/* ============================================
   Claude Code Academy - Beautiful Styles
   Split-Screen Learning Experience
   ============================================ */

/* ============================================
   CSS Variables - Design System
   ============================================ */
:root {
    /* Colors - Dark Theme (Default) */
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --bg-elevated: #1c2128;

    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-tertiary: #6e7681;

    --accent-primary: #58a6ff;
    --accent-secondary: #1f6feb;
    --accent-hover: #388bfd;

    --border-primary: #30363d;
    --border-secondary: #21262d;

    --success: #3fb950;
    --warning: #d29922;
    --error: #f85149;
    --info: #58a6ff;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-accent: linear-gradient(135deg, #58a6ff 0%, #1f6feb 100%);
    --gradient-success: linear-gradient(135deg, #3fb950 0%, #2ea043 100%);

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.6);

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Layout */
    --header-height: 64px;
    --sidebar-width: 320px;
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
}

/* Light Theme */
body.light-theme {
    --bg-primary: #ffffff;
    --bg-secondary: #f6f8fa;
    --bg-tertiary: #eaeef2;
    --bg-elevated: #ffffff;

    --text-primary: #24292f;
    --text-secondary: #57606a;
    --text-tertiary: #6e7781;

    --accent-primary: #0969da;
    --accent-secondary: #0550ae;
    --accent-hover: #0860ca;

    --border-primary: #d0d7de;
    --border-secondary: #eaeef2;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* ============================================
   Base Styles
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   Header
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-primary);
    z-index: 1000;
    box-shadow: var(--shadow-md);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 var(--spacing-xl);
    max-width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    cursor: pointer;
    transition: transform var(--transition-base);
}

.logo:hover {
    transform: scale(1.05);
}

.logo i {
    font-size: 1.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Main Navigation */
.main-nav {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: transparent;
    border: none;
    border-radius: var(--border-radius-md);
    color: var(--text-secondary);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-base);
}

.nav-btn:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.nav-btn.active {
    background: var(--accent-primary);
    color: white;
}

/* Header Actions */
.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.btn-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    border-radius: var(--border-radius-md);
    color: var(--text-secondary);
    font-size: 1.1rem;
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn-icon:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transform: translateY(-2px);
}

/* ============================================
   Main Container
   ============================================ */
.main-container {
    display: flex;
    margin-top: var(--header-height);
    height: calc(100vh - var(--header-height));
    overflow: hidden;
}

/* ============================================
   Sidebar
   ============================================ */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-primary);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: transform var(--transition-base);
}

.sidebar.collapsed {
    transform: translateX(-100%);
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-primary);
}

.sidebar-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Search Box */
.search-box {
    position: relative;
    padding: var(--spacing-md) var(--spacing-lg);
}

.search-box i {
    position: absolute;
    left: calc(var(--spacing-lg) + var(--spacing-md));
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-tertiary);
}

.search-box input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-sm) var(--spacing-sm) var(--spacing-2xl);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-primary);
    border-radius: var(--border-radius-md);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    transition: all var(--transition-base);
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-primary);
    background: var(--bg-primary);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.1);
}

/* Progress Overview */
.progress-overview {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border-primary);
}

.progress-label {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-sm);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.progress-percent {
    font-weight: 600;
    color: var(--accent-primary);
}

.progress-bar {
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 999px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 999px;
    transition: width var(--transition-slow);
}

/* Sidebar Navigation */
.sidebar-nav {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-md) 0;
}

.module-group {
    margin-bottom: var(--spacing-md);
}

.module-group-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.module-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-base);
    cursor: pointer;
    border-left: 3px solid transparent;
}

.module-item:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border-left-color: var(--accent-primary);
}

.module-item.active {
    background: var(--bg-elevated);
    color: var(--accent-primary);
    border-left-color: var(--accent-primary);
    font-weight: 500;
}

.module-item.completed {
    color: var(--success);
}

.module-icon {
    width: 20px;
    text-align: center;
}

.module-title {
    flex: 1;
    font-size: 0.9rem;
}

.module-badge {
    padding: 2px 6px;
    background: var(--accent-primary);
    border-radius: var(--border-radius-sm);
    font-size: 0.7rem;
    font-weight: 600;
    color: white;
}

/* ============================================
   Content Wrapper (Split Screen)
   ============================================ */
.content-wrapper {
    flex: 1;
    display: flex;
    overflow: hidden;
    position: relative;
}

