/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #22c55e;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background-color: #f8fafc;
    --card-background: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

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

/* Navigation */
.navbar {
    background-color: var(--card-background);
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.navbar-nav {
    display: flex;
    gap: 20px;
    list-style: none;
}

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

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

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    text-align: center;
}

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

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

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

.btn-secondary:hover {
    background-color: #475569;
}

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
}

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

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

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

.btn-lg {
    padding: 15px 30px;
    font-size: 1.1rem;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.875rem;
}

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

/* Cards */
.card {
    background-color: var(--card-background);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 24px;
    margin-bottom: 20px;
}

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

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

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

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-error {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: 4px;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 80px 20px;
    background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
    color: white;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
}

.hero p {
    font-size: 1.25rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 30px;
}

/* Features Grid */
.features {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    padding: 60px 0;
}

@media (max-width: 992px) {
    .features {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 576px) {
    .features {
        grid-template-columns: 1fr;
    }
}

.feature-card {
    text-align: center;
    padding: 20px 16px;
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 12px;
}

.feature-card h3 {
    margin-bottom: 8px;
    font-size: 1.1rem;
}

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

/* Dashboard */
.dashboard-header {
    padding: 40px 0 20px;
}

.dashboard-header h1 {
    font-size: 2rem;
    margin-bottom: 8px;
}

.dashboard-header p {
    color: var(--text-secondary);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 12px;
    margin-bottom: 20px;
}

.stat-card {
    text-align: center;
    padding: 14px 16px;
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Module Selection */
.module-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.module-card {
    padding: 30px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    border: 2px solid transparent;
}

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

.module-card.selected {
    border-color: var(--primary-color);
}

.module-card h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
}

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

/* Question Display */
.question-container {
    max-width: 800px;
    margin: 40px auto;
}

.passage-box {
    background-color: #f1f5f9;
    border-left: 4px solid var(--primary-color);
    padding: 20px;
    margin-bottom: 24px;
    border-radius: 0 8px 8px 0;
    line-height: 1.8;
}

.question-text {
    font-size: 1.125rem;
    font-weight: 500;
    margin-bottom: 20px;
}

.options-list {
    list-style: none;
}

.option-item {
    margin-bottom: 12px;
}

.option-btn {
    width: 100%;
    text-align: left;
    padding: 16px 20px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--card-background);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 1rem;
}

.option-btn:hover {
    border-color: var(--primary-color);
    background-color: #f8fafc;
}

.option-btn.selected {
    border-color: var(--primary-color);
    background-color: #eff6ff;
}

.option-btn.correct {
    border-color: var(--success-color);
    background-color: #f0fdf4;
}

.option-btn.incorrect {
    border-color: var(--error-color);
    background-color: #fef2f2;
}

.option-btn.show-correct {
    border-color: var(--success-color);
    background-color: #f0fdf4;
}

.option-label {
    font-weight: 600;
    margin-right: 10px;
    color: var(--primary-color);
}

/* Explanation Box */
.explanation-box {
    margin-top: 24px;
    padding: 20px;
    border-radius: 8px;
}

.explanation-box.correct {
    background-color: #f0fdf4;
    border: 1px solid var(--success-color);
}

.explanation-box.incorrect {
    background-color: #fef2f2;
    border: 1px solid var(--error-color);
}

.explanation-title {
    font-weight: 600;
    margin-bottom: 8px;
}

/* Test Interface */
.test-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 30px;
}

.timer {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

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

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

.question-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 30px;
}

.nav-btn {
    width: 40px;
    height: 40px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--card-background);
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s;
}

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

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

.nav-btn.answered {
    background-color: #dbeafe;
    border-color: #93c5fd;
}

.nav-btn.flagged {
    background-color: #fef3c7;
    border-color: var(--warning-color);
}

.nav-btn.nav-finish-btn {
    width: auto;
    padding: 0 12px;
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
    font-size: 0.85rem;
}

.nav-btn.nav-finish-btn:hover {
    background-color: #1d4ed8;
    border-color: #1d4ed8;
}

.question-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.flag-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: transparent;
    cursor: pointer;
    transition: all 0.2s;
}

.flag-btn:hover, .flag-btn.flagged {
    border-color: var(--warning-color);
    background-color: #fef3c7;
}

/* Results Page */
.results-header {
    text-align: center;
    padding: 40px 0;
}

.score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), #1d4ed8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    margin: 0 auto 20px;
}

.score-value {
    font-size: 3rem;
    font-weight: 700;
}

.score-label {
    font-size: 0.875rem;
    opacity: 0.9;
}

.results-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    max-width: 600px;
    margin: 0 auto 40px;
}

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

.summary-value {
    font-size: 1.5rem;
    font-weight: 600;
}

.summary-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Progress Charts */
.progress-bar {
    height: 8px;
    background-color: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: var(--primary-color);
    border-radius: 4px;
    transition: width 0.3s;
}

.progress-fill.success {
    background-color: var(--success-color);
}

/* History Table */
.history-table {
    width: 100%;
    border-collapse: collapse;
}

.history-table th,
.history-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.history-table th {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.history-table tr:hover {
    background-color: #f8fafc;
}

