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

:root {
    /* Colors */
    --bg-page: #000000;
    --bg-surface: #141414;
    --border-subtle: #262626;
    --border-hover: #3F3F46;
    --primary-500: #007AC2;
    --primary-300: #40A5E6;
    --text-primary: #E4E4E7;
    --text-secondary: #A1A1AA;
    --text-inverse: #FFFFFF;
    --success: #22C55E;
    --error: #EF4444;
    --warning: #F59E0B;
    
    /* Typography */
    --font-primary: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    
    /* Spacing */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-xxl: 64px;
    
    /* Border Radius */
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition-fast: 0.2s ease-in-out;
    --transition-smooth: 0.25s ease-out;
}

/* Loading Screen */
#loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-page);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.loading-content {
    text-align: center;
    color: var(--text-primary);
}

.loading-logo {
    font-size: 48px;
    margin-bottom: var(--spacing-md);
    animation: pulse 2s infinite;
}

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

.loading-content h2 {
    font-family: var(--font-primary);
    font-size: 24px;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.loading-bar {
    width: 200px;
    height: 4px;
    background: var(--border-subtle);
    border-radius: 2px;
    overflow: hidden;
    margin: 0 auto var(--spacing-sm);
}

.loading-progress {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-500), var(--primary-300));
    width: 0%;
    animation: loading 3s ease-in-out forwards;
}

@keyframes loading {
    to { width: 100%; }
}

.loading-content p {
    font-size: 14px;
    color: var(--text-secondary);
}

/* App Layout */
.app {
    display: flex;
    min-height: 100vh;
    background: var(--bg-page);
    color: var(--text-primary);
    font-family: var(--font-primary);
}

/* Sidebar */
.sidebar {
    width: 280px;
    background: var(--bg-surface);
    border-right: 1px solid var(--border-subtle);
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    z-index: 1000;
}

.sidebar-header {
    padding: var(--spacing-xl) var(--spacing-md);
    border-bottom: 1px solid var(--border-subtle);
}

.sidebar-header h1 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.overall-progress {
    margin-bottom: var(--spacing-sm);
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-subtle);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: var(--spacing-xs);
}

.progress-fill {
    height: 100%;
    background: var(--primary-500);
    width: 0%;
    transition: width var(--transition-smooth);
}

.progress-text {
    font-size: 12px;
    color: var(--text-secondary);
}

.nav-menu {
    padding: var(--spacing-sm) 0;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    border-left: 3px solid transparent;
}

.nav-item:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.nav-item.active {
    background: rgba(0, 122, 194, 0.1);
    border-left-color: var(--primary-500);
    color: var(--text-primary);
}

.nav-icon {
    font-size: 20px;
    margin-right: var(--spacing-sm);
    width: 24px;
    text-align: center;
}

.nav-content {
    flex: 1;
}

.nav-content span {
    display: block;
    font-weight: 500;
    font-size: 14px;
}

.nav-content small {
    display: block;
    font-size: 11px;
    color: var(--text-secondary);
    margin-top: 2px;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: 280px;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.header {
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-subtle);
    padding: var(--spacing-md) var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 20px;
    cursor: pointer;
}

.header h1 {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-primary);
}

/* Content Area */
.content {
    flex: 1;
    padding: var(--spacing-xl);
    max-width: 1440px;
    width: 100%;
}

/* Views */
.view {
    display: none;
}

.view.active {
    display: block;
}

/* Hero Section */
.hero-section {
    text-align: center;
    margin-bottom: var(--spacing-xxl);
}

.hero-section h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
}

.hero-description {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
}

.exam-info {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.info-card {
    background: var(--bg-surface);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    min-width: 150px;
    text-align: center;
    transition: all var(--transition-smooth);
}

.info-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-2px);
}

.info-card h3 {
    font-size: 24px;
    font-weight: 600;
    color: var(--primary-500);
    margin-bottom: var(--spacing-xs);
}

