/* ==========================================================================
   IO Patina — common theme · accents
   --------------------------------------------------------------------------
   Same metal, different oxide.

   Every property loads the identical theme and overrides one triple:
   --accent (links and marks on light), --accent-deep (hover and pressed), and
   --accent-light (the on-dark pair). Nothing else changes. Set the property on
   the root element:

       <html lang="en" data-property="verdigris">

   Or, if the site cannot set an attribute on <html>, redeclare the three
   custom properties in its own stylesheet — the values are printed below.

   --------------------------------------------------------------------------
   HOW THESE WERE DERIVED

   The design document asks for accents that "sit at the same lightness and
   chroma as Bronze, so contrast is inherited rather than re-tested", and then
   states them as oklch(0.47 0.055 H). Those two things disagree: Bronze
   #7C5F3E measures oklch(0.507 0.061 69.4), so a sibling written at L 0.47
   lands a visible step darker than the colour it is supposed to match —
   6.20:1 against Bronze's 5.22:1 for the Oxide case.

   The rule is the part worth keeping, so each accent below is Bronze's own
   measured lightness and chroma with the hue rotated, and nothing else. The
   family now lands within 0.27 of a contrast step of each other, which is
   what "inherited rather than re-tested" was asking for.

   The values ship as sRGB hex rather than as oklch(). Colours in this system
   are fixed, not computed at runtime, so the wider gamut buys nothing, and hex
   needs no fallback on an old browser. The oklch triple each value came from
   is in the comment beside it.

     property     --accent            --accent-deep        --accent-light
     ---------------------------------------------------------------------
     bronze       #7c5f3e  5.22:1     #5e4629  7.81:1      #c8b092  9.08:1
     verdigris    #367070  5.02:1     #215454  7.56:1      #90bfbe  9.35:1
     oxide        #855854  5.29:1     #663f3c  7.95:1      #d2a9a4  8.96:1
     graphite     #4a4c4e  7.65:1     #2c2f33 11.92:1      #c6c4bf 10.85:1

   The first two ratios are measured on Paper #F3F1ED and need 4.5:1; the
   third is measured on Deep Ink #0F1114 and needs 7:1. All twelve pass.
   Re-measure with theme/check-contrast.mjs if any value is ever changed.
   ========================================================================== */

/* --------------------------------------------------------------------------
   Bronze — iopatina.com
   The company. Serif-led, widest measure, dark metal hero, one dark band per
   page. This is the theme's default, so it is also what you get with no
   data-property attribute at all; it is repeated here so the set is complete
   and so a property can be switched back explicitly.
   -------------------------------------------------------------------------- */
:root,
[data-property='bronze'] {
  --accent: #7c5f3e; /* oklch(0.507 0.061 69.4) — published, never re-derived */
  --accent-deep: #5e4629; /* oklch(0.413 0.054 70.6) */
  --accent-light: #c8b092; /* oklch(0.770 0.050 73.2) — Portal Gold */
}

/* --------------------------------------------------------------------------
   Verdigris — iopatina.org (IO Patina Labs)
   Research. Mono-led, narrower measure, a dated index instead of cards, and a
   light hero: the metal belongs to the parent, so the lab does without it.
   -------------------------------------------------------------------------- */
[data-property='verdigris'] {
  --accent: #367070; /* oklch(0.507 0.061 195) */
  --accent-deep: #215454; /* oklch(0.413 0.054 195) */
  --accent-light: #90bfbe; /* oklch(0.770 0.050 195) */
}

/* --------------------------------------------------------------------------
   Oxide — product landings and store
   Denser than the company pages, one action above the fold, and the product
   interface carries the page rather than a headline.
   -------------------------------------------------------------------------- */
[data-property='oxide'] {
  --accent: #855854; /* oklch(0.507 0.061 25) */
  --accent-deep: #663f3c; /* oklch(0.413 0.054 25) */
  --accent-light: #d2a9a4; /* oklch(0.770 0.050 25) */
}

/* --------------------------------------------------------------------------
   Graphite — docs and support
   No accent at all. Reading speed is the whole brief, so links are the body
   neutral one step darker, and there is no metal, no dark band, and no hero.
   -------------------------------------------------------------------------- */
[data-property='graphite'] {
  --accent: #4a4c4e;
  --accent-deep: #2c2f33;
  --accent-light: #c6c4bf;
}

/* --------------------------------------------------------------------------
   Portal Gold stays reserved for iopatina.com's dark surfaces, so the parent
   keeps the metal and the divisions keep the patina. The mark itself is never
   recoloured to a property accent — it is Deep Ink, Paper, or Portal Gold, as
   published on iopatina.com/brand/.
   -------------------------------------------------------------------------- */