/* ── RESET & TOKENS ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0b0b14;
  --bg-raised: #14141f;
  --text: #f2f2f7;
  --text-secondary: #b7b7c9;
  --text-muted: #7d7d92;
  --rule: rgba(255,255,255,0.08);
  --accent: #7fd8ff;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial,
          'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SF Mono', 'Cascadia Code', 'Courier New', Courier, monospace;

  /* Criterion colours, used on tabs, chips and page headers. */
  --crit-a: #ff7aa8;
  --crit-b: #ffb84d;
  --crit-c: #8ce99a;
  --crit-d: #7fd8ff;
  --crit-e: #c9a3ff;

  /* A4 portrait at 96dpi. Every page is exactly this size; the track is
     scaled to fit the viewport by iasample.js. */
  --page-w: 794px;
  --page-h: 1123px;
  --page-pad: 46px;

  /* Paper */
  --paper: #ffffff;
  --ink: #16161c;
  --ink-soft: #4a4a58;
  --ink-faint: #8d8d9c;
  --paper-rule: #d9d9e2;
  --placeholder: #f2f3f7;
  --placeholder-rule: #c8cad6;
}

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

a { color: inherit; }

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--accent); color: #0b0b14; padding: 10px 16px; font-weight: 700;
}
.skip-link:focus { left: 8px; top: 8px; }

/* ── TOP BAR ──────────────────────────────────────────────────── */
.ia-bar {
  flex-shrink: 0;
  background: rgba(11,11,20,0.92);
  border-bottom: 1px solid var(--rule);
  padding: 8px 16px 0;
}
.ia-bar-top {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
  padding-bottom: 8px;
}
.ia-title {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.ia-title span { color: var(--text-muted); font-weight: 500; }
.ia-bar-spacer { flex: 1 1 auto; }

.ia-attribution { font-size: 12px; color: var(--text-muted); letter-spacing: 0.04em; }
.ia-attribution a { color: var(--accent); text-decoration: none; font-weight: 500; }
.ia-attribution a:hover { text-decoration: underline; }

.ia-toggle {
  appearance: none; cursor: pointer; font: inherit;
  font-size: 0.78rem; font-weight: 600;
  color: var(--text-secondary);
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--rule);
  border-radius: 20px;
  padding: 5px 13px;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}
.ia-toggle:hover { color: var(--text); background: rgba(255,255,255,0.09); }
.ia-toggle[aria-pressed="true"] {
  color: #0b0b14; background: var(--accent); border-color: var(--accent);
}
.ia-toggle:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

/* Page counter and step arrows */
.ia-stepper { display: flex; align-items: center; gap: 6px; }
.ia-step {
  appearance: none; cursor: pointer; font: inherit; line-height: 1;
  width: 28px; height: 28px; border-radius: 50%;
  display: grid; place-items: center;
  color: var(--text-secondary);
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--rule);
}
.ia-step:hover { color: var(--text); background: rgba(255,255,255,0.1); }
.ia-step:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.ia-counter {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--text-muted);
  min-width: 92px;
  text-align: center;
  font-variant-numeric: tabular-nums;
}

/* ── QUICK LINKS ──────────────────────────────────────────────── */
.ia-quicklinks {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding-bottom: 9px;
  scrollbar-width: thin;
}
.ia-quicklinks::-webkit-scrollbar { height: 4px; }
.ia-quicklinks::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 2px; }

.ql {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  text-decoration: none;
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--ql-colour, var(--rule));
  border-radius: 4px;
  padding: 5px 11px;
  white-space: nowrap;
  transition: background 0.15s ease, color 0.15s ease;
}
.ql:hover { color: var(--text); background: rgba(255,255,255,0.09); }
.ql:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.ql-crit { color: var(--ql-colour); font-weight: 800; letter-spacing: 0.06em; }
.ql-pages { font-family: var(--font-mono); font-size: 0.68rem; color: var(--text-muted); }
.ql.is-active {
  color: #0b0b14;
  background: var(--ql-colour);
  border-color: var(--ql-colour);
}
.ql.is-active .ql-crit, .ql.is-active .ql-pages { color: rgba(0,0,0,0.62); }

.ql[data-crit="A"] { --ql-colour: var(--crit-a); }
.ql[data-crit="B"] { --ql-colour: var(--crit-b); }
.ql[data-crit="C"] { --ql-colour: var(--crit-c); }
.ql[data-crit="D"] { --ql-colour: var(--crit-d); }
.ql[data-crit="E"] { --ql-colour: var(--crit-e); }

/* ── HORIZONTAL PAGE TRACK ────────────────────────────────────── */
.ia-scroller {
  flex: 1 1 auto;
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: x mandatory;
  overscroll-behavior-x: contain;
}
.ia-scroller::-webkit-scrollbar { height: 9px; }
.ia-scroller::-webkit-scrollbar-track { background: rgba(255,255,255,0.03); }
.ia-scroller::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.16); border-radius: 5px; }
.ia-scroller::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.28); }

.ia-track {
  display: flex;
  align-items: center;
  gap: 26px;
  padding: 22px 40px;
  width: max-content;
  /* zoom is set by iasample.js so a whole A4 page fits the viewport height */
}

