/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --success-color: #16a34a;
    --error-color: #dc2626;
    --warning-color: #d97706;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-lg: 0 4px 6px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navbar */
.navbar {
    background: var(--card-bg);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.nav-brand a {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
}

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

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

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
    flex: 1;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
}

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

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

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

.btn-secondary:hover {
    background: #cbd5e1;
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-google {
    background: white;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.875rem 1.5rem;
}

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

.btn-google svg {
    width: 20px;
    height: 20px;
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
}

.alert-error {
    background: #fef2f2;
    color: var(--error-color);
    border: 1px solid #fecaca;
}

.alert-info {
    background: #eff6ff;
    color: var(--primary-color);
    border: 1px solid #bfdbfe;
}

/* Login Page */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
}

.login-card {
    background: var(--card-bg);
    padding: 3rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
    max-width: 400px;
}

.login-card h1 {
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.login-card > p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.features {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.feature {
    display: flex;
    flex-direction: column;
}

.feature strong {
    color: var(--text-primary);
}

.feature span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

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

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.quiz-header h1 {
    font-size: 1.5rem;
}

.timer {
    background: var(--card-bg);
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.timer-value {
    font-size: 1.5rem;
    font-weight: 700;
    font-family: monospace;
    color: var(--primary-color);
}

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

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

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

/* Passage Section */
.passage-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 0.75rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.passage-section h2 {
    font-size: 1.125rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.passage-text {
    line-height: 1.8;
    text-align: justify;
}

/* Question Cards */
.question-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 0.75rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.question-number {
    font-weight: 600;
    color: var(--primary-color);
}

.question-meta {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.question-text {
    margin-bottom: 1rem;
    font-weight: 500;
}

/* Options */
.options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.option {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.2s;
}

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

.option input[type="radio"] {
    display: none;
}

.option input[type="radio"]:checked + .option-label {
    background: var(--primary-color);
    color: white;
}

.option input[type="radio"]:checked ~ .option-text {
    color: var(--primary-color);
    font-weight: 500;
}

.option-label {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--border-color);
    border-radius: 50%;
    font-weight: 600;
    font-size: 0.875rem;
    flex-shrink: 0;
}

.option-text {
    flex: 1;
}

/* Quiz Actions */
.quiz-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.progress-indicator {
    color: var(--text-secondary);
}

#answered-count {
    font-weight: 600;
    color: var(--primary-color);
}

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

.results-header {
    text-align: center;
    margin-bottom: 2rem;
}

.quiz-date {
    color: var(--text-secondary);
}

.score-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    text-align: center;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-lg);
}

.score-main {
    margin-bottom: 0.5rem;
}

.score-value {
    font-size: 4rem;
    font-weight: 700;
    color: var(--primary-color);
}

.score-total {
    font-size: 2rem;
    color: var(--text-secondary);
}

.score-percentage {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.time-taken {
    color: var(--text-secondary);
}

/* Category Breakdown */
.category-breakdown {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 0.75rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.category-breakdown h2 {
    margin-bottom: 1rem;
}

.category-grid {
    display: grid;
    gap: 1rem;
}

.category-stat {
    display: grid;
    grid-template-columns: 1fr auto auto;
    align-items: center;
    gap: 1rem;
}

.category-name {
    font-size: 0.875rem;
}

.category-score {
    font-weight: 600;
    font-size: 0.875rem;
}

.category-bar {
    width: 100px;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

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

/* Review Cards */
.review-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 0.75rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--border-color);
}

.review-card.correct {
    border-left-color: var(--success-color);
}

.review-card.incorrect {
    border-left-color: var(--error-color);
}

.review-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.result-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.75rem;
    font-weight: 600;
}

.result-badge.correct {
    background: #dcfce7;
    color: var(--success-color);
}

.result-badge.incorrect {
    background: #fef2f2;
    color: var(--error-color);
}

.options-review {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin: 1rem 0;
}

.option-review {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    border-radius: 0.5rem;
    background: var(--bg-color);
}

.option-review.correct-answer {
    background: #dcfce7;
}

.option-review.wrong-answer {
    background: #fef2f2;
}

.checkmark {
    color: var(--success-color);
    font-weight: bold;
    margin-left: auto;
}

.crossmark {
    color: var(--error-color);
    font-weight: bold;
    margin-left: auto;
}

.explanation {
    background: #eff6ff;
    padding: 1rem;
    border-radius: 0.5rem;
    margin-top: 1rem;
}

.explanation strong {
    color: var(--primary-color);
}

.time-spent {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

/* Results Actions */
.results-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 2rem;
}

/* History Page */
.history-container h1 {
    margin-bottom: 2rem;
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.history-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 0.75rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-decoration: none;
    color: inherit;
    box-shadow: var(--shadow);
    transition: all 0.2s;
}

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

.history-date {
    font-weight: 600;
}

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

.history-score .percentage {
    color: var(--text-secondary);
}

.history-time {
    color: var(--text-secondary);
    font-family: monospace;
}

.no-history {
    text-align: center;
    padding: 3rem;
}

.no-history p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

/* No Quiz Page */
.no-quiz-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 50vh;
}

.no-quiz-card {
    background: var(--card-bg);
    padding: 3rem;
    border-radius: 1rem;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.no-quiz-card h1 {
    margin-bottom: 1rem;
}

.no-quiz-card p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.no-quiz-card .btn {
    margin-top: 1.5rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
    border-top: 1px solid var(--border-color);
}

/* Responsive */
@media (max-width: 640px) {
    .container {
        padding: 1rem;
    }

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

    .question-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .quiz-actions {
        flex-direction: column;
        gap: 1rem;
    }

    .category-stat {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .history-card {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .features {
        flex-direction: column;
    }
}