/* ============================================
   ГЕОХРОМ: ТЕРРАЭНЕРГЕТИКА
   Подземный кристаллический стиль
   ============================================ */

:root {
    /* Crystal colors */
    --amethyst: #9b59b6;
    --amethyst-glow: rgba(155, 89, 182, 0.6);
    --emerald: #2ecc71;
    --emerald-glow: rgba(46, 204, 113, 0.5);
    --sapphire: #3498db;
    --sapphire-glow: rgba(52, 152, 219, 0.5);
    --ruby: #e74c3c;
    --ruby-glow: rgba(231, 76, 60, 0.5);
    --topaz: #f39c12;
    --topaz-glow: rgba(243, 156, 18, 0.5);
    --diamond: #ecf0f1;
    --diamond-glow: rgba(236, 240, 241, 0.8);

    /* Underground palette */
    --deep-black: #0a0a0f;
    --cave-dark: #12121a;
    --obsidian: #1a1a2e;
    --basalt: #252540;
    --granite: #3d3d5c;
    --slate: #5a5a7a;

    /* Magma */
    --magma-core: #ff4500;
    --magma-mid: #ff6b35;
    --magma-edge: #ffa500;
    --magma-glow: rgba(255, 69, 0, 0.4);

    /* Ice */
    --ice-core: #00bfff;
    --ice-mid: #87ceeb;
    --ice-edge: #e0ffff;
    --ice-glow: rgba(0, 191, 255, 0.4);

    /* Text */
    --text-primary: #e8e8f0;
    --text-secondary: rgba(232, 232, 240, 0.7);
    --text-muted: rgba(232, 232, 240, 0.5);

    /* Fonts */
    --font-display: 'Cinzel', serif;
    --font-body: 'Cormorant', serif;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.4s ease;
    --transition-slow: 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
   RESET & BASE
   ============================================ */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-primary);
    background: var(--deep-black);
    overflow-x: hidden;
    min-height: 100vh;
}

::selection {
    background: var(--amethyst);
    color: white;
}

/* ============================================
   ANIMATED BACKGROUNDS
   ============================================ */

.bg-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.bg-crystals {
    background:
        radial-gradient(ellipse at 20% 80%, var(--amethyst-glow) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, var(--sapphire-glow) 0%, transparent 40%),
        radial-gradient(ellipse at 60% 90%, var(--emerald-glow) 0%, transparent 45%),
        radial-gradient(ellipse at 10% 30%, var(--ruby-glow) 0%, transparent 35%);
    opacity: 0.4;
    animation: crystalPulse 15s ease-in-out infinite;
}

.bg-magma {
    background:
        radial-gradient(ellipse at 50% 100%, var(--magma-glow) 0%, transparent 60%);
    opacity: 0.3;
    animation: magmaPulse 8s ease-in-out infinite;
}

@keyframes crystalPulse {
    0%, 100% { opacity: 0.3; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.05); }
}

@keyframes magmaPulse {
    0%, 100% { opacity: 0.2; }
    50% { opacity: 0.4; }
}

/* Floating particles */
.bg-particles {
    background-image:
        radial-gradient(2px 2px at 20px 30px, var(--diamond), transparent),
        radial-gradient(2px 2px at 40px 70px, var(--amethyst), transparent),
        radial-gradient(1px 1px at 90px 40px, var(--emerald), transparent),
        radial-gradient(2px 2px at 130px 80px, var(--sapphire), transparent),
        radial-gradient(1px 1px at 160px 30px, var(--topaz), transparent);
    background-size: 200px 100px;
    animation: particleFloat 60s linear infinite;
    opacity: 0.6;
}

@keyframes particleFloat {
    0% { background-position: 0 0; }
    100% { background-position: 200px -1000px; }
}

/* ============================================
   FLOATING CRYSTALS
   ============================================ */

.crystal-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
    overflow: hidden;
}

