:root {
    --color-cream: #F8F5F0;
    --color-paper: #FFFEF9;
    --color-paper-back: #F5F2ED;
    --color-ink: #1A1612;
    --color-ink-light: #4A4540;
    --color-ink-faded: #8A857D;
    --color-red: #8B2323;
    --color-red-dark: #5C1717;
    --color-gold: #B8956A;
    --color-gold-light: #D4B896;
    --font-display: 'Cormorant', serif;
    --font-body: 'Libre Baskerville', serif;
    --font-sans: 'Instrument Sans', sans-serif;
}

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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
}

body {
    font-family: var(--font-body);
    background: linear-gradient(135deg, #2C2420 0%, #1A1612 50%, #0D0B0A 100%);
    color: var(--color-ink);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
}

body.dragging { cursor: grabbing; }

body::before {
    content: '';
    position: fixed;
    inset: 0;
    background: radial-gradient(ellipse at 30% 20%, rgba(184, 149, 106, 0.08) 0%, transparent 50%),
                radial-gradient(ellipse at 70% 80%, rgba(139, 35, 35, 0.05) 0%, transparent 40%);
    pointer-events: none;
}

::selection {
    background: var(--color-gold-light);
    color: var(--color-ink);
}

/* Controls */
.controls {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 1.5rem;
    z-index: 1000;
    background: rgba(26, 22, 18, 0.95);
    backdrop-filter: blur(20px);
    padding: 1rem 2rem;
    border-radius: 50px;
    border: 1px solid rgba(255,255,255,0.1);
}

.nav-btn {
    width: 50px;
    height: 50px;
    border: 1px solid rgba(255,255,255,0.2);
    background: transparent;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    color: rgba(255,255,255,0.6);
}

.nav-btn:hover:not(:disabled) {
    background: rgba(255,255,255,0.1);
    border-color: var(--color-gold);
    color: var(--color-gold);
    transform: scale(1.05);
}

.nav-btn:disabled { opacity: 0.3; cursor: not-allowed; }

.nav-btn svg {
    width: 20px;
    height: 20px;
    stroke: currentColor;
    stroke-width: 2;
    fill: none;
}

.page-indicator {
    font-family: var(--font-sans);
    font-size: 0.75rem;
    letter-spacing: 0.15em;
    color: rgba(255,255,255,0.5);
    min-width: 100px;
    text-align: center;
}

.zoom-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-left: 1rem;
    padding-left: 1.5rem;
    border-left: 1px solid rgba(255,255,255,0.1);
}

.zoom-btn {
    width: 36px;
    height: 36px;
    border: 1px solid rgba(255,255,255,0.15);
    background: transparent;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    color: rgba(255,255,255,0.5);
    font-size: 1.2rem;
}

.zoom-btn:hover {
    background: rgba(255,255,255,0.1);
    color: var(--color-gold);
}

.zoom-level {
    font-family: var(--font-sans);
    font-size: 0.7rem;
    color: rgba(255,255,255,0.4);
    min-width: 45px;
    text-align: center;
}

.help-hint {
    position: fixed;
    top: 2rem;
    right: 2rem;
    z-index: 1000;
    font-family: var(--font-sans);
    font-size: 0.7rem;
    color: rgba(255,255,255,0.4);
    letter-spacing: 0.1em;
    text-align: right;
    line-height: 2;
}

.help-hint kbd {
    background: rgba(255,255,255,0.1);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    margin-left: 0.5rem;
}

/* Book Container */
.book-wrapper {
    perspective: 2500px;
    transform-style: preserve-3d;
}

.book-container {
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.3s ease;
    will-change: transform; /* Performance hint for zoom */
}

.book {
    width: 1300px;
    height: 850px;
    position: relative;
    transform-style: preserve-3d;
    transform: rotateX(3deg);
}

/* Book shadow - realistic drop shadow */
.book::after {
    content: '';
    position: absolute;
    bottom: -60px;
    left: 5%;
    width: 90%;
    height: 80px;
    background: radial-gradient(ellipse, rgba(0,0,0,0.4) 0%, rgba(0,0,0,0.2) 40%, transparent 70%);
    filter: blur(30px);
    opacity: 0.8;
}

