/* ============================================
   Biology Exams - Stylesheet
   Color Scheme:
   - Primary (Deep Teal): #115e59
   - Secondary (Sage): #5eead4
   - Accent (Warm Orange): #ea580c
   - Background (Warm Off-White): #fafaf9
   - Card/Surface (Cream): #fffbeb
   - Text (Dark Brown-Gray): #292524
   - Success (Muted Green): #16a34a
   - Error (Soft Red): #dc2626
   
   Performance Optimizations Applied:
   - GPU-accelerated animations
   - content-visibility for lazy rendering
   - will-change hints for smooth animations
   - Reduced reflows with transform instead of layout props
   ============================================ */

/* Reset & Base Styles */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Performance: Enable hardware acceleration globally */
html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

:root {
    --primary: #115e59;
    --primary-light: #0f766e;
    --primary-dark: #0d4a44;
    --secondary: #5eead4;
    --accent: #ea580c;
    --accent-hover: #c2410c;
    --background: #fafaf9;
    --surface: #fffbeb;
    --surface-hover: #fef3c7;
    --text: #292524;
    --text-light: #78716c;
    --success: #16a34a;
    --success-light: #dcfce7;
    --error: #dc2626;
    --error-light: #fee2e2;
    --border: #e7e5e4;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-lg: rgba(0, 0, 0, 0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    /* Performance: Faster transitions */
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease-out;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    direction: rtl;
    /* Performance: Prevent layout shifts */
    overflow-x: hidden;
}

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

/* Pages */
.page {
    display: none;
    min-height: 100vh;
}

.page.active {
    display: block;
    animation: fadeIn 0.4s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Header */
.header {
    text-align: center;
    padding: 40px 20px;
    margin-bottom: 30px;
}

.main-title {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 10px;
    font-weight: 700;
}

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

/* User Section */
.user-section {
    max-width: 500px;
    margin: 0 auto 40px;
    text-align: center;
}

.input-label {
    display: block;
    margin-bottom: 12px;
    font-size: 1.1rem;
    color: var(--text);
    font-weight: 500;
}

.name-input {
    width: 100%;
    padding: 14px 20px;
    font-size: 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    background-color: var(--surface);
    color: var(--text);
    transition: var(--transition);
    margin-bottom: 16px;
    text-align: center;
}

.name-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(17, 94, 89, 0.1);
}

.name-input::placeholder {
    color: var(--text-light);
}

/* Buttons */
.btn {
    padding: 12px 28px;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: inherit;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

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

.btn-secondary:hover:not(:disabled) {
    background-color: var(--surface-hover);
    border-color: var(--primary);
}

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

.btn-accent:hover:not(:disabled) {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.btn-icon {
    background: none;
    border: none;
    padding: 8px;
    color: var(--text-light);
    cursor: pointer;
    transition: var(--transition);
}

.btn-icon:hover {
    color: var(--primary);
    transform: scale(1.1);
}

.btn-exam {
    width: 100%;
    margin-top: 16px;
    padding: 14px;
}

/* Greeting */
.greeting-container {
    padding: 20px;
    background-color: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 8px var(--shadow);
}

.greeting {
    font-size: 1.3rem;
    color: var(--primary);
    margin-bottom: 12px;
    font-weight: 600;
}

#display-name {
    color: var(--accent);
}

/* Exam Selection */
.section-title {
    text-align: center;
    font-size: 1.8rem;
    color: var(--primary);
    margin-bottom: 30px;
    font-weight: 700;
}

.exams-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 30px;
}

.exam-card {
    background-color: var(--surface);
    border-radius: var(--radius-lg);
    padding: 28px;
    text-align: center;
    transition: var(--transition);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.exam-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transform: scaleX(0);
    transition: var(--transition);
}

.exam-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 24px var(--shadow-lg);
    border-color: var(--secondary);
}

.exam-card:hover::before {
    transform: scaleX(1);
}

.exam-icon {
    font-size: 3rem;
    margin-bottom: 16px;
}

.exam-title {
    font-size: 1.4rem;
    color: var(--primary);
    margin-bottom: 12px;
    font-weight: 700;
}