.floating-crystal {
    position: absolute;
    width: 20px;
    height: 40px;
    background: linear-gradient(135deg, var(--amethyst) 0%, var(--sapphire) 100%);
    clip-path: polygon(50% 0%, 100% 25%, 100% 75%, 50% 100%, 0% 75%, 0% 25%);
    opacity: 0.6;
    animation: crystalFloat 20s ease-in-out infinite;
    filter: blur(1px);
}

.floating-crystal::before {
    content: '';
    position: absolute;
    inset: 2px;
    background: linear-gradient(135deg, rgba(255,255,255,0.3) 0%, transparent 50%);
    clip-path: inherit;
}

@keyframes crystalFloat {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
        opacity: 0.4;
    }
    25% {
        transform: translateY(-30px) rotate(90deg);
        opacity: 0.7;
    }
    50% {
        transform: translateY(-10px) rotate(180deg);
        opacity: 0.5;
    }
    75% {
        transform: translateY(-40px) rotate(270deg);
        opacity: 0.6;
    }
}

/* ============================================
   BOOK CONTAINER
   ============================================ */

.book-container {
    display: flex;
    min-height: 100vh;
    position: relative;
    z-index: 10;
}

/* ============================================
   SIDEBAR NAVIGATION
   ============================================ */

.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 320px;
    height: 100vh;
    background: linear-gradient(180deg, var(--cave-dark) 0%, var(--obsidian) 100%);
    border-right: 1px solid rgba(155, 89, 182, 0.2);
    display: flex;
    flex-direction: column;
    z-index: 100;
    transform: translateX(0);
    transition: transform var(--transition-slow);
    overflow: hidden;
}

.sidebar::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 1px;
    height: 100%;
    background: linear-gradient(180deg,
        transparent 0%,
        var(--amethyst) 20%,
        var(--sapphire) 50%,
        var(--emerald) 80%,
        transparent 100%);
    animation: sidebarGlow 5s ease-in-out infinite;
}

@keyframes sidebarGlow {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 0.8; }
}

.sidebar.collapsed {
    transform: translateX(-320px);
}

.sidebar-header {
    padding: 2rem;
    text-align: center;
    border-bottom: 1px solid rgba(155, 89, 182, 0.2);
    background: linear-gradient(180deg, rgba(155, 89, 182, 0.1) 0%, transparent 100%);
}

.logo-crystal {
    width: 60px;
    height: 80px;
    margin: 0 auto 1rem;
    background: linear-gradient(180deg, var(--amethyst) 0%, var(--sapphire) 50%, var(--emerald) 100%);
    clip-path: polygon(50% 0%, 100% 20%, 100% 80%, 50% 100%, 0% 80%, 0% 20%);
    position: relative;
    animation: logoPulse 3s ease-in-out infinite;
}

.logo-crystal::before {
    content: '';
    position: absolute;
    inset: 4px;
    background: linear-gradient(180deg, rgba(255,255,255,0.4) 0%, transparent 50%, rgba(0,0,0,0.2) 100%);
    clip-path: inherit;
}

@keyframes logoPulse {
    0%, 100% { filter: brightness(1) drop-shadow(0 0 10px var(--amethyst-glow)); }
    50% { filter: brightness(1.2) drop-shadow(0 0 20px var(--amethyst-glow)); }
}

.sidebar-header h2 {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: 0.2em;
    background: linear-gradient(90deg, var(--amethyst), var(--diamond), var(--sapphire));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.3rem;
}

.sidebar-header .subtitle {
    font-size: 0.85rem;
    color: var(--text-muted);
    letter-spacing: 0.3em;
    text-transform: uppercase;
}

.nav-content {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
}

.nav-content::-webkit-scrollbar {
    width: 4px;
}

.nav-content::-webkit-scrollbar-track {
    background: var(--obsidian);
}

.nav-content::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--amethyst), var(--sapphire));
    border-radius: 2px;
}

.nav-part {
    margin-bottom: 1.5rem;
}

.nav-part-title {
    font-family: var(--font-display);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--amethyst);
    padding: 0.5rem 1rem;
    margin-bottom: 0.5rem;
    border-left: 2px solid var(--amethyst);
}

