:root {
    --accent-cyan: #00f2ff;
    --font-serif: 'Merriweather', serif;
    --font-sans: 'Inter', sans-serif;
    --font-mono: 'Fira Code', monospace;
    --font-display: 'Orbitron', sans-serif;
}

body.theme-dark {
    --bg-dark: #050505;
    --sidebar-bg: #0a0a0a;
    --text-main: #d1d1d1;
    --text-dim: #888;
    --border-color: #222;
    --bg-gradient: radial-gradient(circle at 50% 0%, #111 0%, #050505 70%);
}

body.theme-light {
    --bg-dark: #f5f5f5;
    --sidebar-bg: #ffffff;
    --text-main: #222222;
    --text-dim: #666;
    --border-color: #ddd;
    --bg-gradient: radial-gradient(circle at 50% 0%, #ffffff 0%, #f5f5f5 70%);
}

body {
    margin: 0;
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-sans);
    line-height: 1.6;
    overflow: hidden;
    transition: background-color 0.3s, color 0.3s;
}

.reader-container {
    display: flex;
    height: 100vh;
}

.sidebar {
    width: 250px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    padding: 20px;
    display: flex;
    flex-direction: column;
}

.logo h1 {
    font-family: var(--font-display);
    font-size: 22px;
    letter-spacing: 4px;
    margin-bottom: 40px;
    text-align: center;
    color: var(--text-main);
    text-transform: uppercase;
}

.highlight {
    color: var(--accent-cyan);
    text-shadow: 0 0 15px rgba(0, 242, 255, 0.6);
}

.desktop-nav {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.desktop-nav a {
    color: var(--text-dim);
    text-decoration: none;
    padding: 12px;
    border-radius: 4px;
    font-size: 14px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-left: 2px solid transparent;
}

.desktop-nav a:hover, .desktop-nav a.active {
    background-color: rgba(0, 242, 255, 0.05);
    color: var(--accent-cyan);
    border-left: 2px solid var(--accent-cyan);
}

/* Settings Menu */
#settings-trigger {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--sidebar-bg);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-size: 24px;
    cursor: pointer;
    z-index: 100;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}

.settings-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.settings-modal.hidden { display: none; }

.settings-content {
    width: 350px;
    padding: 25px;
    background: var(--sidebar-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
}

.settings-header h3 { font-family: var(--font-display); margin: 0; font-size: 16px; color: var(--accent-cyan); }
.close-btn { background: none; border: none; color: var(--text-dim); cursor: pointer; font-size: 20px; }

.settings-group { margin-bottom: 20px; }
.settings-group label { display: block; font-size: 12px; color: var(--text-dim); margin-bottom: 10px; text-transform: uppercase; letter-spacing: 1px; }

.toggle-row { display: flex; gap: 5px; background: rgba(0,0,0,0.2); padding: 4px; border-radius: 4px; }
.toggle-row button { 
    flex: 1; 
    padding: 8px; 
    background: transparent; 
    border: none; 
    color: var(--text-dim); 
    cursor: pointer; 
    font-size: 13px;
    border-radius: 2px;
}
.toggle-row button.active { background: var(--accent-cyan); color: #000; font-weight: bold; }

.size-controls { display: flex; align-items: center; justify-content: space-between; background: rgba(0,0,0,0.2); padding: 10px; border-radius: 4px; }
.size-controls button { background: var(--border-color); border: none; color: var(--text-main); width: 40px; height: 30px; cursor: pointer; }
.size-controls span { font-weight: bold; color: var(--accent-cyan); }

/* Header Bar - COMPACT VERSION */
.reader-header {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 10px;
    background: transparent;
    gap: 8px;
    margin-bottom: 5px;
    width: 100%;
    max-width: 700px;
    flex-wrap: wrap;
}

.header-btn {
    background: rgba(0, 0, 0, 0.6);
    border: 1px solid var(--border-color);
    color: var(--text-dim);
    padding: 6px 12px;
    border-radius: 4px;
    font-family: var(--font-display);
    font-size: 10px;
    letter-spacing: 1px;
    cursor: pointer;
    transition: all 0.3s;
    text-transform: uppercase;
    backdrop-filter: blur(5px);
    min-width: 70px;
}

.header-btn.active {
    background: var(--accent-cyan) !important;
    color: #000 !important;
    border-color: var(--accent-cyan) !important;
    font-weight: bold;
    box-shadow: 0 0 15px rgba(0, 242, 255, 0.6);
}

/* Immersive Mode Styles */
body.immersive-mode {
    --bg-dark: #020202;
    --text-main: #e0faff;
}

#noise-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    opacity: 0.03;
    z-index: 9999;
    background-image: url('https://upload.wikimedia.org/wikipedia/commons/7/76/Noise_600x600.png');
    display: none;
}

body.immersive-mode #noise-overlay {
    display: block;
    animation: grain 0.5s steps(10) infinite;
}

@keyframes grain {
    0%, 100% { transform:translate(0, 0) }
    10% { transform:translate(-5%, -10%) }
    30% { transform:translate(3%, -15%) }
    50% { transform:translate(12%, 9%) }
    70% { transform:translate(9%, 4%) }
    90% { transform:translate(-1%, 7%) }
}

.glitch-text {
    position: relative;
    display: inline-block;
    color: #ff4d4d;
}

body.immersive-mode .glitch-text::before,
body.immersive-mode .glitch-text::after {
    content: attr(data-text);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.resonance-text {
    color: var(--accent-cyan);
    text-shadow: 0 0 8px rgba(0, 242, 255, 0.8);
}

/* Mobile Nav */
.mobile-nav {
    display: none;
    margin-bottom: 20px;
}

#chapter-select {
    width: 100%;
    padding: 10px;
    background-color: var(--bg-dark);
    color: var(--accent-cyan);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
}

.content-area {
    flex: 1;
    padding: 40px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    background-image: var(--bg-gradient);
}

.markdown-body {
    max-width: 700px;
    width: 100%;
    flex: 1;
}

/* Notes Modal */
#notes-panel {
    position: fixed;
    top: 0;
    right: 0;
    width: 400px;
    height: 100%;
    background: var(--sidebar-bg);
    border-left: 1px solid var(--border-color);
    z-index: 1500;
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease;
}

#notes-panel.hidden {
    transform: translateX(100%);
}

.notes-header { padding: 20px; border-bottom: 1px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
.notes-body { flex: 1; padding: 20px; display: flex; flex-direction: column; gap: 15px; overflow-y: auto; }
#chapter-notes-area { flex: 1; min-height: 200px; background: rgba(0,0,0,0.3); border: 1px solid var(--border-color); color: #fff; padding: 15px; resize: none; border-radius: 4px; font-family: 'Inter', sans-serif; font-size: 16px; }
.notes-footer { padding: 20px; padding-bottom: calc(20px + env(safe-area-inset-bottom)); } 
.sync-btn { width: 100%; background: var(--accent-cyan); color: #000; border: none; padding: 18px; font-size: 14px; font-family: 'Orbitron', sans-serif; letter-spacing: 1px; font-weight: bold; cursor: pointer; border-radius: 4px; box-shadow: 0 4px 15px rgba(0, 242, 255, 0.3); }

/* Scrollbar */
.content-area::-webkit-scrollbar {
    width: 4px;
}
.content-area::-webkit-scrollbar-track {
    background: #020202;
}
.content-area::-webkit-scrollbar-thumb {
    background: #1a1a1a;
}
.content-area::-webkit-scrollbar-thumb:hover {
    background: var(--accent-cyan);
}

/* Focus Mode */
body.focus-mode .sidebar { display: none; }

/* Responsive */
@media (max-width: 768px) {
    .reader-container { flex-direction: column; }
    .sidebar { width: auto; height: auto; border-right: none; border-bottom: 1px solid var(--border-color); padding: 15px; }
    .desktop-nav { display: none; }
    .mobile-nav { display: block; }
    .content-area { padding: 20px 15px; }
    #notes-panel { width: 100%; }
}