/* Indisea overlays and scrims.

   THIS FILE USED TO BE elevation.css AND DEFINED --shadow-none PLUS A FOUR-STEP
   --elevation-N-surface SCALE. Both were removed, deliberately:

     - There are no shadows, ever, so a --shadow-none token is a shadow API in a
       brand that has none. A consuming agent that finds it reasonably infers
       there are other shadow values.
     - Levels 1 and 2 resolved to the SAME value (--surface-card), because the
       system only has two surfaces. A four-step scale over two surfaces encodes
       nothing and implies a layered elevation model that does not exist.

   Depth in this system is ONE SURFACE STEP: stone canvas, nearly-white card. On
   charcoal it is charcoal and nearly charcoal. Use --surface-canvas and
   --surface-card directly. A surface on its OWN value takes a 1px
   --border-same-on-same edge; see readme.md, "No shadows, ever".

   What legitimately lives here: the state and structure borders, and the three
   overlay values. An overlay reads as raised through a flat fill over a scrim,
   never through a shadow. */
:root{
  /* borders are STATE and STRUCTURE, never resting card decoration */
  --border-hover: var(--border-strong);
  --border-rule: var(--border-hairline);
  --overlay-surface: var(--surface-card); /* @kind color */
  --scrim: color-mix(in srgb, var(--indisea-stone-900) 40%, transparent);
  /* blur is used only for scrims and sticky headers over content */
  --blur-sticky: saturate(180%) blur(12px); /* @kind color */
}