/* ============================================
   DBT Course — Custom Theme & Animations
   Base: ../css/fkti-light-theme.css
   ============================================ */

:root {
    --dbt-primary: #ff694a;
    --dbt-primary-dark: #e5532e;
    --dbt-secondary: #1e3a5f;
    --dbt-accent: #24b47e;
    --dbt-accent-light: #6ee7b7;
    --dbt-bg: #fefcfb;
    --dbt-surface: #ffffff;
    --dbt-text: #1e293b;
    --dbt-text-light: #64748b;
    --dbt-code-bg: #0f172a;
    --dbt-gradient: linear-gradient(135deg, #ff694a 0%, #e5532e 50%, #c2410c 100%);
    --dbt-gradient-cool: linear-gradient(135deg, #1e3a5f 0%, #0f172a 100%);
    --dbt-gradient-green: linear-gradient(135deg, #059669 0%, #10b981 50%, #34d399 100%);
}

/* ---- Page-level ---- */
body {
    font-family: 'Nunito', sans-serif;
    background: var(--dbt-bg);
    color: var(--dbt-text);
    line-height: 1.75;
    overflow-x: hidden;
}

/* ---- Animated background particles ---- */
.page-bg-particles {
    position: fixed;
    inset: 0;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}
.page-bg-particles .orb {
    position: absolute;
    border-radius: 50%;
    opacity: 0.08;
    animation: orbFloat 20s ease-in-out infinite alternate;
}
.page-bg-particles .orb:nth-child(1) { width: 400px; height: 400px; background: var(--dbt-primary); top: -100px; left: -100px; animation-duration: 25s; }
.page-bg-particles .orb:nth-child(2) { width: 300px; height: 300px; background: var(--dbt-accent); bottom: -80px; right: -80px; animation-duration: 30s; animation-delay: -5s; }
.page-bg-particles .orb:nth-child(3) { width: 200px; height: 200px; background: #6366f1; top: 50%; left: 60%; animation-duration: 22s; animation-delay: -10s; }

@keyframes orbFloat {
    0%   { transform: translate(0, 0) scale(1); }
    50%  { transform: translate(40px, -30px) scale(1.1); }
    100% { transform: translate(-20px, 20px) scale(0.95); }
}

/* ---- Hero / Header ---- */
.lesson-hero {
    background: var(--dbt-gradient);
    color: #fff;
    padding: 60px 40px 50px;
    border-radius: 0 0 40px 40px;
    text-align: center;
    position: relative;
    overflow: hidden;
    margin-bottom: 40px;
}
.lesson-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.06'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E") repeat;
    opacity: 0.5;
}
.lesson-hero > * { position: relative; z-index: 1; }
.lesson-hero .badge {
    display: inline-block;
    background: rgba(255,255,255,0.2);
    backdrop-filter: blur(6px);
    padding: 8px 22px;
    border-radius: 30px;
    font-weight: 700;
    font-size: 0.9em;
    margin-bottom: 16px;
    letter-spacing: 1px;
}
.lesson-hero h1 {
    font-size: 2.8em;
    font-weight: 800;
    margin-bottom: 12px;
    text-shadow: 0 2px 20px rgba(0,0,0,0.15);
}
.lesson-hero .subtitle {
    font-size: 1.25em;
    opacity: 0.92;
    max-width: 650px;
    margin: 0 auto;
}

/* ---- Container ---- */
.lesson-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 24px 80px;
}

/* ---- Top nav bar ---- */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 28px;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(12px);
    border-radius: 16px;
    margin-bottom: 30px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    position: sticky;
    top: 12px;
    z-index: 100;
}
.lesson-nav a {
    color: var(--dbt-primary);
    text-decoration: none;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: color 0.2s;
}
.lesson-nav a:hover { color: var(--dbt-primary-dark); }

