:root {
  /* Typography */
  --font-display: "Syne", system-ui, sans-serif;
  --font-body: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;

  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.8125rem);
  --text-sm: clamp(0.8125rem, 0.78rem + 0.2vw, 0.875rem);
  --text-base: clamp(0.9375rem, 0.9rem + 0.2vw, 1rem);
  --text-lg: clamp(1.0625rem, 1rem + 0.3vw, 1.125rem);
  --text-xl: clamp(1.25rem, 1.1rem + 0.6vw, 1.5rem);
  --text-2xl: clamp(1.5rem, 1.2rem + 1.2vw, 2rem);
  --text-3xl: clamp(2rem, 1.5rem + 2vw, 3rem);
  --text-4xl: clamp(2.5rem, 1.8rem + 3vw, 4.5rem);
  --text-hero: clamp(2.75rem, 2rem + 4vw, 5.5rem);

  --leading-tight: 1.15;
  --leading-snug: 1.35;
  --leading-normal: 1.6;

  --weight-regular: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  --weight-extrabold: 800;

  /* Spacing */
  --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;
  --space-32: 8rem;

  /* Layout */
  --container-max: 1280px;
  --container-narrow: 720px;
  --header-height: 72px;

  /* Breakpoints (reference) */
  /* 768px tablet, 1024px desktop, 1280px wide */

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Border radius */
  --radius-sm: 2px;
  --radius-md: 4px;
  --radius-lg: 8px;

  /* Z-index */
  --z-header: 100;
  --z-overlay: 200;
  --z-modal: 300;
  --z-back-top: 90;
}

[data-theme="dark"],
:root {
  --color-bg: #0a0a0a;
  --color-bg-elevated: #141414;
  --color-bg-subtle: #1a1a1a;
  --color-surface: #111111;
  --color-border: #2a2a2a;
  --color-border-strong: #3a3a3a;
  --color-text: #f5f5f0;
  --color-text-muted: #a0a0a0;
  --color-text-subtle: #707070;
  --color-accent: #ff3d00;
  --color-accent-hover: #ff5722;
  --color-accent-text: #0a0a0a;
  --color-overlay: rgba(10, 10, 10, 0.85);
  --color-focus-ring: #ff3d00;
  --color-success: #22c55e;
  --color-error: #ef4444;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
  --color-bg: #f5f5f0;
  --color-bg-elevated: #ffffff;
  --color-bg-subtle: #ebebe6;
  --color-surface: #ffffff;
  --color-border: #d4d4d0;
  --color-border-strong: #b0b0ac;
  --color-text: #0a0a0a;
  --color-text-muted: #5a5a5a;
  --color-text-subtle: #8a8a8a;
  --color-accent: #ff3d00;
  --color-accent-hover: #e63600;
  --color-accent-text: #ffffff;
  --color-overlay: rgba(245, 245, 240, 0.92);
  --color-focus-ring: #ff3d00;
  --color-success: #16a34a;
  --color-error: #dc2626;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
}