/* ==========================================
   DESIGN SYSTEM & VARIABLES
   ========================================== */
:root {
    /* Color Palette: Sophisticated archival tones */
    --bg-color: #f5f1e8;        /* Warm Ivory / Archival Paper */
    --text-color: #242321;      /* Deep Charcoal */
    --text-muted: #6e6a63;      /* Muted Warm Gray */
    --accent-color: #7a3038;    /* Muted Burgundy / Oxblood */
    --accent-hover: #5e242a;    /* Muted Burgundy Hover */
    --bg-secondary: #ddd5c7;    /* Warm Beige */
    --border-color: rgba(36, 35, 33, 0.15); /* Fine border gray */
    --border-dark: #242321;
    --white: #ffffff;
    
    /* Typography */
    --font-serif: 'Cormorant Garamond', Georgia, 'Times New Roman', serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-mono: ui-monospace, SFMono-Regular, SF Mono, Menlo, Monaco, Consolas, monospace;

    /* Layout Limits */
    --container-max-width: 1040px;
    --reading-max-width: 780px;
    --transition-speed: 0.25s;
}

/* ==========================================
   RESET & BASE STYLES
   ========================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.65;
    letter-spacing: -0.009em;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin-right: auto;
    margin-left: auto;
    padding-right: 24px;
    padding-left: 24px;
}

/* Focus outline for accessibility */
*:focus-visible {
    outline: 1.5px solid var(--accent-color);
    outline-offset: 4px;
}

/* Skip to content link */
.skip-to-content {
    position: absolute;
    top: -100px;
    left: 24px;
    background-color: var(--text-color);
    color: var(--bg-color);
    padding: 12px 24px;
    z-index: 100;
    font-family: var(--font-sans);
    font-size: 13px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    text-decoration: none;
    transition: top var(--transition-speed) ease;
}

.skip-to-content:focus {
    top: 24px;
}

/* Common Typographic Elements */
h1, h2, h3, h4 {
    font-family: var(--font-serif);
    font-weight: 500;
    line-height: 1.2;
    color: var(--text-color);
}

p {
    font-family: var(--font-sans);
    font-weight: 400;
}

.font-mono {
    font-family: var(--font-mono);
    font-size: 0.85em;
    letter-spacing: -0.02em;
}

/* Archival Line Dividers */
.archival-rule {
    border: none;
    border-top: 1px solid var(--border-color);
    margin-top: 16px;
    margin-bottom: 40px;
}

/* ==========================================
   HEADER SECTION
   ========================================== */
.site-header {
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-color);
    position: sticky;
    top: 0;
    z-index: 50;
}

.header-container {
    height: 90px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Stacked Editorial Logo Title */
.site-logo {
    display: flex;
    flex-direction: column;
    line-height: 1.25;
}

.logo-line-1 {
    font-family: var(--font-sans);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.22em;
    color: var(--text-muted);
}

.logo-line-2 {
    font-family: var(--font-serif);
    font-size: clamp(16px, 2.2vw, 19px);
    font-weight: 500;
    letter-spacing: 0.02em;
    color: var(--text-color);
    margin-top: 2px;
}

/* Language switch styles */
.lang-switch-nav {
    display: flex;
    align-items: center;
    gap: 4px;
}

.lang-toggle-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    padding: 8px 12px;
    min-height: 44px; /* Accessible tap target */
    display: inline-flex;
    align-items: center;
    transition: color var(--transition-speed) ease;
}

.lang-toggle-btn.active {
    color: var(--accent-color);
    font-weight: 600;
    position: relative;
}

.lang-toggle-btn.active::after {
    content: '';
    position: absolute;
    bottom: 8px;
    left: 12px;
    right: 12px;
    height: 1.5px;
    background-color: var(--accent-color);
}

.lang-toggle-btn:hover:not(.active) {
    color: var(--text-color);
}

.lang-divider {
    color: var(--border-color);
    user-select: none;
    font-size: 12px;
}

