/*
 * Styles for the demo shell only (index.html and compare.html).
 * Sample pages under findings/ never load this file.
 *
 * Colour pairs and contrast ratios (WCAG 2.1 AA: text 4.5:1, non-text 3:1).
 *
 * Light scheme
 *   text        #1a1a1a on bg      #ffffff  17.40:1
 *   muted       #555555 on bg      #ffffff   7.46:1
 *   link        #0b57d0 on bg      #ffffff   6.39:1
 *   text        #1a1a1a on surface #f2f2f2  15.55:1
 *   link        #0b57d0 on surface #f2f2f2   5.70:1
 *   border      #767676 on bg      #ffffff   4.54:1
 *   text        #1a1a1a on button  #e6e6e6  13.94:1
 *   border      #767676 on button  #e6e6e6   3.64:1
 *   pressed text #ffffff on pressed #1a1a1a  17.40:1
 *   focus ring  #0b57d0 on bg      #ffffff   6.39:1
 *
 * Dark scheme
 *   text        #e6e6e6 on bg      #121212  15.01:1
 *   muted       #b3b3b3 on bg      #121212   8.93:1
 *   link        #8ab4f8 on bg      #121212   8.89:1
 *   text        #e6e6e6 on surface #1e1e1e  13.36:1
 *   link        #8ab4f8 on surface #1e1e1e   7.91:1
 *   border      #8c8c8c on bg      #121212   5.57:1
 *   text        #e6e6e6 on button  #2a2a2a  11.50:1
 *   border      #8c8c8c on button  #2a2a2a   4.27:1
 *   pressed text #121212 on pressed #e6e6e6  15.01:1
 *   focus ring  #8ab4f8 on bg      #121212   8.89:1
 *
 * Forced colours
 *   None of the pairs above survive; the user agent substitutes the user's
 *   system palette. See the forced-colors block by .toggle for what that
 *   costs the pressed state and how it is restated.
 */

:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --text: #1a1a1a;
  --muted: #555555;
  --link: #0b57d0;
  --surface: #f2f2f2;
  --border: #767676;
  --button-bg: #e6e6e6;
  --pressed-bg: #1a1a1a;
  --pressed-text: #ffffff;
  --focus: #0b57d0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --text: #e6e6e6;
    --muted: #b3b3b3;
    --link: #8ab4f8;
    --surface: #1e1e1e;
    --border: #8c8c8c;
    --button-bg: #2a2a2a;
    --pressed-bg: #e6e6e6;
    --pressed-text: #121212;
    --focus: #8ab4f8;
  }
}

* {
  box-sizing: border-box;
}

html {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Ubuntu, Cantarell, "Helvetica Neue", Arial, sans-serif;
  font-size: 100%;
  line-height: 1.5;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
}

a {
  color: var(--link);
}

a:hover {
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

/* Skip link: visually hidden until focused, then the first thing on screen. */
.skip-link {
  position: absolute;
  left: 0.5rem;
  top: -10rem;
  padding: 0.5rem 1rem;
  background: var(--bg);
  color: var(--link);
  border: 2px solid var(--border);
  z-index: 10;
}

.skip-link:focus {
  top: 0.5rem;
}

/* Header and navigation */
.site-header {
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  align-items: baseline;
}

.site-name {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.site-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1rem;
}

/* Main content */
main {
  padding: 1rem;
  max-width: 90rem;
  margin: 0 auto;
}

h1 {
  font-size: 1.75rem;
  margin: 0.5rem 0 1rem;
}

h2 {
  font-size: 1.25rem;
  margin: 1.5rem 0 0.5rem;
}

.muted {
  color: var(--muted);
}

/* Catalog table */
.catalog {
  border-collapse: collapse;
  width: 100%;
}

.catalog caption {
  text-align: left;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.catalog th,
.catalog td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  text-align: left;
  vertical-align: top;
}

.catalog th {
  background: var(--surface);
}

.table-wrap {
  overflow-x: auto;
}

/* Compare page */
.compare-controls {
  margin: 0 0 1rem;
}

.toggle {
  font: inherit;
  padding: 0.5rem 1rem;
  background: var(--button-bg);
  color: var(--text);
  border: 2px solid var(--border);
  border-radius: 0.25rem;
  cursor: pointer;
}

.toggle[aria-pressed="true"] {
  background: var(--pressed-bg);
  color: var(--pressed-text);
  border-color: var(--pressed-bg);
}

/*
 * Forced colours (Windows High Contrast, Firefox and Chromium).
 *
 * The user agent discards author colours and substitutes the user's system
 * palette, so --pressed-bg and --pressed-text never reach the screen: both
 * toggle states resolve to the same ButtonFace/ButtonText pair and look
 * identical. Author-declared CSS system colour keywords are exempt from that
 * substitution, so both states are restated in terms of them.
 * Highlight/HighlightText is the pair the platform itself uses for a selected
 * or pressed control. border-style is not a colour and is never substituted,
 * so the doubled border is a second, non-colour cue. Both states carry the
 * same 3px border width so the toggle does not shift when it is pressed
 * (2px is too narrow for `double` to draw two lines).
 *
 * System keywords alone are not enough. A discarded author colour falls back
 * to the user agent's own button styles, including its :hover colours, which
 * in Firefox can match the pressed fill: under a resting pointer both states
 * look pressed. Chromium paints a Canvas-coloured backplate behind text, and
 * where HighlightText is close to Canvas the pressed label disappears.
 * forced-color-adjust: none opts the toggle out of both. It is safe here only
 * because every colour the toggle uses in this block is a system keyword, so
 * the user's palette still applies; the cost is the user agent's hover
 * styling on this one control.
 *
 * Highlight is also a plausible substitute for the focus outline, and the
 * pressed fill would swallow it; CanvasText keeps the ring distinct from it.
 */
@media (forced-colors: active) {
  .toggle {
    forced-color-adjust: none;
    background-color: ButtonFace;
    color: ButtonText;
    border-color: ButtonText;
    border-width: 3px;
  }

  .toggle[aria-pressed="true"] {
    background-color: Highlight;
    color: HighlightText;
    border-color: HighlightText;
    border-style: double;
  }

  .toggle:focus-visible {
    outline-color: CanvasText;
  }
}

.panes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

/* Serial mode: one column, in DOM order (Before, After). */
.panes.serial {
  grid-template-columns: 1fr;
}

/* Narrow viewports stack the panes regardless of the toggle. */
@media (max-width: 56rem) {
  .panes {
    grid-template-columns: 1fr;
  }
}

.pane h2 {
  margin-top: 0;
}

.pane iframe {
  width: 100%;
  height: 70vh;
  min-height: 20rem;
  border: 1px solid var(--border);
  background: #ffffff; /* sample pages set their own colours; default to a white canvas */
}

.pane p {
  margin: 0.5rem 0 0;
}

/* Diff: the div is the focusable scroll container; the pre inside it is plain text. */
.diff {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 1rem;
  max-height: 70vh;
  overflow: auto;
}

.diff pre {
  margin: 0;
  font-family: ui-monospace, "Cascadia Mono", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.9rem;
  line-height: 1.4;
}

/* Error / status message */
.notice {
  border: 1px solid var(--border);
  background: var(--surface);
  padding: 1rem;
}

/* Visually hidden, still read by screen readers (link-text suffixes). */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}