7 @@
 
     <div class="main-content">
       <div class="editor-header">
+        <button id="sidebar-toggle" class="sidebar-toggle" type="button" aria-label="Toggle file tree" aria-controls="sidebar" aria-expanded="false">☰</button>
         <div class="file-info">
           <span id="save-status" class="save-status"></span>
           <span class="runtime-hint" title="Python runs locally in your browser via Pyodide; completions use Jedi in the same runtime.">Browser · Pyodide</span>
@@ -87,6 +90,6 @@
     </div>
   </div>
 
-  <script type="module" src="/static/script.js?v=26"></script>
+  <script type="module" src="/static/script.js?v=27"></script>
 </body>
 </html>
diff --git a/src/static/login.html b/src/static/login.html
index 8e966f9..031504f 100644
--- a/src/static/login.html
+++ b/src/static/login.html
@@ -3,7 +3,7 @@
 <head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <title>Sign in — Python Editor</title>
+  <title>Sign in — LED Editor</title>
   <link rel="icon" href="data:,">
   <style>
     * { box-sizing: border-box; }
diff --git a/src/static/register.html b/src/static/register.html
index 944b822..a65b5a5 100644
--- a/src/static/register.html
+++ b/src/static/register.html
@@ -3,7 +3,7 @@
 <head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <title>Register — Python Editor</title>
+  <title>Register — LED Editor</title>
   <link rel="icon" href="data:,">
   <style>
     * { box-sizing: border-box; }
diff --git a/src/static/script.js b/src/static/script.js
index 11feca0..94c6487 100644
--- a/src/static/script.js
+++ b/src/static/script.js
@@ -705,7 +705,43 @@ class TextEditor {
     this.hideCompletionDropdown();
   }
 
+  isMobileViewport() {
+    return typeof window !== 'undefined' && window.matchMedia && window.matchMedia('(max-width: 768px)').matches;
+  }
+
+  setMobileSidebarOpen(open) {
+    const sidebar = document.getElementById('sidebar');
+    const backdrop = document.getElementById('sidebar-backdrop');
+    const toggle = document.getElementById('sidebar-toggle');
+    if (!sidebar || !backdrop || !toggle) return;
+    sidebar.classList.toggle('is-open', open);
+    backdrop.classList.toggle('is-open', open);
+    backdrop.hidden = !open;
+    toggle.setAttribute('aria-expanded', String(open));
+  }
+
+  setupMobileSidebar() {
+    const toggle = document.getElementById('sidebar-toggle');
+    const backdrop = document.getElementById('sidebar-backdrop');
+    if (!toggle || !backdrop) return;
+    toggle.addEventListener('click', () => {
+      const sidebar = document.getElementById('sidebar');
+      const isOpen = sidebar?.classList.contains('is-open');
+      this.setMobileSidebarOpen(!isOpen);
+    });
+    backdrop.addEventListener('click', () => this.setMobileSidebarOpen(false));
+    document.addEventListener('keydown', (event) => {
+      if (event.key === 'Escape') {
+        const sidebar = document.getElementById('sidebar');
+        if (sidebar?.classList.contains('is-open')) {
+          this.setMobileSidebarOpen(false);
+        }
+      }
+    });
+  }
+
   setupEventListeners() {
+    this.setupMobileSidebar();
     const persistSession = () => {
       this.saveSessionState();
     };
@@ -1061,6 +1097,9 @@ class TextEditor {
           await this.toggleDirectory(path);
         } else if (!isDirectory) {
           this.openFile(path);
+          if (this.isMobileViewport()) {
+            this.setMobileSidebarOpen(false);
+          }
         } else {
           this.renderFileTree();
         }
diff --git a/src/static/styles.css b/src/static/styles.css
index 5f85345..aa07265 100644
--- a/src/static/styles.css
+++ b/src/static/styles.css
@@ -9,12 +9,45 @@ body {
   background-color: #f5f5f5;
   height: 100dvh;
   overflow: hidden;
+  -webkit-text-size-adjust: 100%;
+  overscroll-behavior: none;
+}
+
+button,
+.tab,
+.file-item,
+.mode-btn {
+  touch-action: manipulation;
 }
 
 .container {
   display: flex;
   height: 100dvh;
   overflow: hidden;
+  position: relative;
+}
+
+.sidebar-toggle {
+  display: none;
+  align-items: center;
+  justify-content: center;
+  width: 40px;
+  height: 40px;
+  border: 1px solid #cbd5e0;
+  background: white;
+  color: #2d3748;
+  border-radius: 8px;
+  font-size: 1.2rem;
+  cursor: pointer;
+  flex-shrink: 0;
+}
+
+.sidebar-toggle:hover {
+  background: #f7fafc;
+}
+
+.sidebar-backdrop {
+  display: none;
 }
 
 /* Sidebar */
@@ -543,86 +576,155 @@ body {
 
 /* Responsive design */
 @media (max-width: 768px) {
-  body {
-    height: 100dvh;
-    overflow: hidden;
-  }
-
   .container {
     flex-direction: column;
-    height: 100dvh;
-    overflow: hidden;
   }
 
