@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');
        
:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --dark-gradient: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    --light-gradient: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #475569;
    --accent-color: #3b82f6;
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --accent-color: #3b82f6;
}

* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-weight: 400;
    line-height: 1.6;
}

.gradient-bg {
    background: var(--primary-gradient);
}

.glass-effect {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

[data-theme="dark"] .glass-effect {
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.card-hover {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.card-hover:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] .card-hover:hover {
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.3), 0 10px 10px -5px rgba(0, 0, 0, 0.2);
}

.animate-fade-in {
    animation: fadeIn 0.6s ease-out forwards;
    opacity: 0;
    transform: translateY(20px);
}

@keyframes fadeIn {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-slide-in {
    animation: slideIn 0.5s ease-out forwards;
    opacity: 0;
    transform: translateX(-20px);
}

@keyframes slideIn {
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 3px;
    background: var(--accent-gradient);
    z-index: 1000;
    transition: width 0.1s ease;
}

.reading-time {
    font-size: 0.75rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.section-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    scroll-margin-top: 8rem;
}

[data-theme="dark"] .section-card {
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
}

.sidebar-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    border-radius: 0.75rem;
    transition: all 0.2s ease;
    color: var(--text-secondary);
    text-decoration: none;
    border: 1px solid transparent;
}

.sidebar-link:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    transform: translateX(4px);
}

.sidebar-link.active {
    background: var(--accent-gradient);
    color: white;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.theme-toggle {
    position: relative;
    width: 60px;
    height: 30px;
    background: var(--bg-tertiary);
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.theme-toggle::before {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 24px;
    height: 24px;
    background: white;
    border-radius: 50%;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

[data-theme="dark"] .theme-toggle::before {
    transform: translateX(28px);
    background: #1e293b;
}

.font-size-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-tertiary);
    padding: 0.5rem;
    border-radius: 0.5rem;
    border: 1px solid var(--border-color);
}

.font-size-btn {
    width: 32px;
    height: 32px;
    border-radius: 0.25rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.font-size-btn:hover {
    background: var(--bg-primary);
    color: var(--text-primary);
}

.lang-btn {
    font-size: 1.5rem;
    cursor: pointer;
    opacity: 0.5;
    transition: opacity 0.2s;
    background: none;
    border: none;
    padding: 0;
}

.lang-btn.active, .lang-btn:hover {
    opacity: 1;
}

.search-suggestions {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    margin-top: 0.25rem;
    max-height: 200px;
    overflow-y: auto;
    z-index: 50;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.search-suggestion {
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: background-color 0.2s ease;
    border-bottom: 1px solid var(--border-color);
}

.search-suggestion:hover {
    background: var(--bg-secondary);
}

.search-suggestion:last-child {
    border-bottom: none;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--accent-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #2563eb;
}

.tooltip {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--bg-primary);
    color: var(--text-primary);
    padding: 0.5rem 0.75rem;
    border-radius: 0.375rem;
    font-size: 0.875rem;
    white-space: nowrap;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-color);
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s ease;
    z-index: 1000;
}

.tooltip::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 4px solid transparent;
    border-top-color: var(--bg-primary);
}

.tooltip-container:hover .tooltip {
    opacity: 1;
    visibility: visible;
}

mark {
    background: linear-gradient(120deg, #fef08a 0%, #fbbf24 100%);
    padding: 2px 4px;
    border-radius: 3px;
    font-weight: 500;
}

[data-theme="dark"] mark {
    background: linear-gradient(120deg, #fbbf24 0%, #f59e0b 100%);
    color: #1e293b;
}

.floating-controls {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    z-index: 100;
}

.floating-btn {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    border: none;
    background: var(--accent-gradient);
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 25px rgba(59, 130, 246, 0.3);
    font-size: 1.25rem;
}

.floating-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 35px rgba(59, 130, 246, 0.4);
}

.bookmarks-panel {
    position: fixed;
    top: 0;
    right: -400px;
    width: 400px;
    height: 100vh;
    background: var(--bg-primary);
    border-left: 1px solid var(--border-color);
    z-index: 200;
    transition: right 0.3s ease;
    overflow-y: auto;
    padding: 2rem;
    display: none;
}

.bookmarks-panel.open {
    right: 0;
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 150;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    display: none;
}

.overlay.active {
    opacity: 1;
    visibility: visible;
}

@media (max-width: 768px) {
    .bookmarks-panel {
        width: 100%;
        right: -100%;
    }
    
    .floating-controls {
        bottom: 1rem;
        right: 1rem;
    }
    
    .floating-btn {
        width: 48px;
        height: 48px;
        font-size: 1rem;
    }
}