/* ---- Section cards ---- */
.section {
    background: var(--dbt-surface);
    border-radius: 20px;
    padding: 36px 32px;
    margin-bottom: 32px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 4px 24px rgba(0,0,0,0.04);
    transition: transform 0.3s, box-shadow 0.3s;
}
.section:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 32px rgba(0,0,0,0.07);
}
.section h2 {
    font-size: 1.8em;
    font-weight: 800;
    color: var(--dbt-secondary);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 3px solid var(--dbt-primary);
    display: inline-block;
}
.section h3 {
    font-size: 1.35em;
    font-weight: 700;
    color: var(--dbt-secondary);
    margin: 24px 0 12px;
}

/* ---- ELI5 (Explain Like I'm 5) box ---- */
.eli5-box {
    background: linear-gradient(135deg, #fef9c3 0%, #fef08a 100%);
    border: 2px dashed #eab308;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
    position: relative;
}
.eli5-box::before {
    content: '👶 Explain Like I\'m 5';
    display: block;
    font-weight: 800;
    color: #92400e;
    margin-bottom: 10px;
    font-size: 1.05em;
}
.eli5-box p { color: #78350f; margin: 0; line-height: 1.8; }

/* ---- Real-life analogy box ---- */
.real-life {
    background: linear-gradient(135deg, #fff7ed 0%, #fed7aa 100%);
    border: 2px solid #f97316;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
}
.real-life::before {
    content: '🌍 Real-Life Example';
    display: block;
    font-weight: 800;
    color: #9a3412;
    margin-bottom: 10px;
    font-size: 1.05em;
}
.real-life p { color: #7c2d12; }

/* ---- Visual example box ---- */
.visual-example {
    background: linear-gradient(135deg, #ecfdf5 0%, #d1fae5 100%);
    border: 2px solid #10b981;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
}
.visual-example::before {
    content: '🎨 Visual Explanation';
    display: block;
    font-weight: 800;
    color: #065f46;
    margin-bottom: 10px;
    font-size: 1.05em;
}

/* ---- Step box ---- */
.step-box {
    background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%);
    border: 2px solid #3b82f6;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
}

/* ---- Formula / concept box ---- */
.formula-box {
    background: linear-gradient(135deg, #f5f3ff 0%, #ede9fe 100%);
    border: 2px solid #8b5cf6;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
}

/* ---- Important / warning box ---- */
.important-box {
    background: linear-gradient(135deg, #fef2f2 0%, #fecaca 100%);
    border: 2px solid #ef4444;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
}
.important-box::before {
    content: '⚠️ Important';
    display: block;
    font-weight: 800;
    color: #991b1b;
    margin-bottom: 10px;
}

/* ---- Pro tip box ---- */
.pro-tip {
    background: linear-gradient(135deg, #f0fdf4 0%, #bbf7d0 100%);
    border: 2px solid #22c55e;
    border-radius: 16px;
    padding: 24px 28px;
    margin: 24px 0;
}
.pro-tip::before {
    content: '💡 Pro Tip';
    display: block;
    font-weight: 800;
    color: #166534;
    margin-bottom: 10px;
}

/* ---- Code blocks ---- */
.code-block {
    background: var(--dbt-code-bg);
    border-radius: 14px;
    padding: 20px 24px;
    margin: 20px 0;
    overflow-x: auto;
    position: relative;
    border: 1px solid #334155;
}
.code-block pre {
    margin: 0;
    font-family: 'Fira Code', 'JetBrains Mono', monospace;
    font-size: 0.9em;
    line-height: 1.7;
    color: #e2e8f0;
}
.code-block code { font-family: inherit; }
.code-block .comment  { color: #64748b; }
.code-block .keyword  { color: #c084fc; }
.code-block .function { color: #67e8f9; }
.code-block .string   { color: #86efac; }
.code-block .number   { color: #fdba74; }
.code-block .output   { color: #c4b5fd; }
.code-block .label {
    display: inline-block;
    background: rgba(255,105,74,0.2);
    color: #ff694a;
    padding: 2px 10px;
    border-radius: 6px;
    font-size: 0.8em;
    font-weight: 700;
    margin-bottom: 10px;
    font-family: 'Nunito', sans-serif;
}

