/* --- Global Custom Properties (Theme Engine) --- */
:root {
    --bg-primary: #0f172a;       /* Slate 900 */
    --bg-secondary: #1e293b;     /* Slate 800 */
    --bg-accent: #334155;        /* Slate 700 */
    --text-primary: #f8fafc;     /* Slate 50 */
    --text-secondary: #94a3b8;   /* Slate 400 */
    --accent-color: #38bdf8;     /* Sky 400 (SRE Tech Blue) */
    --accent-success: #4ade80;   /* Green 400 */
    --border-color: #1e293b;
    --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --max-width: 1200px;
}

[data-theme="light"] {
    --bg-primary: #f8fafc;       /* Slate 50 */
    --bg-secondary: #ffffff;     /* Pure White */
    --bg-accent: #f1f5f9;        /* Slate 100 */
    --text-primary: #0f172a;     /* Slate 900 */
    --text-secondary: #475569;   /* Slate 600 */
    --accent-color: #0284c7;     /* Sky 630 */
    --accent-success: #16a34a;   /* Green 600 */
    --border-color: #e2e8f0;     /* Slate 200 */
}

/* --- Base Resets & Layout --- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    text-decoration: underline;
}

/* --- Layout Wrappers --- */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* --- Header & Navigation --- */
header {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4.5rem;
}

.logo {
    font-size: 1.3rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    color: var(--text-primary);
}

.logo span {
    color: var(--accent-color);
}

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

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
}

.nav-links a:hover, .nav-links a.active {
    color: var(--accent-color);
    text-decoration: none;
}

/* --- Interactive Utilities --- */
.theme-toggle-btn {
    background: none;
    border: 1px solid var(--border-color);
    padding: 0.5rem;
    border-radius: 0.375rem;
    cursor: pointer;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle-btn:hover {
    background-color: var(--bg-accent);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
    background: none;
    border: none;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: 0.3s;
}

/* --- Component Cards & Panels --- */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1.5rem;
    transition: transform 0.2s ease, border-color 0.2s ease;
}

.card:hover {
    transform: translateY(-2px);
    border-color: var(--accent-color);
}

/* --- Technical Documentation Blocks --- */
pre {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1.25rem;
    position: relative;
    overflow-x: auto;
    margin: 1.5rem 0;
}

code {
    font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
    font-size: 0.9rem;
}

.copy-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background-color: var(--bg-accent);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-size: 0.75rem;
    cursor: pointer;
    transition: all 0.2s;
}

.copy-btn:hover {
    color: var(--text-primary);
    background-color: var(--accent-color);
}

/* --- Mermaid Diagrams Wrapper --- */
.mermaid-container {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1.5rem;
    margin: 1.5rem 0;
    display: flex;
    justify-content: center;
}

/* --- Footer --- */
footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: auto;
}

/* --- Mobile Responsiveness --- */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 4.5rem;
        left: 0;
        width: 100%;
        background-color: var(--bg-secondary);
        flex-direction: column;
        padding: 2rem;
        border-bottom: 1px solid var(--border-color);
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    }

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