:root {
            --ink: #111827; /* Dark gray for high contrast but softer than pure black */
            --paper: #ffffff; /* Pure white background */
            --paper-dark: #f9fafb; /* Off-white for slight contrast */
            --red: #ef4444;
            --gold: #3b82f6; /* Modern blue accent */
            --muted: #6b7280; /* Clean medium gray */
            --serif: 'Inter', 'Outfit', sans-serif;
            --mono: 'DM Mono', monospace;
            --card-bg: #ffffff;
            --card-border: rgba(0,0,0,0.05);
            --card-shadow: 0 2px 4px rgba(0,0,0,0.02);
            --card-shadow-hover: 0 10px 25px rgba(0,0,0,0.06);
            --sidebar-active-bg: #eff6ff; /* Blinkist style light blue active state */
            --sidebar-active-text: #2563eb;
        }
        
        /* Blinkist Clean Aesthetic Overrides for Light Mode */
        body:not(.dark-theme) .book-card-year,
        body:not(.dark-theme) .author-label,
        body:not(.dark-theme) .book-card-actions {
            display: none !important;
        }
        body:not(.dark-theme) .book-card-author-wrapper {
            border-top: none !important;
            margin-top: 0.1rem !important;
            padding-top: 0 !important;
        }
        body:not(.dark-theme) .book-card {
            box-shadow: var(--card-shadow) !important;
        }
        body:not(.dark-theme) .book-card:hover {
            box-shadow: var(--card-shadow-hover) !important;
            transform: translateY(-4px) !important;
            border-color: rgba(0,0,0,0.08) !important;
        }
        body:not(.dark-theme) .book-card-title {
            font-size: 1.05rem !important;
            font-weight: 700 !important;
            margin-bottom: 0.1rem !important;
        }
        body:not(.dark-theme) .book-card-author {
            font-size: 0.85rem !important;
            color: var(--muted) !important;
            font-weight: 500 !important;
        }
        body:not(.dark-theme) .book-cat-tag {
            background: #ffffff !important;
            color: #374151 !important;
            border: 1px solid rgba(0,0,0,0.08) !important;
            box-shadow: 0 1px 2px rgba(0,0,0,0.05) !important;
        }
        body:not(.dark-theme) .sidebar-link.active,
        body:not(.dark-theme) .sidebar-link:hover {
            background: var(--sidebar-active-bg) !important;
            color: var(--sidebar-active-text) !important;
            border-radius: 8px;
            padding-left: 1rem; /* Indent slightly for active state */
        }
        body:not(.dark-theme) .sidebar-link {
            transition: all 0.2s ease;
            padding: 0.5rem;
            margin-bottom: 0.2rem;
        }
        body.dark-theme {
            --ink: #ffffff;
            --paper: #0a0a0a;
            --paper-dark: #141414;
            --muted: #d0cdc8;
            --card-bg: rgba(22, 20, 18, 0.7);
            --card-border: rgba(255, 255, 255, 0.08);
            --card-shadow: 0 12px 30px rgba(0, 0, 0, 0.5);
            --card-shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.6), 0 0 20px rgba(212, 175, 55, 0.15);
        }
        body.dark-theme .nav-bar {
            background: rgba(14, 13, 11, 0.7) !important;
            border-bottom: 1px solid rgba(244, 240, 232, 0.1) !important;
        }
        body.dark-theme .sidebar {
            background: #111 !important;
            border-right: 1px solid rgba(255, 255, 255, 0.1) !important;
        }
        body.dark-theme .nav-actions {
            background: rgba(17, 17, 17, 0.95) !important;
            border-top-color: rgba(255,255,255,0.1) !important;
        }
        
