/* ===================================
   OpenAI Agent Builder Training Platform
   Apple-Inspired Design System
   =================================== */

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

:root {
    /* Apple SF Pro Font Stack */
    --font-primary: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    --font-mono: "SF Mono", Monaco, Consolas, "Courier New", monospace;
    
    /* Apple Color Palette */
    --color-primary: #007AFF;
    --color-primary-dark: #0051D5;
    --color-primary-light: #4DA2FF;
    
    --color-success: #34C759;
    --color-warning: #FF9500;
    --color-error: #FF3B30;
    
    --color-text-primary: #1d1d1f;
    --color-text-secondary: #6e6e73;
    --color-text-tertiary: #86868b;
    
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f5f5f7;
    --color-bg-tertiary: #e5e5e7;
    
    --color-border: #d2d2d7;
    --color-border-light: #e5e5e7;
    
    /* Spacing System */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-xxl: 64px;
    --spacing-xxxl: 96px;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-xl: 24px;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05), 0 2px 4px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.05), 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.06), 0 10px 10px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 17px;
    line-height: 1.47059;
    color: var(--color-text-primary);
    background: var(--color-bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.1;
    letter-spacing: -0.003em;
}

h1 {
    font-size: 56px;
    line-height: 1.07143;
    letter-spacing: -0.005em;
}

h2 {
    font-size: 48px;
    line-height: 1.08349;
    letter-spacing: -0.003em;
}

h3 {
    font-size: 32px;
    line-height: 1.125;
    letter-spacing: 0.004em;
}

h4 {
    font-size: 24px;
    line-height: 1.16667;
}

/* Responsive Typography */
@media (max-width: 1068px) {
    h1 { font-size: 48px; }
    h2 { font-size: 40px; }
    h3 { font-size: 28px; }
}

@media (max-width: 734px) {
    h1 { font-size: 40px; }
    h2 { font-size: 32px; }
    h3 { font-size: 24px; }
    body { font-size: 16px; }
}

/* ===================================
   Layout & Containers
   =================================== */
.container {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

@media (max-width: 734px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
}

.section {
    padding: var(--spacing-xxxl) 0;
}

@media (max-width: 734px) {
    .section {
        padding: var(--spacing-xl) 0;
    }
}

.alt-bg {
    background: var(--color-bg-secondary);
}

/* ===================================
   Hero Section
   =================================== */
.hero-section {
    background: linear-gradient(180deg, var(--color-bg-secondary) 0%, var(--color-bg-primary) 100%);
    padding: var(--spacing-xxxl) 0;
    text-align: center;
}

.hero-content {
    max-width: 980px;
    margin: 0 auto;
}

.hero-title {
    margin-bottom: var(--spacing-sm);
    animation: fadeInUp 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.hero-subtitle {
    font-size: 21px;
    line-height: 1.381;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
    animation: fadeInUp 0.8s cubic-bezier(0.4, 0, 0.2, 1) 0.1s backwards;
}

/* Form Styles */
.personalization-form {
    max-width: 700px;
    margin: var(--spacing-xxl) auto 0;
    background: var(--color-bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    text-align: left;
    animation: fadeInUp 0.8s cubic-bezier(0.4, 0, 0.2, 1) 0.2s backwards;
}

.form-title {
    font-size: 28px;
    margin-bottom: var(--spacing-xs);
    text-align: center;
}

.form-description {
    color: var(--color-text-secondary);
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.user-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.form-group label {
    font-weight: 500;
    font-size: 15px;
    color: var(--color-text-primary);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.form-group label i {
    color: var(--color-primary);
    font-size: 14px;
}

.form-group input,
.form-group textarea {
    font-family: var(--font-primary);
    font-size: 17px;
    padding: 12px 16px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    background: var(--color-bg-primary);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(0, 122, 255, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* Buttons */
.btn-primary,
.btn-secondary {
    font-family: var(--font-primary);
    font-size: 17px;
    font-weight: 500;
    padding: 14px 28px;
    border: none;
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-base);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

.btn-secondary:hover {
    background: var(--color-bg-tertiary);
    transform: translateY(-2px);
}

/* ===================================
   Section Headers
   =================================== */
.section-title {
    text-align: center;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-primary);
}

.section-subtitle {
    text-align: center;
    font-size: 21px;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

/* ===================================
   Video Overview Section
   =================================== */
.video-overview-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
    align-items: start;
}

