:root {
    color-scheme: light dark;
    --bg: #f7f7f5;
    --card-bg: #ffffff;
    --ink: #1f2328;
    --muted: #6b7280;
    --persist: #1a7f5a;
    --persist-bg: #eafaf3;
    --volatile: #b45309;
    --volatile-bg: #fdf3e7;
    --border: #e5e7eb;
    font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    line-height: 1.5;
}

main {
    max-width: 880px;
    margin: 0 auto;
    padding: 2.5rem 1.5rem 4rem;
}

h1 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}

p.intro {
    color: var(--muted);
    max-width: 60ch;
}

code {
    background: #eceef1;
    padding: 0.1rem 0.35rem;
    border-radius: 4px;
    font-size: 0.9em;
}

.columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
    margin-top: 2rem;
}

@media (max-width: 640px) {
    .columns {
        grid-template-columns: 1fr;
    }
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-left: 4px solid var(--border);
    border-radius: 8px;
    padding: 1.25rem 1.5rem;
}

.card.persist {
    border-left-color: var(--persist);
}

.card.volatile {
    border-left-color: var(--volatile);
}

.card h2 {
    font-size: 1.05rem;
    margin: 0 0 0.75rem;
}

.card.persist h2 {
    color: var(--persist);
}

.card.volatile h2 {
    color: var(--volatile);
}

.meta {
    font-size: 0.85rem;
    color: var(--muted);
    margin: 0.15rem 0;
}

.card button {
    margin-top: 0.75rem;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    border: 1px solid var(--border);
    background: #f3f4f6;
    cursor: pointer;
    font-size: 0.9rem;
}

.card.persist button {
    background: var(--persist-bg);
    border-color: var(--persist);
    color: var(--persist);
}

.card.volatile button {
    background: var(--volatile-bg);
    border-color: var(--volatile);
    color: var(--volatile);
}

.card button:focus-visible,
textarea:focus-visible {
    outline: 2px solid #2563eb;
    outline-offset: 2px;
}

label {
    display: block;
    margin-top: 1rem;
    font-size: 0.85rem;
    color: var(--muted);
}

textarea {
    width: 100%;
    margin-top: 0.35rem;
    padding: 0.6rem;
    border-radius: 6px;
    border: 1px solid var(--border);
    font-family: inherit;
    font-size: 0.95rem;
    resize: vertical;
}

.callout {
    margin-top: 2rem;
    padding: 1rem 1.25rem;
    border-radius: 8px;
    background: #eef2ff;
    border: 1px solid #c7d2fe;
    font-size: 0.9rem;
}