/* ==========================================
   EDITORIAL IMAGE & CAPTION COMPONENT
   ========================================== */
.editorial-figure {
    display: flex;
    flex-direction: column;
    margin: 0;
    width: 100%;
}

.image-wrapper {
    background-color: var(--white);
    padding: 12px;
    border: 1px solid var(--border-color);
    display: block;
    box-shadow: 0 4px 16px rgba(36, 35, 33, 0.03);
}

.editorial-img {
    display: block;
    width: 100%;
    height: auto;
    object-fit: cover;
    filter: sepia(10%) contrast(98%);
}

.editorial-caption {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-top: 12px;
    border-left: 2px solid var(--accent-color);
    padding-left: 10px;
    line-height: 1.4;
}

/* ==========================================
   HERO SECTION
   ========================================== */
.hero-section {
    padding-top: 60px;
    padding-bottom: 60px;
    border-bottom: 1px solid var(--border-color);
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 40px;
    align-items: center;
}

.hero-visual {
    order: -1; /* Mobile order: image above text */
    max-width: 420px;
    width: 100%;
    margin-left: auto;
    margin-right: auto;
}

.hero-content {
    width: 100%;
}

.hero-eyebrow {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.20em;
    color: var(--accent-color);
    display: block;
    margin-bottom: 16px;
}

.hero-title {
    font-size: clamp(34px, 5.5vw, 52px);
    margin-bottom: 24px;
    letter-spacing: -0.025em;
    line-height: 1.15;
    font-weight: 400;
    white-space: pre-line;
}

.hero-subtext {
    font-family: var(--font-serif);
    font-size: clamp(17px, 2.3vw, 21px);
    font-style: italic;
    color: var(--text-muted);
    line-height: 1.55;
    font-weight: 400;
}

/* ==========================================
   SECTION HEADER (NUMBER & TITLE)
   ========================================== */
.section-header {
    display: flex;
    align-items: baseline;
    gap: 16px;
}

.section-number {
    font-family: var(--font-serif);
    font-size: 20px;
    color: var(--accent-color);
    font-weight: 500;
}

.section-title {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.18em;
    color: var(--text-muted);
}

/* ==========================================
   MISSION SECTION
   ========================================== */
.mission-section {
    padding-top: 80px;
    padding-bottom: 80px;
    border-bottom: 1px solid var(--border-color);
}

.mission-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 48px;
    align-items: start;
}

.mission-statement {
    font-size: clamp(24px, 3.5vw, 32px);
    font-weight: 400;
    line-height: 1.3;
    letter-spacing: -0.02em;
    color: var(--text-color);
    margin-bottom: 32px;
}

.mission-paragraphs {
    display: flex;
    flex-direction: column;
    gap: 20px;
    font-size: 16px;
    color: var(--text-muted);
}

.mission-right {
    max-width: 420px;
    margin-left: auto;
    margin-right: auto;
}

/* ==========================================
   RESEARCH JOURNEY SECTION (TIMELINE)
   ========================================== */
.journey-section {
    padding-top: 80px;
    padding-bottom: 80px;
    border-bottom: 1px solid var(--border-color);
}

.timeline-layout {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 40px;
    position: relative;
}

.timeline-step {
    display: flex;
    flex-direction: column;
    position: relative;
    padding-left: 28px;
}

.timeline-marker {
    position: absolute;
    left: 0;
    top: 6px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: var(--accent-color);
}

.timeline-label {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.15em;
    color: var(--accent-color);
    margin-bottom: 2px;
}

.timeline-desc {
    font-family: var(--font-serif);
    font-size: 17px;
    color: var(--text-color);
    font-weight: 500;
}

.timeline-connector {
    width: 1px;
    height: 24px;
    background-color: var(--border-color);
    margin-left: 4px;
}

/* ==========================================
   ARCHIVE STRIP SECTION
   ========================================== */
.archive-strip-section {
    padding-top: 80px;
    padding-bottom: 80px;
    border-bottom: 1px solid var(--border-color);
}

