:root{
  /* Type */
  --font-system: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
  --step--1: clamp(0.85rem, 0.82rem + 0.2vw, 0.95rem);
  --step-0:  clamp(1.00rem, 0.98rem + 0.2vw, 1.10rem);
  --step-1:  clamp(1.25rem, 1.20rem + 0.3vw, 1.35rem);
  --step-2:  clamp(1.50rem, 1.42rem + 0.5vw, 1.65rem);
  --step-3:  clamp(2.00rem, 1.90rem + 0.8vw, 2.30rem);

  /* Spacing */
  --space-1: .25rem;
  --space-2: .5rem;
  --space-3: .75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;

  /* Radii */
  --r-1: 6px;
  --r-2: 12px;
  --r-3: 16px;

  /* Shadows */
  --shadow-1: 0 1px 2px rgba(0,0,0,.06), 0 1px 4px rgba(0,0,0,.04);
  --shadow-2: 0 4px 12px rgba(0,0,0,.10);
  --shadow-3: 0 10px 30px rgba(0,0,0,.15);

  /* Color roles (overridden by themes) */
  --bg: #f7fafc;
  --ink: #1f2937;
  --muted: #6b7280;
  --card: #ffffff;
  --border: #e5e7eb;
  --accent: #2563eb;
  --accent-ink: #ffffff;
  --surface-tint: rgba(37,99,235,0.08);
  --surface-hover: rgba(37,99,235,0.12);

  --success: #26a269;
  --warn: #e5a50a;
  --error: #c01c28;

  /* Layout */
  --container-md: 1100px;
  --page-gutter: clamp(var(--space-4), 5vw, var(--space-7));
}