/* ============================================
   AI MASTERY FOR PROFESSIONALS
   Design System & Styles
   ============================================ */

/* --- CSS Variables / Design Tokens --- */
:root {
    /* Colors - warm, professional, welcoming */
    --color-primary: #2563EB;
    --color-primary-hover: #1D4ED8;
    --color-primary-light: #DBEAFE;
    --color-primary-subtle: #EFF6FF;
    --color-accent: #7C3AED;
    --color-accent-light: #EDE9FE;
    --color-success: #059669;
    --color-success-light: #D1FAE5;
    --color-warning: #D97706;
    --color-warning-light: #FEF3C7;
    --color-danger: #DC2626;
    --color-danger-light: #FEE2E2;

    --color-bg: #FAFBFC;
    --color-surface: #FFFFFF;
    --color-surface-hover: #F8FAFC;
    --color-border: #E2E8F0;
    --color-border-light: #F1F5F9;

    --color-text: #1E293B;
    --color-text-secondary: #475569;
    --color-text-muted: #94A3B8;
    --color-text-inverse: #FFFFFF;

    /* Typography */
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-heading: 'Merriweather', Georgia, serif;

    --text-xs: 0.8125rem;
    --text-sm: 0.9375rem;
    --text-base: 1.0625rem;
    --text-lg: 1.1875rem;
    --text-xl: 1.375rem;
    --text-2xl: 1.75rem;
    --text-3xl: 2.25rem;
    --text-4xl: 3rem;

    --leading-tight: 1.3;
    --leading-normal: 1.7;
    --leading-relaxed: 1.85;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Layout */
    --sidebar-width: 320px;
    --topbar-height: 64px;
    --content-max-width: 800px;
    --border-radius: 10px;
    --border-radius-lg: 16px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 8px 10px -6px rgba(0,0,0,0.06);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;
}

/* Dark theme */
[data-theme="dark"] {
    --color-bg: #0F172A;
    --color-surface: #1E293B;
    --color-surface-hover: #334155;
    --color-border: #334155;
    --color-border-light: #1E293B;
    --color-text: #F1F5F9;
    --color-text-secondary: #CBD5E1;
    --color-text-muted: #64748B;
    --color-primary-light: #1E3A5F;
    --color-primary-subtle: #172554;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.3);
}

/* Font size overrides */
[data-fontsize="large"] {
    --text-base: 1.25rem;
    --text-lg: 1.375rem;
    --text-xl: 1.5rem;
    --text-2xl: 2rem;
    --text-3xl: 2.5rem;
}
[data-fontsize="x-large"] {
    --text-base: 1.4375rem;
    --text-lg: 1.5625rem;
    --text-xl: 1.75rem;
    --text-2xl: 2.25rem;
    --text-3xl: 2.75rem;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    line-height: var(--leading-normal);
    color: var(--color-text);
    background: var(--color-bg);
    overflow-x: hidden;
}

h1, h2, h3, h4 {
    font-family: var(--font-heading);
    line-height: var(--leading-tight);
    color: var(--color-text);
}

a {
    color: var(--color-primary);
    text-decoration: none;
}
a:hover { text-decoration: underline; }

img { max-width: 100%; height: auto; }

/* --- Screens --- */
.screen {
    display: none;
    min-height: 100vh;
}
.screen.active { display: flex; }

/* ============================================
   LANGUAGE TOGGLE
   ============================================ */
.lang-toggle {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: var(--text-xs);
    font-weight: 600;
    user-select: none;
}
#welcome-screen #lang-toggle-welcome.lang-toggle {
    position: absolute;
    top: 52px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 10;
    gap: 8px;
}

/* Promo banner */
#welcome-screen #promo-banner.promo-banner {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 15;
    background: rgba(255, 255, 255, 0.06);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    backdrop-filter: blur(12px);
    padding: 10px 20px;
    text-align: center;
}
.promo-banner-inner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}
.promo-text {
    color: rgba(255, 255, 255, 0.85);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 600;
    letter-spacing: 0.5px;
}
.promo-fire { display: none; }
.promo-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--color-success);
    box-shadow: 0 0 8px rgba(5, 150, 105, 0.6);
    animation: promoDotPulse 2s ease infinite;
}
.promo-countdown {
    color: rgba(255, 255, 255, 0.6);
    font-family: var(--font-body);
    font-size: var(--text-xs);
    font-weight: 500;
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.5px;
}
@keyframes promoDotPulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

