/* 2CExam Online - Professional Quiz System Styles */

:root {
    --primary: #1e40af;
    --primary-dark: #1e3a8a;
    --primary-light: #3b82f6;
    --secondary: #64748b;
    --success: #059669;
    --warning: #d97706;
    --danger: #dc2626;
    --background: #f8fafc;
    --surface: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--background);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

/* Layout */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.page-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    width: 32px;
    height: 32px;
    background: var(--primary);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
}

.nav {
    display: flex;
    gap: 24px;
    align-items: center;
}

.nav-link {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover {
    color: var(--primary);
}

.nav-link.active {
    color: var(--primary);
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-name {
    font-weight: 500;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
}

.btn-secondary {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
}

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

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

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

.btn-lg {
    padding: 14px 28px;
    font-size: 1.1rem;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.85rem;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text);
}

.form-input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.1);
}

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

.form-error {
    color: var(--danger);
    font-size: 0.85rem;
    margin-top: 4px;
}

/* Cards */
.card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    padding: 24px;
}

.card-header {
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Auth Pages */
.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
}

.auth-card {
    width: 100%;
    max-width: 420px;
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 40px;
}

.auth-logo {
    text-align: center;
    margin-bottom: 32px;
}

.auth-logo h1 {
    font-size: 1.75rem;
    color: var(--primary);
    margin-top: 12px;
}

.auth-logo p {
    color: var(--text-light);
    margin-top: 4px;
}

.auth-footer {
    text-align: center;
    margin-top: 24px;
    color: var(--text-light);
}

.auth-footer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

/* Dashboard */
.main-content {
    flex: 1;
    padding: 32px 0;
}

.page-header {
    margin-bottom: 32px;
}

.page-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.page-subtitle {
    color: var(--text-light);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 32px;
}

.stat-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow);
}

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

.stat-label {
    color: var(--text-light);
    margin-top: 4px;
}

/* Categories Grid */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.category-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.category-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 16px;
}

.category-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.category-desc {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.category-stats {
    display: flex;
    gap: 16px;
    font-size: 0.85rem;
    color: var(--text-light);
}

/* Quiz Page */
.quiz-container {
    max-width: 800px;
    margin: 0 auto;
}

.quiz-header {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.quiz-info {
    display: flex;
    gap: 24px;
}

.quiz-info-item {
    text-align: center;
}

.quiz-info-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.quiz-info-label {
    font-size: 0.85rem;
    color: var(--text-light);
}

.timer {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
    font-variant-numeric: tabular-nums;
}

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

.timer.danger {
    color: var(--danger);
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.question-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow);
}

.question-number {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 12px;
}

.question-text {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: 24px;
    line-height: 1.5;
}

.options-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option-item {
    display: flex;
    align-items: center;
    padding: 16px 20px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
}

.option-item:hover {
    border-color: var(--primary-light);
    background: rgba(59, 130, 246, 0.05);
}

.option-item.selected {
    border-color: var(--primary);
    background: rgba(59, 130, 246, 0.1);
}

.option-item.correct {
    border-color: var(--success);
    background: rgba(5, 150, 105, 0.1);
}

.option-item.incorrect {
    border-color: var(--danger);
    background: rgba(220, 38, 38, 0.1);
}

.option-letter {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--background);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    margin-right: 16px;
    flex-shrink: 0;
}

.option-item.selected .option-letter {
    background: var(--primary);
    color: white;
}

.option-text {
    flex: 1;
}

.quiz-actions {
    margin-top: 24px;
    display: flex;
    justify-content: space-between;
}

.progress-bar {
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    margin-bottom: 24px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary);
    transition: width 0.3s;
}

/* Results Page */
.results-card {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow);
    max-width: 600px;
    margin: 0 auto;
}

.results-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    margin: 0 auto 24px;
}

.results-icon.success {
    background: rgba(5, 150, 105, 0.1);
    color: var(--success);
}

.results-icon.warning {
    background: rgba(217, 119, 6, 0.1);
    color: var(--warning);
}

.results-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.results-subtitle {
    color: var(--text-light);
    margin-bottom: 32px;
}

.score-display {
    font-size: 4rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 8px;
}

.score-label {
    color: var(--text-light);
    margin-bottom: 32px;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 32px;
    padding: 24px;
    background: var(--background);
    border-radius: var(--radius);
}

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

.result-stat-value {
    font-size: 1.5rem;
    font-weight: 700;
}

.result-stat-label {
    font-size: 0.85rem;
    color: var(--text-light);
}

/* Leaderboard */
.leaderboard-table {
    width: 100%;
    border-collapse: collapse;
}

.leaderboard-table th,
.leaderboard-table td {
    padding: 16px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.leaderboard-table th {
    font-weight: 600;
    color: var(--text-light);
    font-size: 0.85rem;
    text-transform: uppercase;
}

.leaderboard-table tr:hover {
    background: var(--background);
}

.rank-badge {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
}

.rank-1 {
    background: #fef3c7;
    color: #d97706;
}

.rank-2 {
    background: #e5e7eb;
    color: #6b7280;
}

.rank-3 {
    background: #fed7aa;
    color: #c2410c;
}

/* History */
.history-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.history-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.history-info h4 {
    font-weight: 600;
    margin-bottom: 4px;
}

.history-info p {
    font-size: 0.85rem;
    color: var(--text-light);
}

.history-score {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
}

/* Alerts */
.alert {
    padding: 16px 20px;
    border-radius: var(--radius);
    margin-bottom: 20px;
}

.alert-error {
    background: rgba(220, 38, 38, 0.1);
    color: var(--danger);
    border: 1px solid rgba(220, 38, 38, 0.2);
}

.alert-success {
    background: rgba(5, 150, 105, 0.1);
    color: var(--success);
    border: 1px solid rgba(5, 150, 105, 0.2);
}

/* Loading */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 32px;
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    margin-bottom: 20px;
}

.modal-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.modal-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 24px;
}

/* Tabs */
.tabs {
    display: flex;
    border-bottom: 1px solid var(--border);
    margin-bottom: 24px;
}

.tab {
    padding: 12px 24px;
    background: none;
    border: none;
    font-size: 1rem;
    color: var(--text-light);
    cursor: pointer;
    position: relative;
    transition: color 0.2s;
}

.tab:hover {
    color: var(--text);
}

.tab.active {
    color: var(--primary);
    font-weight: 500;
}

.tab.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
}

/* Utility Classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.mb-4 { margin-bottom: 16px; }
.mb-8 { margin-bottom: 32px; }
.hidden { display: none !important; }

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-wrap: wrap;
        gap: 16px;
    }

    .nav {
        order: 3;
        width: 100%;
        justify-content: center;
        gap: 16px;
    }

    .quiz-header {
        flex-direction: column;
        gap: 20px;
    }

    .results-stats {
        grid-template-columns: 1fr;
    }

    .auth-card {
        padding: 24px;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}