/* ---- Data tables ---- */
.data-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin: 20px 0;
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid #e2e8f0;
}
.data-table thead th {
    background: var(--dbt-gradient);
    color: #fff;
    padding: 14px 18px;
    font-weight: 700;
    text-align: left;
    font-size: 0.95em;
}
.data-table tbody td {
    padding: 12px 18px;
    border-bottom: 1px solid #f1f5f9;
    font-size: 0.95em;
}
.data-table tbody tr:hover { background: #fff7ed; }
.data-table tbody tr:last-child td { border-bottom: none; }

/* ---- Comparison cards ---- */
.comparison-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin: 24px 0;
}
.comparison-card {
    background: var(--dbt-surface);
    border-radius: 16px;
    padding: 24px;
    border: 2px solid #e2e8f0;
    transition: all 0.3s;
}
.comparison-card:hover {
    border-color: var(--dbt-primary);
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(255,105,74,0.12);
}
.comparison-card h4 {
    font-size: 1.15em;
    margin-bottom: 12px;
    color: var(--dbt-secondary);
}

/* ---- Interactive quiz ---- */
.interactive-quiz {
    background: linear-gradient(135deg, #fff7ed 0%, #ffedd5 100%);
    border: 2px solid var(--dbt-primary);
    border-radius: 16px;
    padding: 28px;
    margin: 30px 0;
}
.interactive-quiz h3 { color: var(--dbt-primary-dark); }
.quiz-option {
    display: block;
    padding: 12px 18px;
    margin: 8px 0;
    background: #fff;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
}
.quiz-option:hover {
    border-color: var(--dbt-primary);
    background: #fff7ed;
}
.quiz-option.correct { border-color: #22c55e; background: #f0fdf4; }
.quiz-option.wrong   { border-color: #ef4444; background: #fef2f2; }

/* ---- Animated pipeline / flow diagrams ---- */
.pipeline-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    padding: 30px 10px;
    overflow-x: auto;
    margin: 24px 0;
}
.pipeline-step {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 100px;
    animation: fadeSlideUp 0.6s ease both;
}
.pipeline-step:nth-child(2) { animation-delay: 0.15s; }
.pipeline-step:nth-child(3) { animation-delay: 0.30s; }
.pipeline-step:nth-child(4) { animation-delay: 0.45s; }
.pipeline-step:nth-child(5) { animation-delay: 0.60s; }
.pipeline-step:nth-child(6) { animation-delay: 0.75s; }
.pipeline-step:nth-child(7) { animation-delay: 0.90s; }

.pipeline-icon {
    width: 64px;
    height: 64px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8em;
    margin-bottom: 8px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}
.pipeline-label {
    font-size: 0.85em;
    font-weight: 700;
    text-align: center;
    color: var(--dbt-text);
}
.pipeline-arrow {
    font-size: 1.6em;
    color: var(--dbt-primary);
    margin: 0 4px;
    animation: arrowPulse 1.5s ease-in-out infinite;
}

@keyframes arrowPulse {
    0%, 100% { opacity: 0.4; transform: translateX(0); }
    50%      { opacity: 1;   transform: translateX(4px); }
}

@keyframes fadeSlideUp {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ---- Animated DAG / lineage ---- */
.dag-container {
    background: var(--dbt-code-bg);
    border-radius: 16px;
    padding: 30px;
    margin: 24px 0;
    position: relative;
    overflow: hidden;
}
.dag-container svg { width: 100%; height: auto; }
.dag-node {
    animation: dagNodeAppear 0.5s ease both;
}
.dag-node:nth-child(2) { animation-delay: 0.2s; }
.dag-node:nth-child(3) { animation-delay: 0.4s; }
.dag-node:nth-child(4) { animation-delay: 0.6s; }
.dag-node:nth-child(5) { animation-delay: 0.8s; }