/* Book spine - subtle center shadow */
.book-spine {
    position: absolute;
    left: 50%;
    top: 0;
    transform: translateX(-50%);
    width: 8px;
    height: 100%;
    background: linear-gradient(90deg,
        transparent 0%,
        rgba(0,0,0,0.08) 20%,
        rgba(0,0,0,0.12) 50%,
        rgba(0,0,0,0.08) 80%,
        transparent 100%);
    z-index: 1000;
    pointer-events: none;
}

/* Static pages (left side - already flipped) */
.static-page {
    position: absolute;
    width: 650px;
    height: 100%;
    background: var(--color-paper);
    border-radius: 0;
    left: 0;
    overflow: hidden;
    box-shadow: inset -5px 0 15px rgba(0,0,0,0.03);
}

.static-page::before {
    content: '';
    position: absolute;
    right: 0;
    top: 0;
    width: 30px;
    height: 100%;
    background: linear-gradient(to left, rgba(0,0,0,0.04), transparent);
    pointer-events: none;
}

/* Right static page */
.static-page-right {
    position: absolute;
    width: 650px;
    height: 100%;
    background: var(--color-paper);
    border-radius: 0;
    right: 0;
    overflow: hidden;
    box-shadow: inset 5px 0 15px rgba(0,0,0,0.03);
}

.static-page-right::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 30px;
    height: 100%;
    background: linear-gradient(to right, rgba(0,0,0,0.04), transparent);
    pointer-events: none;
}

/* Flippable pages */
.flip-page {
    position: absolute;
    width: 650px;
    height: 100%;
    right: 0;
    transform-style: preserve-3d;
    transform-origin: left center;
    transition: transform 1s cubic-bezier(0.645, 0.045, 0.355, 1.000);
    cursor: pointer;
    will-change: transform; /* Performance hint for animations */
}

.flip-page.flipping {
    transition: transform 0.8s cubic-bezier(0.390, 0.575, 0.565, 1.000);
}

.flip-page.flipped {
    transform: rotateY(-180deg);
}

/* Front and back of flip page */
.page-front,
.page-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    overflow: hidden;
    border-radius: 0;
}

.page-front {
    background: var(--color-paper);
    z-index: 1;
    box-shadow:
        0 2px 8px rgba(0,0,0,0.08),
        inset 5px 0 15px rgba(0,0,0,0.02);
}

.page-front::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 30px;
    height: 100%;
    background: linear-gradient(to right, rgba(0,0,0,0.05), transparent);
    pointer-events: none;
}

.page-back {
    background: var(--color-paper);
    transform: rotateY(180deg);
    border-radius: 0;
    box-shadow:
        0 2px 8px rgba(0,0,0,0.08),
        inset -5px 0 15px rgba(0,0,0,0.02);
}

.page-back::before {
    content: '';
    position: absolute;
    right: 0;
    top: 0;
    width: 30px;
    height: 100%;
    background: linear-gradient(to left, rgba(0,0,0,0.04), transparent);
    pointer-events: none;
}

/* Paper texture */
.page-front::after,
.page-back::after {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
    opacity: 0.025;
    pointer-events: none;
}

/* Page content */
.page-content {
    width: 100%;
    height: 100%;
    padding: 3.5rem;
    overflow: hidden;
    position: relative;
}

.page-number {
    position: absolute;
    bottom: 2rem;
    font-family: var(--font-sans);
    font-size: 0.7rem;
    color: var(--color-ink-faded);
    letter-spacing: 0.1em;
}

.page-front .page-number { right: 3.5rem; }
.page-back .page-number { left: 3.5rem; }
.static-page .page-number { left: 3.5rem; }
.static-page-right .page-number { right: 3.5rem; }

/* Cover styles */
.cover-dark {
    background: var(--color-ink) !important;
    color: var(--color-paper);
}

.cover-dark::after { opacity: 0.015; }

.cover-content {
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    padding-bottom: 1rem;
    position: relative;
}

.cover-circles {
    position: absolute;
    top: 5%;
    right: -30%;
    width: 450px;
    height: 450px;
    opacity: 0.12;
}

.cover-circle {
    position: absolute;
    border: 1px solid rgba(255,255,255,0.4);
    border-radius: 50%;
}

.cover-circle:nth-child(1) { width: 100%; height: 100%; }
.cover-circle:nth-child(2) { width: 70%; height: 70%; top: 15%; left: 15%; }
.cover-circle:nth-child(3) { width: 40%; height: 40%; top: 30%; left: 30%; border-color: var(--color-gold); }

