/* Modern Design System - Educational Theme */
:root {
    /* Primary Colors - Educational Green */
    --color-primary: #059669;
    --color-primary-light: #10b981;
    --color-primary-dark: #047857;
    --color-primary-50: #f0fdf4;
    --color-primary-100: #dcfce7;
    --color-primary-500: #22c55e;

    /* Secondary Colors - Learning Blue */
    --color-secondary: #0284c7;
    --color-secondary-light: #0ea5e9;
    --color-secondary-dark: #0369a1;
    --color-secondary-50: #f0f9ff;
    --color-secondary-100: #e0f2fe;

    /* Success & Status Colors */
    --color-success: #16a34a;
    --color-warning: #f59e0b;
    --color-error: #dc2626;
    --color-info: --color-secondary;

    /* Neutral Colors */
    --color-white: #ffffff;
    --color-gray-50: #f8fafc;
    --color-gray-100: #f1f5f9;
    --color-gray-200: #e2e8f0;
    --color-gray-300: #cbd5e1;
    --color-gray-400: #94a3b8;
    --color-gray-500: #64748b;
    --color-gray-600: #475569;
    --color-gray-700: #334155;
    --color-gray-800: #1e293b;
    --color-gray-900: #0f172a;

    /* Semantic Colors */
    --color-background: var(--color-gray-50);
    --color-surface: var(--color-white);
    --color-text-primary: var(--color-gray-900);
    --color-text-secondary: var(--color-gray-600);
    --color-text-muted: var(--color-gray-500);
    --color-border: var(--color-gray-200);
    --color-border-light: var(--color-gray-100);

    /* Shadows */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    --radius-xl: 12px;
    --radius-2xl: 16px;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
}

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

body {
    font-family: var(--font-sans);
    line-height: 1.6;
    color: var(--color-text-primary);
    background: linear-gradient(135deg, var(--color-primary-50) 0%, var(--color-secondary-50) 50%, var(--color-primary-100) 100%);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    text-align: center;
    margin-bottom: var(--space-8);
    color: var(--color-text-primary);
    position: relative;
    padding: var(--space-8) 0;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--space-3);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

header p {
    font-size: 1.2rem;
    color: var(--color-text-secondary);
    font-weight: 500;
}

/* Admin Toggle Button */
.admin-toggle-btn {
    position: absolute;
    top: 0;
    right: 0;
    padding: 8px 16px;
    border: none;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85em;
    font-weight: 500;
    transition: all 0.2s ease;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.admin-toggle-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.admin-toggle-btn.admin-active {
    background: rgba(255, 255, 255, 0.9);
    color: #333;
    font-weight: 600;
}

/* Admin-only elements */
.admin-only {
    transition: all 0.3s ease;
}

.admin-only.hidden {
    display: none !important;
}

/* Advanced Settings */
.advanced-settings {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 12px;
    padding: 24px;
    margin: 20px 0;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.advanced-settings h3 {
    color: #333;
    margin-bottom: 8px;
    font-size: 1.3em;
    font-weight: 600;
}

.settings-description {
    color: #666;
    margin-bottom: 24px;
    font-size: 0.95em;
    line-height: 1.5;
}

.prompt-section {
    margin-bottom: 24px;
}

.prompt-section label {
    display: block;
    color: #333;
    font-weight: 600;
    margin-bottom: 8px;
    font-size: 0.95em;
}

.prompt-input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-family: 'Monaco', 'Menlo', 'Consolas', monospace;
    font-size: 0.85em;
    line-height: 1.5;
    resize: vertical;
    min-height: 80px;
    background: #fafafa;
    transition: all 0.2s ease;
}

.prompt-input:focus {
    outline: none;
    border-color: #667eea;
    background: white;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.prompt-actions {
    margin-top: 8px;
}

.settings-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 24px;
    padding-top: 16px;
    border-top: 1px solid rgba(0, 0, 0, 0.1);
}

.btn-small {
    padding: var(--space-1) var(--space-3);
    font-size: 0.75rem;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    cursor: pointer;
    font-weight: 500;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
}

.btn-small.secondary {
    background: var(--color-surface);
    color: var(--color-text-secondary);
    border-color: var(--color-border);
    box-shadow: var(--shadow-xs);
}