.nav-chapter {
    display: block;
    padding: 0.7rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    border-radius: 8px;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.nav-chapter::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 3px;
    height: 100%;
    background: linear-gradient(180deg, var(--amethyst), var(--sapphire));
    transform: scaleY(0);
    transition: transform var(--transition-fast);
}

.nav-chapter:hover {
    background: rgba(155, 89, 182, 0.1);
    color: var(--text-primary);
}

.nav-chapter:hover::before {
    transform: scaleY(1);
}

.nav-chapter.active {
    background: rgba(155, 89, 182, 0.2);
    color: var(--diamond);
}

.nav-chapter.active::before {
    transform: scaleY(1);
}

/* Depth indicator */
.sidebar-footer {
    padding: 1.5rem;
    border-top: 1px solid rgba(155, 89, 182, 0.2);
    background: linear-gradient(0deg, rgba(255, 69, 0, 0.1) 0%, transparent 100%);
}

.depth-indicator {
    text-align: center;
}

.depth-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--text-muted);
}

.depth-bar {
    height: 8px;
    background: var(--obsidian);
    border-radius: 4px;
    margin: 0.5rem 0;
    overflow: hidden;
    position: relative;
}

.depth-fill {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--emerald), var(--topaz), var(--magma-core));
    border-radius: 4px;
    transition: width var(--transition-medium);
    position: relative;
}

.depth-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: depthShine 2s ease-in-out infinite;
}

@keyframes depthShine {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

.depth-value {
    font-family: var(--font-display);
    font-size: 1.2rem;
    color: var(--magma-mid);
    text-shadow: 0 0 10px var(--magma-glow);
}

/* Sidebar toggle */
.sidebar-toggle {
    position: fixed;
    left: 320px;
    top: 1rem;
    width: 44px;
    height: 44px;
    background: var(--obsidian);
    border: 1px solid rgba(155, 89, 182, 0.3);
    border-radius: 0 8px 8px 0;
    cursor: pointer;
    z-index: 101;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    transition: all var(--transition-slow);
}

.sidebar-toggle span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--amethyst);
    transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
    background: rgba(155, 89, 182, 0.2);
}

.sidebar.collapsed + .sidebar-toggle {
    left: 0;
    border-radius: 0 8px 8px 0;
}

/* ============================================
   MAIN CONTENT
   ============================================ */

.content {
    flex: 1;
    margin-left: 320px;
    transition: margin-left var(--transition-slow);
    min-height: 100vh;
}

.sidebar.collapsed ~ .content {
    margin-left: 0;
}

/* ============================================
   COVER PAGE
   ============================================ */

.cover-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.cover-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at center bottom, var(--magma-glow) 0%, transparent 60%),
        radial-gradient(ellipse at center, var(--obsidian) 0%, var(--deep-black) 100%);
}

.cover-crystals {
    position: absolute;
    inset: 0;
    background-image:
        url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'%3E%3Cpolygon fill='%239b59b620' points='50,0 100,25 100,75 50,100 0,75 0,25'/%3E%3C/svg%3E");
    background-size: 60px 60px;
    opacity: 0.3;
    animation: coverCrystals 30s linear infinite;
}

@keyframes coverCrystals {
    0% { background-position: 0 0; }
    100% { background-position: 60px 120px; }
}

.cover-content {
    position: relative;
    text-align: center;
    padding: 2rem;
    max-width: 800px;
}

.title-container {
    margin-bottom: 3rem;
}

.rune-circle {
    width: 200px;
    height: 200px;
    margin: 0 auto 2rem;
    border: 2px solid var(--amethyst);
    border-radius: 50%;
    position: relative;
    animation: runeRotate 60s linear infinite;
}

.rune-circle::before {
    content: '';
    position: absolute;
    inset: 10px;
    border: 1px solid var(--sapphire);
    border-radius: 50%;
    animation: runeRotate 40s linear infinite reverse;
}