@media (max-width: 1068px) {
    .video-overview-grid {
        grid-template-columns: 1fr;
    }
}

.video-container {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.video-wrapper {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
}

.video-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.video-meta {
    padding: var(--spacing-md);
}

.video-title {
    font-size: 21px;
    margin-bottom: var(--spacing-xs);
}

.video-author {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}

.video-duration {
    color: var(--color-text-tertiary);
    font-size: 15px;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.key-takeaways {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.takeaways-title {
    font-size: 24px;
}

.takeaway-cards {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.takeaway-card {
    background: var(--color-bg-primary);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

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

.takeaway-icon {
    font-size: 32px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.takeaway-card h4 {
    margin-bottom: var(--spacing-xs);
}

.takeaway-card p {
    color: var(--color-text-secondary);
    font-size: 15px;
    line-height: 1.5;
}

/* ===================================
   Learning Grid
   =================================== */
.learning-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

@media (max-width: 1068px) {
    .learning-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 734px) {
    .learning-grid {
        grid-template-columns: 1fr;
    }
}

.learning-card {
    background: var(--color-bg-primary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

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

.learning-icon {
    font-size: 40px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.learning-card h3 {
    font-size: 21px;
    margin-bottom: var(--spacing-sm);
}

.learning-card p {
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* ===================================
   Interactive Video with Timestamps
   =================================== */
.interactive-video-grid {
    display: grid;
    grid-template-columns: 350px 1fr;
    gap: var(--spacing-xl);
}

@media (max-width: 1068px) {
    .interactive-video-grid {
        grid-template-columns: 1fr;
    }
}

.timestamps-panel {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    height: fit-content;
    position: sticky;
    top: var(--spacing-md);
}

@media (max-width: 1068px) {
    .timestamps-panel {
        position: static;
    }
}

.timestamps-title {
    font-size: 19px;
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--color-border-light);
}

.timestamps-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    max-height: 600px;
    overflow-y: auto;
}

.timestamp-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.timestamp-item:hover {
    background: var(--color-bg-secondary);
}

.timestamp-item.active {
    background: rgba(0, 122, 255, 0.1);
    color: var(--color-primary);
}

.timestamp-time {
    font-family: var(--font-mono);
    font-size: 14px;
    font-weight: 600;
    color: var(--color-primary);
    min-width: 45px;
}

.timestamp-label {
    font-size: 15px;
    line-height: 1.4;
}

.video-player-section {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

/* ===================================
   Tools & Apps Grid
   =================================== */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
}

@media (max-width: 1068px) {
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 734px) {
    .tools-grid {
        grid-template-columns: 1fr;
    }
}

.tool-card {
    background: var(--color-bg-primary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
}

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

.tool-icon {
    font-size: 36px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.tool-card h3 {
    font-size: 19px;
    margin-bottom: var(--spacing-sm);
}

.tool-card p {
    color: var(--color-text-secondary);
    font-size: 15px;
    line-height: 1.5;
    flex-grow: 1;
    margin-bottom: var(--spacing-md);
}

.tool-link {
    color: var(--color-primary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    transition: all var(--transition-fast);
}

.tool-link:hover {
    gap: 12px;
}

/* ===================================
   Impact Grid
   =================================== */
.impact-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-xl);
}

@media (max-width: 1068px) {
    .impact-grid {
        grid-template-columns: 1fr;
    }
}

.impact-card {
    background: var(--color-bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

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

.impact-icon {
    font-size: 48px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.impact-card h3 {
    font-size: 28px;
    margin-bottom: var(--spacing-md);
}

.impact-stat {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md);
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.1) 0%, rgba(0, 122, 255, 0.05) 100%);
    border-radius: var(--radius-md);
}

.stat-number {
    font-size: 56px;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
}

.stat-label {
    font-size: 15px;
    color: var(--color-text-secondary);
    font-weight: 500;
}

.impact-card > p {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.5;
}

.impact-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.impact-list li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 15px;
    color: var(--color-text-secondary);
}

.impact-list i {
    color: var(--color-success);
    font-size: 14px;
}

/* ===================================
   Personalized SMB Section
   =================================== */
.personalized-section {
    border-top: 2px solid var(--color-primary);
}

.company-highlight {
    color: var(--color-primary);
    font-weight: 600;
}

.role-highlight {
    color: var(--color-primary);
    font-weight: 500;
}

.task-highlight {
    font-style: italic;
    color: var(--color-text-secondary);
}