.info-card p {
    font-size: 14px;
    color: var(--text-secondary);
}

/* Domains Overview */
.domains-overview {
    margin-top: var(--spacing-xxl);
}

.domains-overview h2 {
    font-size: 32px;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.domains-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.domain-card {
    background: var(--bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    padding: var(--spacing-md);
    transition: all var(--transition-smooth);
    cursor: pointer;
}

.domain-card:hover {
    border-color: var(--primary-500);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 122, 194, 0.2);
}

.domain-header {
    display: flex;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.domain-number {
    background: var(--primary-500);
    color: var(--text-inverse);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    margin-right: var(--spacing-sm);
}

.domain-header h3 {
    font-size: 20px;
    font-weight: 600;
    flex: 1;
}

.domain-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

.domain-weight {
    background: rgba(0, 122, 194, 0.1);
    color: var(--primary-500);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    font-size: 12px;
    font-weight: 500;
    display: inline-block;
}

/* Domain Header Section */
.domain-header-section {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border-subtle);
}

.domain-header-section h1 {
    font-size: 32px;
    font-weight: 600;
}

.domain-stats {
    display: flex;
    gap: var(--spacing-md);
}

.domain-stats span {
    background: var(--bg-surface);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    font-size: 14px;
    border: 1px solid var(--border-subtle);
}

.domain-stats .weight {
    color: var(--primary-500);
    font-weight: 500;
}

/* Concept Cards */
.concept-cards {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xxl);
}

.concept-card {
    background: var(--bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    padding: var(--spacing-md);
    transition: all var(--transition-smooth);
}

.concept-card:hover {
    border-color: var(--border-hover);
}

.concept-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.concept-card > p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.concept-details h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--primary-500);
}

.concept-details p, .concept-details li {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

.concept-details ul {
    margin-left: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.concept-details li {
    margin-bottom: var(--spacing-xs);
}

/* Quiz Section */
.quiz-section {
    margin-top: var(--spacing-xxl);
}

.quiz-section h2 {
    font-size: 32px;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.quiz-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-lg);
}

.quiz-card {
    background: var(--bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    padding: var(--spacing-md);
    transition: all var(--transition-smooth);
}

.quiz-card:hover {
    border-color: var(--primary-500);
    transform: translateY(-2px);
}

.quiz-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.quiz-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.quiz-meta {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    font-size: 12px;
    color: var(--text-secondary);
}

.quiz-meta span {
    background: rgba(255, 255, 255, 0.05);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
}

/* Buttons */
.btn-primary {
    background: var(--primary-500);
    color: var(--text-inverse);
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 14px;
}

.btn-primary:hover {
    background: var(--primary-300);
    transform: translateY(-2px);
}

.btn-primary:active {
    transform: translateY(0px) scale(0.98);
}

.btn-secondary {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-subtle);
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 14px;
}

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

/* Quiz Modal */
.quiz-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    padding: var(--spacing-md);
}

.quiz-modal.active {
    display: flex;
}

.quiz-content {
    background: var(--bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    width: 100%;
    max-width: 800px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
}

.quiz-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border-subtle);
}

.quiz-header h2 {
    font-size: 24px;
    font-weight: 600;
}

.quiz-close {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 20px;
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.quiz-close:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

.quiz-progress {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.quiz-progress .progress-bar {
    width: 100px;
    height: 6px;
}

.quiz-progress .progress-fill {
    background: var(--primary-500);
}

.quiz-progress-text {
    font-size: 12px;
    color: var(--text-secondary);
}

.quiz-body {
    flex: 1;
    padding: var(--spacing-md);
    overflow-y: auto;
}

.question-container {
    margin-bottom: var(--spacing-md);
}

.question {
    font-size: 18px;
    font-weight: 500;
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.options {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.option {
    background: var(--bg-page);
    border: 2px solid var(--border-subtle);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    min-height: 52px;
    display: flex;
    align-items: center;
}

.option:hover {
    border-color: var(--border-hover);
    background: #1F1F1F;
    transform: scale(1.01);
}

.option.selected {
    border-color: var(--primary-500);
    background: rgba(0, 122, 194, 0.1);
}

.option.correct {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.1);
}

.option.incorrect {
    border-color: var(--error);
    background: rgba(239, 68, 68, 0.1);
}

