:root {
	/* Brand colours — tinted neutrals and one Instant orange accent. */
	--instant-bg: oklch(99.2% 0.003 82);
	--instant-surface: oklch(97.3% 0.008 79);
	--instant-text: oklch(19% 0.032 255);
	--instant-muted: oklch(44% 0.025 255);
	--instant-accent: oklch(58% 0.22 40);
	--instant-border: oklch(88.5% 0.012 80);
	--instant-radius: 0.75rem;

	--color-paper: var(--instant-bg);
	--color-paper-2: var(--instant-surface);
	--color-paper-3: oklch(93.5% 0.018 75);
	--color-ink: var(--instant-text);
	--color-ink-2: oklch(29% 0.035 255);
	--color-muted: var(--instant-muted);
	--color-rule: var(--instant-border);
	--color-rule-strong: oklch(74% 0.02 75);
	--color-accent: var(--instant-accent);
	--color-accent-text: oklch(52% 0.195 38);
	--color-accent-soft: oklch(94.5% 0.05 52);
	--color-accent-ink: oklch(99% 0.004 80);
	--color-japan: oklch(55% 0.22 28);
	--color-japan-soft: oklch(96% 0.032 25);
	--color-utility: oklch(96.8% 0.008 250);
	--color-white: oklch(99.6% 0.004 80);
	--color-overlay-soft: oklch(16% 0.03 255 / 0.08);
	--color-overlay-medium: oklch(16% 0.03 255 / 0.16);
	--color-focus: oklch(42% 0.16 255);
	--color-success: oklch(39% 0.105 150);
	--color-disabled: oklch(65% 0.012 255);
	--color-transparent: transparent;

	/* System-only typography: no remote font request. */
	--font-body: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
	--font-display: ui-rounded, "Arial Rounded MT Bold", "Segoe UI", system-ui, sans-serif;
	--font-mono: ui-monospace, "SFMono-Regular", Consolas, monospace;
	--text-xs: 0.75rem;
	--text-sm: 0.875rem;
	--text-base: 1rem;
	--text-lg: 1.125rem;
	--text-xl: clamp(1.5rem, 2.1vw, 2rem);
	--text-2xl: clamp(2.55rem, 6.8vw, 5rem);
	--leading-tight: 1.02;
	--leading-copy: 1.6;

	/* Four-point rhythm. */
	--space-1: 0.25rem;
	--space-2: 0.5rem;
	--space-3: 0.75rem;
	--space-4: 1rem;
	--space-5: 1.25rem;
	--space-6: 1.5rem;
	--space-8: 2rem;
	--space-10: 2.5rem;
	--space-12: 3rem;
	--space-16: 4rem;
	--space-20: 5rem;
	--space-24: 6rem;
	--shell: 78rem;
	--measure: 42rem;

	--radius-sm: 0.375rem;
	--radius-md: var(--instant-radius);
	--radius-lg: 1rem;
	--radius-pill: 999rem;
	--shadow-card: 0 0.5rem 1.5rem var(--color-overlay-soft);
	--shadow-lift: 0 1rem 2.5rem var(--color-overlay-medium);
	--control-height: 2.75rem;

	--dur-micro: 100ms;
	--dur-short: 180ms;
	--dur-long: 300ms;
	--ease-out: cubic-bezier(0.16, 1, 0.3, 1);
	--ease-in: cubic-bezier(0.7, 0, 0.84, 0);
	--ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);

	--z-base: 0;
	--z-raised: 10;
	--z-nav: 20;
}