+  /* Sidebar becomes an off-canvas drawer. */
   .sidebar {
-    width: 100%;
-    max-height: 30vh;
-    min-height: 170px;
+    position: fixed;
+    top: 0;
+    left: 0;
+    bottom: 0;
+    width: min(82vw, 320px);
+    height: 100dvh;
+    transform: translateX(-100%);
+    transition: transform 0.2s ease;
+    z-index: 50;
+    box-shadow: 2px 0 16px rgba(0, 0, 0, 0.25);
+    padding-top: env(safe-area-inset-top);
+    padding-bottom: env(safe-area-inset-bottom);
   }
 
-  .sidebar-header {
-    padding: 0.7rem 0.8rem;
+  .sidebar.is-open {
+    transform: translateX(0);
   }
 
-  .file-tree {
-    min-height: 100px;
+  .sidebar-backdrop {
+    display: block;
+    position: fixed;
+    inset: 0;
+    background: rgba(0, 0, 0, 0.45);
+    z-index: 40;
+    opacity: 0;
+    pointer-events: none;
+    transition: opacity 0.2s ease;
+  }
+
+  .sidebar-backdrop.is-open {
+    opacity: 1;
+    pointer-events: auto;
+  }
+
+  .sidebar-backdrop[hidden] {
+    /* Even when the JS hasn't toggled it yet, hide on desktop only. Mobile keeps it
+       in the layer for transitions; explicit [hidden] still wins via display:none below. */
+    display: none;
+  }
+
+  .sidebar-toggle {
+    display: inline-flex;
+  }
+
+  .sidebar-actions button {
+    min-width: 40px;
+    min-height: 40px;
+    font-size: 1.15rem;
   }
 
   .main-content {
+    width: 100%;
     min-height: 0;
   }
 
   .editor-header {
-    padding: 0.65rem;
+    padding: 0.55rem 0.65rem;
     flex-wrap: wrap;
-    gap: 0.55rem;
-    align-items: stretch;
+    gap: 0.45rem;
+    align-items: center;
+    padding-top: max(0.55rem, env(safe-area-inset-top));
   }
 
   .file-info {
-    width: 100%;
-    justify-content: space-between;
+    flex: 1 1 auto;
+    min-width: 0;
+    gap: 0.5rem;
+    flex-wrap: wrap;
+  }
+
+  .file-info .runtime-hint {
+    font-size: 0.7rem;
+    padding: 0.15rem 0.4rem;
   }
 
   .mode-toggle {
     order: 3;
   }
 
+  .mode-btn {
+    min-height: 36px;
+    padding: 0.5rem 0.85rem;
+  }
+
   .editor-actions {
     width: 100%;
     order: 4;
     flex-wrap: wrap;
+    gap: 0.4rem;
   }
 
   .editor-actions button {
-    flex: 1 1 100px;
+    flex: 1 1 110px;
+    min-height: 40px;
+    font-size: 0.95rem;
   }
 
   .run-main-toggle {
-    width: 100%;
-    justify-content: flex-start;
-    flex: 1 1 100%;
+    flex: 1 1 calc(50% - 0.4rem);
+    min-height: 40px;
+    font-size: 0.85rem;
   }
 
   .tabs {
     padding: 0.3rem 0.35rem;
+    gap: 0.3rem;
+    -webkit-overflow-scrolling: touch;
+  }
+
+  .tab {
+    padding: 0.45rem 0.55rem;
   }
 
   .tab-title {
-    max-width: 150px;
+    max-width: 140px;
+  }
+
+  .tab-close {
+    font-size: 18px;
+    padding: 0 0.25rem;
   }
 
   .editor-container {
-    min-height: 46vh;
+    min-height: 42vh;
   }
 
   .cm-editor {
-    font-size: 13px;
+    font-size: 14px; /* >=16px would prevent iOS zoom but feels too large here; CM is contenteditable so no zoom anyway. */
   }
-  
+
   .modal-content {
-    width: 90%;
-    margin: 20% auto;
+    width: min(92vw, 420px);
+    margin: 18vh auto;
+    padding: 1.25rem;
+  }
+
+  .modal-content input {
+    font-size: 16px; /* prevent iOS focus zoom */
+  }
+
+  .modal-actions button {
+    min-height: 40px;
+    flex: 1 1 100px;
   }
 
   .led-grid {
@@ -640,8 +742,24 @@ body {
     flex-wrap: wrap;
   }
 
+  .led-sim-actions button {
+    flex: 1 1 80px;
+    min-height: 36px;
+  }
+
   .console-container {
-    height: 180px;
+    height: 160px;
+  }
+
+  .file-item {
+    padding: 0.65rem 0.5rem;
+  }
+}
+
+/* Hide drawer affordances entirely on desktop, even with [hidden] flipped off. */
+@media (min-width: 769px) {
+  .sidebar-backdrop {
+    display: none !important;
   }
 }
 
