/* ============================================================
   OAKS — Spacing, radii, shadows, layout, motion
   ============================================================ */
:root {
  /* Spacing — 4px base */
  --space-0: 0;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
  --space-20: 80px;
  --space-24: 96px;
  --space-32: 128px;

  /* Radii — friendly, rounded (edtech) */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-2xl: 32px;
  --radius-pill: 999px;
  --radius-circle: 50%;

  /* Shadows — soft, cool-tinted (navy-based, never pure black) */
  --shadow-xs: 0 1px 2px rgba(40, 60, 83, 0.06);
  --shadow-sm: 0 1px 3px rgba(40, 60, 83, 0.10), 0 1px 2px rgba(40, 60, 83, 0.06);
  --shadow-md: 0 4px 12px rgba(40, 60, 83, 0.10), 0 2px 4px rgba(40, 60, 83, 0.06);
  --shadow-lg: 0 12px 28px rgba(40, 60, 83, 0.14), 0 4px 10px rgba(40, 60, 83, 0.07);
  --shadow-xl: 0 24px 48px rgba(15, 23, 42, 0.18);
  --shadow-brand: 0 8px 22px rgba(7, 149, 201, 0.30);
  --shadow-inner: inset 0 1px 2px rgba(40, 60, 83, 0.08);

  /* Focus ring */
  --ring-brand: 0 0 0 3px rgba(7, 149, 201, 0.32);

  /* Layout */
  --container-sm: 640px;   /* @kind other */
  --container-md: 768px;   /* @kind other */
  --container-lg: 1024px;  /* @kind other */
  --container-xl: 1200px;  /* @kind other */
  --container-2xl: 1320px; /* @kind other */

  /* Motion */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);       /* @kind other */
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);   /* @kind other */
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);/* @kind other */
  --dur-fast: 120ms;  /* @kind other */
  --dur-base: 200ms;  /* @kind other */
  --dur-slow: 320ms;  /* @kind other */
}