/* ═══════════════════════════════════════════════════════════
   BOOKS.CSS
   Everything book and page-related
   - Book spreads (two-page layouts)
   - Hero spreads with folios
   - Chapter openers
   - Margin notes
   - Page numbers and styling
   - Paper textures
   - Images within book contexts
   
   Design philosophy: 
   Emulate the feel of an open book with depth and perspective
   ═══════════════════════════════════════════════════════════ */

/* Book spread layout */
.book-spread {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: var(--space-xl) auto;  /* Auto margins for centering */
    max-width: var(--container-wider);  /* Wider by default: 1400px */
    position: relative;
}

.book-spread::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, transparent, var(--color-border), transparent);
    transform: translateX(-50%);
}

.book-page {
    position: relative;
    background: var(--color-surface);
    min-height: 600px;
    box-shadow: var(--shadow-gentle);
}

/* Make pages wider with more padding by default */
.book-page .page-content {
    padding: var(--space-xl) 3.5rem;  /* More horizontal padding */
}

.book-page--left {
    border-radius: 12px 0 0 12px;
    transform: perspective(2000px) rotateY(1deg);
    transform-origin: right center;
}

.book-page--right {
    border-radius: 0 12px 12px 0;
    transform: perspective(2000px) rotateY(-1deg);
    transform-origin: left center;
}

.page-content {
    padding: var(--space-xl);
    position: relative;
    z-index: 2;
}

.page-number {
    position: absolute;
    bottom: var(--space-md);
    right: var(--space-md);
    font-size: 0.9rem;
    color: var(--color-text-tertiary);
}

/* Paper textures */
.paper-texture {
    background-color: #fff;
    background-image: 
        linear-gradient(rgba(200, 200, 200, 0.1) 1px, transparent 1px),
        linear-gradient(90deg, rgba(200, 200, 200, 0.1) 1px, transparent 1px);
    background-size: 40px 40px;
}

.paper-texture-light {
    background-color: #fafaf8;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100"><filter id="noise"><feTurbulence type="fractalNoise" baseFrequency="0.8" numOctaves="1" stitchTiles="stitch"/></filter><rect width="100" height="100" filter="url(%23noise)" opacity="0.08"/></svg>');
}

/* Book images */
.book-image {
    width: 100%;
    height: auto;
    border-radius: 8px;
    margin-bottom: var(--space-sm);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.chapter-image {
    border-radius: 12px;
}

.image-caption {
    font-size: 0.9rem;
    color: var(--color-text-tertiary);
    text-align: center;
    margin-top: -0.5rem;
    margin-bottom: var(--space-md);
}

/* Chapter opener */
.chapter-marker {
    margin-bottom: var(--space-lg);
}

.chapter-number {
    font-size: 1.2rem;
    color: var(--color-accent);
    border-bottom: 2px solid var(--color-accent);
    padding-bottom: 0.25rem;
}

.chapter-title {
    font-family: var(--font-serif);
    font-size: 3.5rem;
    line-height: 1.1;
    margin-bottom: var(--space-md);
    color: var(--color-text-primary);
}

/* Margin notes */
.margin-note {
    position: absolute;
    width: 150px;
    padding: 0.5rem;
    font-size: 0.85rem;
    background: var(--note-yellow);
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

.margin-note--right {
    right: -80px;
    top: 100px;
    transform: rotate(2deg);
}

/* Sticky notes flow */
.sticky-notes-flow {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    margin: var(--space-xl) 0;
    flex-wrap: wrap;
}

.sticky-note {
    padding: 1.5rem;
    min-width: 140px;
    text-align: center;
    box-shadow: 0 8px 16px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
}

.sticky-note--yellow {
    background: var(--note-yellow);
    border-bottom: 3px solid #e6c34c;
}

.sticky-note--blue {
    background: var(--note-blue);
    border-bottom: 3px solid #7aa5c2;
}

.sticky-note--green {
    background: var(--note-green);
    border-bottom: 3px solid #8bb591;
}

.note-number {
    display: block;
    font-size: 2rem;
    font-family: var(--font-serif);
    color: var(--color-accent);
    margin-bottom: 0.5rem;
}