.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
}

@media (max-width: 1068px) {
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
}

.use-case-card {
    background: var(--color-bg-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.use-case-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.use-case-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-lg);
    gap: var(--spacing-md);
}

.use-case-header h3 {
    font-size: 21px;
}

.use-case-badge {
    background: var(--color-primary);
    color: white;
    font-size: 13px;
    font-weight: 600;
    padding: 6px 12px;
    border-radius: 20px;
    white-space: nowrap;
}

.before-after {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

@media (max-width: 734px) {
    .before-after {
        grid-template-columns: 1fr;
    }
}

.before,
.after {
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
}

.before {
    background: rgba(255, 59, 48, 0.05);
    border: 1px solid rgba(255, 59, 48, 0.2);
}

.after {
    background: rgba(52, 199, 89, 0.05);
    border: 1px solid rgba(52, 199, 89, 0.2);
}

.before h4,
.after h4 {
    font-size: 17px;
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.before h4 i {
    color: var(--color-error);
}

.after h4 i {
    color: var(--color-success);
}

.scenario {
    font-size: 15px;
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: rgba(0, 0, 0, 0.02);
    border-radius: var(--radius-sm);
}

.before ul,
.after ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.before ul li,
.after ul li {
    font-size: 14px;
    color: var(--color-text-secondary);
}

.workflow-diagram {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
}

.workflow-diagram h4 {
    font-size: 17px;
    margin-bottom: var(--spacing-md);
}

.workflow-steps {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
}

@media (max-width: 734px) {
    .workflow-steps {
        flex-direction: column;
    }
}

.workflow-step {
    flex: 1;
    text-align: center;
}

.step-node {
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.workflow-step p {
    font-size: 13px;
    color: var(--color-text-secondary);
}

.workflow-arrow {
    color: var(--color-primary);
    font-size: 20px;
}

@media (max-width: 734px) {
    .workflow-arrow {
        transform: rotate(90deg);
    }
}

.implementation-cta {
    margin-top: var(--spacing-xxl);
    text-align: center;
    padding: var(--spacing-xl);
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.1) 0%, rgba(0, 122, 255, 0.05) 100%);
    border-radius: var(--radius-lg);
}

.implementation-cta h3 {
    font-size: 28px;
    margin-bottom: var(--spacing-sm);
}

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

/* ===================================
   Exercises Section
   =================================== */
.exercises-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.exercise-card {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.exercise-header {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
    padding: var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.exercise-number {
    background: rgba(255, 255, 255, 0.2);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 700;
}

.exercise-header h3 {
    flex: 1;
    font-size: 24px;
}

.exercise-difficulty {
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
}

.exercise-difficulty.easy {
    background: var(--color-success);
    color: white;
}

.exercise-difficulty.medium {
    background: var(--color-warning);
    color: white;
}

.exercise-difficulty.hard {
    background: var(--color-error);
    color: white;
}

.exercise-content {
    padding: var(--spacing-xl);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.exercise-objective,
.exercise-steps,
.exercise-code,
.exercise-tips {
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
}

.exercise-objective {
    background: rgba(0, 122, 255, 0.05);
    border-left: 4px solid var(--color-primary);
}

.exercise-steps {
    background: var(--color-bg-secondary);
}

.exercise-code {
    background: var(--color-text-primary);
    color: #f0f0f0;
}

.exercise-tips {
    background: rgba(52, 199, 89, 0.05);
    border-left: 4px solid var(--color-success);
}

.exercise-objective h4,
.exercise-steps h4,
.exercise-code h4,
.exercise-tips h4 {
    font-size: 17px;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.exercise-code h4 {
    color: white;
}

.exercise-objective p,
.exercise-tips p {
    color: var(--color-text-secondary);
}

.exercise-steps ol {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    padding-left: var(--spacing-md);
}

.exercise-steps li {
    padding-left: var(--spacing-sm);
}

.exercise-steps strong {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text-primary);
}

.exercise-steps p,
.exercise-steps code {
    color: var(--color-text-secondary);
    font-size: 15px;
}

.exercise-code pre {
    overflow-x: auto;
    margin: 0;
}

.exercise-code code {
    font-family: var(--font-mono);
    font-size: 14px;
    line-height: 1.6;
    display: block;
    color: #f0f0f0;
}

