feat: add sidebar panel system with icon strip and panel toggle

src/index.html

@@ -8,6 +8,7 @@
     <link rel="stylesheet" href="styles.css">
     <link rel="stylesheet" href="styles-modern.css">
     <link rel="stylesheet" href="styles-concreteinfo.css">
+    <link rel="stylesheet" href="styles-sidebar.css">
     <!-- Load external resources asynchronously -->
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/default.min.css" media="print" onload="this.media='all'">
     <script defer src="https://cdn.jsdelivr.net/npm/mermaid@10/dist/mermaid.min.js"></script>
@@ -1293,7 +1294,48 @@
             </div>
         </div>
 
-        <div class="editor-container">
+        <div class="main-content" id="main-content">
+            <!-- Sidebar -->
+            <div class="sidebar collapsed" id="sidebar">
+                <div class="sidebar-icons">
+                    <button class="sidebar-icon" data-panel="explorer" title="File Explorer (Ctrl+Shift+E)">
+                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                            <path d="M22 19a2 2 0 01-2 2H4a2 2 0 01-2-2V5a2 2 0 012-2h5l2 3h9a2 2 0 012 2z"/>
+                        </svg>
+                    </button>
+                    <button class="sidebar-icon" data-panel="git" title="Git (Ctrl+Shift+G)">
+                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                            <line x1="6" y1="3" x2="6" y2="15"/>
+                            <circle cx="18" cy="6" r="3"/>
+                            <circle cx="6" cy="6" r="3"/>
+                            <path d="M18 9a9 9 0 01-9 9"/>
+                        </svg>
+                    </button>
+                    <button class="sidebar-icon" data-panel="snippets" title="Snippets (Ctrl+Shift+S)">
+                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                            <polyline points="16 18 22 12 16 6"/>
+                            <polyline points="8 6 2 12 8 18"/>
+                        </svg>
+                    </button>
+                    <button class="sidebar-icon" data-panel="templates" title="Templates">
+                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                            <rect x="3" y="3" width="18" height="18" rx="2" ry="2"/>
+                            <line x1="3" y1="9" x2="21" y2="9"/>
+                            <line x1="9" y1="21" x2="9" y2="9"/>
+                        </svg>
+                    </button>
+                </div>
+                <div class="sidebar-panel" id="sidebar-panel">
+                    <div class="sidebar-panel-header">
+                        <span class="sidebar-panel-title"></span>
+                        <button class="sidebar-panel-close" title="Close panel">&times;</button>
+                    </div>
+                    <div class="sidebar-panel-content" id="sidebar-panel-content"></div>
+                </div>
+            </div>
+
+            <!-- Editor Container -->
+            <div class="editor-container">
             <div class="tab-content active" id="tab-content-1" data-tab-id="1">
                 <div id="editor-pane-1" class="pane">
                     <div class="editor-wrapper">
@@ -1403,6 +1445,7 @@
                     <canvas id="pdf-canvas"></canvas>
                 </div>
             </div>
+            </div>
         </div>
 
         <div class="status-bar">

src/renderer.js

@@ -10,6 +10,7 @@ const DOMPurify = require('dompurify');
 const hljs = require('highlight.js');
 const { createEditor } = require('./editor/codemirror-setup');
 const { undo, redo } = require('@codemirror/commands');
+const { SidebarManager } = require('./sidebar/sidebar-manager');
 
 // Configure marked with highlight extension
 marked.use(markedHighlight({
@@ -1006,6 +1007,25 @@ let tabManager;
 document.addEventListener('DOMContentLoaded', () => {
     tabManager = new TabManager();
 
+    // Initialize sidebar
+    const sidebarManager = new SidebarManager();
+    sidebarManager.registerPanel('explorer', {
+        title: 'Explorer',
+        render: (container) => { container.innerHTML = '<p style="color:#888;padding:8px;">File explorer coming soon...</p>'; }
+    });
+    sidebarManager.registerPanel('git', {
+        title: 'Git',
+        render: (container) => { container.innerHTML = '<p style="color:#888;padding:8px;">Git panel coming soon...</p>'; }
+    });
+    sidebarManager.registerPanel('snippets', {
+        title: 'Snippets',
+        render: (container) => { container.innerHTML = '<p style="color:#888;padding:8px;">Snippets coming soon...</p>'; }
+    });
+    sidebarManager.registerPanel('templates', {
+        title: 'Templates',
+        render: (container) => { container.innerHTML = '<p style="color:#888;padding:8px;">Templates coming soon...</p>'; }
+    });
+
     // Initialize CodeMirror for the initial tab (tab 1)
     const editorContainer = document.getElementById('editor-cm-1');
     if (editorContainer) {