.note-text {
    font-family: var(--font-sans);
    font-weight: 500;
}

.rotated-left {
    transform: rotate(-1deg);
}

.rotated-right {
    transform: rotate(1deg);
}

/* Note stack */
.note-stack {
    position: relative;
    margin-bottom: var(--space-lg);
}

.note-stack .note {
    margin-bottom: -2rem;
}

.note-stack .note:last-child {
    margin-bottom: 0;
}

.note-stack .note:nth-child(1) { z-index: 3; }
.note-stack .note:nth-child(2) { z-index: 2; }
.note-stack .note:nth-child(3) { z-index: 1; }

/* Torn paper effect */
.torn-paper {
    background: #fff;
    padding: var(--space-md);
    margin: var(--space-md) 0;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.05));
    clip-path: polygon(0 0, 100% 0, 98% 95%, 95% 98%, 90% 96%, 85% 99%, 80% 97%, 75% 98%, 70% 96%, 65% 99%, 60% 97%, 55% 98%, 50% 96%, 45% 99%, 40% 97%, 35% 98%, 30% 96%, 25% 99%, 20% 97%, 15% 98%, 10% 96%, 5% 99%, 0 95%);
}

/* Doodle corner */
.doodle-corner {
    position: absolute;
    bottom: var(--space-lg);
    left: var(--space-lg);
    opacity: 0.3;
    width: 100px;
    height: 100px;
}

.doodle-svg {
    width: 100%;
    height: 100%;
    color: var(--color-accent);
}

/* Quick sketch */
.quick-sketch {
    margin-top: var(--space-lg);
    padding: var(--space-sm);
    background: rgba(0,0,0,0.02);
    border-radius: 8px;
}

.sketch-label {
    font-size: 0.85rem;
    color: var(--color-text-tertiary);
    margin-bottom: 0.5rem;
}

.sketch-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
}

.sketch-dot {
    width: 8px;
    height: 8px;
    background: var(--color-accent);
    border-radius: 50%;
    opacity: 0.3;
}

/* Highlight box */
.highlight-box {
    background: rgba(107, 142, 168, 0.1);
    padding: var(--space-md);
    border-left: 4px solid var(--color-accent);
    margin: var(--space-md) 0;
    font-style: italic;
}

/* Graph paper */
.graph-paper {
    background: #fff;
    padding: var(--space-md);
    margin: var(--space-md) 0;
    border: 1px solid var(--color-border);
}

.graph-container {
    width: 100%;
    height: 200px;
    position: relative;
}

.graph-svg {
    width: 100%;
    height: 100%;
}

.graph-label {
    text-align: center;
    margin-top: 0.5rem;
    color: var(--color-accent);
}

/* Formula highlight */
.formula-highlight {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    background: rgba(255, 255, 200, 0.3);
    padding: var(--space-md);
    border-radius: 50px;
    margin: var(--space-lg) 0;
}

.formula {
    font-size: 1.5rem;
    font-family: var(--font-serif);
    font-weight: 500;
}

.formula-small {
    font-size: 1rem;
    font-family: var(--font-serif);
    text-align: center;
    margin-top: 0.5rem;
}

/* Polaroid style */
.polaroid-note {
    background: white;
    padding: 0.75rem 0.75rem 1.5rem 0.75rem;
    box-shadow: 0 8px 16px rgba(0,0,0,0.1);
    width: 220px;
}

.polaroid-image {
    width: 100%;
    height: 160px;
    overflow: hidden;
    margin-bottom: 0.75rem;
}

.polaroid-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.polaroid-caption {
    text-align: center;
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}

/* Bookmarks */
.bookmark-group {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.5rem;
    margin-top: var(--space-lg);
}

.bookmark {
    padding: 0.5rem 1.5rem 0.5rem 1rem;
    background: var(--note-blue);
    border-radius: 0 20px 20px 0;
    position: relative;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.bookmark--blue { background: var(--note-blue); }
.bookmark--green { background: var(--note-green); }
.bookmark--peach { background: var(--note-peach); }

/* Index card */
.index-card {
    background: #fff;
    padding: var(--space-md);
    border-radius: 8px;
    box-shadow: 0 8px 16px rgba(0,0,0,0.05);
    width: 100%;
    margin-top: var(--space-lg);
    border: 1px solid var(--color-border);
}

.card-header {
    border-bottom: 2px dashed var(--color-border);
    padding-bottom: 0.5rem;
    margin-bottom: 1rem;
}

