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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    background: #000000;
    color: #ffffff;
}

::selection {
    background: #ffffff;
    color: #000000;
}

/* Header Styles */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 64px;
    background: #000000;
    border-bottom: 1px solid #1a1a1a;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    z-index: 100;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.menu-toggle {
    background: transparent;
    border: none;
    color: #ffffff;
    cursor: pointer;
    padding: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    transition: background 0.2s;
}

.menu-toggle:hover {
    background: #1a1a1a;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 18px;
    font-weight: 600;
    color: #ffffff;
}

.header-center {
    flex: 1;
    display: flex;
    justify-content: center;
}

.main-nav {
    display: flex;
    gap: 32px;
}

.nav-link {
    color: #888888;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: color 0.2s;
    position: relative;
    padding: 4px 0;
}

.nav-link:hover {
    color: #ffffff;
}

.nav-link.active {
    color: #ffffff;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -20px;
    left: 0;
    right: 0;
    height: 2px;
    background: #ffffff;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.icon-button {
    background: transparent;
    border: none;
    color: #888888;
    cursor: pointer;
    padding: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    transition: all 0.2s;
    text-decoration: none;
}

.icon-button:hover {
    background: #1a1a1a;
    color: #ffffff;
}

.btn-primary {
    background: #ffffff;
    color: #000000;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-primary:hover {
    background: #e6e6e6;
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: #ffffff;
    border: 1px solid #333333;
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-secondary:hover {
    border-color: #666666;
    background: #0a0a0a;
    transform: translateY(-1px);
}

/* Sidebar Styles */
.sidebar {
    position: fixed;
    top: 64px;
    left: 0;
    width: 280px;
    height: calc(100vh - 64px);
    background: #000000;
    border-right: 1px solid #1a1a1a;
    overflow-y: auto;
    transition: transform 0.3s ease;
    z-index: 50;
}

.sidebar.closed {
    transform: translateX(-100%);
}

.sidebar-content {
    padding: 24px 0;
}

.sidebar-title {
    color: #666666;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 0 16px;
    margin-bottom: 12px;
}

.sidebar-item {
    margin-bottom: 2px;
}

.sidebar-link {
    display: flex;
    align-items: center;
    color: #888888;
    font-size: 14px;
    padding: 8px 16px;
    cursor: pointer;
    transition: all 0.2s;
    border-left: 2px solid transparent;
    user-select: none;
}

.sidebar-link:hover {
    color: #ffffff;
    background: #0a0a0a;
}

.sidebar-link.active {
    color: #ffffff;
    background: #0a0a0a;
    border-left-color: #ffffff;
    font-weight: 500;
}

.chevron {
    display: flex;
    align-items: center;
    margin-right: 6px;
    color: #666666;
}

.sidebar-children {
    display: none;
}

.sidebar-children.open {
    display: block;
}

/* Custom scrollbar for sidebar */
.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
    background: #1a1a1a;
    border-radius: 3px;
}

.sidebar::-webkit-scrollbar-thumb:hover {
    background: #333333;
}

/* Main Content Styles */
.main-content {
    margin-left: 280px;
    margin-top: 64px;
    min-height: calc(100vh - 64px);
    background: #000000;
    transition: margin-left 0.3s ease;
}

.main-content.expanded {
    margin-left: 0;
}

.content-wrapper {
    display: flex;
    max-width: 1400px;
    margin: 0 auto;
}

.article {
    flex: 1;
    max-width: 800px;
    padding: 48px 64px;
    color: #ffffff;
}

.page-title {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 32px;
    color: #ffffff;
    line-height: 1.2;
}

.video-container {
    margin: 32px 0;
    border-radius: 12px;
    overflow: hidden;
    background: #0a0a0a;
    border: 1px solid #1a1a1a;
    background-image: url("yt-image.png");
}

.video-embed {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
}

.video-embed iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.lead-text {
    font-size: 18px;
    line-height: 1.7;
    color: #cccccc;
    margin: 24px 0;
}

.lead-text strong {
    color: #ffffff;
    font-weight: 600;
}

.feature-list {
    list-style: none;
    padding: 0;
    margin: 24px 0;
}

.feature-list li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 12px;
    color: #cccccc;
    line-height: 1.6;
}