/* Subscribe box */
.subscribe-box {
    margin-top: var(--space-lg);
    text-align: center;
}
.subscribe-label {
    color: rgba(255, 255, 255, 0.7);
    font-size: var(--text-sm);
    margin-bottom: var(--space-sm);
    font-weight: 500;
    letter-spacing: 0.3px;
}
.subscribe-form {
    display: flex;
    gap: 8px;
    justify-content: center;
    max-width: 420px;
    margin: 0 auto;
}
.subscribe-input {
    flex: 1;
    padding: 10px 16px;
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    background: rgba(255, 255, 255, 0.06);
    color: #fff;
    font-size: var(--text-sm);
    font-family: var(--font-body);
    backdrop-filter: blur(8px);
    outline: none;
    transition: border-color 0.2s;
}
.subscribe-input::placeholder { color: rgba(255, 255, 255, 0.35); }
.subscribe-input:focus { border-color: var(--color-primary); }
.subscribe-btn {
    padding: 10px 20px;
    border-radius: 8px;
    border: none;
    background: var(--color-primary);
    color: #fff;
    font-size: var(--text-sm);
    font-weight: 600;
    font-family: var(--font-body);
    cursor: pointer;
    transition: opacity 0.2s;
    white-space: nowrap;
}
.subscribe-btn:hover { opacity: 0.85; }
.subscribe-btn:disabled { opacity: 0.5; cursor: default; }
.subscribe-msg {
    margin-top: var(--space-xs);
    font-size: var(--text-xs);
    min-height: 1.2em;
}
.subscribe-msg--ok { color: var(--color-success); }
.subscribe-msg--err { color: var(--color-danger); }

.lang-toggle--topbar {
    margin-left: auto;
    margin-right: auto;
    flex-shrink: 0;
}
.lang-btn {
    background: none;
    border: none;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-body);
    line-height: 1;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.lang-btn .flag {
    font-size: 1.2em;
    line-height: 1;
}
.lang-btn:hover {
    color: var(--color-text-secondary);
    background: rgba(0,0,0,0.05);
}
.lang-btn.active {
    background: var(--color-primary);
    color: var(--color-text-inverse);
}
#welcome-screen .lang-toggle--welcome .lang-btn {
    color: rgba(255,255,255,0.5);
    font-size: var(--text-lg);
    padding: 10px 20px;
    border-radius: 10px;
}
#welcome-screen .lang-toggle--welcome .lang-btn .flag {
    font-size: 1.4em;
}
#welcome-screen .lang-toggle--welcome .lang-btn:hover {
    color: rgba(255,255,255,0.8);
    background: rgba(255,255,255,0.08);
}
#welcome-screen .lang-toggle--welcome .lang-btn.active {
    background: rgba(255,255,255,0.15);
    color: #FFFFFF;
}
#welcome-screen .lang-toggle--welcome .lang-separator {
    color: rgba(255,255,255,0.2);
    font-size: var(--text-lg);
}
.lang-separator {
    color: var(--color-text-muted);
    font-weight: 400;
}

/* ============================================
   WELCOME SCREEN
   ============================================ */
#welcome-screen {
    position: relative;
    overflow: hidden;
    align-items: center;
    justify-content: center;
    padding: var(--space-xl);
    background: #0F172A;
}

/* Interactive canvas neural network background */
#neural-canvas {
    position: absolute;
    inset: 0;
    z-index: 0;
    pointer-events: none; /* let parent handle mouse events */
}

/* Keep all welcome screen children above the canvas */
#welcome-screen > *:not(#neural-canvas) {
    position: relative;
    z-index: 1;
}

.welcome-container {
    max-width: 680px;
    text-align: center;
    animation: fadeInUp 0.8s ease;
}

