:root {
    color-scheme: light dark;
    --bg: #ffffff;
    --fg: #0f172a;
    /* slate-900 */
    --muted: #64748b;
    /* slate-500 */
    --border: #e2e8f0;
    /* slate-200 */
    --link: #6366f1;
    /* indigo-500 */
    --primary: #4f46e5;
    /* indigo-600 */
    --accent: #14b8a6;
    /* teal-500 */
    --surface: #ffffff;
    --surface-2: #f8fafc;
    /* slate-50 */
    --shadow: 0 10px 25px rgba(2, 6, 23, 0.06);
    --max: 880px;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0b1220;
        /* slate-950 */
        --fg: #e2e8f0;
        /* slate-200 */
        --muted: #94a3b8;
        /* slate-400 */
        --border: #1e293b;
        /* slate-800 */
        --link: #818cf8;
        /* indigo-400 */
        --primary: #6366f1;
        /* indigo-500 */
        --accent: #2dd4bf;
        /* teal-400 */
        --surface: #0f172a;
        /* slate-900 */
        --surface-2: #0b1220;
        /* slate-950 */
        --shadow: 0 12px 30px rgba(0, 0, 0, 0.35);
    }
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    background: linear-gradient(180deg, var(--surface-2), var(--bg));
    color: var(--fg);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, "Noto Sans", sans-serif;
    line-height: 1.8;
    font-size: clamp(15px, 1.2vw, 17px);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--max);
    margin: 0 auto;
    padding: 2.25rem 1.25rem 3rem;
}

.page-header {
    margin: 0 0 1.75rem 0;
    padding: 2rem 1.25rem;
    background: radial-gradient(1200px 600px at 10% -20%, rgba(99, 102, 241, .18), transparent 60%),
        radial-gradient(1200px 600px at 90% -30%, rgba(20, 184, 166, .18), transparent 60%),
        linear-gradient(180deg, var(--surface), var(--surface-2));
    border: 1px solid var(--border);
    border-radius: 18px;
    box-shadow: var(--shadow);
}

.page-header h1 {
    margin: 0 0 .4rem 0;
    font-weight: 800;
    letter-spacing: .2px;
    font-size: clamp(1.6rem, 3.2vw, 2.4rem);
}

.page-header .muted {
    margin-top: .25rem;
}

.muted {
    color: var(--muted);
}

.lead {
    padding: 1.1rem 1.1rem 1.1rem 1.1rem;
    border: 1px solid var(--border);
    background: linear-gradient(180deg, var(--surface), var(--surface-2));
    border-radius: 14px;
    margin: 1.25rem 0 1.75rem;
    box-shadow: var(--shadow);
}

section {
    margin: 1.6rem 0;
}

h2 {
    position: relative;
    font-size: clamp(1.05rem, 1.6vw, 1.25rem);
    margin: 1.75rem 0 .65rem;
    font-weight: 750;
}

h2::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -8px;
    width: 72px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 999px;
}

ul,
ol {
    padding-left: 1.25rem;
}

ul li,
ol li {
    margin: .3rem 0;
}

dt {
    font-weight: 700;
}

dd {
    margin: 0 0 .65rem 0;
}

.page-footer {
    margin-top: 3rem;
    padding: 1rem 1.25rem 0;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: .75rem;
    flex-wrap: wrap;
}

.page-footer nav a {
    display: inline-block;
    padding: .45rem .8rem;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--surface);
    box-shadow: var(--shadow);
}

a {
    color: var(--link);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* Code/blockquote (future-proof) */
code,
pre {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

blockquote {
    border-left: 4px solid var(--border);
    margin: 1rem 0;
    padding: .25rem .75rem;
    color: var(--muted);
}