.btn-small.secondary:hover {
    background: var(--color-gray-50);
    color: var(--color-text-primary);
    border-color: var(--color-gray-300);
}

.btn-small.primary {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-xs);
}

.btn-small.primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

/* Quiz/Flashcard Editing */
.question-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 16px;
}

.question-controls, .flashcard-controls-header {
    display: flex;
    gap: 8px;
    flex-shrink: 0;
}

.question-edit-form, .flashcard-edit-form {
    background: #f8f9fa;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    padding: 16px;
    margin: 16px 0;
}

.edit-input {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-family: inherit;
    font-size: 0.9em;
    margin-bottom: 12px;
    resize: vertical;
}

.edit-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 2px rgba(102, 126, 234, 0.2);
}

.edit-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    margin-bottom: 12px;
}

.edit-option-input {
    padding: 8px 12px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-size: 0.9em;
}

.edit-option-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 2px rgba(102, 126, 234, 0.2);
}

.edit-correct {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
}

.edit-correct label {
    font-weight: 600;
    color: #495057;
}

.edit-select {
    padding: 6px 10px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-size: 0.9em;
}

.edit-actions {
    display: flex;
    gap: 8px;
    justify-content: flex-end;
    margin-top: 16px;
}

.edit-flashcard label {
    display: block;
    font-weight: 600;
    color: #495057;
    margin-bottom: 6px;
    margin-top: 12px;
}

.edit-flashcard label:first-child {
    margin-top: 0;
}

/* Navigation Bar */
.nav-bar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    padding: 12px 0;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

.nav-left {
    flex: 1;
}

.nav-session-title {
    font-weight: 600;
    color: #333;
    font-size: 0.95em;
    max-width: 300px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.nav-right {
    display: flex;
    gap: 10px;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border: none;
    background: rgba(255, 255, 255, 0.8);
    color: #333;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85em;
    font-weight: 500;
    transition: all 0.2s ease;
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.nav-btn:hover {
    background: white;
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.nav-btn:active {
    transform: translateY(0);
}

.nav-icon {
    font-size: 1em;
}

.nav-text {
    font-size: 0.85em;
}

/* Section Management */
.section {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    margin-bottom: var(--space-6);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition-normal);
}

.section.hidden {
    display: none;
}

.section h2 {
    margin-bottom: var(--space-6);
    color: var(--color-text-primary);
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.025em;
}

/* Upload Area */
.upload-area {
    border: 2px dashed var(--color-primary-light);
    border-radius: var(--radius-xl);
    padding: var(--space-10) var(--space-6);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-normal);
    background: var(--color-primary-50);
    position: relative;
}

.upload-area:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-100);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.upload-area.dragover {
    border-color: var(--color-success);
    background: var(--color-primary-100);
    box-shadow: var(--shadow-xl);
    transform: scale(1.02);
}

.upload-content .upload-icon {
    font-size: 3rem;
    margin-bottom: var(--space-4);
    opacity: 0.8;
}

.upload-content p {
    margin-bottom: var(--space-3);
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--color-text-primary);
}

.file-types {
    color: var(--color-text-muted);
    font-size: 0.875rem;
    font-weight: 400;
}

/* File List */
.file-list {
    margin-top: 20px;
}

.file-item {
    display: flex;
    align-items: center;
    justify-content: between;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 10px;
}

.file-item .file-name {
    flex-grow: 1;
    margin-left: 10px;
}

.file-item .file-size {
    color: #666;
    font-size: 0.9em;
}

/* Buttons */
.btn {
    padding: var(--space-3) var(--space-6);
    border: 1px solid transparent;
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    text-align: center;
    position: relative;
    overflow: hidden;
    font-family: var(--font-sans);
}

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

.btn.primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn.primary:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

.btn.secondary {
    background: var(--color-surface);
    color: var(--color-text-primary);
    border-color: var(--color-border);
    box-shadow: var(--shadow-xs);
}

.btn.secondary:hover {
    background: var(--color-gray-50);
    border-color: var(--color-gray-300);
    box-shadow: var(--shadow-sm);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: var(--shadow-xs) !important;
    pointer-events: none;
}