.welcome-badge {
    display: inline-block;
    background: rgba(255,255,255,0.1);
    color: #93C5FD;
    font-size: var(--text-xs);
    font-weight: 600;
    letter-spacing: 0.15em;
    padding: var(--space-sm) var(--space-lg);
    border-radius: 100px;
    border: 1px solid rgba(147, 197, 253, 0.2);
    margin-bottom: var(--space-xl);
}

.welcome-title {
    font-family: var(--font-heading);
    font-size: clamp(2.5rem, 6vw, 4rem);
    color: #FFFFFF;
    margin-bottom: var(--space-lg);
    font-weight: 700;
}
.welcome-title .highlight {
    background: linear-gradient(135deg, #60A5FA, #A78BFA);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-subtitle {
    font-size: var(--text-lg);
    color: #94A3B8;
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-2xl);
    max-width: 560px;
    margin-left: auto;
    margin-right: auto;
}

.welcome-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-2xl);
    margin-bottom: var(--space-2xl);
    flex-wrap: wrap;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}
.stat-number {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: #FFFFFF;
}
.stat-label {
    font-size: var(--text-sm);
    color: #64748B;
    margin-top: var(--space-xs);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    background: var(--color-primary);
    color: var(--color-text-inverse);
    font-family: var(--font-body);
    font-size: var(--text-base);
    font-weight: 600;
    padding: 14px 28px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.btn-primary:hover {
    background: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}
.btn-primary.btn-large {
    font-size: var(--text-lg);
    padding: 18px 36px;
    border-radius: var(--border-radius-lg);
}

/* Welcome buttons row */
.welcome-buttons {
    display: flex;
    gap: 16px;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
}

/* Slides button */
.btn-slides {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-body);
    font-size: var(--text-lg);
    font-weight: 600;
    padding: 18px 36px;
    border-radius: var(--border-radius-lg);
    text-decoration: none;
    border: 2px solid rgba(167, 139, 250, 0.4);
    background: rgba(167, 139, 250, 0.1);
    color: #A78BFA;
    cursor: pointer;
    transition: all var(--transition-base);
}
.btn-slides:hover {
    background: rgba(167, 139, 250, 0.2);
    border-color: rgba(167, 139, 250, 0.6);
    transform: translateY(-1px);
    color: #C4B5FD;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    background: transparent;
    color: var(--color-text-secondary);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 500;
    padding: 12px 24px;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.btn-secondary:hover {
    background: var(--color-surface-hover);
    border-color: var(--color-text-muted);
}

#welcome-screen .btn-secondary {
    color: #64748B;
    border-color: rgba(255,255,255,0.1);
    margin-top: var(--space-md);
}
#welcome-screen .btn-secondary:hover {
    color: #94A3B8;
    border-color: rgba(255,255,255,0.2);
    background: rgba(255,255,255,0.05);
}

.btn-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: none;
    border: none;
    border-radius: var(--border-radius);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.btn-icon:hover {
    background: var(--color-surface-hover);
    color: var(--color-text);
}

.home-btn {
    margin-right: var(--space-sm);
}

.btn-check {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    background: var(--color-success-light);
    color: var(--color-success);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 600;
    padding: 12px 24px;
    border: 2px solid var(--color-success);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.btn-check:hover {
    background: var(--color-success);
    color: white;
}
.btn-check.completed {
    background: var(--color-success);
    color: white;
    pointer-events: none;
}

.btn-danger {
    background: var(--color-danger-light);
    color: var(--color-danger);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 600;
    padding: 10px 20px;
    border: 1px solid var(--color-danger);
    border-radius: var(--border-radius);
    cursor: pointer;
}
.btn-danger:hover {
    background: var(--color-danger);
    color: white;
}

/* ============================================
   TOP BAR
   ============================================ */
.topbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--topbar-height);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    padding: 0 var(--space-lg);
    gap: var(--space-md);
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.topbar-title {
    font-family: var(--font-heading);
    font-size: var(--text-base);
    font-weight: 700;
    color: var(--color-text);
    white-space: nowrap;
}