.exercise-tips ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.exercise-tips li {
    color: var(--color-text-secondary);
    font-size: 15px;
    padding-left: var(--spacing-md);
    position: relative;
}

.exercise-tips li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--color-success);
    font-weight: bold;
}

/* ===================================
   Knowledge Check / Quiz
   =================================== */
.quiz-container {
    max-width: 800px;
    margin: 0 auto;
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: var(--spacing-xl);
}

.quiz-progress {
    margin-bottom: var(--spacing-lg);
}

.progress-bar {
    height: 8px;
    background: var(--color-bg-secondary);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: var(--spacing-sm);
}

.progress-fill {
    height: 100%;
    background: var(--color-primary);
    transition: width var(--transition-slow);
    width: 20%;
}

.progress-text {
    text-align: center;
    color: var(--color-text-secondary);
    font-size: 15px;
}

.quiz-questions {
    position: relative;
}

.quiz-question {
    display: none;
    animation: fadeIn 0.4s ease;
}

.quiz-question.active {
    display: block;
}

.question-text {
    font-size: 21px;
    margin-bottom: var(--spacing-lg);
    line-height: 1.4;
}

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

.quiz-option {
    position: relative;
}

.quiz-option input[type="radio"] {
    position: absolute;
    opacity: 0;
}

.quiz-option label {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-bg-secondary);
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
}

.quiz-option:hover label {
    background: var(--color-bg-tertiary);
}

.quiz-option input[type="radio"]:checked + label {
    background: rgba(0, 122, 255, 0.1);
    border-color: var(--color-primary);
}

.quiz-option.correct label {
    background: rgba(52, 199, 89, 0.1);
    border-color: var(--color-success);
}

.quiz-option.incorrect label {
    background: rgba(255, 59, 48, 0.1);
    border-color: var(--color-error);
}

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

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

.quiz-option.correct .option-letter {
    background: var(--color-success);
    color: white;
}

.quiz-option.incorrect .option-letter {
    background: var(--color-error);
    color: white;
}

.option-text {
    flex: 1;
    font-size: 17px;
}

.question-feedback {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    display: none;
}

.question-feedback.show {
    display: block;
    animation: fadeIn 0.4s ease;
}

.question-feedback.correct {
    background: rgba(52, 199, 89, 0.1);
    color: var(--color-success);
}

.question-feedback.incorrect {
    background: rgba(255, 59, 48, 0.1);
    color: var(--color-error);
}

/* Quiz Score */
.quiz-score {
    text-align: center;
}

.score-circle {
    position: relative;
    width: 200px;
    height: 200px;
    margin: 0 auto var(--spacing-lg);
}

.score-circle svg {
    transform: rotate(-90deg);
}

.score-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.score-number {
    font-size: 48px;
    font-weight: 700;
    color: var(--color-primary);
}

.score-label {
    font-size: 15px;
    color: var(--color-text-secondary);
}

.score-message {
    font-size: 28px;
    margin-bottom: var(--spacing-sm);
}

.score-encouragement {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
}

/* ===================================
   Flashcards Section
   =================================== */
.flashcard-section {
    margin-bottom: var(--spacing-xxl);
}

.flashcard-section-title {
    font-size: 28px;
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    color: var(--color-text-primary);
}

.flashcard-section-title i {
    color: var(--color-primary);
}

.flashcard-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
}

@media (max-width: 1068px) {
    .flashcard-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 734px) {
    .flashcard-grid {
        grid-template-columns: 1fr;
    }
}

.flashcard {
    perspective: 1000px;
    height: 300px;
    cursor: pointer;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    box-shadow: var(--shadow-md);
}

.flashcard-front {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: white;
}

.flashcard-back {
    background: var(--color-bg-primary);
    color: var(--color-text-primary);
    transform: rotateY(180deg);
    border: 2px solid var(--color-primary);
}

.card-number {
    position: absolute;
    top: var(--spacing-sm);
    left: var(--spacing-sm);
    background: rgba(255, 255, 255, 0.2);
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 14px;
}

.flashcard-back .card-number {
    background: rgba(0, 122, 255, 0.1);
    color: var(--color-primary);
}

.card-icon,
.answer-icon {
    font-size: 48px;
    margin-bottom: var(--spacing-md);
}

.flashcard-front h4 {
    font-size: 21px;
    margin-bottom: var(--spacing-md);
}

.flip-hint {
    font-size: 13px;
    opacity: 0.8;
    margin-top: auto;
}

.flashcard-back p {
    font-size: 17px;
    line-height: 1.5;
    color: var(--color-text-secondary);
}

