/*
 * Core semantic color system.
 *
 * Themes override the small set of inputs below; every semantic color is then
 * derived from them in OKLCH. The stepped numeric scales (brand / warning /
 * destructive / secondary) are NOT derived here — they live as per-theme values
 * in the theme files and are mapped to utilities in packages/config/css/theme.css.
 */

:root {
  /*
   * Hue inputs. A single --hue used to drive both the neutral surface/text ramp
   * and the brand, so the two could never drift apart. They are now split so a
   * theme can run, say, a cool-gray surface against the green brand:
   *   --surface-hue  tints backgrounds, text and borders (the neutral ramp)
   *   --primary-hue  is the brand hue that --primary is built from
   * Both default to --hue (Supabase green ≈159° in OKLCH), so a theme that only
   * sets --hue keeps surfaces and brand locked together as before; override
   * either one to let them diverge. */
  --hue: 159;
  --surface-hue: var(--hue);
  --primary-hue: var(--hue);
  /* Root defaults mirror the dark theme (the app's default appearance). */
  --chroma: 0.016;
  --surface: 0.17;

  --foreground-lightness: 0.95;
  /* How far muted/tertiary text sits from --surface toward --foreground-lightness
     (0 = surface, 1 = full foreground) at --contrast 0.5; themes override. */
  --muted-foreground-level: 0.8;
  --tertiary-foreground-level: 0.65;

  /*
   * Global contrast knob, 0 to 1. Default 0.5 is the comfortable baseline; 0 keeps
   * borders and accent barely visible over muted surfaces; 1 pushes them to full
   * strength. Foreground hits --foreground-lightness at 0.5; below that it eases
   * toward the surface down to --contrast-text-floor at 0. Muted and tertiary
   * foreground lightness sits at the theme base level (a surface→foreground mix) at
   * 0.5 and eases up toward foreground or down toward half that base as contrast moves.
   *
   * --contrast-delta is -1 at 0, 0 at 0.5, +1 at 1 — shared offset from baseline;
   * --contrast-up / --contrast-down are its positive / negative halves.
   * --contrast-border ramps [floor, 1] over --contrast and squares it so most of
   * the range lives toward full strength. ((delta + 1) / 2 simplifies to contrast.)
   */
  --contrast: 0.5;
  --contrast-delta: calc((var(--contrast) - 0.5) / 0.5);
  /* positive and negative halves of the delta, reused below */
  --contrast-up: max(0, var(--contrast-delta));
  --contrast-down: max(0, calc(var(--contrast-delta) * -1));
  --contrast-text-floor: 0.9;
  --contrast-border-floor: 0.05;
  --contrast-text: calc(1 - (1 - var(--contrast-text-floor)) * var(--contrast-down));
  --contrast-border-linear: calc(
    var(--contrast-border-floor) + (1 - var(--contrast-border-floor)) * var(--contrast)
  );
  --contrast-border: calc(var(--contrast-border-linear) * var(--contrast-border-linear));

  /*
   * Surface elevation. Each surface steps its lightness away from --background
   * by `--elevation-step * ratio`, where the ratios are shared across themes and
   * the step is signed: positive brightens as surfaces rise, negative darkens.
   *
   * The default step reproduces the historical behavior (≈3% per level mixed
   * toward the foreground): dark themes brighten and the light baseline darkens.
   * The light theme overrides --elevation-step (and lowers --surface for
   * headroom) so its higher surfaces brighten toward white instead — giving a
   * single "higher = lighter" model in both modes. 0 = flat (no elevation).
   */
  --elevation-1: 1;
  --elevation-2: 1.5;
  --elevation-3: 2;
  --elevation-4: 3;
  /* Signed span surface→foreground (+ in dark, − in light). */
  --tone-span: calc(var(--foreground-lightness) - var(--surface));
  --elevation-step: calc(var(--tone-span) * 0.04);
  /*
   * Foreground overlays for muted / accent / tertiary. Alpha is tuned so each level
   * matches the lightness delta of the same elevation ratio on --background; a
   * translucent --foreground layer then composites with whatever surface sits
   * beneath (lightens in dark, darkens in light). Steps: muted (e1) → accent
   * (e2) → tertiary (e3).
   */
  /* max(span, -span) is equivalent to abs(span), but works across the browser
     versions supported by Tailwind v4. */
  --surface-overlay-unit: calc(
    var(--elevation-step) / max(var(--tone-span), calc(var(--tone-span) * -1))
  );
  --muted-alpha: calc(var(--surface-overlay-unit) * var(--elevation-1));
  --accent-alpha: calc(var(--surface-overlay-unit) * var(--elevation-2));
  --tertiary-alpha: calc(var(--surface-overlay-unit) * var(--elevation-3));