.topbar-progress {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.progress-text {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
    white-space: nowrap;
}

.progress-bar-mini {
    width: 120px;
    height: 6px;
    background: var(--color-border);
    border-radius: 100px;
    overflow: hidden;
}
.progress-fill-mini {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    border-radius: 100px;
    transition: width var(--transition-slow);
}

/* ============================================
   SIDEBAR
   ============================================ */
.course-layout {
    display: flex;
    padding-top: var(--topbar-height);
    min-height: 100vh;
}

.sidebar {
    position: fixed;
    top: var(--topbar-height);
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: var(--color-surface);
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    z-index: 50;
    transition: transform var(--transition-base);
}

.sidebar-header {
    padding: var(--space-lg);
    border-bottom: 1px solid var(--color-border-light);
}
.sidebar-header h2 {
    font-size: var(--text-base);
    font-weight: 700;
    margin-bottom: var(--space-md);
}

.overall-progress {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--color-border);
    border-radius: 100px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    border-radius: 100px;
    transition: width var(--transition-slow);
}
.progress-label {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
}

.sidebar-nav {
    padding: var(--space-sm) 0;
}

/* Module group */
.module-group {
    margin-bottom: var(--space-xs);
}
.module-header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-lg);
    cursor: pointer;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text);
    transition: background var(--transition-fast);
    user-select: none;
}
.module-header:hover {
    background: var(--color-surface-hover);
}

.module-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: 8px;
    background: var(--color-primary-light);
    color: var(--color-primary);
    font-size: var(--text-xs);
    font-weight: 700;
    flex-shrink: 0;
}
.module-number.completed {
    background: var(--color-success-light);
    color: var(--color-success);
}

.module-title {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.module-chevron {
    transition: transform var(--transition-fast);
    color: var(--color-text-muted);
}
.module-group.expanded .module-chevron {
    transform: rotate(90deg);
}

.module-chapters {
    display: none;
    padding-left: var(--space-sm);
}
.module-group.expanded .module-chapters {
    display: block;
}

/* Chapter item */
.chapter-item {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: 10px var(--space-lg) 10px 52px;
    cursor: pointer;
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    transition: all var(--transition-fast);
    border-left: 3px solid transparent;
}
.chapter-item:hover {
    background: var(--color-surface-hover);
    color: var(--color-text);
}
.chapter-item.active {
    background: var(--color-primary-subtle);
    color: var(--color-primary);
    border-left-color: var(--color-primary);
    font-weight: 600;
}
.chapter-item.completed {
    color: var(--color-success);
}

.chapter-status {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.chapter-status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--color-border);
}
.chapter-item.active .chapter-status-dot {
    background: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}
.chapter-item.completed .chapter-status-dot {
    background: var(--color-success);
}

.chapter-item-title {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ============================================
   MAIN CONTENT AREA
   ============================================ */
.content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: var(--space-2xl) var(--space-xl);
    min-height: calc(100vh - var(--topbar-height));
}

.chapter-container {
    max-width: var(--content-max-width);
    margin: 0 auto;
}

.chapter-breadcrumb {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--space-md);
}

.chapter-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.chapter-duration {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--color-text-muted);
    background: var(--color-border-light);
    padding: 4px 12px;
    border-radius: 100px;
}

.chapter-type {
    display: inline-flex;
    align-items: center;
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 4px 12px;
    border-radius: 100px;
}
.chapter-type[data-type="concept"] { background: var(--color-primary-light); color: var(--color-primary); }
.chapter-type[data-type="hands-on"] { background: var(--color-success-light); color: var(--color-success); }
.chapter-type[data-type="exercise"] { background: var(--color-accent-light); color: var(--color-accent); }
.chapter-type[data-type="motivation"] { background: var(--color-warning-light); color: var(--color-warning); }
.chapter-type[data-type="mindset"] { background: #FFF7ED; color: #C2410C; }
.chapter-type[data-type="framework"] { background: #F0FDF4; color: #15803D; }
.chapter-type[data-type="comparison"] { background: #FEF9C3; color: #A16207; }
.chapter-type[data-type="strategy"] { background: #FCE7F3; color: #BE185D; }
.chapter-type[data-type="resources"] { background: #ECFDF5; color: #047857; }