.archive-strip-desc {
    font-family: var(--font-serif);
    font-size: 18px;
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 40px;
}

.archive-strip-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 40px;
}

.archive-strip-item {
    display: flex;
    flex-direction: column;
    margin: 0;
    position: relative;
}

.archive-item-number {
    position: absolute;
    top: 24px;
    right: 24px;
    font-family: var(--font-serif);
    font-size: 16px;
    color: var(--text-muted);
    opacity: 0.5;
}

/* Ratio crops using CSS aspect-ratio */
.item-portrait .image-wrapper {
    aspect-ratio: 3 / 4;
}

.item-square .image-wrapper {
    aspect-ratio: 1 / 1;
}

.item-landscape .image-wrapper {
    aspect-ratio: 4 / 3;
}

.archive-strip-item .editorial-img {
    height: 100%;
}

/* ==========================================
   WHY SUPPORT STATEMENT SECTION
   ========================================== */
.why-support-layout {
    max-width: var(--reading-max-width);
    margin-bottom: 56px;
}

.why-support-statement {
    font-size: clamp(24px, 3.5vw, 32px);
    font-weight: 400;
    line-height: 1.35;
    letter-spacing: -0.02em;
    color: var(--accent-color);
    margin-bottom: 16px;
}

.why-support-desc {
    font-family: var(--font-sans);
    font-size: 16px;
    color: var(--text-muted);
    max-width: 580px;
}

/* ==========================================
   SUPPORT & CONTRIBUTION DETAILS
   ========================================== */
.support-section {
    padding-top: 80px;
    padding-bottom: 100px;
}

.support-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 56px;
}

.support-col {
    display: flex;
    flex-direction: column;
}

.support-col-title {
    font-family: var(--font-sans);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.15em;
    color: var(--accent-color);
    margin-bottom: 24px;
}

.support-col-desc {
    color: var(--text-muted);
    font-size: 16px;
    line-height: 1.6;
    margin-bottom: 32px;
    max-width: 440px;
}

/* Button Customizations */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    text-decoration: none;
    cursor: pointer;
    min-height: 46px;
    padding: 14px 28px;
    transition: all var(--transition-speed) ease;
    border-radius: 0;
}

.btn-primary.btn-burgundy {
    background-color: var(--accent-color);
    color: var(--bg-color);
    border: 1px solid var(--accent-color);
}

.btn-primary.btn-burgundy:hover {
    background-color: var(--accent-hover);
    border-color: var(--accent-hover);
    transform: translateY(-1px);
}

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

.btn-secondary {
    background-color: transparent;
    color: var(--text-color);
    border: 1px solid var(--border-dark);
}

.btn-secondary:hover {
    background-color: var(--border-dark);
    color: var(--bg-color);
}

.btn-small {
    padding: 6px 14px;
    min-height: 38px;
    font-size: 11px;
    letter-spacing: 0.05em;
}

.btn.copied {
    background-color: #2e7d32;
    color: var(--white);
    border-color: #2e7d32;
}

/* VietQR block positioning */
.vietqr-composition {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    margin-bottom: 32px;
}

.vietqr-box {
    background-color: var(--white);
    padding: 16px;
    border: 1px solid var(--border-color);
    display: inline-flex;
    box-shadow: 0 4px 12px rgba(36, 35, 33, 0.04);
}

.vietqr-img {
    display: block;
}

.vietqr-instruction {
    margin-top: 12px;
    font-family: var(--font-sans);
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
}

/* Bank Details rows */
.bank-details-panel {
    display: flex;
    flex-direction: column;
    max-width: 460px;
}

.bank-detail-row {
    display: flex;
    flex-direction: column;
    padding-top: 16px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.bank-label {
    font-family: var(--font-sans);
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.bank-value {
    font-family: var(--font-sans);
    font-size: 15px;
    font-weight: 500;
}