  /*
   * Status hues stay anchored to amber / red but pull a fraction of the way
   * toward the brand --primary-hue for harmony, then clamp to their perceptual
   * category so "warning" always reads amber and "destructive" always reads red
   * no matter what --primary-hue is. --status-hue-pull: 0 = fixed amber/red,
   * 1 = fully brand-relative. At the default --primary-hue the pull term is 0, so
   * these resolve to their bases (warning 75 / destructive 25 / info 288).
   * --brand-hue-reference is the --primary-hue at which pull is zero; keep it
   * equal to the default brand hue.
   * Warning sits at 75 (amber), not higher toward yellow — yellow can't darken
   * without going olive, so it loses contrast on light surfaces. Info is a violet
   * (matching the "no additional charge" badge); like the others it pulls a touch
   * with the brand --primary-hue but clamps so it always reads violet.
   */
  --brand-hue-reference: 159;
  --status-hue-pull: 0.15;
  --warning-hue: clamp(
    65,
    calc(75 + (var(--primary-hue) - var(--brand-hue-reference)) * var(--status-hue-pull)),
    95
  );
  --destructive-hue: clamp(
    12,
    calc(25 + (var(--primary-hue) - var(--brand-hue-reference)) * var(--status-hue-pull)),
    42
  );
  --info-hue: clamp(
    272,
    calc(288 + (var(--primary-hue) - var(--brand-hue-reference)) * var(--status-hue-pull)),
    302
  );
  /*
   * Expressive (status) colors are deliberately NOT derived from the neutral
   * surface→foreground span the way text and surfaces are. An expressive color
   * has its own identity; tying its lightness to the theme's text ramp is what
   * left warning under-saturated in light mode and too dark in dark mode.
   *
   * Instead each is anchored to a fixed target lightness near its hue's chroma
   * peak and a single shared --expressive-chroma. That chroma is a flat constant,
   * deliberately NOT derived from the neutral --chroma knob: status colors must
   * stay legible even when the brand is dialed toward grayscale. It sits inside
   * sRGB at these lightnesses, so no gamut mapping is required.
   *
   * The dark-mode lightness anchors live here; light mode runs darker (set in
   * light.css) so the fills hold contrast against the near-white surface.
   */
  --expressive-chroma: 0.14;
  --warning-lightness: 0.8;
  --destructive-lightness: 0.75;
  --info-lightness: 0.7;

  /* shadcn semantic pairs */
  --background: oklch(var(--surface) calc(var(--chroma) * 0.5) var(--surface-hue));
  --foreground-chroma: calc(var(--chroma) * 0.55);
  --foreground: oklch(
    calc(var(--surface) + var(--tone-span) * var(--contrast-text)) var(--foreground-chroma)
      var(--surface-hue)
  );
  /* Inverse of --foreground: canvas-coloured text for use on inverted fills
     (bg-foreground, bg-black / dark:bg-white, etc). Not the same as
     --primary-foreground, which stays dark for the vivid primary fill. */
  --foreground-contrast: oklch(var(--surface) calc(var(--chroma) * 0.55) var(--surface-hue));

  --card: oklch(from var(--background) calc(l + var(--elevation-step) * var(--elevation-1)) c h);
  --card-foreground: var(--foreground);
  --popover: oklch(from var(--background) calc(l + var(--elevation-step) * var(--elevation-2)) c h);
  --popover-foreground: var(--foreground);

  /* Primary is the brand-derived accent: a fixed, vivid Supabase green on
     --primary-hue, mode-invariant and decoupled from the --chroma knob so it
     holds its identity even as neutrals desaturate. NOTE: the `brand` utility
     (--color-brand in theme.css) is deliberately NOT this — it maps to the
     per-theme --brand-default scale (master behavior) while we resolve how
     `brand` is used across the interface. */
  --primary: oklch(0.76 0.15 var(--primary-hue));
  --primary-foreground: oklch(
    min(var(--surface), var(--foreground-lightness)) calc(var(--chroma) * 0.45) var(--primary-hue)
  );