.chapter-title {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-2xl);
    color: var(--color-text);
}

/* Chapter body content styles */
.chapter-body {
    font-size: var(--text-base);
    line-height: var(--leading-relaxed);
    color: var(--color-text);
}

.chapter-body h2 {
    font-size: var(--text-xl);
    margin-top: var(--space-2xl);
    margin-bottom: var(--space-md);
}
.chapter-body h3 {
    font-size: var(--text-lg);
    margin-top: var(--space-xl);
    margin-bottom: var(--space-md);
}

.chapter-body p {
    margin-bottom: var(--space-lg);
}

.chapter-body ul, .chapter-body ol {
    margin-bottom: var(--space-lg);
    padding-left: var(--space-xl);
}
.chapter-body li {
    margin-bottom: var(--space-sm);
}

.chapter-body strong {
    font-weight: 600;
    color: var(--color-text);
}

/* Callout boxes */
.callout {
    padding: var(--space-lg);
    border-radius: var(--border-radius);
    margin: var(--space-xl) 0;
    border-left: 4px solid;
}
.callout-tip {
    background: var(--color-primary-subtle);
    border-color: var(--color-primary);
}
.callout-warning {
    background: var(--color-warning-light);
    border-color: var(--color-warning);
}
.callout-success {
    background: var(--color-success-light);
    border-color: var(--color-success);
}
.callout-exercise {
    background: var(--color-accent-light);
    border-color: var(--color-accent);
}

.callout-title {
    font-weight: 700;
    font-size: var(--text-base);
    margin-bottom: var(--space-sm);
}

/* Step-by-step instructions */
.steps {
    counter-reset: step;
    list-style: none;
    padding-left: 0;
    margin: var(--space-xl) 0;
}
.steps li {
    counter-increment: step;
    position: relative;
    padding-left: 52px;
    padding-bottom: var(--space-lg);
    border-left: 2px solid var(--color-border);
    margin-left: 16px;
    margin-bottom: 0;
}
.steps li:last-child {
    border-left-color: transparent;
    padding-bottom: 0;
}
.steps li::before {
    content: counter(step);
    position: absolute;
    left: -17px;
    top: 0;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--color-primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: var(--text-sm);
}

/* Key takeaway */
.key-takeaway {
    background: linear-gradient(135deg, var(--color-primary-subtle), var(--color-accent-light));
    border-radius: var(--border-radius-lg);
    padding: var(--space-xl);
    margin: var(--space-2xl) 0;
    text-align: center;
}
.key-takeaway-label {
    font-size: var(--text-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-primary);
    margin-bottom: var(--space-sm);
}
.key-takeaway p {
    font-family: var(--font-heading);
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--color-text);
    margin: 0;
}

/* ============================================
   SCREENSHOT PLACEHOLDER CARDS
   Professional visual cards with glass effect
   ============================================ */
.screenshot-placeholder {
    position: relative;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 50%, #f1f5f9 100%);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: 56px 32px 40px;
    margin: var(--space-xl) 0;
    text-align: center;
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    font-style: italic;
    line-height: var(--leading-normal);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: box-shadow var(--transition-base), transform var(--transition-base);
}

/* Hover lift effect */
.screenshot-placeholder:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

/* Subtle shimmer/glass overlay */
.screenshot-placeholder::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 60%;
    height: 100%;
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.3) 50%,
        transparent 100%
    );
    transform: skewX(-20deg);
    pointer-events: none;
    animation: shimmer 8s ease-in-out infinite;
}