.cover-tag {
    font-family: var(--font-sans);
    font-size: 0.6rem;
    font-weight: 500;
    letter-spacing: 0.4em;
    text-transform: uppercase;
    color: var(--color-gold);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.cover-tag::before {
    content: '';
    width: 30px;
    height: 1px;
    background: var(--color-gold);
}

.cover h1 {
    font-family: var(--font-display);
    font-size: 3.8rem;
    font-weight: 300;
    line-height: 0.95;
    margin-bottom: 1.5rem;
}

.cover h1 em {
    font-style: italic;
    color: var(--color-gold-light);
}

.cover-subtitle {
    font-family: var(--font-display);
    font-size: 1rem;
    font-style: italic;
    color: rgba(255,255,255,0.6);
    line-height: 1.6;
}

/* Chapter number background */
.chapter-number {
    font-family: var(--font-display);
    font-size: 7rem;
    font-weight: 300;
    color: rgba(0,0,0,0.04);
    position: absolute;
    top: 0.5rem;
    right: 1.5rem;
    line-height: 1;
    pointer-events: none;
}

.cover-dark .chapter-number { color: rgba(255,255,255,0.04); }

.chapter-label {
    font-family: var(--font-sans);
    font-size: 0.6rem;
    font-weight: 500;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--color-red);
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.chapter-label::before {
    content: '';
    width: 20px;
    height: 1px;
    background: currentColor;
}

.page-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 400;
    line-height: 1.2;
    margin-bottom: 1.2rem;
    color: var(--color-ink);
}

.page-title em { font-style: italic; }

.cover-dark .chapter-label { color: var(--color-gold); }
.cover-dark .page-title { color: var(--color-paper); }

/* Content */
.content h3 {
    font-family: var(--font-display);
    font-size: 1.3rem;
    font-weight: 500;
    margin-bottom: 0.8rem;
    color: var(--color-ink);
}

.content p {
    font-size: 0.82rem;
    line-height: 1.85;
    color: var(--color-ink-light);
    margin-bottom: 0.9rem;
    text-align: justify;
    hyphens: auto;
}

.content p.lead {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-style: italic;
    line-height: 1.65;
    color: var(--color-ink);
    text-align: left;
    margin-bottom: 1.2rem;
}

.cover-dark .content p { color: rgba(255,255,255,0.75); }
.cover-dark .content p.lead { color: rgba(255,255,255,0.9); }

.content ul {
    list-style: none;
    margin: 0.8rem 0;
}

.content li {
    font-size: 0.82rem;
    color: var(--color-ink-light);
    padding-left: 1.3rem;
    margin-bottom: 0.5rem;
    position: relative;
}

.content li::before {
    content: '—';
    position: absolute;
    left: 0;
    color: var(--color-red);
}

.cover-dark .content li { color: rgba(255,255,255,0.75); }
.cover-dark .content li::before { color: var(--color-gold); }

/* Pull quote */
.pull-quote {
    padding: 1.5rem 0;
    border-top: 1px solid rgba(0,0,0,0.08);
    border-bottom: 1px solid rgba(0,0,0,0.08);
    margin: 1.5rem 0;
}

.pull-quote p {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-style: italic;
    line-height: 1.5;
    color: var(--color-ink);
    text-align: left !important;
}

.pull-quote cite {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.6rem;
    font-style: normal;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-ink-faded);
    margin-top: 0.8rem;
}

/* Image placeholder */
.image-placeholder {
    width: 100%;
    height: 100%;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(145deg, #E8E4DD 0%, #DAD6CF 100%);
    border: 1px solid rgba(0,0,0,0.06);
    position: relative;
    transition: all 0.3s ease;
}

.image-placeholder:hover {
    background: linear-gradient(145deg, #E0DCD5 0%, #D2CEC7 100%);
}

.placeholder-icon {
    width: 50px;
    height: 50px;
    margin-bottom: 0.8rem;
    opacity: 0.25;
}

.placeholder-icon svg {
    width: 100%;
    height: 100%;
    stroke: var(--color-ink);
    stroke-width: 0.5;
    fill: none;
}

.placeholder-label {
    font-family: var(--font-sans);
    font-size: 0.55rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-ink-faded);
}

.placeholder-title {
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-style: italic;
    color: var(--color-ink-light);
    margin-top: 0.3rem;
}

.placeholder-size {
    font-family: var(--font-sans);
    font-size: 0.5rem;
    color: var(--color-ink-faded);
    margin-top: 0.6rem;
}

