html { scroll-behavior: smooth; }

:root {
    --primary: #b8860b;
    --primary-light: #daa520;
    --primary-dark: #5c3d1a;
    --secondary: #8b4513;
    --accent: #f4a460;
    --bg: #fdf8ef;
    --card-bg: #ffffff;
    --text: #333333;
    --text-light: #666666;
    --sidebar-bg: #5c3d1a;
    --sidebar-text: #f5e6d0;
    --sidebar-active: #daa520;
    --en-color: #2563eb;
    --en-bg: #eff6ff;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

/* ── Main Content ── */
.main {
    margin-left: 0;
    flex: 1;
    min-width: 0;
}

.content {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 2rem 4rem;
}

/* ── English word highlighting ── */
.en {
    color: var(--en-color);
    background: var(--en-bg);
    padding: 0.1em 0.35em;
    border-radius: 4px;
    cursor: pointer;
    border-bottom: 2px dotted var(--en-color);
    position: relative;
    font-weight: 500;
    transition: background 0.2s;
    white-space: nowrap;
}
.en:hover { background: #dbeafe; }
.en:active { background: #bfdbfe; }
.en::before {
    content: '\1F50A';
    font-size: 0.6em;
    margin-right: 0.2em;
    opacity: 0;
    transition: opacity 0.2s;
}
.en:hover::before { opacity: 0.6; }

/* Tooltip */
.en::after {
    content: attr(data-th);
    position: absolute;
    bottom: 130%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--sidebar-bg);
    color: white;
    padding: 0.3em 0.7em;
    border-radius: 6px;
    font-size: 0.8rem;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
    z-index: 50;
}
.en:hover::after { opacity: 1; }

/* ── Chapter Navigation ── */
.chapter-nav {
    display: flex;
    justify-content: space-between;
    padding: 1.5rem 0;
    margin-top: 3rem;
    border-top: 2px solid var(--primary-light);
}
.nav-arrow {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    padding: 0.6rem 1.2rem;
    border: 2px solid var(--primary);
    border-radius: 8px;
    transition: all 0.2s;
}
.nav-arrow:hover {
    background: var(--primary);
    color: white;
}

/* ── Mobile ── */
@media (max-width: 768px) {
    .main { margin-left: 0; }
    .content { padding: 1.5rem 1rem 3rem; }
}

/* ── Content Sections ── */
.content-section { margin-bottom: 1.5rem; }
.content-section p { margin-bottom: 1rem; }

/* ── Typography ── */
@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400;0,700;1,400&family=Lora:ital,wght@0,400;0,600;1,400&family=Sarabun:wght@300;400;600;700&display=swap');

body {
    font-family: 'Sarabun', 'Lora', 'Segoe UI', Tahoma, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.8;
    display: flex;
    min-height: 100vh;
    font-size: 1.05rem;
}

.content h2 {
    font-family: 'Playfair Display', 'Sarabun', Georgia, serif;
    color: var(--primary-dark);
    font-size: 1.7rem;
    margin: 2.5rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-light);
    letter-spacing: 0.02em;
}
.content h3 {
    font-family: 'Playfair Display', 'Sarabun', Georgia, serif;
    color: var(--primary);
    font-size: 1.25rem;
    margin: 2rem 0 0.8rem;
    letter-spacing: 0.01em;
}
.content h3.section-header {
    border-left: 4px solid var(--primary-light);
    padding-left: 0.8rem;
    margin-top: 2.5rem;
}
.content h4 {
    font-family: 'Sarabun', 'Segoe UI', sans-serif;
    color: var(--text);
    font-size: 1.05rem;
    font-weight: 600;
    margin: 1.5rem 0 0.6rem;
}
.content p {
    margin-bottom: 1.4rem;
    text-align: justify;
    line-height: 2;
    font-size: 1.05rem;
    text-indent: 1.5em;
}
.content p.drop-cap { text-indent: 0; }
.content h3 + p { text-indent: 0; }
.content p + p { text-indent: 1.5em; }