.option .option-letter {
    font-weight: 600;
    margin-right: var(--spacing-sm);
    color: var(--primary-500);
    width: 20px;
}

.option .option-text {
    flex: 1;
    line-height: 1.5;
}

.option .feedback-icon {
    margin-left: var(--spacing-sm);
    font-size: 16px;
}

.explanation {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: rgba(0, 122, 194, 0.05);
    border-left: 3px solid var(--primary-500);
    border-radius: var(--radius-md);
}

.explanation h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-500);
}

.explanation p {
    line-height: 1.6;
    color: var(--text-secondary);
}

.quiz-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    border-top: 1px solid var(--border-subtle);
}

.quiz-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.quiz-status {
    font-size: 14px;
    color: var(--text-secondary);
}

/* Results Modal */
.results-content {
    text-align: center;
}

.score-display {
    margin-bottom: var(--spacing-lg);
}

.score-circle {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: conic-gradient(var(--primary-500) 0deg, var(--primary-500) 0deg, var(--border-subtle) 0deg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-md);
    position: relative;
}

.score-circle::before {
    content: '';
    position: absolute;
    width: 80px;
    height: 80px;
    background: var(--bg-surface);
    border-radius: 50%;
}

.score-percentage {
    position: relative;
    z-index: 1;
    font-size: 24px;
    font-weight: 600;
    color: var(--primary-500);
}

.results-content h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.results-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.results-breakdown h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    text-align: left;
}

.topic-breakdown {
    text-align: left;
}

.topic-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xs) 0;
    border-bottom: 1px solid var(--border-subtle);
}

.topic-item:last-child {
    border-bottom: none;
}

.topic-name {
    font-size: 14px;
}

.topic-score {
    font-size: 14px;
    font-weight: 500;
}

.topic-score.excellent {
    color: var(--success);
}

.topic-score.good {
    color: var(--primary-500);
}

.topic-score.needs-improvement {
    color: var(--warning);
}

/* Mobile Navigation */
.mobile-nav {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-surface);
    border-top: 1px solid var(--border-subtle);
    padding: var(--spacing-xs);
    z-index: 1000;
}

.mobile-nav-item {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    font-size: 11px;
}

.mobile-nav-item.active {
    color: var(--primary-500);
}

.mobile-nav-item span {
    font-size: 18px;
}

.mobile-nav-item small {
    font-size: 10px;
}

/* Responsive Design */
@media (max-width: 1023px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform var(--transition-smooth);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .hero-section h1 {
        font-size: 36px;
    }
    
    .exam-info {
        gap: var(--spacing-sm);
    }
    
    .domains-grid {
        grid-template-columns: 1fr;
    }
    
    .domain-header-section {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }
    
    .quiz-cards {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 767px) {
    .content {
        padding: var(--spacing-md);
    }
    
    .hero-section h1 {
        font-size: 28px;
    }
    
    .hero-description {
        font-size: 16px;
    }
    
    .exam-info {
        flex-direction: column;
        align-items: center;
    }
    
    .concept-cards {
        gap: var(--spacing-md);
    }
    
    .concept-card {
        padding: var(--spacing-sm);
    }
    
    .quiz-content {
        margin: var(--spacing-xs);
        max-height: 95vh;
    }
    
    .quiz-header {
        padding: var(--spacing-sm);
        flex-wrap: wrap;
        gap: var(--spacing-sm);
    }
    
    .quiz-body {
        padding: var(--spacing-sm);
    }
    
    .quiz-footer {
        padding: var(--spacing-sm);
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .mobile-nav {
        display: flex;
    }
}

/* Animations */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.view.active {
    animation: slideIn 0.3s ease-out;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-surface);
}

::-webkit-scrollbar-thumb {
    background: var(--border-subtle);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border-hover);
}

/* Print Styles */
@media print {
    .sidebar,
    .mobile-nav,
    .quiz-modal {
        display: none !important;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .header {
        position: static;
    }
    
    .content {
        padding: 0;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .concept-card,
    .domain-card {
        break-inside: avoid;
        border: 1px solid #ccc;
    }
}