/* ============================================
   Panels (Left & Right)
   ============================================ */
.panel {
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
    overflow: hidden;
}

.panel-left {
    flex: 1;
    min-width: 300px;
}

.panel-right {
    flex: 1;
    min-width: 300px;
    background: var(--bg-secondary);
}

/* Panel Header */
.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-primary);
}

.panel-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.panel-title i {
    color: var(--accent-primary);
}

.panel-actions {
    display: flex;
    gap: var(--spacing-sm);
}

/* Panel Content */
.panel-content {
    flex: 1;
    padding: var(--spacing-2xl);
    overflow-y: auto;
    line-height: 1.8;
}

.panel-content h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
    line-height: 1.2;
}

.panel-content h2 {
    font-size: 1.5rem;
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    border-bottom: 2px solid var(--border-primary);
    padding-bottom: var(--spacing-sm);
}

.panel-content h3 {
    font-size: 1.25rem;
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.panel-content p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

.panel-content ul,
.panel-content ol {
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-xl);
}

.panel-content li {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

.panel-content code {
    padding: 2px 6px;
    background: var(--bg-tertiary);
    border-radius: var(--border-radius-sm);
    font-family: var(--font-mono);
    font-size: 0.9em;
    color: var(--accent-primary);
}

.panel-content pre {
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-lg);
    background: var(--bg-tertiary);
    border-radius: var(--border-radius-md);
    overflow-x: auto;
    border-left: 4px solid var(--accent-primary);
}

.panel-content pre code {
    padding: 0;
    background: transparent;
    color: var(--text-primary);
}

.panel-content blockquote {
    margin: var(--spacing-lg) 0;
    padding-left: var(--spacing-lg);
    border-left: 4px solid var(--accent-primary);
    color: var(--text-secondary);
    font-style: italic;
}

/* Panel Footer */
.panel-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-primary);
}

/* Buttons */
.btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--border-radius-md);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: var(--bg-elevated);
}

/* ============================================
   Resizer
   ============================================ */
.resizer {
    width: 8px;
    background: var(--bg-tertiary);
    cursor: col-resize;
    position: relative;
    transition: background var(--transition-base);
}

.resizer:hover {
    background: var(--accent-primary);
}

.resizer::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 3px;
    height: 40px;
    background: var(--border-primary);
    border-radius: 999px;
}

.resizer:hover::before {
    background: white;
}

/* ============================================
   Code Panel
   ============================================ */
.code-editor-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Code Tabs */
.code-tabs {
    display: flex;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-primary);
}

.code-tab {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    color: var(--text-secondary);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-base);
}

.code-tab:hover {
    color: var(--text-primary);
    background: var(--bg-secondary);
}

.code-tab.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
    background: var(--bg-primary);
}

/* Code Content */
.code-content {
    flex: 1;
    position: relative;
    overflow: hidden;
}

.code-tab-content {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: none;
    flex-direction: column;
}

.code-tab-content.active {
    display: flex;
}

/* Code Editor */
.code-editor {
    flex: 1;
    padding: var(--spacing-lg);
    background: var(--bg-primary);
    border: none;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.6;
    resize: none;
    outline: none;
}

/* Language Select */
.language-select {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-primary);
    border-radius: var(--border-radius-md);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition-base);
}

.language-select:hover {
    border-color: var(--accent-primary);
}

.language-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.1);
}

/* Output Container */
.output-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
}

.output-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-primary);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.btn-sm {
    width: 32px;
    height: 32px;
    font-size: 0.85rem;
}

.output-content {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    line-height: 1.6;
    color: var(--text-secondary);
    white-space: pre-wrap;
}

/* Examples Container */
.examples-container {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
}

.example-card {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: var(--border-radius-md);
    transition: all var(--transition-base);
}

.example-card:hover {
    border-color: var(--accent-primary);
    box-shadow: var(--shadow-md);
}

.example-card h4 {
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.example-card p {
    margin-bottom: var(--spacing-md);
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.example-code {
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: var(--border-radius-sm);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    overflow-x: auto;
}

.btn-load-example {
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--accent-primary);
    border: none;
    border-radius: var(--border-radius-sm);
    color: white;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn-load-example:hover {
    background: var(--accent-hover);
}