.history-table .mock-test-row {
    background-color: #f0f9ff;
    border-left: 3px solid var(--primary-color);
}

.history-table .mock-test-row:hover {
    background-color: #e0f2fe;
}

.history-table .mock-test-row td:first-child {
    padding-left: 13px;
}

.history-table .mock-test-section {
    background-color: #fafafa;
}

.history-table .mock-test-section:hover {
    background-color: #f5f5f5;
}

.history-table .mock-test-section td {
    padding-top: 8px;
    padding-bottom: 8px;
    font-size: 0.9rem;
}

/* Alerts */
.alert {
    padding: 16px 20px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.alert-success {
    background-color: #f0fdf4;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.alert-error {
    background-color: #fef2f2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.alert-info {
    background-color: #eff6ff;
    color: #1e40af;
    border: 1px solid #bfdbfe;
}

/* Loading Spinner */
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.loading-container {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 60px;
}

/* Auth Pages */
.auth-container {
    max-width: 400px;
    margin: 60px auto;
    padding: 0 20px;
}

.auth-card {
    padding: 40px;
}

.auth-card h1 {
    text-align: center;
    margin-bottom: 8px;
}

.auth-card .subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 30px;
}

.auth-footer {
    text-align: center;
    margin-top: 20px;
    color: var(--text-secondary);
}

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

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .navbar .container {
        flex-direction: column;
        gap: 15px;
    }

    .navbar-nav {
        gap: 15px;
    }

    .test-header {
        flex-direction: column;
        gap: 15px;
    }

    .question-actions {
        flex-direction: column;
        gap: 15px;
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.hidden { display: none !important; }
.flex { display: flex; }
.flex-between { justify-content: space-between; }
.gap-2 { gap: 16px; }

/* Tag Styles */
.tag-container {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag-chip {
    display: inline-flex;
    align-items: center;
    padding: 6px 14px;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
}

.tag-chip:hover {
    background-color: var(--border-color);
    color: var(--text-primary);
}

.tag-chip.selected {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

.tag-chip.all-tag {
    font-weight: 600;
}

/* Review Filter Styles */
.review-filter {
    display: flex;
    gap: 8px;
}

.filter-btn {
    padding: 6px 16px;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    background-color: transparent;
    color: var(--text-secondary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

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

/* Calculator Styles */
.calculator-toggle {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: transparent;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.95rem;
    color: var(--text-primary);
}

.calculator-toggle:hover {
    border-color: var(--primary-color);
    background-color: #eff6ff;
}

.calculator-toggle.active {
    border-color: var(--primary-color);
    background-color: #eff6ff;
    color: var(--primary-color);
}

.calculator-panel {
    position: fixed;
    top: 0;
    right: -840px;
    width: 840px;
    height: 100vh;
    background-color: var(--card-background);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.15);
    z-index: 1000;
    transition: right 0.3s ease;
    display: flex;
    flex-direction: column;
}

.calculator-panel.open {
    right: 0;
}

.calculator-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--background-color);
}

.calculator-header h3 {
    font-size: 1rem;
    font-weight: 600;
    margin: 0;
}

.calculator-close {
    width: 32px;
    height: 32px;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    transition: all 0.2s;
}

.calculator-close:hover {
    background-color: var(--border-color);
    color: var(--text-primary);
}

.calculator-body {
    flex: 1;
    padding: 0;
    overflow: hidden;
}

#desmos-calculator {
    width: 100%;
    height: 100%;
}

.calculator-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.3);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.calculator-overlay.open {
    opacity: 1;
    visibility: visible;
}

/* Responsive calculator */
@media (max-width: 480px) {
    .calculator-panel {
        width: 100%;
        right: -100%;
    }
}

/* SAT Score Display Styles */
.sat-scores-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 12px;
    margin: 16px 0;
}

.sat-score-card {
    background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 14px 16px;
    text-align: center;
}

.sat-score-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.sat-score-value {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1;
    margin-bottom: 2px;
}

.sat-score-range {
    font-size: 0.7rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.sat-score-level {
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 2px;
}

.sat-score-percentile {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.sat-section-stats {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.sat-total-score .sat-section-stats {
    color: rgba(255, 255, 255, 0.9);
}

.sat-total-score {
    background: linear-gradient(135deg, var(--primary-color) 0%, #1d4ed8 100%);
    color: white;
}

.sat-total-score .sat-score-label,
.sat-total-score .sat-score-range,
.sat-total-score .sat-score-percentile {
    color: rgba(255, 255, 255, 0.8);
}

.sat-total-score .sat-score-value,
.sat-total-score .sat-score-level {
    color: white;
}

.estimated-score-note {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-align: center;
    margin-top: 8px;
    font-style: italic;
}

/* Dashboard SAT Score Section */
.dashboard-sat-scores {
    margin-bottom: 24px;
}

.dashboard-sat-scores .card-title {
    display: flex;
    align-items: center;
    gap: 8px;
}

.score-badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    background-color: var(--background-color);
    border-radius: 20px;
    font-size: 0.75rem;
    color: var(--text-secondary);
}