/* Modern, Interactive Databricks ML Exam Simulator Styles */

:root {
    --primary-color: #0066cc;
    --primary-dark: #004499;
    --secondary-color: #00a86b;
    --accent-color: #ff6b35;
    --success-color: #28a745;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --info-color: #17a2b8;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-muted: #adb5bd;
    
    --border-color: #dee2e6;
    --border-radius: 12px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --box-shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

/* Header Styles */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--box-shadow);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo i {
    font-size: 2rem;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.user-stats {
    display: flex;
    gap: 1.5rem;
}

.stat {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    font-weight: 600;
}

.stat i {
    color: var(--primary-color);
}

/* Main Content */
.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.screen {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Welcome Screen */
.welcome-container {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    padding: 3rem;
    box-shadow: var(--box-shadow-lg);
    text-align: center;
}

.welcome-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-header p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.game-modes {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.mode-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 2rem;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.mode-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
    border-color: var(--primary-color);
}

.mode-card.selected {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-dark);
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
}

.mode-card.selected i {
    color: white;
}

.mode-card.selected h3 {
    color: white;
}

.mode-card.selected p {
    color: rgba(255, 255, 255, 0.9);
}

.mode-card i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.mode-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.mode-card p {
    color: var(--text-secondary);
}

.difficulty-selector {
    margin-bottom: 3rem;
}

.difficulty-selector h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.difficulty-options {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.difficulty-btn {
    padding: 0.75rem 2rem;
    border: 2px solid var(--border-color);
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.difficulty-btn:hover,
.difficulty-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.welcome-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    align-items: center;
    margin-top: 2rem;
}

.start-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 1rem 2rem;
    font-size: 1.2rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.browse-btn {
    background: linear-gradient(135deg, var(--secondary-color), #008a5a);
    color: white;
    border: none;
    padding: 1rem 2rem;
    font-size: 1.2rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.start-btn:hover, .browse-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-lg);
}

/* Question Browser Screen */
.browser-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

.browser-header {
    text-align: center;
    margin-bottom: 2rem;
    position: relative;
}

.browser-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.browser-header p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.back-btn {
    position: absolute;
    left: 0;
    top: 0;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
}

.back-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.browser-controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.filter-group label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.filter-group select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
}

.filter-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.clear-filters-btn {
    background: var(--danger-color);
    color: white;
    border: none;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    width: 100%;
    justify-content: center;
}

.clear-filters-btn:hover {
    background: #c82333;
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.start-filtered-exam-btn {
    background: var(--success-color);
    color: white;
    border: none;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    width: 100%;
    justify-content: center;
}

.start-filtered-exam-btn:hover {
    background: #218838;
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.browser-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-primary);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: center;
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-lg);
}

.stat-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.questions-table-container {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
}

.questions-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.questions-table th {
    background: var(--bg-secondary);
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: var(--text-primary);
    border-bottom: 2px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

.questions-table td {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    vertical-align: top;
}

.questions-table tbody tr {
    transition: var(--transition);
}

.questions-table tbody tr:hover {
    background: var(--bg-secondary);
}

.question-id {
    font-weight: 600;
    color: var(--primary-color);
    font-size: 1.1rem;
}

.topic-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.topic-badge:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.topic-badge.active {
    border-color: var(--text-primary);
    box-shadow: 0 0 0 2px rgba(0, 102, 204, 0.2);
}

.topic-mlflow { background: #e3f2fd; color: #1976d2; }
.topic-delta-lake { background: #e8f5e8; color: #2e7d32; }
.topic-automl { background: #fff3e0; color: #f57c00; }
.topic-feature-store { background: #f3e5f5; color: #7b1fa2; }
.topic-model-serving { background: #e0f2f1; color: #00695c; }
.topic-workspace { background: #fce4ec; color: #c2185b; }

.difficulty-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: capitalize;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.difficulty-badge:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.difficulty-badge.active {
    border-color: var(--text-primary);
    box-shadow: 0 0 0 2px rgba(0, 102, 204, 0.2);
}

.difficulty-beginner { background: #e8f5e8; color: #2e7d32; }
.difficulty-intermediate { background: #fff3e0; color: #f57c00; }
.difficulty-advanced { background: #ffebee; color: #c62828; }

.status-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: capitalize;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.status-badge:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.status-badge.active {
    border-color: var(--text-primary);
    box-shadow: 0 0 0 2px rgba(0, 102, 204, 0.2);
}

.status-attempted { background: #e8f5e8; color: #2e7d32; }
.status-not-attempted { background: #f5f5f5; color: #757575; }

.question-preview {
    max-width: 300px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.action-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.8rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.action-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
}

.action-btn i {
    font-size: 0.8rem;
}

/* Responsive Design for Question Browser */
@media (max-width: 768px) {
    .browser-container {
        padding: 1rem;
    }
    
    .browser-header h2 {
        font-size: 2rem;
    }
    
    .back-btn {
        position: static;
        margin-bottom: 1rem;
    }
    
    .browser-controls {
        grid-template-columns: 1fr;
    }
    
    .browser-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .questions-table-container {
        overflow-x: auto;
    }
    
    .questions-table {
        min-width: 600px;
    }
    
    .question-preview {
        max-width: 200px;
    }
}

/* Exam Screen */
.exam-header {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--box-shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.progress-info {
    flex: 1;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transition: width 0.3s ease;
    border-radius: 4px;
}