/* Code Hints */
.code-hints {
    padding: var(--spacing-lg);
    background: var(--bg-tertiary);
    border-top: 1px solid var(--border-primary);
}

.hint-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent-primary);
}

.hint-content {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ============================================
   Floating Action Buttons
   ============================================ */
.fab-container {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    z-index: 900;
}

.fab {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 1.25rem;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-base);
}

.fab:hover {
    transform: scale(1.1) translateY(-2px);
    box-shadow: var(--shadow-xl);
}

/* ============================================
   Modal
   ============================================ */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: none;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    z-index: 2000;
    animation: fadeIn var(--transition-base);
}

.modal.active {
    display: flex;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-content {
    width: 90%;
    max-width: 800px;
    max-height: 90vh;
    background: var(--bg-secondary);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    animation: slideUp var(--transition-slow);
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-xl);
    background: var(--gradient-primary);
    color: white;
}

.modal-header h2 {
    margin: 0;
    font-size: 1.5rem;
}

.modal-close {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: var(--border-radius-md);
    color: white;
    font-size: 1.25rem;
    cursor: pointer;
    transition: all var(--transition-base);
}

.modal-close:hover {
    background: rgba(255, 255, 255, 0.3);
}

.modal-body {
    padding: var(--spacing-2xl);
    overflow-y: auto;
    max-height: calc(90vh - 120px);
}

/* Welcome Grid */
.welcome-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.welcome-card {
    padding: var(--spacing-xl);
    background: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: var(--border-radius-md);
    text-align: center;
    transition: all var(--transition-base);
}

.welcome-card:hover {
    border-color: var(--accent-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.welcome-card i {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-card h3 {
    margin-bottom: var(--spacing-sm);
    font-size: 1.1rem;
    color: var(--text-primary);
}

.welcome-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.welcome-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
}

/* ============================================
   Loading Overlay
   ============================================ */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: none;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: var(--spacing-lg);
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(4px);
    z-index: 3000;
}

.loading-overlay.active {
    display: flex;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid var(--bg-tertiary);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-overlay p {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* ============================================
   Toast Notifications
   ============================================ */
.toast-container {
    position: fixed;
    top: calc(var(--header-height) + var(--spacing-lg));
    right: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    z-index: 1500;
}

.toast {
    min-width: 300px;
    padding: var(--spacing-lg);
    background: var(--bg-elevated);
    border: 1px solid var(--border-primary);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    animation: slideInRight var(--transition-base);
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(100px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.toast.success { border-left: 4px solid var(--success); }
.toast.warning { border-left: 4px solid var(--warning); }
.toast.error { border-left: 4px solid var(--error); }
.toast.info { border-left: 4px solid var(--info); }

.toast-icon {
    font-size: 1.25rem;
}

.toast.success .toast-icon { color: var(--success); }
.toast.warning .toast-icon { color: var(--warning); }
.toast.error .toast-icon { color: var(--error); }
.toast.info .toast-icon { color: var(--info); }

.toast-content {
    flex: 1;
}

.toast-title {
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.toast-message {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* ============================================
   Scrollbar Styles
   ============================================ */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-primary);
    border-radius: 999px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-primary);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1200px) {
    :root {
        --sidebar-width: 280px;
    }

    .panel-content {
        padding: var(--spacing-xl);
    }
}

@media (max-width: 768px) {
    .main-nav {
        display: none;
    }

    .sidebar {
        position: absolute;
        top: 0;
        left: 0;
        bottom: 0;
        z-index: 100;
        box-shadow: var(--shadow-xl);
    }

    .content-wrapper {
        flex-direction: column;
    }

    .resizer {
        display: none;
    }

    .panel-left,
    .panel-right {
        min-width: 100%;
    }

    .panel-content {
        padding: var(--spacing-md);
    }

    .fab-container {
        bottom: var(--spacing-md);
        right: var(--spacing-md);
    }
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
    .header,
    .sidebar,
    .panel-footer,
    .panel-right,
    .fab-container,
    .resizer {
        display: none !important;
    }

    .panel-left {
        width: 100% !important;
        max-width: 100% !important;
    }

    .panel-content {
        padding: 0;
    }
}

/* ============================================
   Utility Classes
   ============================================ */
.hidden { display: none !important; }
.visible { display: block !important; }
.text-center { text-align: center; }
.text-right { text-align: right; }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }