:root {
    color-scheme: light;

    /* Semantic color system. Light mode is an intentional brand decision. */
    --dd-bg: #fbfbfd;
    --dd-surface: #fefeff;
    --dd-surface-muted: #f3f4f7;
    --dd-text: #111218;
    --dd-text-muted: #5f626b;
    --dd-accent: #0068d7;
    --dd-accent-hover: #0059b8;
    --dd-on-accent: #f8fbff;
    --dd-border: #dfe1e7;
    --dd-focus: #0068d7;

    /* Shadows are tinted to the cool neutral world, never pure black. */
    --dd-shadow-color: 31 47 72;
    --dd-shadow-soft: 0 18px 45px rgb(var(--dd-shadow-color) / 0.10);
    --dd-shadow-hover: 0 22px 54px rgb(var(--dd-shadow-color) / 0.14);

    /* Shape rule: soft content surfaces, quieter controls, pill actions. */
    --dd-radius-surface: 18px;
    --dd-radius-control: 12px;
    --dd-radius-pill: 999px;

    /* Type roles. A licensed/self-hosted brand face can replace these later. */
    --dd-font-display: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --dd-font-body: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --dd-type-body: 1rem;
    --dd-type-small: 0.875rem;
    --dd-leading-body: 1.65;
    --dd-leading-display: 1.04;
    --dd-reading-measure: 70ch;

    /* Layout and rhythm. */
    --dd-shell: 1120px;
    --dd-content: 760px;
    --dd-gutter: clamp(1.125rem, 4vw, 1.5rem);
    --dd-section-space: clamp(4rem, 8vw, 6rem);
    --dd-space-1: 0.5rem;
    --dd-space-2: 0.75rem;
    --dd-space-3: 1rem;
    --dd-space-4: 1.5rem;
    --dd-space-5: 2rem;

    /* Motion and layers. */
    --dd-ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --dd-duration-fast: 180ms;
    --dd-layer-header: 100;
}