@keyframes dagNodeAppear {
    from { opacity: 0; transform: scale(0.7); }
    to   { opacity: 1; transform: scale(1); }
}

.dag-edge {
    stroke-dasharray: 8 4;
    animation: dagEdgeFlow 1.5s linear infinite;
}
@keyframes dagEdgeFlow {
    to { stroke-dashoffset: -24; }
}

/* ---- Timeline ---- */
.timeline {
    position: relative;
    padding-left: 40px;
    margin: 30px 0;
}
.timeline::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(to bottom, var(--dbt-primary), var(--dbt-accent));
    border-radius: 3px;
}
.timeline-item {
    position: relative;
    margin-bottom: 32px;
    animation: fadeSlideUp 0.5s ease both;
}
.timeline-item::before {
    content: '';
    position: absolute;
    left: -33px;
    top: 6px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--dbt-primary);
    border: 3px solid #fff;
    box-shadow: 0 0 0 3px var(--dbt-primary);
}
.timeline-year {
    font-weight: 800;
    color: var(--dbt-primary);
    font-size: 1.1em;
    margin-bottom: 6px;
}

/* ---- Animated folder tree ---- */
.folder-tree {
    background: var(--dbt-code-bg);
    border-radius: 14px;
    padding: 24px 28px;
    margin: 20px 0;
    font-family: 'Fira Code', monospace;
    font-size: 0.9em;
    line-height: 2;
    color: #e2e8f0;
}
.folder-tree .folder {
    color: #fbbf24;
    font-weight: 700;
    cursor: pointer;
    transition: color 0.2s;
}
.folder-tree .folder:hover { color: #fde68a; }
.folder-tree .file { color: #94a3b8; }
.folder-tree .file-sql { color: #67e8f9; }
.folder-tree .file-yml { color: #86efac; }
.folder-tree .file-csv { color: #fdba74; }
.folder-tree .indent { margin-left: 24px; display: block; }
.folder-tree .indent-2 { margin-left: 48px; display: block; }
.folder-tree .indent-3 { margin-left: 72px; display: block; }

/* ---- Stats grid ---- */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 16px;
    margin: 24px 0;
}
.stat-card {
    background: var(--dbt-surface);
    border-radius: 16px;
    padding: 20px;
    text-align: center;
    border: 2px solid #e2e8f0;
    transition: all 0.3s;
}
.stat-card:hover {
    border-color: var(--dbt-primary);
    transform: translateY(-3px);
}
.stat-number {
    font-size: 2em;
    font-weight: 800;
    background: var(--dbt-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.stat-label {
    font-size: 0.85em;
    color: var(--dbt-text-light);
    font-weight: 600;
    margin-top: 4px;
}

/* ---- Navigation buttons (prev/next) ---- */
.nav-buttons {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    margin-top: 40px;
    padding-top: 30px;
    border-top: 2px solid #f1f5f9;
}
.nav-btn-prev, .nav-btn-next {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: 14px;
    font-weight: 700;
    text-decoration: none;
    font-size: 0.95em;
    transition: all 0.25s;
    border: 2px solid #e2e8f0;
    color: var(--dbt-text);
    background: #fff;
}
.nav-btn-prev:hover, .nav-btn-next:hover {
    border-color: var(--dbt-primary);
    color: var(--dbt-primary);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255,105,74,0.12);
}
.nav-btn-next {
    background: var(--dbt-gradient);
    color: #fff;
    border-color: transparent;
}
.nav-btn-next:hover {
    color: #fff;
    box-shadow: 0 6px 20px rgba(255,105,74,0.3);
}

/* ---- Animated typing effect ---- */
.typing-effect {
    overflow: hidden;
    border-right: 3px solid var(--dbt-primary);
    white-space: nowrap;
    animation: typing 3s steps(40, end), blink 0.75s step-end infinite;
    font-family: 'Fira Code', monospace;
}
@keyframes typing {
    from { width: 0; }
    to   { width: 100%; }
}
@keyframes blink {
    50% { border-color: transparent; }
}

