/* Cadence — spacing. 4pt grid, 8pt rhythm, 16 governs the horizontal system:
   screen margin = card padding = grid gutter = 16. One alignment line per screen. */
:root {
  --space-0:0; --space-1:2px; --space-2:4px; --space-3:8px; --space-4:12px;
  --space-5:16px; --space-6:20px; --space-7:24px; --space-8:32px;
  --space-9:40px; --space-10:48px; --space-12:64px; --space-16:96px;

  --layout-margin:16px;
  --layout-gutter:16px;
  --layout-carousel-peek:24px; /* every rail shows a sliver of the next card */

  --size-row-min:44px;      /* HIG floor — nothing tappable is smaller */
  --size-row-default:56px;
  --size-row-media:72px;
  --size-control-lg:52px;   /* buttons, inputs */
  --size-fab:56px;
  --size-tabbar:49px;
  --size-transport:88px;    /* excludes safe area */
  --size-cover-aspect:0.667; /* rigid 2:3 book cover, never stretched or cropped */
}