/* ── Drop cap ── */
.drop-cap::first-letter {
    font-family: 'Playfair Display', Georgia, serif;
    font-size: 3.2em;
    float: left;
    line-height: 0.8;
    padding-right: 0.1em;
    padding-top: 0.1em;
    color: var(--primary-dark);
    font-weight: 700;
}

/* ── Chapter hero banner ── */
.chapter-hero {
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 40%, var(--primary-light) 100%);
    color: white;
    padding: 3rem 2rem 2.5rem;
    border-radius: 16px;
    margin-bottom: 2.5rem;
    position: relative;
    overflow: hidden;
}
.chapter-hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 60%;
    height: 200%;
    background: radial-gradient(ellipse, rgba(255,255,255,0.08) 0%, transparent 70%);
    pointer-events: none;
}
.chapter-hero h1 {
    font-family: 'Playfair Display', Georgia, serif;
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 0.3rem;
    letter-spacing: 0.03em;
}
.chapter-hero .subtitle {
    font-size: 1.1rem;
    opacity: 0.85;
    font-weight: 300;
    margin-bottom: 1rem;
}
.chapter-hero .chapter-meta {
    font-size: 0.85rem;
    opacity: 0.7;
    border-top: 1px solid rgba(255,255,255,0.2);
    padding-top: 0.8rem;
    margin-top: 0.5rem;
}

/* ── Section images ── */
.section-image {
    width: 100%;
    border-radius: 12px;
    margin: 1.5rem 0;
    box-shadow: 0 4px 20px rgba(0,0,0,0.12);
}
.image-float-right {
    float: right;
    width: 45%;
    margin: 0 0 1.5rem 1.5rem;
    border-radius: 12px;
    box-shadow: 0 3px 15px rgba(0,0,0,0.1);
}
.image-float-left {
    float: left;
    width: 45%;
    margin: 0 1.5rem 1.5rem 0;
    border-radius: 12px;
    box-shadow: 0 3px 15px rgba(0,0,0,0.1);
}
.image-caption {
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-light);
    font-style: italic;
    margin-top: -0.5rem;
    margin-bottom: 1.5rem;
}
.clearfix::after {
    content: '';
    display: table;
    clear: both;
}

/* ── Visual divider ── */
.section-divider {
    text-align: center;
    margin: 2.5rem 0;
    color: var(--primary-light);
    font-size: 1.2rem;
    letter-spacing: 0.5em;
    opacity: 0.5;
}

/* ── Pull quote ── */
.pull-quote {
    font-family: 'Playfair Display', Georgia, serif;
    font-size: 1.3rem;
    font-style: italic;
    color: var(--primary-dark);
    border-left: 4px solid var(--accent);
    padding: 1rem 1.5rem;
    margin: 2rem 0;
    background: linear-gradient(90deg, rgba(244,164,96,0.08), transparent);
    line-height: 1.7;
}
.pull-quote .attribution {
    display: block;
    font-size: 0.85rem;
    font-style: normal;
    color: var(--text-light);
    margin-top: 0.5rem;
}

/* ── Reading progress bar ── */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    z-index: 9999;
    transition: width 0.1s;
}

@media (max-width: 768px) {
    .chapter-hero h1 { font-size: 1.6rem; }
    .chapter-hero { padding: 2rem 1.5rem; }
    .image-float-right, .image-float-left {
        float: none;
        width: 100%;
        margin: 1rem 0;
    }
}

/* ── Page Navigation ── */
.page-nav {
    display: flex;
    justify-content: space-between;
    padding: 1.5rem 0;
    margin-top: 2rem;
    border-top: 1px solid var(--primary);
}
.page-nav a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: background 0.2s;
}
.page-nav a:hover { background: rgba(184, 134, 11, 0.15); }
.page-nav-next { margin-left: auto; }
.page-nav-prev { margin-right: auto; }

/* ── Chapter Nav Bar ── */
.chapter-nav-bar {
    background: var(--primary-dark);
    display: flex;
    align-items: center;
    padding: 0.4rem 0.8rem;
    gap: 0.5rem;
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-home {
    font-size: 1.2rem;
    text-decoration: none;
}
.ch-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.2rem;
    flex: 1;
    justify-content: center;
}
.ch-links a {
    color: var(--sidebar-text);
    text-decoration: none;
    padding: 0.4rem 0.7rem;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 600;
    transition: all 0.2s;
    white-space: nowrap;
}
.ch-links a:hover { background: rgba(255,255,255,0.1); }
.ch-links a.ch-active {
    background: var(--primary-light);
    color: white;
}

