/* Spacing — a 4px base with a compressed low end so control padding stays
   honest. Section rhythm is the only place large values are used. */
:root {
  --sp-0: 0; /* @kind spacing */
  --sp-1: 0.25rem;   /* 4  */
  --sp-2: 0.5rem;    /* 8  */
  --sp-3: 0.75rem;   /* 12 */
  --sp-4: 1rem;      /* 16 */
  --sp-5: 1.25rem;   /* 20 */
  --sp-6: 1.5rem;    /* 24 */
  --sp-8: 2rem;      /* 32 */
  --sp-10: 2.5rem;   /* 40 */
  --sp-12: 3rem;     /* 48 */
  --sp-14: 3.5rem;   /* 56 */
  --sp-16: 4rem;     /* 64 */
  --sp-20: 5rem;     /* 80 */
  --sp-28: 7rem;     /* 112 */

  /* Vertical rhythm: sections are separated by space and a hairline, never
     by alternating background colours. */
  --section-y: var(--sp-20);
  --section-y-lg: var(--sp-28);

  /* Gutters. Mobile first — 24px at 390px, 32px from 640px up. */
  --gutter: var(--sp-6);
  --container-narrow: 46rem;
  --container: 68rem;
  --container-wide: 80rem;
}

@media (min-width: 640px) {
  :root { --gutter: var(--sp-8); }
}