.feature-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 6px;
    height: 6px;
    background: #666666;
    border-radius: 50%;
}

.content-section {
    margin: 48px 0;
}

.content-section h2 {
    font-size: 32px;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 16px;
    margin-top: 48px;
    scroll-margin-top: 80px;
}

.content-section h3 {
    font-size: 24px;
    font-weight: 600;
    color: #ffffff;
    margin-bottom: 16px;
    margin-top: 32px;
    scroll-margin-top: 80px;
}

.content-section p {
    font-size: 16px;
    line-height: 1.7;
    color: #cccccc;
    margin-bottom: 16px;
}

.content-section ul {
    list-style: none;
    padding: 0;
    margin: 16px 0;
}

.content-section ul li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 10px;
    color: #cccccc;
    line-height: 1.6;
}

.content-section ul li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 6px;
    height: 6px;
    background: #666666;
    border-radius: 50%;
}

.code-block {
    background: #0a0a0a;
    border: 1px solid #1a1a1a;
    border-radius: 8px;
    padding: 16px;
    margin: 24px 0;
    overflow-x: auto;
}

.code-block pre {
    margin: 0;
    font-family: 'Fira Code', 'Courier New', monospace;
    font-size: 14px;
}

.code-block code {
    color: #00ff88;
    font-family: 'Fira Code', 'Courier New', monospace;
}

.next-page {
    margin-top: 64px;
    padding-top: 32px;
    border-top: 1px solid #1a1a1a;
}

.next-link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 24px;
    background: #0a0a0a;
    border: 1px solid #1a1a1a;
    border-radius: 12px;
    text-decoration: none;
    transition: all 0.2s;
}

.next-link:hover {
    background: #121212;
    border-color: #333333;
    transform: translateX(4px);
}

.next-label {
    font-size: 12px;
    color: #666666;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.next-title {
    font-size: 18px;
    font-weight: 600;
    color: #ffffff;
}

/* Table of Contents */
.table-of-contents {
    width: 240px;
    padding: 48px 32px;
    position: sticky;
    top: 80px;
    height: fit-content;
    max-height: calc(100vh - 120px);
    overflow-y: auto;
}

.toc-title {
    font-size: 12px;
    font-weight: 600;
    color: #666666;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 16px;
}

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

.toc-link {
    font-size: 13px;
    color: #888888;
    text-decoration: none;
    transition: color 0.2s;
    line-height: 1.5;
}

.toc-link:hover {
    color: #ffffff;
}

.toc-link-nested {
    padding-left: 16px;
    font-size: 12px;
}

/* Custom scrollbar for TOC */
.table-of-contents::-webkit-scrollbar {
    width: 4px;
}

.table-of-contents::-webkit-scrollbar-track {
    background: transparent;
}

.table-of-contents::-webkit-scrollbar-thumb {
    background: #1a1a1a;
    border-radius: 2px;
}

.table-of-contents::-webkit-scrollbar-thumb:hover {
    background: #333333;
}

/* Responsive Styles */
@media (max-width: 1200px) {
    .table-of-contents {
        display: none;
    }
    
    .article {
        max-width: 100%;
    }
}

@media (max-width: 768px) {
    .header-center {
        display: none;
    }
    
    .header-right .btn-secondary {
        display: none;
    }
    
    .sidebar {
        width: 100%;
        max-width: 280px;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .article {
        padding: 32px 24px;
    }
    
    .page-title {
        font-size: 36px;
    }
    
    .content-section h2 {
        font-size: 28px;
    }
    
    .content-section h3 {
        font-size: 20px;
    }
}

.code-block {
    background: #111;
    color: #00ffcc;
    padding: 15px;
    border-radius: 6px;
    overflow-x: auto;
    font-size: 14px;
    margin: 15px 0;
}

.modal {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background: #fff;
    padding: 25px;
    border-radius: 8px;
    text-align: center;
    width: 320px;
    animation: fadeIn 0.2s ease-in-out;
}

.modal-content button {
    margin-top: 15px;
    padding: 8px 15px;
    border: none;
    background: #000;
    color: #fff;
    cursor: pointer;
    border-radius: 4px;
}

@keyframes fadeIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}