  --secondary: oklch(
    from var(--background) calc(l + var(--elevation-step) * var(--elevation-3)) c h
  );
  --secondary-foreground: var(--foreground);
  --tertiary: oklch(from var(--foreground) l c h / var(--tertiary-alpha));
  --tertiary-foreground-mix: calc(
    var(--tertiary-foreground-level) + (1 - var(--tertiary-foreground-level)) * var(--contrast-up) -
      var(--tertiary-foreground-level) * 0.5 * var(--contrast-down)
  );
  --tertiary-foreground: oklch(
    calc(var(--surface) + var(--tone-span) * var(--tertiary-foreground-mix))
      var(--foreground-chroma) var(--surface-hue)
  );
  --muted: oklch(from var(--foreground) l c h / var(--muted-alpha));
  --muted-foreground-mix: calc(
    var(--muted-foreground-level) + (1 - var(--muted-foreground-level)) * var(--contrast-up) -
      var(--muted-foreground-level) * 0.5 * var(--contrast-down)
  );
  --muted-foreground: oklch(
    calc(var(--surface) + var(--tone-span) * var(--muted-foreground-mix)) var(--foreground-chroma)
      var(--surface-hue)
  );
  --accent: oklch(from var(--foreground) l c h / var(--accent-alpha));
  --accent-foreground: var(--foreground);

  /*
   * Control surface roles (design sync: sunk fields + raised choosers):
   *   --field          sunk text entry (Input, Textarea, filled MultiSelect)
   *   --control-raised raised chooser plate (Select, empty MultiSelect)
   *   --control        alias of --control-raised
   *
   * Alpha overlays relative to the local plate (page, sheet, card) — not solids
   * from --background. Page-relative solids sit between canvas (e0) and Sheet
   * (popover e2) and vanish on light near the white ceiling.
   *
   * Field soft always-sink via black. --field-alpha is a theme input (stronger in
   * dark.css) because the same absolute opacity is obvious on light plates and
   * near-invisible on dark ones. Default is softer than the old foreground/[.026]
   * wash. Raised is a soft white lift so selects read button-like without stark
   * wells. Borders carry most hover chrome (--border-control-hover). Light raises
   * still have little headroom on sheets; sheets matching app background would
   * widen that later.
   *
   * Default Button stays opaque card/popover for occluding chrome (DEPR-636).
   * Floating clusters can wrap in a solid Popover as a follow-up.
   */
  --field-alpha: 0.015;
  --field: oklch(0 0 0 / var(--field-alpha));
  --control-raised: oklch(1 0 0 / calc(var(--muted-alpha) * 0.65));
  --control: var(--control-raised);

  --warning: oklch(var(--warning-lightness) var(--expressive-chroma) var(--warning-hue));
  --destructive: oklch(
    var(--destructive-lightness) var(--expressive-chroma) var(--destructive-hue)
  );
  /*
   * Text that sits on the solid fill: dark ink on light fills (amber), white on
   * dark fills (red). The clamp turns the fill's own lightness into a hard flip
   * around L≈0.62 — (0.62 − l) is negative for light fills (→ floor 0.12) and
   * positive for dark fills (→ ceil 0.99) — so on-colors stay legible and keep
   * flipping correctly if the anchors are retuned. A trace of hue chroma keeps
   * the ink from reading as flat gray.
   */
  --warning-foreground: oklch(
    from var(--warning) clamp(0.12, calc((0.62 - l) * 100), 0.99) calc(c * 0.08) h
  );
  --destructive-foreground: oklch(
    from var(--destructive) clamp(0.12, calc((0.62 - l) * 100), 0.99) calc(c * 0.08) h
  );
  --info: oklch(var(--info-lightness) var(--expressive-chroma) var(--info-hue));
  --info-foreground: oklch(
    from var(--info) clamp(0.12, calc((0.62 - l) * 100), 0.99) calc(c * 0.08) h
  );

  /* Status border tokens for subtle / tinted surfaces */
  --border-destructive: oklch(from var(--destructive) l c h / 30%);
  --border-warning: oklch(from var(--warning) l c h / 30%);
  --border-info: oklch(from var(--info) l c h / 30%);
  --border-brand: oklch(from var(--primary) l c h / 30%);

  --border: oklch(
    from var(--foreground) l calc(c * 0.54) h / calc(2% + 20% * var(--contrast-border))
  );
  --input: oklch(
    from var(--foreground) l calc(c * 0.5) h / calc(3% + 38% * var(--contrast-border))
  );
  /*
   * Shared interactive border for control chrome (inputs, selects, default /
   * dashed Button, radio cards). Pairs with rest --border-control / --border-strong.
   * Stronger than --border-stronger; softer than a full muted-foreground stroke.
   */
  --border-control-hover: oklch(
    from var(--foreground) l calc(c * 0.5) h / calc(12% + 58% * var(--contrast-border))
  );
  --ring: oklch(from var(--primary) l c h / 55%);
}