:root {
    --primary: #2563EB;
    --primary-dark: #1D4ED8;
    --secondary: #64748B;
    --bg-light: #F8FAFC;
    --text-dark: #1E293B;
    --text-light: #475569;
    --white: #FFFFFF;
    --border: #E2E8F0;
    --success: #10B981;
    --warning: #F59E0B;
    --danger: #EF4444;
    --code-bg: #1e293b;
    --code-text: #e2e8f0;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
}

/* Header & Nav */
header {
    background-color: var(--white);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1);
}

.navbar {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-light);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--primary);
}

.hamburger {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-dark);
}

/* Hero Section (Index) */
.hero {
    background: linear-gradient(to right, var(--primary), var(--primary-dark));
    color: var(--white);
    padding: 4rem 1rem;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.25rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 2rem;
}

.cta-button {
    display: inline-block;
    background-color: var(--white);
    color: var(--primary);
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    text-decoration: none;
    transition: transform 0.2s;
}

.cta-button:hover {
    transform: translateY(-2px);
}

/* Layout for Manuals */
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 3rem;
}

/* Sidebar TOC */
.sidebar {
    position: sticky;
    top: 6rem;
    height: calc(100vh - 8rem);
    overflow-y: auto;
    padding-right: 1rem;
}

.toc-title {
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-dark);
    text-transform: uppercase;
    font-size: 0.875rem;
    letter-spacing: 0.05em;
}

.toc ul {
    list-style: none;
}

.toc li {
    margin-bottom: 0.5rem;
}

.toc a {
    text-decoration: none;
    color: var(--text-light);
    font-size: 0.95rem;
    display: block;
    padding: 0.25rem 0;
    border-left: 2px solid transparent;
    padding-left: 1rem;
    transition: all 0.2s;
}

.toc a:hover, .toc a.active {
    color: var(--primary);
    border-left-color: var(--primary);
}

.toc ul ul {
    margin-left: 1rem;
    margin-top: 0.5rem;
}

/* Main Content */
.content {
    background: var(--white);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1);
    min-width: 0; /* Prevent overflow */
}

/* Markdown Styles */
.content h1 {
    font-size: 2.25rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
    border-bottom: 2px solid var(--border);
    padding-bottom: 1rem;
}

.content h2 {
    font-size: 1.75rem;
    margin: 2rem 0 1rem;
    color: var(--text-dark);
}

.content h3 {
    font-size: 1.5rem;
    margin: 1.5rem 0 1rem;
    color: var(--text-dark);
}

.content p {
    margin-bottom: 1rem;
    color: var(--text-light);
}

.content ul, .content ol {
    margin-bottom: 1rem;
    padding-left: 2rem;
    color: var(--text-light);
}

.content li {
    margin-bottom: 0.5rem;
}

.content blockquote {
    border-left: 4px solid var(--primary);
    background-color: #EFF6FF;
    padding: 1rem;
    margin: 1.5rem 0;
    border-radius: 0 0.5rem 0.5rem 0;
    color: var(--text-dark);
}

.content pre {
    background-color: var(--code-bg);
    color: var(--code-text);
    padding: 1rem;
    border-radius: 0.5rem;
    overflow-x: auto;
    margin-bottom: 1.5rem;
}

.content code {
    font-family: 'Fira Code', monospace;
    font-size: 0.9em;
}

.content p code {
    background-color: #F1F5F9;
    color: var(--primary-dark);
    padding: 0.2rem 0.4rem;
    border-radius: 0.25rem;
}

.content table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1.5rem;
}

.content th, .content td {
    border: 1px solid var(--border);
    padding: 0.75rem;
    text-align: left;
}

.content th {
    background-color: #F8FAFC;
    font-weight: 600;
}

.content img {
    max-width: 100%;
    height: auto;
    border-radius: 0.5rem;
    margin: 1rem 0;
}

.content hr {
    border: 0;
    border-top: 1px solid var(--border);
    margin: 2rem 0;
}

/* Footer */
footer {
    background-color: var(--white);
    padding: 2rem 0;
    margin-top: 4rem;
    border-top: 1px solid var(--border);
    text-align: center;
    color: var(--text-light);
}

/* Utilities */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: -3rem auto 3rem;
    padding: 0 1rem;
    position: relative;
    z-index: 10;
}

.card {
    background: var(--white);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    transition: transform 0.2s, box-shadow 0.2s;
    text-decoration: none;
    color: inherit;
    border: 1px solid var(--border);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    border-color: var(--primary);
}

.card h3 {
    color: var(--primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.card p {
    color: var(--text-light);
}

/* Responsive */
@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
    }

    .hamburger {
        display: block;
    }

    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: 0;
        margin-top: 1rem;
        border-top: 1px solid var(--border);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links li {
        width: 100%;
    }

    .nav-links a {
        display: block;
        padding: 1rem 0;
        border-bottom: 1px solid #f1f5f9;
    }

    .container {
        grid-template-columns: 1fr;
    }

    .sidebar {
        display: none; /* Hide TOC on mobile or make it collapsible */
    }
}