.exam-description {
    color: var(--text-light);
    margin-bottom: 16px;
    font-size: 0.95rem;
    min-height: 48px;
}

.exam-meta {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.exam-questions,
.exam-marks {
    background-color: var(--primary-light);
    color: white;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 600;
}

.exam-score {
    margin-bottom: 12px;
    padding: 8px;
    background-color: var(--success-light);
    color: var(--success);
    border-radius: var(--radius-sm);
    font-weight: 600;
    display: none;
}

.exam-score.show {
    display: block;
}

/* Exam Page */
.exam-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border);
}

.exam-page-title {
    font-size: 1.5rem;
    color: var(--primary);
    font-weight: 700;
}

.timer {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--accent);
    background-color: var(--surface);
    padding: 10px 20px;
    border-radius: var(--radius-md);
    font-family: 'Courier New', monospace;
}

/* Progress */
.progress-container {
    margin-bottom: 30px;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 0.95rem;
    color: var(--text-light);
}

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

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    border-radius: var(--radius-sm);
    transition: width 0.5s ease-out;
    width: 0%;
}

/* Question */
.question-container {
    background-color: var(--surface);
    border-radius: var(--radius-lg);
    padding: 30px;
    margin-bottom: 24px;
    box-shadow: 0 2px 8px var(--shadow);
}

.question-header {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 20px;
    align-items: center;
}

.question-number {
    background-color: var(--primary);
    color: white;
    padding: 6px 16px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.question-type {
    background-color: var(--surface-hover);
    padding: 6px 16px;
    border-radius: var(--radius-sm);
    color: var(--text-light);
    font-size: 0.9rem;
}

.question-marks {
    background-color: var(--accent);
    color: white;
    padding: 6px 16px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.question-text {
    font-size: 1.2rem;
    color: var(--text);
    margin-bottom: 24px;
    line-height: 1.8;
    font-weight: 500;
}

/* Options */
.options-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option {
    background-color: white;
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1rem;
}

.option:hover:not(.disabled) {
    border-color: var(--primary);
    background-color: var(--surface-hover);
    transform: translateX(-4px);
}

.option.selected {
    border-color: var(--primary);
    background-color: var(--primary-light);
    color: white;
}

.option.disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

.option-letter {
    width: 36px;
    height: 36px;
    background-color: var(--secondary);
    color: var(--primary-dark);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

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

/* Navigation */
.navigation-buttons {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    margin-top: 30px;
}

.navigation-buttons .btn {
    flex: 1;
    max-width: 200px;
}

/* Results Page */
.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 30px;
    border-bottom: 2px solid var(--border);
}

.results-title {
    font-size: 1.8rem;
    color: var(--primary);
    font-weight: 700;
}

.score-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    margin-bottom: 40px;
}

.score-card {
    background-color: var(--surface);
    border-radius: var(--radius-lg);
    padding: 30px;
    text-align: center;
    box-shadow: 0 4px 12px var(--shadow);
}

.score-label {
    font-size: 1rem;
    color: var(--text-light);
    margin-bottom: 10px;
}

.score-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 5px;
}

.score-total {
    color: var(--text-light);
    font-size: 1.1rem;
}

.score-percentage {
    display: flex;
    align-items: center;
    justify-content: center;
}

.percentage-circle {
    width: 120px;
    height: 120px;
}

.percentage-circle .circle-bg {
    fill: none;
    stroke: var(--border);
    stroke-width: 3;
}

.percentage-circle .circle-fill {
    fill: none;
    stroke: var(--success);
    stroke-width: 3;
    stroke-linecap: round;
    transition: stroke-dasharray 1s ease-out;
}

.percentage-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.score-details {
    display: flex;
    flex-direction: column;
    gap: 12px;
    justify-content: center;
}

.detail-item {
    display: flex;
    justify-content: space-between;
    padding: 12px 16px;
    background-color: white;
    border-radius: var(--radius-md);
}