.bank-account-row {
    flex-direction: column;
}

.bank-account-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

#account-number-text {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--text-color);
}

/* ==========================================
   FOOTER SECTION
   ========================================== */
.site-footer {
    padding-bottom: 80px;
    background-color: var(--bg-color);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

@media (min-width: 768px) {
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
}

.footer-text {
    font-family: var(--font-sans);
    font-size: 12px;
    letter-spacing: 0.02em;
    color: var(--text-muted);
    margin: 0;
}

.footer-links {
    display: flex;
    gap: 8px;
    align-items: center;
}

.footer-link {
    font-family: var(--font-sans);
    font-size: 12px;
    color: var(--text-muted);
    text-decoration: none;
    transition: color var(--transition-speed);
}

.footer-link:hover {
    color: var(--accent-color);
}

.footer-link-divider {
    font-size: 10px;
    color: var(--border-color);
    user-select: none;
}

/* ==========================================
   RESPONSIVE DESIGN BREAKPOINTS
   ========================================== */

/* Tablet & Desktop (768px and up) */
@media (min-width: 768px) {
    body {
        font-size: 17px;
    }
    
    .container {
        padding-right: 48px;
        padding-left: 48px;
    }

    /* Hero section split */
    .hero-section {
        padding-top: 100px;
        padding-bottom: 100px;
    }

    .hero-grid {
        grid-template-columns: 1.1fr 0.9fr;
        gap: 60px;
    }

    .hero-visual {
        order: 0; /* Desktop order: text left, visual right */
        max-width: 100%;
        margin-left: 0;
        margin-right: 0;
    }

    .mission-section, .journey-section, .archive-strip-section, .support-section {
        padding-top: 110px;
        padding-bottom: 110px;
    }

    /* Asymmetric Mission Layout */
    .mission-layout {
        grid-template-columns: 1.1fr 0.9fr;
        gap: 60px;
    }

    .mission-right {
        max-width: 100%;
        margin-left: 0;
        margin-right: 0;
    }

    /* Horizontal Journey Timeline */
    .timeline-layout {
        flex-direction: row;
        justify-content: space-between;
        align-items: flex-start;
        gap: 20px;
    }

    .timeline-step {
        flex-grow: 0;
        flex-shrink: 0;
        width: 220px;
        padding-left: 0;
        padding-top: 24px;
    }

    .timeline-marker {
        left: 0;
        top: 0;
    }

    .timeline-connector {
        flex-grow: 1;
        width: auto;
        height: 1px;
        margin-left: 0;
        margin-top: 4px;
        align-self: flex-start;
    }

    /* Asymmetric Archive Visual Strip */
    .archive-strip-grid {
        grid-template-columns: 1fr 1fr 1.3fr;
        gap: 32px;
        align-items: start;
    }

    /* Support details split */
    .support-grid {
        grid-template-columns: 1fr 1fr;
        gap: 72px;
    }

    .vietnam-col {
        border-left: 1px solid var(--border-color);
        padding-left: 56px;
    }

    .bank-detail-row {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        padding-top: 18px;
        padding-bottom: 18px;
    }

    .bank-label {
        margin-bottom: 0;
    }

    .bank-account-row {
        flex-direction: row;
    }

    .bank-account-wrapper {
        justify-content: flex-end;
    }

    .site-logo {
        line-height: 1.15;
    }
}

/* Large Screens */
@media (min-width: 1040px) {
    .container {
        padding-right: 24px;
        padding-left: 24px;
    }
}

/* ==========================================================================
   APPENDED INTERACTIVE BOOK VIEWER, SEARCH, LIGHTBOX, AND MODAL LAYOUTS
   ========================================================================== */

.hero-supporting {
    font-family: var(--font-sans);
    font-size: 15px;
    color: var(--text-muted);
    line-height: 1.6;
    margin-top: 20px;
    max-width: 540px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-top: 32px;
    flex-wrap: wrap;
}

