:root {
    color-scheme: light dark;
    --bg: #fafafa;
    --fg: #1a1a1a;
    --border: #ccc;
    --muted: #666;
    --accent: #2563eb;
}
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #111;
        --fg: #eee;
        --border: #444;
        --muted: #999;
        --accent: #60a5fa;
    }
}
* {
    box-sizing: border-box;
}
body {
    margin: 0;
    font-family: system-ui, sans-serif;
    background: var(--bg);
    color: var(--fg);
}
main {
    max-width: 760px;
    margin: 0 auto;
    padding: 2rem 1rem;
}
h1 {
    margin: 0 0 0.25rem;
}
.sub {
    color: var(--muted);
    margin: 0 0 2rem;
}
hr {
    border: 0;
    border-top: 1px solid var(--border);
    margin: 2.5rem 0;
}
h2 {
    margin: 0 0 1rem;
    font-size: 1.2rem;
}
.back {
    display: inline-block;
    margin-bottom: 1.5rem;
    color: var(--muted);
    text-decoration: none;
    font-size: 0.9rem;
}
.back:hover {
    color: var(--accent);
}

.control {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}
.control input[type='range'] {
    flex: 1;
    accent-color: var(--accent);
}
.control .num {
    width: 4.5rem;
    padding: 0.4rem 0.5rem;
    font: inherit;
    text-align: center;
    font-variant-numeric: tabular-nums;
    background: transparent;
    color: inherit;
    border: 1px solid var(--border);
    border-radius: 6px;
}
.control .num:focus {
    outline: 2px solid var(--accent);
}