:root {
    /* Sirius brand kit: `brand sirius.png` is the visual source of truth. */
    /* Restored platform-native stack: the approved previous typography. */
    --ds-font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
    --ds-font-display: var(--ds-font-sans);
    --ds-font-weight-regular: 400;
    --ds-font-weight-medium: 500;
    --ds-font-weight-strong: 700;
    --ds-font-weight-display: 700;

    /* Shared typography roles. Sites opt in through their own scoped modules. */
    --ds-type-body-size: 16px;
    --ds-type-body-leading: 1.55;
    --ds-type-heading-leading: 1.04;
    --ds-type-heading-tracking: -.035em;
    --ds-type-label-leading: 1.2;
    --ds-type-label-tracking: .09em;
    --ds-type-weight-heading: var(--ds-font-weight-medium);
    --ds-type-weight-ui: var(--ds-font-weight-medium);
    --ds-type-weight-label: var(--ds-font-weight-medium);
    --ds-type-weight-emphasis: 600;

    /* Brand palette. State colours are deliberate accessible derivatives. */
    --ds-color-brand-red: #ef3124;
    --ds-color-brand-black: #010101;
    --ds-color-brand-grey: #a4a5a9;
    --ds-color-brand-light: #f2f2f2;
    --ds-color-accent: var(--ds-color-brand-red);
    --ds-color-accent-strong: #c9251a;
    --ds-color-accent-hover: #a91f17;
    --ds-color-accent-soft: #fff0ef;
    --ds-color-accent-on-dark: #ff8b84;
    --ds-color-focus: #9d211a;
    --ds-color-text: var(--ds-color-brand-black);
    --ds-color-text-muted: #5e595c;
    --ds-color-text-subtle: #777174;
    --ds-color-line: #d8d4d6;
    --ds-color-page: var(--ds-color-brand-light);
    --ds-color-surface: #ffffff;
    --ds-color-surface-soft: #e9e7e8;
    /* Dark surfaces remain readable, but are graphite rather than pure black. */
    --ds-color-graphite: #26282b;
    --ds-color-inverse: var(--ds-color-graphite);
    --ds-color-footer: var(--ds-color-graphite);
    --ds-color-on-inverse: #ffffff;
    --ds-color-on-inverse-muted: #d6d1d3;

    /* Four-pixel base rhythm. Components compose only these values. */
    --ds-space-1: 4px;
    --ds-space-2: 8px;
    --ds-space-3: 12px;
    --ds-space-4: 16px;
    --ds-space-5: 20px;
    --ds-space-6: 24px;
    --ds-space-7: 32px;
    --ds-space-8: 40px;
    --ds-space-9: 48px;
    --ds-space-10: 56px;
    --ds-space-11: 64px;
    --ds-space-12: 72px;
    --ds-space-13: 96px;

    --ds-container: 1180px;
    --ds-gutter-mobile: 20px;
    --ds-gutter-desktop: 32px;
    --ds-section-compact: 56px;
    --ds-section-mobile: 72px;
    --ds-section-standard: 72px;
    --ds-section-desktop: 96px;
    --ds-footer-top: 56px;
    --ds-footer-bottom-mobile: 120px;
    --ds-footer-bottom-desktop: 64px;

    /* Shape and touch targets. */
    --ds-radius-small: 8px;
    --ds-radius-control: 14px;
    --ds-radius-card: 20px;
    --ds-radius-feature: 24px;
    --ds-radius-round: 999px;
    --ds-control-height: 52px;
    --ds-touch-target: 44px;
    --ds-icon-small: 18px;
    --ds-icon-medium: 20px;
    --ds-icon-large: 24px;
    --ds-icon-stroke: 1.8;

    /* Motion stays useful, restrained, and removable. */
    --ds-ease-out: cubic-bezier(.23, 1, .32, 1);
    --ds-duration-press: 140ms;
    --ds-duration-ui: 180ms;
    --ds-duration-reveal: 280ms;
}