.rune-circle::after {
    content: '';
    position: absolute;
    inset: 20px;
    border: 1px dashed var(--emerald);
    border-radius: 50%;
    animation: runeRotate 30s linear infinite;
}

@keyframes runeRotate {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.main-title {
    font-family: var(--font-display);
}

.title-line {
    display: block;
    font-size: clamp(3rem, 10vw, 6rem);
    font-weight: 900;
    letter-spacing: 0.3em;
    background: linear-gradient(180deg,
        var(--diamond) 0%,
        var(--amethyst) 50%,
        var(--sapphire) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: none;
    filter: drop-shadow(0 0 30px var(--amethyst-glow));
    animation: titleGlow 3s ease-in-out infinite;
}

@keyframes titleGlow {
    0%, 100% { filter: drop-shadow(0 0 30px var(--amethyst-glow)); }
    50% { filter: drop-shadow(0 0 50px var(--amethyst-glow)) drop-shadow(0 0 80px var(--sapphire-glow)); }
}

.title-divider {
    display: block;
    width: 200px;
    height: 2px;
    margin: 1rem auto;
    background: linear-gradient(90deg, transparent, var(--amethyst), var(--sapphire), var(--emerald), var(--sapphire), var(--amethyst), transparent);
}

.title-sub {
    display: block;
    font-size: clamp(1rem, 3vw, 1.5rem);
    font-weight: 400;
    letter-spacing: 0.5em;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

.tagline {
    font-size: 1.2rem;
    color: var(--text-muted);
    font-style: italic;
}

.cover-quote {
    margin: 3rem 0;
    padding: 2rem;
    background: rgba(155, 89, 182, 0.1);
    border-left: 3px solid var(--amethyst);
    border-radius: 0 12px 12px 0;
}

.cover-quote blockquote {
    font-size: 1.3rem;
    font-style: italic;
    color: var(--text-secondary);
    line-height: 2;
}

/* Enter button */
.enter-button {
    position: relative;
    padding: 1.2rem 3rem;
    font-family: var(--font-display);
    font-size: 1.1rem;
    letter-spacing: 0.2em;
    color: var(--diamond);
    background: linear-gradient(135deg, var(--amethyst) 0%, var(--sapphire) 100%);
    border: none;
    border-radius: 50px;
    cursor: pointer;
    overflow: hidden;
    transition: all var(--transition-medium);
}

.enter-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 40px var(--amethyst-glow);
}

.btn-glow {
    position: absolute;
    inset: -2px;
    background: linear-gradient(135deg, var(--amethyst), var(--sapphire), var(--emerald), var(--amethyst));
    background-size: 300% 300%;
    border-radius: inherit;
    z-index: -1;
    animation: btnGlow 3s ease-in-out infinite;
    filter: blur(10px);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.enter-button:hover .btn-glow {
    opacity: 1;
}

@keyframes btnGlow {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.btn-crystals {
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(2px 2px at 20% 30%, rgba(255,255,255,0.8), transparent),
        radial-gradient(2px 2px at 80% 70%, rgba(255,255,255,0.6), transparent),
        radial-gradient(1px 1px at 50% 50%, rgba(255,255,255,0.4), transparent);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.enter-button:hover .btn-crystals {
    opacity: 1;
}

.scroll-hint {
    margin-top: 3rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.scroll-arrow {
    width: 30px;
    height: 30px;
    margin: 0 auto 0.5rem;
    border-left: 2px solid var(--amethyst);
    border-bottom: 2px solid var(--amethyst);
    transform: rotate(-45deg);
    animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
    0%, 100% { transform: rotate(-45deg) translate(0, 0); opacity: 0.5; }
    50% { transform: rotate(-45deg) translate(5px, 5px); opacity: 1; }
}

/* ============================================
   CHAPTER PAGES
   ============================================ */

.chapter {
    padding: 4rem 2rem;
    max-width: 900px;
    margin: 0 auto;
    min-height: 100vh;
}