/* Archival Metadata Table */
.archival-metadata-table {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-top: 40px;
    border-top: 1px solid var(--border-color);
    padding-top: 24px;
}

@media (min-width: 480px) {
    .archival-metadata-table {
        grid-template-columns: repeat(4, 1fr);
    }
}

.meta-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.meta-label {
    font-family: var(--font-sans);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.15em;
    color: var(--accent-color);
}

.meta-value {
    font-family: var(--font-serif);
    font-size: 17px;
    font-weight: 500;
    color: var(--text-color);
}

.mission-paragraphs p {
    margin-bottom: 12px;
}

.mission-p-en {
    font-family: var(--font-sans);
    font-size: 16px;
    color: var(--text-color);
    line-height: 1.65;
}

.mission-p-vi {
    font-family: var(--font-serif);
    font-style: italic;
    font-size: 17px;
    color: var(--text-muted);
    line-height: 1.6;
    border-left: 2px solid var(--border-color);
    padding-left: 16px;
    margin-top: 8px;
}

/* Book Section Base */
.book-section {
    padding-top: 80px;
    padding-bottom: 80px;
    border-bottom: 1px solid var(--border-color);
}

/* Search Bar */
.book-search-container {
    position: relative;
    max-width: 580px;
    margin-bottom: 40px;
}

.search-input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

#book-search-input, #fs-search-input {
    width: 100%;
    background-color: var(--white);
    border: 1px solid var(--border-color);
    padding: 12px 16px 12px 40px;
    font-family: var(--font-sans);
    font-size: 14px;
    color: var(--text-color);
    outline: none;
    border-radius: 0;
    transition: border-color var(--transition-speed);
}

#book-search-input:focus, #fs-search-input:focus {
    border-color: var(--accent-color);
    box-shadow: 0 2px 8px rgba(122, 48, 56, 0.05);
}

.search-icon {
    position: absolute;
    left: 14px;
    color: var(--text-muted);
    font-size: 14px;
}

/* Search Results Dropdown */
.search-results-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-color);
    border: 1px solid var(--border-dark);
    box-shadow: 0 8px 30px rgba(36, 35, 33, 0.12);
    z-index: 60;
    max-height: 380px;
    overflow-y: auto;
    display: none;
    margin-top: 4px;
}

.search-results-dropdown.active {
    display: block;
}

.search-results-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.search-result-item {
    border-bottom: 1px solid var(--border-color);
}

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

.search-result-link {
    width: 100%;
    display: flex;
    text-align: left;
    background: none;
    border: none;
    padding: 12px 16px;
    cursor: pointer;
    font-family: var(--font-sans);
    transition: background-color var(--transition-speed);
    align-items: flex-start;
    gap: 16px;
}

.search-result-link:hover {
    background-color: var(--white);
}

.result-number {
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 600;
    color: var(--accent-color);
    background-color: rgba(122, 48, 56, 0.08);
    padding: 2px 6px;
    white-space: nowrap;
}

.result-details {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.result-title {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-color);
}

.result-chapter {
    font-size: 11px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.search-no-results {
    padding: 16px;
    font-family: var(--font-sans);
    font-size: 13px;
    color: var(--text-muted);
    text-align: center;
}

.search-more-indicator {
    padding: 8px 16px;
    font-family: var(--font-sans);
    font-size: 11px;
    color: var(--accent-color);
    text-align: center;
    background-color: rgba(36, 35, 33, 0.02);
    font-weight: 500;
}

/* Book Container Grid */
.book-container {
    display: grid;
    grid-template-columns: 1fr;
    gap: 40px;
}

@media (min-width: 768px) {
    .book-container {
        grid-template-columns: 0.95fr 1.05fr;
        gap: 60px;
        align-items: start;
    }
    
    .book-details-column {
        position: sticky;
        top: 120px;
        max-height: calc(100vh - 160px);
        display: flex;
        flex-direction: column;
        justify-content: space-between;
    }
}