/* ── Accordion (collapsible sections) ── */
.accordion { margin-bottom: 0.8rem; }
.accordion-header {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary));
    color: white;
    padding: 0.8rem 1.2rem;
    border-radius: 10px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: 'Sarabun', sans-serif;
    font-size: 1.05rem;
    font-weight: 600;
    transition: all 0.3s;
    user-select: none;
}
.accordion-header:hover { background: var(--primary-light); }
.accordion-header .arrow { transition: transform 0.3s; font-size: 0.85rem; }
.accordion.open .accordion-header { border-radius: 10px 10px 0 0; }
.accordion.open .accordion-header .arrow { transform: rotate(180deg); }
.accordion-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease;
}
.accordion.open .accordion-body { max-height: 8000px; }
.accordion-body-inner { padding: 0.5rem 0 0; }
.accordion-body-inner > p:first-child { text-indent: 0; }
.accordion-body-inner > .pull-quote:first-child + p { text-indent: 0; }

/* ── Section Summary Box ── */
.section-summary {
    background: linear-gradient(135deg, #eff6ff, #fffbf0);
    border: 1px solid rgba(37, 99, 235, 0.2);
    border-left: 4px solid var(--en-color);
    border-radius: 10px;
    padding: 1rem 1.2rem;
    margin: 1.2rem 0 0.6rem;
}
.summary-en {
    color: var(--en-color);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 0.6rem;
    text-indent: 0 !important;
    font-style: italic;
}
.keyword-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}
.keyword-list .en {
    font-size: 0.9rem;
    padding: 0.2em 0.5em;
}

/* ── Glossary Grid ── */
.glossary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 0.8rem;
    margin-top: 1rem;
}
.glossary-card {
    background: #fdf5e6;
    border-radius: 10px;
    padding: 0.8rem 1rem;
    border-left: 3px solid var(--primary);
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}
.glossary-card:hover {
    background: #faebd7;
    transform: translateY(-1px);
}
.glossary-term {
    color: var(--primary);
    font-weight: 700;
    font-size: 1rem;
}
.glossary-def {
    color: #555;
    font-size: 0.85rem;
    margin-top: 0.2rem;
}
@media (max-width: 600px) {
    .glossary-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 380px) {
    .glossary-grid { grid-template-columns: 1fr; }
}

/* ── Callout Box ── */
.callout-box {
    background: linear-gradient(135deg, #fff8e1, #fffde7);
    border: 1px solid #f9a825;
    border-left: 4px solid #f9a825;
    border-radius: 10px;
    padding: 1.2rem 1.4rem;
    margin: 1.5rem 0;
}
.callout-title {
    font-weight: 700;
    font-size: 1rem;
    color: #e65100;
    margin-bottom: 0.6rem;
}
.callout-box p {
    margin-bottom: 0.6rem;
    text-indent: 0 !important;
}
.callout-box ul { margin: 0.4rem 0 0 1.2rem; }
.callout-box li {
    margin-bottom: 0.3rem;
    font-size: 0.95rem;
}

/* ── Key Facts Box ── */
.key-facts {
    background: #fffbf0;
    border: 1px solid var(--primary-light);
    border-radius: 10px;
    padding: 1.2rem 1.4rem;
    margin: 1.5rem 0;
}
.key-facts h4 {
    color: var(--primary);
    margin-bottom: 0.6rem;
}
.key-facts ul {
    margin: 0.4rem 0 0 1.2rem;
}
.key-facts li {
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ── Tables ── */
.content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 0.95rem;
}
.content th {
    background: var(--primary-dark);
    color: white;
    padding: 0.6rem 1rem;
    text-align: left;
    font-weight: 600;
}
.content td {
    padding: 0.5rem 1rem;
    border-bottom: 1px solid #e0d5c5;
}
.content tr:nth-child(even) {
    background: #fdf5e6;
}