/* ============================================================================
   SignalCanvas — Spacing, radii, shadows, motion
   Sharp & technical: small radii (2–8px), tight elevation, fast transitions.
   ============================================================================ */

:root {
  /* ---- Spacing scale (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-24: 96px;

  /* ---- Radii ---------------------------------------------------------------
     Deliberately tight. Chips/kbd = 2px, controls = 4px, icon btns = 6px. */
  --radius-xs: 2px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-pill: 999px;

  /* ---- Borders ------------------------------------------------------------- */
  --border-width: 1px;
  --border-accent: 4px;   /* left-rail accent on primary actions */

  /* ---- Elevation / shadows -------------------------------------------------
     Dark UI: shadows are deep & quiet; "glow" carries emphasis instead. */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 28px rgba(0, 0, 0, 0.5);
  --shadow-modal: 0 16px 48px rgba(0, 0, 0, 0.6);

  /* ---- Glow ----------------------------------------------------------------
     Signature SignalCanvas emphasis: a neon halo, used sparingly. */
  --glow-teal: 0 0 12px rgba(45, 212, 191, 0.45), 0 0 4px rgba(45, 212, 191, 0.6);
  --glow-signal: 0 0 12px rgba(107, 255, 143, 0.45), 0 0 4px rgba(107, 255, 143, 0.6);
  --glow-firefly: drop-shadow(0 0 8px rgba(34, 197, 94, 0.9)) drop-shadow(0 0 4px rgba(34, 197, 94, 0.55)); /* @kind shadow */

  /* ---- Motion --------------------------------------------------------------
     Fast, mechanical. No bounce. */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1); /* @kind other */
  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1); /* @kind other */
  --dur-fast: 100ms; /* @kind other */
  --dur-base: 150ms; /* @kind other */
  --dur-slow: 200ms; /* @kind other */
  --transition-base: 150ms ease; /* @kind other */
}