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

:root {
    --bg-color: #0f1419;
    --text-color: #ffffff;
    --sidebar-bg: #1a2332;
    --content-bg: #151d28;
    --accent: #1bd96a;
    --hover-bg: rgba(27, 217, 106, 0.1);
    --border-color: rgba(255, 255, 255, 0.1);
    --code-bg: #0d1117;
}

[data-theme="light"] {
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --sidebar-bg: #f5f5f5;
    --content-bg: #ffffff;
    --border-color: rgba(0, 0, 0, 0.1);
    --code-bg: #f6f8fa;
    --hover-bg: rgba(27, 217, 106, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}

#themeBtn {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--border-color);
    font-size: 24px;
    cursor: pointer;
    padding: 8px 12px;
    border-radius: 8px;
    transition: all 0.3s ease;
}

#themeBtn:hover {
    transform: scale(1.05);
    background: rgba(255, 255, 255, 0.15);
}

.sun-icon {
    display: none;
}

[data-theme="light"] .sun-icon {
    display: inline;
}

[data-theme="light"] .moon-icon {
    display: none;
}

.lang-toggle {
    position: fixed;
    top: 20px;
    right: 80px;
    z-index: 1000;
}

#langBtn {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    padding: 8px 16px;
    border-radius: 8px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

#langBtn:hover {
    background: rgba(255, 255, 255, 0.15);
}

.arrow {
    font-size: 10px;
    transition: transform 0.3s ease;
}

.lang-toggle.open .arrow {
    transform: rotate(180deg);
}

.lang-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 8px;
    background: var(--sidebar-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    min-width: 160px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
}

[data-theme="light"] .lang-dropdown {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.lang-toggle.open .lang-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 16px;
    color: var(--text-color);
    text-decoration: none;
    transition: background 0.2s ease;
    font-size: 14px;
}

.lang-option:first-child {
    border-radius: 8px 8px 0 0;
}

.lang-option:last-child {
    border-radius: 0 0 8px 8px;
}

.lang-option:hover {
    background: var(--hover-bg);
}

.lang-option.active {
    background: var(--accent);
    color: #000;
    font-weight: 600;
}

.sidebar {
    width: 280px;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    padding: 20px;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
}

.sidebar-header {
    margin-bottom: 30px;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--text-color);
    text-decoration: none;
    font-size: 14px;
    opacity: 0.7;
    margin-bottom: 16px;
    transition: opacity 0.3s ease;
}

.back-link:hover {
    opacity: 1;
}

.sidebar-title {
    font-size: 24px;
    font-weight: 700;
    color: var(--accent);
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-color);
    transition: all 0.3s ease;
    font-size: 15px;
}

.nav-item:hover {
    background: var(--hover-bg);
}

.nav-item.active {
    background: var(--accent);
    color: #000;
    font-weight: 600;
}

.nav-icon {
    font-size: 20px;
}

.main-content {
    margin-left: 280px;
    flex: 1;
    padding: 40px 60px;
    width: 100%;
}

#content-area {
    background: var(--content-bg);
    border-radius: 12px;
    padding: 40px;
    border: 1px solid var(--border-color);
    max-width: 100%;
}

.toc-section {
    margin-top: 8px;
    margin-bottom: 8px;
    padding: 12px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    background: rgba(255, 255, 255, 0.02);
    transition: all 0.3s ease;
}

[data-theme="light"] .toc-section {
    background: rgba(0, 0, 0, 0.02);
}

.toc-header-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    margin-bottom: 8px;
}

.toc-header {
    font-size: 11px;
    font-weight: 800;
    text-transform: uppercase;
    opacity: 0.6;
    letter-spacing: 1px;
}

.toc-toggle {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 4px 8px;
    opacity: 0.5;
    transition: all 0.3s ease;
    font-size: 10px;
    border-radius: 4px;
}

.toc-toggle:hover {
    opacity: 1;
    background: rgba(255, 255, 255, 0.05);
}

.toc-arrow {
    display: inline-block;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.toc-section.collapsed .toc-arrow {
    transform: rotate(-90deg);
}

#tocNav {
    max-height: 1000px;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
    opacity: 1;
}