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

.flashcard-stats {
    margin-top: var(--spacing-xxl);
    display: flex;
    justify-content: center;
    gap: var(--spacing-xxl);
    padding: var(--spacing-xl);
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
}

.stat-item i {
    font-size: 32px;
    color: var(--color-primary);
}

.stat-value {
    font-size: 36px;
    font-weight: 700;
    color: var(--color-primary);
}

.stat-label {
    font-size: 15px;
    color: var(--color-text-secondary);
}

/* ===================================
   FAQ Section
   =================================== */
.faq-container {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.faq-item {
    background: var(--color-bg-primary);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: all var(--transition-base);
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
}

.faq-question {
    padding: var(--spacing-lg);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    user-select: none;
}

.faq-question h3 {
    font-size: 19px;
    color: var(--color-text-primary);
}

.faq-question i {
    color: var(--color-primary);
    font-size: 20px;
    transition: transform var(--transition-base);
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow);
}

.faq-item.active .faq-answer {
    max-height: 1000px;
}

.faq-answer p {
    padding: 0 var(--spacing-lg) var(--spacing-lg);
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* ===================================
   Additional Tips Section
   =================================== */
.tips-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-lg);
}

@media (max-width: 1068px) {
    .tips-grid {
        grid-template-columns: 1fr;
    }
}

.tip-card {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: all var(--transition-base);
}

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

.tip-header {
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.1) 0%, rgba(0, 122, 255, 0.05) 100%);
    padding: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.tip-icon {
    font-size: 32px;
    color: var(--color-primary);
}

.tip-header h3 {
    font-size: 21px;
}

.tip-content {
    padding: var(--spacing-lg);
}

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

.tip-source {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 14px;
    color: var(--color-text-tertiary);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border-light);
}

.tip-source a {
    color: var(--color-primary);
    text-decoration: none;
}

.tip-source a:hover {
    text-decoration: underline;
}

.resources-section {
    margin-top: var(--spacing-xxl);
    padding: var(--spacing-xl);
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.resources-title {
    font-size: 28px;
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.resource-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-md);
}

.resource-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--color-bg-secondary);
    color: var(--color-text-primary);
    text-decoration: none;
    border-radius: var(--radius-xl);
    transition: all var(--transition-base);
    font-size: 15px;
    font-weight: 500;
}

.resource-link:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.resource-link i {
    font-size: 16px;
}

/* ===================================
   Screenshots Section
   =================================== */
.screenshot-gallery {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xxl);
}

.screenshot-item {
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.screenshot-item img {
    width: 100%;
    height: auto;
    display: block;
}

.screenshot-caption {
    padding: var(--spacing-lg);
}

.screenshot-caption h4 {
    font-size: 21px;
    margin-bottom: var(--spacing-sm);
}

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

.visual-tips {
    margin-top: var(--spacing-xxl);
    padding: var(--spacing-xl);
    background: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.visual-tips-title {
    font-size: 28px;
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.visual-tips-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
}

@media (max-width: 1068px) {
    .visual-tips-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 734px) {
    .visual-tips-grid {
        grid-template-columns: 1fr;
    }
}

.visual-tip {
    text-align: center;
    padding: var(--spacing-md);
}

.visual-tip i {
    font-size: 40px;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.visual-tip h4 {
    font-size: 17px;
    margin-bottom: var(--spacing-xs);
}

.visual-tip p {
    font-size: 15px;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

/* ===================================
   Footer CTA
   =================================== */
#footer-cta {
    background: linear-gradient(180deg, var(--color-bg-secondary) 0%, var(--color-bg-primary) 100%);
}

.cta-box {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    padding: var(--spacing-xxl);
    background: var(--color-bg-primary);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
}

.cta-title {
    font-size: 40px;
    margin-bottom: var(--spacing-sm);
}

.cta-subtitle {
    font-size: 21px;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* ===================================
   Footer
   =================================== */
.site-footer {
    background: var(--color-text-primary);
    color: var(--color-bg-secondary);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.site-footer p {
    color: var(--color-text-tertiary);
    font-size: 15px;
    margin-bottom: var(--spacing-xs);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--color-text-tertiary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

/* ===================================
   Animations
   =================================== */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* ===================================
   Accessibility
   =================================== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Focus styles for accessibility */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Reduced motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}