/* Artwork section */
.artwork-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.artwork-number {
    font-family: var(--font-display);
    font-size: 4rem;
    font-weight: 300;
    line-height: 0.8;
    color: rgba(0,0,0,0.06);
}

.artwork-tag {
    font-family: var(--font-sans);
    font-size: 0.5rem;
    font-weight: 500;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--color-red);
    padding: 0.4rem 0.8rem;
    border: 1px solid var(--color-red);
}

.artwork-tag.gold {
    color: var(--color-gold);
    border-color: var(--color-gold);
}

.artwork-title {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 400;
    margin-bottom: 0.2rem;
    color: var(--color-ink);
}

.artwork-subtitle {
    font-family: var(--font-display);
    font-size: 0.9rem;
    font-style: italic;
    color: var(--color-ink-light);
    margin-bottom: 1rem;
}

.artwork-description {
    font-size: 0.8rem;
    color: var(--color-ink-light);
    line-height: 1.75;
    margin-bottom: 1rem;
}

.artwork-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.8rem;
    padding: 1rem 0;
    border-top: 1px solid rgba(0,0,0,0.08);
}

.detail-item label {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.5rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-ink-faded);
    margin-bottom: 0.2rem;
}

.detail-item span {
    font-family: var(--font-display);
    font-size: 0.85rem;
    color: var(--color-ink);
}

.artwork-features h4 {
    font-family: var(--font-sans);
    font-size: 0.5rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-ink-faded);
    margin: 0.8rem 0 0.5rem;
}

.artwork-features ul { list-style: none; }

.artwork-features li {
    font-family: var(--font-display);
    font-size: 0.85rem;
    font-style: italic;
    color: var(--color-ink-light);
    padding: 0.4rem 0;
    border-bottom: 1px solid rgba(0,0,0,0.04);
    padding-left: 1rem;
    position: relative;
}

.artwork-features li::before {
    content: '○';
    position: absolute;
    left: 0;
    font-size: 0.45rem;
    color: var(--color-red);
}

/* Thumbnail grid */
.thumb-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.6rem;
    margin-top: 0.8rem;
}

.thumb-grid .image-placeholder {
    min-height: 80px;
    aspect-ratio: 1;
}

/* Colophon */
.colophon h3 {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 300;
    margin-bottom: 1rem;
    line-height: 1.3;
    color: var(--color-paper);
}

.colophon > p {
    font-size: 0.8rem;
    color: rgba(255,255,255,0.6);
    line-height: 1.75;
    margin-bottom: 1.5rem;
}

.colophon-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.colophon-item label {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.5rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--color-gold);
    margin-bottom: 0.2rem;
}

.colophon-item span {
    font-family: var(--font-display);
    font-size: 0.9rem;
    color: rgba(255,255,255,0.8);
}

.copyright-text {
    position: absolute;
    bottom: 2rem;
    left: 3.5rem;
    font-family: var(--font-sans);
    font-size: 0.55rem;
    color: rgba(255,255,255,0.3);
    letter-spacing: 0.1em;
}

/* Full image page */
.full-image .page-content {
    padding: 0;
}

.full-image .image-placeholder {
    height: 100%;
    min-height: 100%;
    border: none;
    border-radius: 0;
}

.page-back .full-image .image-placeholder {
    border-radius: 0;
}

/* Responsive */
@media (max-width: 1400px) {
    .book { width: 1100px; height: 700px; }
    .static-page, .static-page-right, .flip-page, .page-front, .page-back { width: 550px; }
    .cover h1 { font-size: 3rem; }
    .page-content { padding: 2.5rem; }
}

@media (max-width: 1150px) {
    .book { width: 900px; height: 580px; }
    .static-page, .static-page-right, .flip-page, .page-front, .page-back { width: 450px; }
    .cover h1 { font-size: 2.5rem; }
    .page-content { padding: 2rem; }
    .page-title { font-size: 1.6rem; }
    .help-hint { display: none; }
}

@media (max-width: 950px) {
    .book { width: 700px; height: 480px; }
    .static-page, .static-page-right, .flip-page, .page-front, .page-back { width: 350px; }
    .cover h1 { font-size: 2rem; }
    .page-content { padding: 1.5rem; }
    .controls { padding: 0.7rem 1.2rem; gap: 1rem; }
    .nav-btn { width: 40px; height: 40px; }
}