@keyframes shimmer {
    0%, 100% { left: -100%; }
    50% { left: 150%; }
}

/* Monitor icon via ::before pseudo-element */
.screenshot-placeholder::before {
    content: '';
    display: block;
    width: 48px;
    height: 48px;
    margin: 0 auto 16px;
    opacity: 0.35;
    background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23475569' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='2' y='3' width='20' height='14' rx='2' ry='2'/%3E%3Cline x1='8' y1='21' x2='16' y2='21'/%3E%3Cline x1='12' y1='17' x2='12' y2='21'/%3E%3Cpath d='M6 8h.01M9 8h.01'/%3E%3Crect x='6' y='10' width='12' height='4' rx='1' opacity='0.3'/%3E%3C/svg%3E") center / contain no-repeat;
}

/* Subtle dot-grid pattern in the background for texture */
.screenshot-placeholder {
    background-image:
        linear-gradient(135deg, #f8fafc 0%, #e2e8f0 50%, #f1f5f9 100%),
        radial-gradient(circle at 1px 1px, var(--color-border) 0.5px, transparent 0);
    background-size: 100% 100%, 24px 24px;
    background-blend-mode: normal;
}

/* Image variant: when an actual generated image is placed inside */
.screenshot-placeholder.has-image {
    padding: 0;
    overflow: hidden;
    font-style: normal;
}
.screenshot-placeholder.has-image::before,
.screenshot-placeholder.has-image::after {
    display: none;
}
.screenshot-placeholder.has-image img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: var(--border-radius-lg);
}
.screenshot-placeholder.has-image .image-caption {
    padding: 12px 20px;
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    background: var(--color-surface);
    border-top: 1px solid var(--color-border-light);
    font-style: italic;
    text-align: center;
}

/* Dark theme overrides */
[data-theme="dark"] .screenshot-placeholder {
    background: linear-gradient(135deg, #1e293b 0%, #0f172a 50%, #1a2332 100%);
    border-color: #334155;
    color: #94a3b8;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    background-image:
        linear-gradient(135deg, #1e293b 0%, #0f172a 50%, #1a2332 100%),
        radial-gradient(circle at 1px 1px, #334155 0.5px, transparent 0);
    background-size: 100% 100%, 24px 24px;
}

[data-theme="dark"] .screenshot-placeholder::before {
    background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='2' y='3' width='20' height='14' rx='2' ry='2'/%3E%3Cline x1='8' y1='21' x2='16' y2='21'/%3E%3Cline x1='12' y1='17' x2='12' y2='21'/%3E%3Cpath d='M6 8h.01M9 8h.01'/%3E%3Crect x='6' y='10' width='12' height='4' rx='1' opacity='0.3'/%3E%3C/svg%3E") center / contain no-repeat;
    opacity: 0.25;
}

[data-theme="dark"] .screenshot-placeholder::after {
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.05) 50%,
        transparent 100%
    );
}

[data-theme="dark"] .screenshot-placeholder:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    border-color: #475569;
}

[data-theme="dark"] .screenshot-placeholder.has-image .image-caption {
    background: #1e293b;
    border-color: #334155;
    color: #64748b;
}

/* Responsive adjustments for screenshot placeholders */
@media (max-width: 640px) {
    .screenshot-placeholder {
        padding: 40px 20px 32px;
        font-size: var(--text-xs);
        border-radius: var(--border-radius);
    }
    .screenshot-placeholder::before {
        width: 36px;
        height: 36px;
        margin-bottom: 12px;
    }
}

/* ============================================
   QUIZ SECTION
   ============================================ */
.quiz-section {
    margin-top: var(--space-3xl);
    padding-top: var(--space-2xl);
    border-top: 2px solid var(--color-border);
}

.quiz-title {
    font-size: var(--text-xl);
    color: var(--color-text);
    margin-bottom: var(--space-xl);
}

.quiz-question {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--space-xl);
    margin-bottom: var(--space-lg);
}

.quiz-question-text {
    font-size: var(--text-base);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.quiz-question-number {
    font-size: var(--text-xs);
    font-weight: 700;
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-sm);
}

.quiz-option {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: 14px var(--space-lg);
    margin-bottom: var(--space-sm);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: var(--text-base);
}
.quiz-option:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-subtle);
}
.quiz-option.selected {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}
.quiz-option.correct {
    border-color: var(--color-success);
    background: var(--color-success-light);
}
.quiz-option.incorrect {
    border-color: var(--color-danger);
    background: var(--color-danger-light);
}