.progress-text {
    font-weight: 600;
    color: var(--text-secondary);
}

.exam-stats {
    display: flex;
    gap: 2rem;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
}

.stat-item i {
    color: var(--primary-color);
}

.question-container {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--box-shadow);
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.question-category {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.question-difficulty {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.question-content {
    margin-bottom: 2rem;
}

.question-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.question-image {
    max-width: 100%;
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

.options-container {
    margin-bottom: 2rem;
}

.option {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 1rem 1.5rem;
    margin-bottom: 1rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.option:hover {
    border-color: var(--primary-color);
    background: rgba(0, 102, 204, 0.05);
}

.option.selected {
    border-color: var(--primary-color);
    background: rgba(0, 102, 204, 0.1);
}

.option.correct {
    border-color: var(--success-color);
    background: rgba(40, 167, 69, 0.1);
}

.option.incorrect {
    border-color: var(--danger-color);
    background: rgba(220, 53, 69, 0.1);
}

.option-radio {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    position: relative;
    transition: var(--transition);
}

.option.selected .option-radio {
    border-color: var(--primary-color);
}

.option.selected .option-radio::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 10px;
    height: 10px;
    background: var(--primary-color);
    border-radius: 50%;
}

.option-text {
    flex: 1;
    font-weight: 500;
}

.question-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.submit-btn, .skip-btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.submit-btn {
    background: var(--success-color);
    color: white;
}

.submit-btn:hover:not(:disabled) {
    background: #218838;
    transform: translateY(-2px);
}

.submit-btn:disabled {
    background: var(--text-muted);
    cursor: not-allowed;
}

.skip-btn {
    background: var(--warning-color);
    color: var(--text-primary);
}

.skip-btn:hover {
    background: #e0a800;
    transform: translateY(-2px);
}

/* Results Screen */
.results-container {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    padding: 3rem;
    box-shadow: var(--box-shadow-lg);
    text-align: center;
}

.results-header {
    margin-bottom: 3rem;
}

.score-circle {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
    position: relative;
}

.score-circle::before {
    content: '';
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    bottom: 10px;
    background: var(--bg-primary);
    border-radius: 50%;
}

.score-inner {
    position: relative;
    z-index: 1;
    text-align: center;
}

.score-inner span:first-child {
    display: block;
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
}

.score-label {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.results-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.results-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius);
    padding: 2rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-card i {
    font-size: 2.5rem;
    color: var(--primary-color);
}

.stat-info {
    text-align: left;
}

.stat-value {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
}

.stat-label {
    font-size: 1rem;
    color: var(--text-secondary);
}

.achievements {
    margin-bottom: 3rem;
}

.achievement {
    background: linear-gradient(135deg, var(--accent-color), #ff8c42);
    color: white;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    margin: 1rem 0;
    display: flex;
    align-items: center;
    gap: 1rem;
    animation: slideIn 0.5s ease-out;
}

@keyframes slideIn {
    from { transform: translateX(-100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

.achievement i {
    font-size: 1.5rem;
}

.results-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.action-btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.action-btn.primary {
    background: var(--primary-color);
    color: white;
}

.action-btn.secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

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

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    backdrop-filter: blur(5px);
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.3s ease-out;
}

.modal-content {
    background: var(--bg-primary);
    border-radius: var(--border-radius);
    max-width: 800px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--box-shadow-lg);
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.modal-header {
    padding: 2rem 2rem 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
}

.close-btn:hover {
    color: var(--text-primary);
}

.modal-body {
    padding: 2rem;
}

.explanation-content {
    line-height: 1.8;
}

.explanation-content h4 {
    color: var(--primary-color);
    margin: 1.5rem 0 1rem;
    font-size: 1.2rem;
}

.explanation-content ul {
    margin: 1rem 0;
    padding-left: 2rem;
}

.explanation-content li {
    margin-bottom: 0.5rem;
}

.explanation-content pre {
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: var(--border-radius);
    overflow-x: auto;
    margin: 1rem 0;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
}

.explanation-content code {
    background: var(--bg-secondary);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
}

.modal-footer {
    padding: 1rem 2rem 2rem;
    text-align: center;
}

.continue-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 auto;
}

.continue-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    
    .user-stats {
        gap: 1rem;
    }
    
    .main-content {
        padding: 1rem;
    }
    
    .welcome-container {
        padding: 2rem 1rem;
    }
    
    .welcome-header h2 {
        font-size: 2rem;
    }
    
    .game-modes {
        grid-template-columns: 1fr;
    }
    
    .difficulty-options {
        flex-direction: column;
        align-items: center;
    }
    
    .exam-header {
        flex-direction: column;
        gap: 1rem;
    }
    
    .exam-stats {
        gap: 1rem;
    }
    
    .question-actions {
        flex-direction: column;
    }
    
    .results-stats {
        grid-template-columns: 1fr;
    }
    
    .results-actions {
        flex-direction: column;
    }
    
    .modal-content {
        width: 95%;
        margin: 1rem;
    }
}

/* Animations and Effects */
.pulse {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.bounce {
    animation: bounce 1s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--primary-color);
    border-top: 2px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Success/Error States */
.success {
    color: var(--success-color);
}

.error {
    color: var(--danger-color);
}

.warning {
    color: var(--warning-color);
}

.info {
    color: var(--info-color);
}