/* ---- Pulse animation for icons ---- */
.pulse {
    animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50%      { transform: scale(1.08); }
}

/* ---- Glow effect ---- */
.glow {
    animation: glow 2s ease-in-out infinite alternate;
}
@keyframes glow {
    from { box-shadow: 0 0 5px rgba(255,105,74,0.2), 0 0 10px rgba(255,105,74,0.1); }
    to   { box-shadow: 0 0 15px rgba(255,105,74,0.4), 0 0 30px rgba(255,105,74,0.2); }
}

/* ---- Scroll-triggered fade-in ---- */
.fade-in-section {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in-section.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ---- Core / Non-core boxes ---- */
.core-box {
    background: linear-gradient(135deg, #dcfce7 0%, #bbf7d0 100%);
    border: 2px solid #22c55e;
    border-radius: 16px;
    padding: 24px;
    margin: 20px 0;
}
.core-box::before {
    content: '✅ CORE (Must know)';
    display: block;
    font-weight: 800;
    color: #166534;
    margin-bottom: 10px;
    font-size: 1.05em;
}
.noncore-box {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    border: 2px solid #f59e0b;
    border-radius: 16px;
    padding: 24px;
    margin: 20px 0;
}
.noncore-box::before {
    content: '📚 NON-CORE (Good to know)';
    display: block;
    font-weight: 800;
    color: #92400e;
    margin-bottom: 10px;
    font-size: 1.05em;
}

/* ---- Reflection prompt ---- */
.reflection-prompt {
    background: linear-gradient(135deg, #fff7ed 0%, #ffedd5 100%);
    border-radius: 16px;
    padding: 24px;
    margin: 25px 0;
    border-left: 5px solid var(--dbt-primary);
}
.reflection-prompt::before {
    content: '💭 Reflection';
    display: block;
    font-weight: 800;
    color: var(--dbt-primary-dark);
    margin-bottom: 8px;
}

/* ---- Animated warehouse diagram ---- */
.warehouse-diagram {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    padding: 30px;
    margin: 24px 0;
}
.warehouse-layer {
    background: var(--dbt-surface);
    border: 2px solid #e2e8f0;
    border-radius: 16px;
    padding: 20px;
    min-width: 180px;
    text-align: center;
    transition: all 0.3s;
    animation: fadeSlideUp 0.5s ease both;
}
.warehouse-layer:hover {
    border-color: var(--dbt-primary);
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
}
.warehouse-layer .layer-icon {
    font-size: 2.5em;
    margin-bottom: 8px;
}
.warehouse-layer .layer-name {
    font-weight: 800;
    font-size: 1em;
    color: var(--dbt-secondary);
}
.warehouse-layer .layer-desc {
    font-size: 0.85em;
    color: var(--dbt-text-light);
    margin-top: 4px;
}

/* ---- Back to top ---- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--dbt-gradient);
    color: #fff;
    border: none;
    cursor: pointer;
    font-size: 1.2em;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 16px rgba(255,105,74,0.3);
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s;
    z-index: 999;
}
.back-to-top.show {
    opacity: 1;
    transform: translateY(0);
}
.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 24px rgba(255,105,74,0.4);
}

/* ---- Responsive ---- */
@media (max-width: 768px) {
    .lesson-hero { padding: 40px 20px 35px; }
    .lesson-hero h1 { font-size: 1.8em; }
    .lesson-container { padding: 0 16px 60px; }
    .section { padding: 24px 20px; }
    .pipeline-diagram { flex-wrap: wrap; }
    .nav-buttons { flex-direction: column; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .comparison-cards { grid-template-columns: 1fr; }
    .lesson-nav { padding: 10px 16px; font-size: 0.9em; }
}

@media (max-width: 480px) {
    .lesson-hero h1 { font-size: 1.5em; }
    .stats-grid { grid-template-columns: 1fr 1fr; }
}