.card-list {
    list-style: none;
    padding: 0;
}

.card-list li {
    padding: 0.25rem 0;
    color: var(--color-text-secondary);
}

/* Landscape spread */
.landscape-spread {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.landscape-page {
    background: white;
    padding: var(--space-lg);
    border-radius: 8px;
    box-shadow: var(--shadow-gentle);
    transform: rotate(0.5deg);
}

.landscape-page:last-child {
    transform: rotate(-0.5deg);
}

.landscape-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 8px;
    margin: var(--space-sm) 0;
}

.caption {
    text-align: center;
    font-size: 0.85rem;
    color: var(--color-text-tertiary);
}

/* Handwritten text */
.handwritten {
    font-family: 'Caveat', cursive;
    font-size: 1.2rem;
    line-height: 1.4;
}

.handwritten-btn {
    font-family: 'Caveat', cursive;
    font-size: 1.3rem;
    padding: 0.75rem 2.5rem;
}

/* Notebook page */
.notebook-page {
    background: white;
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-gentle);
    position: relative;
}

.notebook-page--full {
    min-height: 800px;
}

.page-header {
    display: flex;
    gap: 2rem;
    padding: var(--space-md) var(--space-xl);
    border-bottom: 1px solid var(--color-border-light);
}

.hole-punch {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 2px solid var(--color-border);
    background: white;
}

.page-footer {
    padding: var(--space-md);
    border-top: 1px solid var(--color-border-light);
    text-align: center;
}

.page-ref {
    color: var(--color-text-tertiary);
}

/* Exercise card with tear-off */
.exercise-card {
    position: relative;
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--color-border);
    padding: var(--space-lg);
    margin: var(--space-xl) 0;
}

.tear-off-edge {
    position: absolute;
    top: 0;
    right: 0;
    width: 30px;
    height: 30px;
    background: linear-gradient(45deg, transparent 50%, var(--color-border) 50%);
}

.answer-space {
    border-bottom: 2px dashed var(--color-border);
    padding: var(--space-md) 0;
    margin-top: var(--space-md);
}

.answer-hint {
    color: var(--color-text-tertiary);
}

.spacer {
    height: 40px;
}

/* Note tags */
.note-tag {
    position: absolute;
    bottom: -8px;
    right: 10px;
    background: var(--color-accent);
    color: white;
    padding: 0.2rem 0.75rem;
    border-radius: 20px;
    font-size: 0.7rem;
    font-family: 'Inter', sans-serif;
    text-transform: uppercase;
}

/* ═══════════════════════════════════════════════════════════
   HERO BOOK SPREAD (Enhanced folio)
   ═══════════════════════════════════════════════════════════ */

.hero-spread {
    margin-top: var(--space-lg);
    margin-bottom: var(--space-xl);
}

.hero-spread .book-page {
    min-height: 700px;
}

/* Folio introduction styling */
.folio-intro {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.chapter-marker-small {
    font-size: 0.9rem;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.folio-title {
    font-family: var(--font-serif);
    font-size: 3rem;
    line-height: 1.2;
    margin: 0;
    color: var(--color-text-primary);
}

.author-line {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
}

.folio-divider {
    width: 60px;
    height: 2px;
    background: var(--color-accent);
    margin: 1rem 0;
}

.folio-body {
    font-family: var(--font-body);
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--color-text-secondary);
}

.folio-quote {
    padding: 1.5rem;
    background: rgba(107, 142, 168, 0.08);
    border-left: 4px solid var(--color-accent);
    font-size: 1.15rem;
    line-height: 1.6;
    color: var(--color-text-primary);
    margin-top: 2rem;
}

/* Plate image (illustration style) */
.plate-image {
    display: flex;
    flex-direction: column;
    justify-content: center;
    height: 100%;
    padding: 2rem 0;
}

.plate-image .book-image {
    width: 100%;
    height: auto;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    margin-bottom: 1rem;
}

/* Responsive */
@media (max-width: 1200px) {
    .book-spread {
        grid-template-columns: 1fr;
    }
    
    .book-spread::before {
        display: none;
    }
    
    .book-page {
        transform: none !important;
        margin-bottom: var(--space-lg);
    }

    .main-content > .page-section:last-child .book-page {
        margin-bottom: 0 !important;
    }
    
