:root {
    --bg-color: #1a1a2e;
    --text-color: #e8e8e8;
    --accent-color: #4a90d9;
    --border-color: #333;
    --sidebar-width: 220px;
    --sidebar-bg: #151528;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* Sidebar navigation */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem 1rem;
    overflow-y: auto;
    z-index: 10;
}

.sidebar h2 {
    font-size: 1.2rem;
    color: var(--accent-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.sidebar ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.sidebar li {
    display: block;
}

.sidebar a {
    display: block;
    padding: 0.4rem 0.6rem;
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.85rem;
    border-radius: 4px;
    transition: background 0.15s, color 0.15s;
}

.sidebar a:hover {
    background: rgba(74, 144, 217, 0.15);
    color: var(--accent-color);
}

/* Main content */
.content {
    margin-left: var(--sidebar-width);
    padding: 2rem;
}

h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--accent-color);
}

.content > h2 {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
    color: var(--text-color);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
    scroll-margin-top: 1rem;
}

.diagram-container {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    margin-top: 1rem;
}

.diagram {
    flex: 1;
    min-width: 400px;
    background: #252540;
    border-radius: 8px;
    padding: 1rem;
    border: 1px solid var(--border-color);
}

.diagram h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--accent-color);
}

.diagram img,
.diagram object {
    width: 100%;
    height: auto;
    background: white;
    border-radius: 4px;
}

.diagram a {
    display: block;
    text-align: center;
    margin-top: 0.5rem;
    color: var(--accent-color);
    text-decoration: none;
    font-size: 0.9rem;
}

.diagram a:hover {
    text-decoration: underline;
}

.legend {
    margin-top: 2rem;
    padding: 1rem;
    background: #252540;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.legend h3 {
    margin-bottom: 0.5rem;
}

.legend ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.legend li {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.legend .color-box {
    width: 16px;
    height: 16px;
    border-radius: 3px;
}

code {
    background: #333;
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: 'Monaco', 'Consolas', monospace;
    font-size: 0.9em;
}

pre {
    background: #252540;
    padding: 1rem;
    border-radius: 8px;
    overflow-x: auto;
    border: 1px solid var(--border-color);
}

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

/* Responsive: collapse sidebar on small screens */
@media (max-width: 768px) {
    .sidebar {
        position: static;
        width: 100%;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }

    .sidebar ul {
        flex-direction: row;
        flex-wrap: wrap;
    }

    .content {
        margin-left: 0;
    }

    .diagram {
        min-width: 100%;
    }
}