src/sidebar/sidebar-manager.js

@@ -0,0 +1,50 @@
+class SidebarManager {
+    constructor() {
+        this.sidebar = document.getElementById('sidebar');
+        this.panelContent = document.getElementById('sidebar-panel-content');
+        this.panelTitle = document.querySelector('.sidebar-panel-title');
+        this.activePanel = null;
+        this.panels = new Map();
+        this.setupEventListeners();
+    }
+
+    setupEventListeners() {
+        document.querySelectorAll('.sidebar-icon').forEach(btn => {
+            btn.addEventListener('click', () => this.togglePanel(btn.dataset.panel));
+        });
+        document.querySelector('.sidebar-panel-close')?.addEventListener('click', () => this.collapse());
+    }
+
+    registerPanel(name, { title, render }) {
+        this.panels.set(name, { title, render });
+    }
+
+    togglePanel(name) {
+        if (this.activePanel === name) {
+            this.collapse();
+        } else {
+            this.expand(name);
+        }
+    }
+
+    expand(name) {
+        const panel = this.panels.get(name);
+        if (!panel) return;
+        this.sidebar.classList.remove('collapsed');
+        this.panelTitle.textContent = panel.title;
+        this.panelContent.innerHTML = '';
+        panel.render(this.panelContent);
+        this.activePanel = name;
+        document.querySelectorAll('.sidebar-icon').forEach(btn => {
+            btn.classList.toggle('active', btn.dataset.panel === name);
+        });
+    }
+
+    collapse() {
+        this.sidebar.classList.add('collapsed');
+        this.activePanel = null;
+        document.querySelectorAll('.sidebar-icon').forEach(btn => btn.classList.remove('active'));
+    }
+}
+
+module.exports = { SidebarManager };

src/styles-sidebar.css

@@ -0,0 +1,132 @@
+/* Sidebar */
+.main-content {
+    display: flex;
+    flex: 1;
+    overflow: hidden;
+    min-height: 0;
+}
+
+.sidebar {
+    display: flex;
+    flex-shrink: 0;
+    height: 100%;
+    transition: width 0.2s ease;
+}
+
+.sidebar.collapsed {
+    width: 48px;
+}
+
+.sidebar:not(.collapsed) {
+    width: 328px; /* 48px icons + 280px panel */
+}
+
+.sidebar-icons {
+    display: flex;
+    flex-direction: column;
+    width: 48px;
+    background: var(--gray-100, #f3f4f6);
+    border-right: 1px solid var(--gray-200, #e5e7eb);
+    padding: 8px 0;
+    gap: 4px;
+    align-items: center;
+}
+
+.sidebar-icon {
+    width: 36px;
+    height: 36px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    border: none;
+    background: transparent;
+    border-radius: 8px;
+    cursor: pointer;
+    color: var(--gray-500, #6b7280);
+    transition: all 0.15s ease;
+}
+
+.sidebar-icon:hover {
+    background: var(--gray-200, #e5e7eb);
+    color: var(--gray-700, #374151);
+}
+
+.sidebar-icon.active {
+    background: var(--gray-200, #e5e7eb);
+    color: var(--primary-dark, #5661b3);
+    box-shadow: inset 3px 0 0 var(--primary-dark, #5661b3);
+}
+
+.sidebar-panel {
+    width: 280px;
+    background: var(--gray-50, #f9fafb);
+    border-right: 1px solid var(--gray-200, #e5e7eb);
+    display: flex;
+    flex-direction: column;
+    overflow: hidden;
+}
+
+.sidebar.collapsed .sidebar-panel {
+    display: none;
+}
+
+.sidebar-panel-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: 12px 16px;
+    border-bottom: 1px solid var(--gray-200, #e5e7eb);
+    font-weight: 600;
+    font-size: 13px;
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+    color: var(--gray-600, #4b5563);
+}
+
+.sidebar-panel-close {
+    background: none;
+    border: none;
+    font-size: 18px;
+    cursor: pointer;
+    color: var(--gray-400, #9ca3af);
+    padding: 0 4px;
+    border-radius: 4px;
+}
+
+.sidebar-panel-close:hover {
+    background: var(--gray-200, #e5e7eb);
+    color: var(--gray-600, #4b5563);
+}
+
+.sidebar-panel-content {
+    flex: 1;
+    overflow-y: auto;
+    padding: 12px;
+}
+
+/* Dark theme support */
+body[class*="dark"] .sidebar-icons,
+body[class*="dark"] .sidebar-panel {
+    background: #1e1e1e;
+    border-color: #333;
+}
+
+body[class*="dark"] .sidebar-icon {
+    color: #888;
+}
+
+body[class*="dark"] .sidebar-icon:hover {
+    background: #333;
+    color: #ccc;
+}
+
+body[class*="dark"] .sidebar-icon.active {
+    background: #333;
+    color: #8b9aff;
+    box-shadow: inset 3px 0 0 #8b9aff;
+}
+
+body[class*="dark"] .sidebar-panel-header {
+    border-color: #333;
+    color: #ccc;
+}