.toc-section.collapsed #tocNav {
    max-height: 0;
    opacity: 0;
}

#tocNav {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.toc-link {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    color: var(--text-color);
    text-decoration: none;
    font-size: 13px;
    border-radius: 6px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    opacity: 0.8;
    border-left: 3px solid transparent;
    position: relative;
    font-weight: 500;
}

.toc-link:hover {
    background: var(--hover-bg);
    opacity: 1;
    transform: translateX(2px);
}

.toc-link.active {
    background: var(--hover-bg);
    border-left-color: var(--accent);
    opacity: 1;
    font-weight: 700;
    transform: translateX(2px);
}

.toc-icon {
    font-size: 14px;
    flex-shrink: 0;
}

.toc-link.level-2 {
    padding-left: 20px;
}

.toc-link.level-2::before {
    content: '└─';
    position: absolute;
    left: 4px;
    opacity: 0.4;
    font-size: 11px;
    font-weight: 400;
}

.toc-link.level-3 {
    padding-left: 32px;
    font-size: 12px;
}

.toc-link.level-3::before {
    content: '└──';
    position: absolute;
    left: 8px;
    opacity: 0.4;
    font-size: 11px;
    font-weight: 400;
}

[data-theme="light"] #content-area {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

h1 {
    font-size: 36px;
    margin-bottom: 16px;
    color: var(--accent);
}

h2 {
    font-size: 28px;
    margin-top: 32px;
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--border-color);
}

h3 {
    font-size: 22px;
    margin-top: 24px;
    margin-bottom: 12px;
}

p {
    line-height: 1.7;
    margin-bottom: 16px;
    opacity: 0.9;
}

code {
    background: var(--code-bg);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 14px;
}

pre {
    background: var(--code-bg);
    padding: 16px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 16px 0;
    border: 1px solid var(--border-color);
    position: relative;
}

pre code {
    background: none;
    padding: 0;
}

.code-block-wrapper {
    position: relative;
    margin: 16px 0;
}

.copy-button {
    position: absolute;
    top: 8px;
    right: 8px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 12px;
    font-weight: 600;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 6px;
    opacity: 0.7;
}

.copy-button:hover {
    opacity: 1;
    background: rgba(255, 255, 255, 0.15);
    transform: scale(1.05);
}

.copy-button.copied {
    background: var(--accent);
    color: #000;
    opacity: 1;
}

[data-theme="light"] .copy-button {
    background: rgba(0, 0, 0, 0.05);
}

[data-theme="light"] .copy-button:hover {
    background: rgba(0, 0, 0, 0.1);
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

th, td {
    padding: 12px;
    text-align: left;
    border: 1px solid var(--border-color);
}

th {
    background: var(--accent);
    color: #000;
    font-weight: 600;
}

tr:nth-child(even) {
    background: rgba(255, 255, 255, 0.02);
}

[data-theme="light"] tr:nth-child(even) {
    background: rgba(0, 0, 0, 0.02);
}

ul, ol {
    margin-left: 24px;
    margin-bottom: 16px;
}

li {
    margin-bottom: 8px;
    line-height: 1.6;
}

.alert {
    padding: 16px;
    border-radius: 8px;
    margin: 16px 0;
    border-left: 4px solid;
}

.alert-info {
    background: rgba(59, 156, 255, 0.1);
    border-color: #3b9cff;
}

.alert-warning {
    background: rgba(255, 193, 7, 0.1);
    border-color: #ffc107;
}

.alert-success {
    background: rgba(27, 217, 106, 0.1);
    border-color: #1bd96a;
}

a {
    color: #5eb3f6;
    text-decoration: none;
    transition: opacity 0.2s ease;
}

a:hover {
    opacity: 0.8;
    text-decoration: underline;
}

#content-area a {
    color: #5eb3f6;
}

[data-theme="light"] a {
    color: #2196f3;
}

@media (max-width: 1024px) {
    .sidebar {
        width: 240px;
    }
    
    .main-content {
        margin-left: 240px;
        padding: 30px 40px;
    }
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .main-content {
        margin-left: 0;
        padding: 20px;
    }
    
    #content-area {
        padding: 24px;
    }
}