:root {
  --color-text: #000;
  --color-background: #fff;
  /* Outer shell of week + tasks (see styles: wide vs narrow). */
  --radius-shell: 0.65rem;
  --color-border: color-mix(in srgb, var(--color-text) 20%, transparent);
  /* Soft outer glow on day cells + tasks field (hover). */
  --shadow-day-hover: 0 0 0.3em 0.07em color-mix(in srgb, var(--color-text) 22%, transparent);
}