/* Book Details Typography */
.book-metadata-header {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-bottom: 16px;
}

.book-chapter-title {
    font-family: var(--font-sans);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.15em;
    color: var(--accent-color);
    text-transform: uppercase;
}

.book-section-id {
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

.book-title {
    font-size: clamp(24px, 3.5vw, 36px);
    font-weight: 400;
    line-height: 1.25;
    margin-bottom: 24px;
}

.book-metadata-grid {
    display: flex;
    flex-direction: column;
    border-top: 1px solid var(--border-color);
    margin-bottom: 24px;
}

.book-meta-row {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
    font-size: 13px;
}

.book-meta-label {
    font-family: var(--font-sans);
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.book-meta-value {
    font-family: var(--font-sans);
    font-weight: 600;
    color: var(--text-color);
    text-align: right;
}

/* Bilingual Descriptions */
.book-descriptions {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 32px;
}

.book-descriptions p {
    font-size: 15px;
    line-height: 1.6;
    transition: opacity var(--transition-speed) ease;
}

.book-desc-en {
    font-family: var(--font-sans);
}

.book-desc-vi {
    font-family: var(--font-serif);
    font-style: italic;
    border-left: 2px solid var(--border-color);
    padding-left: 12px;
}

.book-descriptions p.active-lang-text {
    opacity: 1;
    color: var(--text-color);
}

.book-descriptions p.muted-lang-text {
    opacity: 0.45;
    color: var(--text-muted);
}

/* Navigation Panel */
.book-navigation-panel {
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
    margin-top: auto;
}

.book-progress-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.book-progress-track {
    flex-grow: 1;
    height: 2px;
    background-color: var(--border-color);
    margin-right: 16px;
    position: relative;
}

.book-progress-fill {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background-color: var(--accent-color);
    transition: width var(--transition-speed) cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.book-progress-text {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--text-muted);
    font-weight: 500;
    white-space: nowrap;
}

.book-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}

.btn-nav {
    background: none;
    border: none;
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--text-color);
    cursor: pointer;
    padding: 10px 16px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    transition: color var(--transition-speed) ease;
}

.btn-nav:hover:not(.disabled) {
    color: var(--accent-color);
}

.btn-nav.disabled {
    color: var(--border-color);
    cursor: not-allowed;
}

/* Right Stacked Plates */
.book-images-column {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.book-plate-figure {
    margin: 0;
    width: 100%;
}

.book-plate-wrapper {
    background-color: var(--white);
    padding: 16px;
    border: 1px solid var(--border-color);
    aspect-ratio: 1 / 1;
    position: relative;
    cursor: zoom-in;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(36, 35, 33, 0.04);
}

.book-plate-img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    opacity: 0;
    transition: opacity 0.5s ease, transform var(--transition-speed) ease;
}

.book-plate-img.loaded {
    opacity: 1;
}

.book-plate-img:hover {
    transform: scale(1.01);
}

.book-plate-caption {
    font-family: var(--font-mono);
    font-size: 10px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-top: 10px;
    text-align: right;
}

/* Skeleton Loaders */
.loading-skeleton {
    background: #eae4d7;
    display: flex;
    align-items: center;
    justify-content: center;
}

.plate-loading-text {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.1em;
    color: var(--text-muted);
    animation: pulse 1.8s infinite ease-in-out;
}

@keyframes pulse {
    0% { opacity: 0.4; }
    50% { opacity: 0.8; }
    100% { opacity: 0.4; }
}

/* Fullscreen Reader Modal */
.fullscreen-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: var(--bg-color);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.fullscreen-modal.active {
    opacity: 1;
    pointer-events: auto;
}

.fs-modal-header {
    height: 80px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 40px;
    background-color: var(--bg-color);
}

.fs-header-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.fs-logo {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.18em;
    color: var(--text-muted);
}

.fs-divider {
    color: var(--border-color);
    font-size: 12px;
}

.fs-section-id {
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 600;
    color: var(--accent-color);
}