.quiz-option-radio {
    width: 22px;
    height: 22px;
    border: 2px solid var(--color-border);
    border-radius: 50%;
    flex-shrink: 0;
    position: relative;
    transition: all var(--transition-fast);
}
.quiz-option.selected .quiz-option-radio {
    border-color: var(--color-primary);
}
.quiz-option.selected .quiz-option-radio::after {
    content: '';
    position: absolute;
    top: 4px;
    left: 4px;
    right: 4px;
    bottom: 4px;
    border-radius: 50%;
    background: var(--color-primary);
}

.quiz-submit {
    margin-top: var(--space-lg);
}

.quiz-results {
    text-align: center;
    padding: var(--space-2xl);
}
.quiz-score {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--space-md);
}
.quiz-feedback {
    font-size: var(--text-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xl);
}

.quiz-explanation {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    margin-top: var(--space-sm);
    padding-top: var(--space-sm);
    border-top: 1px solid var(--color-border-light);
    display: none;
}
.quiz-option.correct .quiz-explanation,
.quiz-option.incorrect .quiz-explanation {
    display: block;
}

/* ============================================
   CHAPTER NAVIGATION
   ============================================ */
.chapter-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: var(--space-3xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--color-border);
    gap: var(--space-md);
}

/* ============================================
   SETTINGS PANEL
   ============================================ */
.settings-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.2s ease;
}

.settings-panel {
    background: var(--color-surface);
    border-radius: var(--border-radius-lg);
    padding: var(--space-2xl);
    width: 90%;
    max-width: 480px;
    box-shadow: var(--shadow-xl);
}
.settings-panel h2 {
    font-size: var(--text-xl);
    margin-bottom: var(--space-xl);
}

.setting-group {
    margin-bottom: var(--space-xl);
}
.setting-group label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
}

.setting-options {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.setting-btn {
    padding: 8px 16px;
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    background: var(--color-surface);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-body);
}
.setting-btn:hover {
    border-color: var(--color-primary);
}
.setting-btn.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* ============================================
   CERTIFICATE
   ============================================ */
#certificate-screen {
    background: linear-gradient(135deg, #FEFCE8, #FFF7ED, #FEF2F2);
    align-items: center;
    justify-content: center;
    padding: var(--space-xl);
}

.certificate {
    background: white;
    border: 3px solid #D4AF37;
    border-radius: var(--border-radius-lg);
    padding: var(--space-3xl);
    max-width: 700px;
    width: 100%;
    text-align: center;
    box-shadow: var(--shadow-xl);
}

.cert-badge {
    font-size: var(--text-xs);
    font-weight: 700;
    letter-spacing: 0.2em;
    color: #D4AF37;
    margin-bottom: var(--space-xl);
}

.certificate h1 {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-sm);
}

.cert-subtitle {
    font-size: var(--text-base);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xl);
}

.cert-divider {
    height: 2px;
    background: linear-gradient(90deg, transparent, #D4AF37, transparent);
    margin: var(--space-xl) auto;
    max-width: 200px;
}

.cert-text {
    font-size: var(--text-base);
    line-height: var(--leading-relaxed);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xl);
}

.cert-date {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--space-md);
}

.cert-score {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--space-xl);
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}


/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
    }
    .sidebar.open {
        transform: translateX(0);
        box-shadow: var(--shadow-xl);
    }
    .content {
        margin-left: 0;
    }
}

@media (max-width: 640px) {
    .welcome-stats {
        gap: var(--space-lg);
    }
    .stat-number {
        font-size: var(--text-2xl);
    }
    .chapter-nav {
        flex-direction: column;
    }
    .chapter-nav button {
        width: 100%;
        justify-content: center;
    }
    .topbar-title {
        display: none;
    }
    .lang-toggle--topbar {
        margin-left: auto;
    }
}

/* Print styles for certificate */
@media print {
    body { background: white; }
    .certificate { border: 2px solid #D4AF37; box-shadow: none; }
    .btn-primary { display: none; }
}