/* Arkum Labs — Shadow & Glow Tokens
   On near-black surfaces, soft drop shadows barely read. Depth is built
   from (1) layered borders + subtle ambient shadow, and (2) a restrained
   cyan "slit glow" reserved for active/focus/key moments. Never neon. */

:root {
  /* ---- Ambient elevation (depth on dark) ---- */
  --shadow-none:   none;
  --shadow-sm:     0 1px 0 0 rgba(0,0,0,0.4),
                   0 1px 2px 0 rgba(0,0,0,0.5);
  --shadow-md:     0 2px 4px -1px rgba(0,0,0,0.5),
                   0 8px 16px -4px rgba(0,0,0,0.55);
  --shadow-lg:     0 8px 24px -6px rgba(0,0,0,0.6),
                   0 24px 48px -12px rgba(0,0,0,0.65);
  --shadow-modal:  0 24px 64px -12px rgba(0,0,0,0.75),
                   0 0 0 1px var(--border-default);

  /* ---- Inset / inner well (inputs, terminals, recessed panels) ---- */
  --shadow-inset:  inset 0 1px 0 0 rgba(0,0,0,0.5),
                   inset 0 0 0 1px rgba(0,0,0,0.25);

  /* ---- Top-edge highlight: the faint "machined" upper border ---- */
  --edge-top:      inset 0 1px 0 0 rgba(255,255,255,0.045); /* @kind shadow */

  /* ---- Cyan glow: the portal light slit. Reserved & restrained. ---- */
  --glow-cyan-sm:  0 0 0 1px color-mix(in oklab, var(--ark-cyan) 45%, transparent),
                   0 0 12px -2px color-mix(in oklab, var(--ark-cyan) 35%, transparent);
  --glow-cyan-md:  0 0 0 1px color-mix(in oklab, var(--ark-cyan) 55%, transparent),
                   0 0 24px -4px color-mix(in oklab, var(--ark-cyan) 45%, transparent);
  --glow-focus:    0 0 0 2px var(--surface-base),
                   0 0 0 4px var(--focus-ring);

  /* ---- Vertical slit gradient (portal seam) for hero/feature accents ---- */
  --slit-cyan:     linear-gradient(180deg,
                     transparent 0%,
                     color-mix(in oklab, var(--ark-cyan) 70%, transparent) 35%,
                     color-mix(in oklab, var(--ark-cyan) 70%, transparent) 65%,
                     transparent 100%); /* @kind other */
}