.fs-header-center {
    flex-grow: 1;
    max-width: 420px;
    margin: 0 40px;
}

.fs-search-container {
    position: relative;
    width: 100%;
}

.fs-close-btn {
    background: none;
    border: 1px solid var(--border-dark);
    padding: 8px 16px;
    font-family: var(--font-sans);
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-color);
    cursor: pointer;
    transition: all var(--transition-speed);
}

.fs-close-btn:hover {
    background-color: var(--text-color);
    color: var(--bg-color);
}

.fs-modal-body {
    flex-grow: 1;
    display: grid;
    grid-template-columns: 1fr;
    overflow: hidden;
}

@media (min-width: 768px) {
    .fs-modal-body {
        grid-template-columns: 460px 1fr;
    }
}

.fs-text-panel {
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 100%;
    overflow-y: auto;
    padding: 40px;
    background-color: rgba(36, 35, 33, 0.01);
}

.fs-text-content {
    display: flex;
    flex-direction: column;
}

.fs-chapter-title {
    font-family: var(--font-sans);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 0.15em;
    color: var(--accent-color);
    text-transform: uppercase;
    margin-bottom: 12px;
}

.fs-title {
    font-size: 28px;
    font-weight: 400;
    line-height: 1.3;
    margin-bottom: 24px;
}

.fs-keyboard-hint {
    font-family: var(--font-sans);
    font-size: 11px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.02em;
    display: none;
}

@media (min-width: 1040px) {
    .fs-keyboard-hint {
        display: inline-block;
    }
}

.fs-images-panel {
    height: 100%;
    overflow-y: auto;
    padding: 60px 40px;
    display: flex;
    flex-direction: column;
    gap: 48px;
    align-items: center;
    background-color: rgba(255, 255, 255, 0.4);
}

.fs-images-panel .book-plate-figure {
    max-width: 580px;
    width: 100%;
}

.fs-images-panel .book-plate-wrapper {
    aspect-ratio: 1 / 1;
}

/* Image Lightbox */
.lightbox-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(20, 20, 20, 0.96);
    z-index: 2000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.lightbox-modal.active {
    opacity: 1;
    pointer-events: auto;
}

.lightbox-content-wrapper {
    position: relative;
    max-width: 85vw;
    max-height: 80vh;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.lightbox-img {
    max-width: 100%;
    max-height: 72vh;
    object-fit: contain;
    border: 1px solid rgba(255, 255, 255, 0.1);
    background-color: #000;
    padding: 12px;
}

.lightbox-caption {
    font-family: var(--font-mono);
    font-size: 10px;
    color: #a8a49c;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-top: 16px;
    text-align: center;
}

.lightbox-close-btn {
    position: absolute;
    top: 24px;
    right: 24px;
    background: none;
    border: none;
    color: var(--white);
    font-size: 28px;
    cursor: pointer;
    opacity: 0.7;
    transition: opacity var(--transition-speed);
}

.lightbox-close-btn:hover {
    opacity: 1;
}

.lightbox-nav-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--white);
    font-size: 48px;
    cursor: pointer;
    opacity: 0.6;
    padding: 16px;
    min-height: 80px;
    transition: opacity var(--transition-speed);
    display: flex;
    align-items: center;
    justify-content: center;
}

.lightbox-nav-btn:hover {
    opacity: 1;
}

.lightbox-nav-btn.prev-btn {
    left: 24px;
}

.lightbox-nav-btn.next-btn {
    right: 24px;
}

@media (max-width: 768px) {
    .lightbox-nav-btn {
        font-size: 32px;
        padding: 8px;
    }
    .lightbox-nav-btn.prev-btn { left: 8px; }
    .lightbox-nav-btn.next-btn { right: 8px; }
    
    .fs-modal-header {
        padding: 0 20px;
    }
    
    .fs-header-center {
        margin: 0 10px;
    }
}