    .hero-spread .book-page {
        min-height: auto;
    }
    
    .folio-title {
        font-size: 2.25rem;
    }
    
    .margin-note {
        position: static;
        width: auto;
        margin-top: var(--space-md);
    }
    
    .landscape-spread {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .folio-title {
        font-size: 1.75rem;
    }
    
    .folio-body {
        font-size: 1rem;
    }
}

/* ═══════════════════════════════════════════════════════════
   BEAUTIFUL NEW ENHANCEMENTS
   Additional paper effects and depth
   ═══════════════════════════════════════════════════════════ */

/* Page curl effect (subtle, top-right corner) */
.book-page--curl::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 0 40px 40px 0;
    border-color: transparent rgba(0, 0, 0, 0.03) transparent transparent;
    pointer-events: none;
}

.book-page--curl::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, 
        rgba(255, 255, 255, 0) 0%,
        rgba(0, 0, 0, 0.02) 100%);
    pointer-events: none;
}

/* Enhanced depth for book spreads (no filter: drop-shadow, it adds a blank strip above the footer) */
.book-spread--depth {
    filter: none;
}

.book-spread--depth .book-page {
    box-shadow: 
        0 2px 4px rgba(0, 0, 0, 0.05),
        0 8px 16px rgba(0, 0, 0, 0.05),
        inset 0 0 0 1px rgba(255, 255, 255, 0.5);
}

/* Aged paper variant */
.paper-aged {
    background-color: #f9f6ed;
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(200, 180, 150, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(200, 180, 150, 0.03) 0%, transparent 50%),
        linear-gradient(rgba(200, 200, 200, 0.08) 1px, transparent 1px),
        linear-gradient(90deg, rgba(200, 200, 200, 0.08) 1px, transparent 1px);
    background-size: 100% 100%, 100% 100%, 30px 30px, 30px 30px;
}

/* Watermark effect (subtle) */
.book-page--watermark::before {
    content: '📚';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) rotate(-15deg);
    font-size: 15rem;
    opacity: 0.02;
    pointer-events: none;
    z-index: 0;
}

/* Full bleed book spread (edge to edge) */
.book-spread--fullbleed {
    grid-template-columns: 1fr 1fr;
    gap: 0;
    max-width: 100%;
    margin: 0;
}

.book-spread--fullbleed::before {
    display: none;
}

.book-spread--fullbleed .book-page {
    border-radius: 0;
    min-height: 0;
}

/* Wider book pages for more content */
.book-page--wide {
    padding: var(--space-xl) 4rem;
}

/* Library stamp effect */
.library-stamp {
    position: absolute;
    bottom: var(--space-lg);
    right: var(--space-lg);
    padding: 0.5rem 1rem;
    border: 2px solid rgba(107, 142, 168, 0.3);
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.75rem;
    color: rgba(107, 142, 168, 0.5);
    transform: rotate(-3deg);
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

/* Bookmark ribbon */
.book-page--bookmark::after {
    content: '';
    position: absolute;
    top: 0;
    right: 80px;
    width: 40px;
    height: 120px;
    background: linear-gradient(to bottom, 
        rgba(107, 142, 168, 0.6) 0%,
        rgba(107, 142, 168, 0.5) 95%,
        transparent 100%);
    box-shadow: 
        0 2px 8px rgba(0, 0, 0, 0.1),
        inset 0 0 0 1px rgba(255, 255, 255, 0.2);
    clip-path: polygon(0 0, 100% 0, 100% 85%, 50% 100%, 0 85%);
}

/* Responsive adjustments for new enhancements */
@media (max-width: 1200px) {
    .book-spread--fullbleed .book-page {
        min-height: auto;
    }
    
    .book-page--bookmark::after {
        right: 40px;
        width: 30px;
        height: 80px;
    }
}

@media (max-width: 768px) {
    /* Stack book-spread vertically on phones so image displays larger */
    .book-spread,
    .book-spread--fullbleed {
        grid-template-columns: 1fr;
    }
    
    .book-page--wide {
        padding: var(--space-lg) var(--space-md);
    }
    
    .book-page--watermark::before {
        font-size: 8rem;
    }
    
    .library-stamp {
        font-size: 0.6rem;
        padding: 0.3rem 0.75rem;
    }
}