        /* Tema Estilo Planeta de Libros */
        body.planeta-theme {
            --ink: #1a1a1a;
            --paper: #ffffff;
            --paper-dark: #f5f5f5;
            --gold: #0f81e4; /* Planeta Blue as primary accent */
            --muted: #444444;
            --card-bg: #ffffff;
            --card-border: #e0e0e0;
            background-color: #ffffff !important;
            color: #1a1a1a !important;
        }
        body.planeta-theme .nav-bar {
            background: #ffffff !important;
            border-bottom: 1px solid #e0e0e0 !important;
            box-shadow: 0 2px 10px rgba(0,0,0,0.05);
        }
        body.planeta-theme .nav-actions {
            background: #ffffff !important;
            border-top-color: #e0e0e0 !important;
        }
        body.planeta-theme .book-card {
            background: #ffffff !important;
            border: 1px solid #e0e0e0 !important;
            box-shadow: 0 4px 6px rgba(0,0,0,0.05) !important;
        }
        body.planeta-theme .book-card-title {
            color: #333333 !important;
        }
        body.planeta-theme .book-card-year, body.planeta-theme .author-label {
            color: #0f81e4 !important;
            font-weight: 600;
        }
        body.sepia-theme {
            --ink: #2a1f0e;
            --paper: #f4ecd8;
            --paper-dark: #e8deb8;
            --muted: #5c4a30;
            --gold: #a67c38;
            --card-bg: #e8deb8;
            --card-border: rgba(42, 31, 14, 0.1);
            background-color: #f4ecd8 !important;
            color: #2a1f0e !important;
        }
        /* Sunset Theme */
        body.sunset-theme {
            --ink: #2e1208;
            --paper: #fcece3;
            --paper-dark: #f0ddd1;
            --muted: #7a4030;
            --gold: #d17a60;
            --card-bg: #f0ddd1;
            --card-border: rgba(46, 18, 8, 0.1);
            background-color: var(--paper) !important;
            color: var(--ink) !important;
        }
        /* Clínico / Mednix Theme */
        body.clinico-theme {
            --ink: #0b3456; /* Strong deep blue/slate for high contrast text */
            --paper: #ffffff;
            --paper-dark: #f0f7fb;
            --muted: #4e6a82;
            --gold: #0eb4c1; /* cyan/teal accent */
            --card-bg: #f0f7fb;
            --card-border: #e0ebf5;
            background-color: #ffffff !important;
            color: #0b3456 !important;
        }
        body.clinico-theme .nav-bar {
            background: #ffffff !important;
            border-bottom: 1px solid #e0ebf5 !important;
            box-shadow: 0 2px 10px rgba(11, 52, 86, 0.05);
        }
        body.clinico-theme .nav-actions {
            background: #ffffff !important;
            border-top-color: #e0ebf5 !important;
        }
        body.clinico-theme .book-card {
            background: #ffffff !important;
            border: 1px solid #e0ebf5 !important;
            box-shadow: 0 4px 6px rgba(11, 52, 86, 0.05) !important;
        }
        body.clinico-theme .book-card-title {
            color: #08253e !important;
        }
        body.clinico-theme .book-card-year, body.clinico-theme .author-label {
            color: #0eb4c1 !important;
            font-weight: 600;
        }
            body.dark-theme .nav-actions button, body.dark-theme .nav-actions .menu-toggle {
                color: #ddd;
            }
            .nav-actions button.active { color: var(--gold); }
            .hide-mobile { display: block !important; font-size: 0.55rem !important; margin-top: 2px; text-transform: capitalize; letter-spacing: normal; }
            .nav-actions button i, .nav-actions button svg { width: 22px; height: 22px; }
            
            .main-content { padding: 1.5rem 1rem 6rem 1rem; }
            h1 { font-size: 2.2rem; }
            h2 { font-size: 1.6rem; }
            h3 { font-size: 1.3rem; }

/* LIQUID GLASS VARIABLES */
:root {
    --glass-bg: rgba(255, 255, 255, 0.25);
    --glass-shadow: 0 2px 8px rgba(0,0,0,0.5);
    --glass-border: 1px solid rgba(255,255,255,0.2);
}

body.dark-theme {
    --glass-bg: rgba(20, 25, 35, 0.40);
    --glass-shadow: 0 2px 8px rgba(0,0,0,0.8);
    --glass-border: 1px solid rgba(255,255,255,0.05);
}

body.planeta-theme, body.sepia-theme, body.sunset-theme {
    --glass-bg: rgba(255, 255, 255, 0.25);
    --glass-shadow: 0 2px 8px rgba(0,0,0,0.5);
    --glass-border: 1px solid rgba(0,0,0,0.05);
}

body.cyberpunk-theme {
    --glass-bg: rgba(0, 255, 255, 0.10);
    --glass-shadow: 0 2px 8px rgba(0,255,255,0.8);
    --glass-border: 1px solid #00ffff;
}

/* LIQUID GLASS CORE CLASSES */
body[data-glass-enabled="true"] .liquid-glass,
body[data-glass-enabled="true"] .ai-message.bot .ai-text-content,
body[data-glass-enabled="true"] .com-toast,
body[data-glass-enabled="true"] .toast,
body[data-glass-enabled="true"] #reading-menu-modal > div,
body[data-glass-enabled="true"] #ai-settings-modal {
    background: var(--glass-bg) !important;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: var(--glass-border) !important;
}

body[data-glass-enabled="true"] .liquid-glass > *,
body[data-glass-enabled="true"] .ai-message.bot .ai-text-content > *,
body[data-glass-enabled="true"] .com-toast > *,
body[data-glass-enabled="true"] .toast > *,
body[data-glass-enabled="true"] #reading-menu-modal > div > *,
body[data-glass-enabled="true"] #ai-settings-modal > * {
    text-shadow: var(--glass-shadow);
}

/* For moving elements like dropdowns, limit blur to 4px */
body[data-glass-enabled="true"] .liquid-glass-dynamic,
body[data-glass-enabled="true"] .search-suggestions-container,
body[data-glass-enabled="true"] #ai-panel {
    background: var(--glass-bg) !important;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: var(--glass-border) !important;
}

body[data-glass-enabled="true"] .liquid-glass-dynamic > *,
body[data-glass-enabled="true"] .search-suggestions-container > *,
body[data-glass-enabled="true"] #ai-panel > * {
    text-shadow: var(--glass-shadow);
}

/* For moving elements like dropdowns, limit blur to 4px */
body[data-glass-enabled="true"] .liquid-glass-dynamic {
    background: var(--glass-bg) !important;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: var(--glass-border) !important;
}

body[data-glass-enabled="true"] .liquid-glass-dynamic > * {
    text-shadow: var(--glass-shadow);
}

/* Cyberpunk Bonus: Shattered Glass for Search Input */
body.cyberpunk-theme[data-glass-enabled="true"] .header-search-bar.liquid-glass,
body.cyberpunk-theme[data-glass-enabled="true"] .header-search-bar {
    clip-path: polygon(0 0, 95% 0, 100% 15%, 100% 100%, 5% 100%, 0 85%);
    border-radius: 0 !important;
    border: 1px solid #00ffff !important;
}