/* Mode Selection */
.mode-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-6);
    margin-bottom: var(--space-6);
}

.mode-btn {
    padding: var(--space-8) var(--space-6);
    text-align: center;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

.mode-btn:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-50);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.mode-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-4);
    opacity: 0.9;
}

.mode-btn h3 {
    margin-bottom: var(--space-3);
    color: var(--color-text-primary);
    font-weight: 600;
    font-size: 1.25rem;
}

.mode-btn p {
    color: var(--color-text-secondary);
    margin: 0;
    font-size: 0.875rem;
    line-height: 1.5;
}

.study-info {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 8px;
    text-align: center;
}

/* Quiz Styles */
.quiz-header {
    display: flex;
    justify-content: between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 15px;
}

.quiz-progress {
    display: flex;
    gap: 20px;
    align-items: center;
}

.score {
    background: #28a745;
    color: white;
    padding: 5px 12px;
    border-radius: 20px;
    font-weight: 600;
}

.question-card {
    background: var(--color-surface);
    padding: var(--space-8);
    border-radius: var(--radius-xl);
    margin-bottom: var(--space-6);
    border: 1px solid var(--color-border-light);
    box-shadow: var(--shadow-sm);
}

.question-card h3 {
    margin-bottom: var(--space-6);
    font-size: 1.25rem;
    line-height: 1.6;
    color: var(--color-text-primary);
    font-weight: 600;
}

.answer-options {
    display: grid;
    gap: 12px;
}

.answer-option {
    padding: var(--space-4) var(--space-5);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: left;
    font-weight: 500;
    box-shadow: var(--shadow-xs);
}

.answer-option:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-50);
    box-shadow: var(--shadow-sm);
    transform: translateY(-1px);
}

.answer-option.selected {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: var(--color-white);
    box-shadow: var(--shadow-md);
}

.answer-option.correct {
    border-color: var(--color-success);
    background: var(--color-success);
    color: var(--color-white);
    box-shadow: var(--shadow-md);
}

.answer-option.incorrect {
    border-color: var(--color-error);
    background: var(--color-error);
    color: var(--color-white);
    box-shadow: var(--shadow-md);
}

.quiz-controls {
    text-align: center;
    margin-top: 20px;
}

/* Flashcard Styles */
.flashcard-header {
    text-align: center;
    margin-bottom: 30px;
}

.flashcard {
    perspective: 1000px;
    height: 300px;
    margin-bottom: 30px;
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    background: #f8f9ff;
    border-radius: 12px;
    padding: 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    cursor: pointer;
    transition: transform 0.6s;
    backface-visibility: hidden;
    border: 2px solid #e9ecef;
}

.flashcard-back {
    transform: rotateY(180deg);
    background: #fff8f0;
}

.flashcard.flipped .flashcard-front {
    transform: rotateY(-180deg);
}

.flashcard.flipped .flashcard-back {
    transform: rotateY(0deg);
}

.flashcard h3 {
    margin-bottom: 20px;
    font-size: 1.4em;
    line-height: 1.4;
}

.flip-hint {
    color: #666;
    font-size: 0.9em;
    margin-top: auto;
}

.flashcard-controls {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.flashcard-back-controls {
    display: flex;
    justify-content: center;
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #e0e0e0;
}

.quiz-back-controls {
    display: flex;
    justify-content: center;
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #e0e0e0;
}

/* Results Styles */
.results-display {
    text-align: center;
}

.final-score {
    margin-bottom: 30px;
}

.final-score h3 {
    font-size: 2em;
    margin-bottom: 10px;
    color: #333;
}

#score-percentage {
    font-size: 3em;
    font-weight: 700;
    margin-bottom: 20px;
}

.results-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.loading-content {
    background: white;
    padding: 40px;
    border-radius: 12px;
    text-align: center;
    max-width: 300px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    .mode-buttons {
        grid-template-columns: 1fr;
    }

    .quiz-header {
        flex-direction: column;
        text-align: center;
    }

    .flashcard-controls {
        flex-direction: column;
    }

    .flashcard-back-controls {
        flex-direction: column;
    }

    .quiz-back-controls {
        flex-direction: column;
    }

    .results-actions {
        flex-direction: column;
    }
}

/* Session Sidebar Styles */
.session-sidebar {
    position: fixed;
    top: 0;
    right: -400px;
    width: 400px;
    height: 100vh;
    background: white;
    box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    transition: right 0.3s ease;
    display: flex;
    flex-direction: column;
}

