/* ============================================================
   Mixto Math — Spacing, radii, shadows, motion
   Friendly + chunky. Generous radii, soft warm elevation, and a
   signature "candy edge" press on primary buttons (a solid darker
   bottom lip that compresses on tap — game feel, not flat web).
   ============================================================ */

:root {
  /* ---- Spacing (4px base grid) ---- */
  --space-0: 0;
  --space-1: 0.25rem;  /* 4 */
  --space-2: 0.5rem;   /* 8 */
  --space-3: 0.75rem;  /* 12 */
  --space-4: 1rem;     /* 16 */
  --space-5: 1.25rem;  /* 20 */
  --space-6: 1.5rem;   /* 24 */
  --space-8: 2rem;     /* 32 */
  --space-10: 2.5rem;  /* 40 */
  --space-12: 3rem;    /* 48 */
  --space-16: 4rem;    /* 64 */
  --space-20: 5rem;    /* 80 */

  /* Minimum kid-safe tap target (PRD P0-10) */
  --tap-min: 44px;
  --tap-comfortable: 56px;

  /* ---- Corner radii (rounded, friendly) ---- */
  --radius-xs: 8px;
  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-2xl: 36px;
  --radius-pill: 999px;

  /* ---- Elevation: soft, warm, navy-tinted shadows ---- */
  --shadow-xs: 0 1px 2px rgba(11, 16, 48, 0.08);
  --shadow-sm: 0 2px 8px rgba(11, 16, 48, 0.10);
  --shadow-md: 0 8px 20px rgba(11, 16, 48, 0.12);
  --shadow-lg: 0 16px 40px rgba(11, 16, 48, 0.16);
  --shadow-xl: 0 28px 64px rgba(11, 16, 48, 0.22);
  /* Glow used on the navy game canvas for celebration / focus */
  --glow-teal: 0 0 0 4px rgba(24, 201, 214, 0.28);
  --glow-orange: 0 0 24px rgba(255, 122, 45, 0.45);
  --glow-mastery: 0 0 28px rgba(40, 208, 114, 0.5);

  /* ---- Signature "candy edge" (chunky button bottom lip) ---- */
  --edge-thickness: 4px;
  --edge-press-travel: 3px;

  /* ---- Motion: bouncy + quick, never sluggish or anxious ---- */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1); /* @kind other */
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1); /* @kind other */ /* overshoot / pop */
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1); /* @kind other */
  --dur-instant: 90ms;   /* @kind other */ /* feedback registers (PRD: <150ms) */
  --dur-quick: 160ms;    /* @kind other */ /* hovers, presses */
  --dur-base: 240ms;     /* @kind other */ /* most transitions */
  --dur-celebrate: 420ms;/* @kind other */ /* mastery pop / reveal */

  /* ---- Layout ---- */
  --container-max: 1200px;
  --container-narrow: 720px;
  --phone-max: 420px;
}