.detail-label {
    color: var(--text-light);
}

.detail-value {
    font-weight: 700;
    font-size: 1.1rem;
}

.detail-value.correct {
    color: var(--success);
}

.detail-value.incorrect {
    color: var(--error);
}

.detail-value.unanswered {
    color: var(--text-light);
}

/* Questions Review */
.review-title {
    font-size: 1.5rem;
    color: var(--primary);
    margin-bottom: 20px;
    font-weight: 700;
}

.review-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
    /* Performance: Enable contain for layout optimization */
    contain: layout style;
}

.review-item {
    background-color: var(--surface);
    border-radius: var(--radius-lg);
    padding: 24px;
    border-right: 4px solid var(--border);
    transition: var(--transition-fast);
    /* Performance: Lazy render off-screen items */
    content-visibility: auto;
    contain-intrinsic-size: auto 200px;
}

.review-item.correct {
    border-right-color: var(--success);
    background-color: var(--success-light);
}

.review-item.incorrect {
    border-right-color: var(--error);
    background-color: var(--error-light);
}

.review-item.unanswered {
    border-right-color: var(--text-light);
}

.review-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 10px;
}

.review-number {
    background-color: var(--primary);
    color: white;
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.review-status {
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.9rem;
}

.review-status.correct {
    background-color: var(--success);
    color: white;
}

.review-status.incorrect {
    background-color: var(--error);
    color: white;
}

.review-status.unanswered {
    background-color: var(--text-light);
    color: white;
}

.review-question {
    font-size: 1.1rem;
    margin-bottom: 16px;
    font-weight: 500;
    line-height: 1.7;
}

.review-answer-section {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.user-answer-label,
.correct-answer-label {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 6px;
}

.user-answer-label {
    color: var(--error);
}

.correct-answer-label {
    color: var(--success);
}

.user-answer,
.correct-answer {
    padding: 10px 16px;
    border-radius: var(--radius-md);
    margin-bottom: 12px;
}

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

.correct-answer {
    background-color: rgba(22, 163, 74, 0.1);
    border: 1px solid var(--success);
}

.explanation-section {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.explanation-title {
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 8px;
}

.explanation-text {
    color: var(--text-light);
    line-height: 1.8;
    font-size: 0.95rem;
}

.model-answer {
    background-color: white;
    padding: 16px;
    border-radius: var(--radius-md);
    margin-top: 12px;
    border: 1px solid var(--border);
}

.model-answer-title {
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 8px;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.95);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

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

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

.loading-text {
    margin-top: 20px;
    color: var(--text-light);
    font-size: 1.1rem;
}

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

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

    .subtitle {
        font-size: 1rem;
    }

    .exams-grid {
        grid-template-columns: 1fr;
    }

    .exam-header {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }

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

    .question-text {
        font-size: 1.1rem;
    }

    .navigation-buttons {
        flex-direction: column-reverse;
    }

    .navigation-buttons .btn {
        max-width: 100%;
        width: 100%;
    }

    .score-summary {
        grid-template-columns: 1fr;
    }

    .score-value {
        font-size: 2.5rem;
    }

    .percentage-circle {
        width: 100px;
        height: 100px;
    }

    .percentage-text {
        font-size: 1.3rem;
    }

    .review-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .container {
        padding: 15px;
    }

    .question-container {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    .main-title {
        font-size: 1.6rem;
    }

    .exam-card {
        padding: 20px;
    }

    .question-container {
        padding: 16px;
    }

    .option {
        padding: 12px 16px;
        font-size: 0.95rem;
    }

    .timer {
        font-size: 1.1rem;
        padding: 8px 16px;
    }
}

/* Print Styles */
@media print {

    .btn,
    .navigation-buttons,
    .loading-overlay {
        display: none !important;
    }

    .page {
        display: block !important;
    }

    body {
        background-color: white;
    }

    .question-container,
    .review-item {
        box-shadow: none;
        border: 1px solid var(--border);
        page-break-inside: avoid;
    }
}