.session-sidebar.open {
    right: 0;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid #e0e0e0;
    background: #f8f9fa;
}

.sidebar-header h3 {
    margin: 0;
    color: #333;
    font-size: 1.2em;
}

.close-btn {
    background: none;
    border: none;
    font-size: 24px;
    color: #666;
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s ease;
}

.close-btn:hover {
    background: #e0e0e0;
    color: #333;
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    padding: 0;
}

.session-list {
    display: flex;
    flex-direction: column;
}

.session-item {
    padding: 15px 20px;
    border-bottom: 1px solid #f0f0f0;
    cursor: pointer;
    transition: background-color 0.2s ease;
    position: relative;
}

.session-item:hover {
    background: #f8f9fa;
}

.session-item.current {
    background: #e3f2fd;
    border-left: 4px solid #2196f3;
}

.session-title {
    font-weight: 600;
    color: #333;
    margin-bottom: 8px;
    font-size: 0.95em;
    line-height: 1.2;
}

.session-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    font-size: 0.8em;
    color: #666;
    margin-bottom: 6px;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.meta-icon {
    font-size: 0.9em;
}

.session-date {
    font-size: 0.75em;
    color: #999;
    margin-top: 4px;
}

.session-score {
    position: absolute;
    top: 12px;
    right: 15px;
    background: #28a745;
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.7em;
    font-weight: 600;
}

.session-score.poor {
    background: #dc3545;
}

.session-score.fair {
    background: #ffc107;
    color: #333;
}

.session-score.good {
    background: #28a745;
}

.session-delete-btn {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 24px;
    height: 24px;
    border: none;
    background: rgba(220, 53, 69, 0.1);
    color: #dc3545;
    border-radius: 4px;
    cursor: pointer;
    font-size: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    opacity: 0.7;
    z-index: 10;
}

.session-delete-btn:hover {
    background: #dc3545;
    color: white;
    opacity: 1;
    transform: scale(1.05);
    box-shadow: 0 2px 4px rgba(220, 53, 69, 0.3);
}

.session-delete-btn:active {
    transform: scale(0.95);
}

.session-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    color: #666;
}

.mini-spinner {
    width: 20px;
    height: 20px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid #007bff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 10px;
}

.no-sessions {
    padding: 40px 20px;
    text-align: center;
    color: #666;
}

.no-sessions .hint {
    font-size: 0.9em;
    color: #999;
    margin-top: 8px;
}

.sidebar-footer {
    border-top: 1px solid #e0e0e0;
    padding: 15px 20px;
    background: #f8f9fa;
}

.btn.small {
    padding: 8px 16px;
    font-size: 0.85em;
}

/* Sidebar Toggle Button */
.sidebar-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: #007bff;
    border: none;
    color: white;
    font-size: 18px;
    cursor: pointer;
    z-index: 999;
    box-shadow: 0 2px 10px rgba(0, 123, 255, 0.3);
    transition: all 0.3s ease;
}

.sidebar-toggle:hover {
    background: #0056b3;
    transform: scale(1.05);
}

.sidebar-toggle.active {
    background: #dc3545;
}

/* Sidebar Overlay */
.sidebar-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.sidebar-overlay.visible {
    opacity: 1;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .session-sidebar {
        width: 100%;
        right: -100%;
    }

    .sidebar-toggle {
        top: 15px;
        right: 15px;
        width: 45px;
        height: 45px;
        font-size: 16px;
    }

    .session-meta {
        flex-direction: column;
        gap: 4px;
    }

    .session-score {
        position: static;
        align-self: flex-start;
        margin-top: 8px;
    }

    /* Navigation Bar Mobile */
    .nav-content {
        padding: 0 15px;
    }

    .nav-session-title {
        max-width: 200px;
        font-size: 0.9em;
    }

    .nav-btn {
        padding: 6px 12px;
        gap: 4px;
    }

    .nav-text {
        display: none;
    }

    .nav-icon {
        font-size: 1.1em;
    }
}