.chapter-header {
    text-align: center;
    margin-bottom: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid rgba(155, 89, 182, 0.2);
    position: relative;
}

.chapter-header::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 3px;
    background: linear-gradient(90deg, var(--amethyst), var(--sapphire));
}

.chapter-number {
    font-family: var(--font-display);
    font-size: 0.8rem;
    letter-spacing: 0.3em;
    color: var(--amethyst);
    text-transform: uppercase;
    margin-bottom: 0.5rem;
}

.chapter-title {
    font-family: var(--font-display);
    font-size: clamp(1.8rem, 5vw, 2.5rem);
    font-weight: 700;
    background: linear-gradient(90deg, var(--diamond), var(--amethyst));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.chapter-subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-style: italic;
}

/* Chapter content */
.chapter-content h3 {
    font-family: var(--font-display);
    font-size: 1.5rem;
    color: var(--amethyst);
    margin: 2.5rem 0 1rem;
    padding-left: 1rem;
    border-left: 3px solid var(--amethyst);
}

.chapter-content p {
    margin-bottom: 1.5rem;
    text-align: justify;
    hyphens: auto;
}

.chapter-content strong {
    color: var(--diamond);
    font-weight: 600;
}

.chapter-content em {
    color: var(--sapphire);
}

/* Lists */
.chapter-content ul,
.chapter-content ol {
    margin: 1.5rem 0;
    padding-left: 2rem;
}

.chapter-content li {
    margin-bottom: 0.5rem;
    position: relative;
}

.chapter-content ul li::marker {
    color: var(--amethyst);
}

/* Blockquotes */
.chapter-content blockquote {
    margin: 2rem 0;
    padding: 1.5rem 2rem;
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.1) 0%, rgba(52, 152, 219, 0.1) 100%);
    border-left: 4px solid var(--amethyst);
    border-radius: 0 12px 12px 0;
    font-style: italic;
    position: relative;
}

.chapter-content blockquote::before {
    content: '"';
    position: absolute;
    top: -10px;
    left: 10px;
    font-size: 4rem;
    font-family: var(--font-display);
    color: var(--amethyst);
    opacity: 0.3;
    line-height: 1;
}

/* Code blocks */
.chapter-content pre {
    margin: 2rem 0;
    padding: 1.5rem;
    background: var(--cave-dark);
    border: 1px solid rgba(155, 89, 182, 0.2);
    border-radius: 12px;
    overflow-x: auto;
    font-family: 'Fira Code', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
}

.chapter-content code {
    background: rgba(155, 89, 182, 0.2);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-family: 'Fira Code', monospace;
    font-size: 0.9em;
}

.chapter-content pre code {
    background: none;
    padding: 0;
}

/* Special blocks */
.crystal-block {
    margin: 2rem 0;
    padding: 2rem;
    background:
        linear-gradient(135deg, rgba(155, 89, 182, 0.15) 0%, rgba(52, 152, 219, 0.15) 100%);
    border: 1px solid rgba(155, 89, 182, 0.3);
    border-radius: 16px;
    position: relative;
    overflow: hidden;
}

.crystal-block::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--amethyst), var(--sapphire), var(--emerald));
}

.crystal-block.fire {
    background: linear-gradient(135deg, rgba(255, 69, 0, 0.1) 0%, rgba(255, 165, 0, 0.1) 100%);
    border-color: rgba(255, 69, 0, 0.3);
}

.crystal-block.fire::before {
    background: linear-gradient(90deg, var(--magma-core), var(--magma-mid), var(--magma-edge));
}

.crystal-block.ice {
    background: linear-gradient(135deg, rgba(0, 191, 255, 0.1) 0%, rgba(224, 255, 255, 0.1) 100%);
    border-color: rgba(0, 191, 255, 0.3);
}

.crystal-block.ice::before {
    background: linear-gradient(90deg, var(--ice-core), var(--ice-mid), var(--ice-edge));
}

/* ============================================
   MEDITATION SECTION SPECIAL STYLING
   ============================================ */

.meditation-section {
    background: linear-gradient(180deg, var(--obsidian) 0%, var(--cave-dark) 100%);
    border-radius: 20px;
    padding: 3rem;
    margin: 3rem 0;
    position: relative;
    overflow: hidden;
}

.meditation-section::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at 30% 20%, var(--amethyst-glow) 0%, transparent 50%),
        radial-gradient(ellipse at 70% 80%, var(--sapphire-glow) 0%, transparent 50%);
    opacity: 0.3;
    animation: meditationGlow 10s ease-in-out infinite;
}

@keyframes meditationGlow {
    0%, 100% { opacity: 0.2; }
    50% { opacity: 0.4; }
}

.meditation-section .step {
    position: relative;
    padding: 1.5rem;
    margin: 1.5rem 0;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    border-left: 4px solid var(--amethyst);
}

.meditation-section .step-number {
    position: absolute;
    top: -15px;
    left: 20px;
    width: 30px;
    height: 30px;
    background: linear-gradient(135deg, var(--amethyst), var(--sapphire));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-size: 0.9rem;
    font-weight: 700;
}

/* ============================================
   PROGRESS BAR
   ============================================ */

.progress-container {
    position: fixed;
    top: 0;
    left: 320px;
    right: 0;
    height: 4px;
    background: var(--obsidian);
    z-index: 1000;
    transition: left var(--transition-slow);
}

.sidebar.collapsed ~ .progress-container {
    left: 0;
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--amethyst), var(--sapphire), var(--emerald));
    transition: width var(--transition-fast);
    position: relative;
}

.progress-bar::after {
    content: '';
    position: absolute;
    right: 0;
    top: 0;
    width: 20px;
    height: 100%;
    background: var(--diamond);
    filter: blur(5px);
    animation: progressGlow 1s ease-in-out infinite;
}

@keyframes progressGlow {
    0%, 100% { opacity: 0.5; }
    50% { opacity: 1; }
}

/* ============================================
   UTILITY BUTTONS
   ============================================ */

.ambience-toggle,
.back-to-top {
    position: fixed;
    width: 50px;
    height: 50px;
    background: var(--obsidian);
    border: 1px solid rgba(155, 89, 182, 0.3);
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    transition: all var(--transition-fast);
}

.ambience-toggle {
    right: 1rem;
    bottom: 5rem;
}

.back-to-top {
    right: 1rem;
    bottom: 1rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.ambience-toggle svg,
.back-to-top svg {
    width: 24px;
    height: 24px;
    fill: var(--amethyst);
    transition: fill var(--transition-fast);
}

.ambience-toggle:hover,
.back-to-top:hover {
    background: rgba(155, 89, 182, 0.2);
    border-color: var(--amethyst);
}

.ambience-toggle:hover svg,
.back-to-top:hover svg {
    fill: var(--diamond);
}

.ambience-toggle.active {
    background: linear-gradient(135deg, var(--amethyst), var(--sapphire));
}

.ambience-toggle.active svg {
    fill: white;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-320px);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .sidebar-toggle {
        left: 0;
    }

    .sidebar.open + .sidebar-toggle {
        left: 320px;
    }

    .content {
        margin-left: 0;
    }

    .progress-container {
        left: 0;
    }
}

@media (max-width: 768px) {
    body {
        font-size: 16px;
    }

    .sidebar {
        width: 280px;
    }

    .chapter {
        padding: 2rem 1rem;
    }

    .cover-content {
        padding: 1rem;
    }

    .rune-circle {
        width: 150px;
        height: 150px;
    }

    .meditation-section {
        padding: 1.5rem;
    }
}

/* ============================================
   ANIMATIONS ON SCROLL
   ============================================ */

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Crystal decorations */
.crystal-decoration {
    position: absolute;
    pointer-events: none;
}

.crystal-decoration.left {
    left: -30px;
    top: 50%;
    transform: translateY(-50%);
}

.crystal-decoration.right {
    right: -30px;
    top: 50%;
    transform: translateY(-50%);
}