/* ── A4 PAGE ──────────────────────────────────────────────────── */
.ia-page {
  flex: 0 0 auto;
  width: var(--page-w);
  height: var(--page-h);
  background: var(--paper);
  color: var(--ink);
  scroll-snap-align: center;
  border-radius: 2px;
  box-shadow: 0 18px 44px rgba(0,0,0,0.55);
  padding: var(--page-pad);
  display: flex;
  flex-direction: column;
  font-size: 13px;
  line-height: 1.45;
  position: relative;
}
.ia-page[data-crit="A"] { --crit: var(--crit-a); }
.ia-page[data-crit="B"] { --crit: var(--crit-b); }
.ia-page[data-crit="C"] { --crit: var(--crit-c); }
.ia-page[data-crit="D"] { --crit: var(--crit-d); }
.ia-page[data-crit="E"] { --crit: var(--crit-e); }

/* Landscape exception, permitted for the criterion D dimension drawings */
.ia-page.is-landscape { width: var(--page-h); height: var(--page-w); }

/* Running head */
.pg-head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding-bottom: 7px;
  border-bottom: 2px solid var(--crit);
  margin-bottom: 16px;
  flex-shrink: 0;
}
.pg-crit {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--crit) 72%, #000);
}
.pg-strand { font-size: 10px; letter-spacing: 0.05em; color: var(--ink-faint); }
.pg-head-spacer { flex: 1 1 auto; }
.pg-num {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}

.pg-body { flex: 1 1 auto; min-height: 0; display: flex; flex-direction: column; gap: 12px; }

/* Headings inside a page */
.pg-title {
  font-size: 20px;
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.15;
}
.pg-subtitle { font-size: 12px; color: var(--ink-soft); }
h3.blk-title {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--ink-soft);
  padding-bottom: 3px;
  border-bottom: 1px solid var(--paper-rule);
  margin-bottom: 6px;
}

/* Placeholder fields: label plus a ruled line to write on */
.fields { display: flex; flex-direction: column; gap: 5px; }
.field { display: flex; gap: 8px; font-size: 11.5px; align-items: baseline; }
.field-label { flex: 0 0 auto; color: var(--ink-soft); font-weight: 600; }
.field-fill {
  flex: 1 1 auto;
  border-bottom: 1px dotted var(--placeholder-rule);
  min-height: 15px;
  color: var(--ink-faint);
  font-style: italic;
}
.field.stacked { flex-direction: column; gap: 2px; }

/* Image plates: where photographs, renders and drawings go */
.plate {
  background: var(--placeholder);
  border: 1px dashed var(--placeholder-rule);
  border-radius: 3px;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 10px;
  color: var(--ink-faint);
  font-size: 10.5px;
  font-style: italic;
  min-height: 90px;
  overflow: hidden;
}
.plate.grow { flex: 1 1 auto; }
.plate img { width: 100%; height: 100%; object-fit: contain; }
.plate-grid { display: grid; gap: 10px; }
.plate-grid.cols-2 { grid-template-columns: 1fr 1fr; }
.plate-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.plate-grid.rows-2 { grid-template-rows: 1fr 1fr; }
.plate-grid.grow { flex: 1 1 auto; min-height: 0; }

/* Annotations, held to the guide's 10 word ceiling */
.anns { display: flex; flex-direction: column; gap: 4px; }
.ann {
  display: flex;
  gap: 7px;
  align-items: baseline;
  font-size: 11px;
  color: var(--ink-soft);
}
.ann-key {
  flex: 0 0 auto;
  width: 15px; height: 15px;
  border-radius: 50%;
  background: var(--crit);
  color: #16161c;
  font-size: 9px;
  font-weight: 800;
  display: grid; place-items: center;
  font-family: var(--font-mono);
}
.ann-text { flex: 1 1 auto; border-bottom: 1px dotted var(--placeholder-rule); font-style: italic; }

/* Tables */
.ia-table { width: 100%; border-collapse: collapse; font-size: 10.5px; }
.ia-table th, .ia-table td {
  border: 1px solid var(--paper-rule);
  padding: 4px 6px;
  text-align: left;
  vertical-align: top;
}
.ia-table th {
  background: color-mix(in srgb, var(--crit) 16%, #fff);
  font-weight: 700;
  font-size: 9.5px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.ia-table td.fill { color: var(--ink-faint); font-style: italic; }
.ia-table tbody tr:nth-child(even) td { background: #fafafd; }

/* Storyboard frames */
.frames { display: grid; gap: 9px; flex: 1 1 auto; min-height: 0; }
.frames.g6 { grid-template-columns: repeat(3, 1fr); grid-template-rows: 1fr 1fr; }
.frames.g4 { grid-template-columns: 1fr 1fr; grid-template-rows: 1fr 1fr; }
.frame { display: flex; flex-direction: column; gap: 5px; min-height: 0; }
.frame .plate { flex: 1 1 auto; min-height: 0; }
.frame-no {
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: color-mix(in srgb, var(--crit) 70%, #000);
}
.frame-ann {
  font-size: 10.5px;
  color: var(--ink-faint);
  font-style: italic;
  border-bottom: 1px dotted var(--placeholder-rule);
  min-height: 14px;
}

/* Prose slot, with the word budget shown so students can see the cost */
.prose {
  font-size: 11.5px;
  color: var(--ink-faint);
  font-style: italic;
  border-left: 2px solid var(--paper-rule);
  padding: 3px 0 3px 9px;
}
.prose p + p { margin-top: 5px; }

/* Footnote strip, since the guide requires sources on the page itself */
.pg-foot {
  flex-shrink: 0;
  margin-top: 12px;
  padding-top: 6px;
  border-top: 1px solid var(--paper-rule);
  display: flex;
  gap: 12px;
  align-items: baseline;
  font-size: 9px;
  color: var(--ink-faint);
}
.pg-foot-notes { flex: 1 1 auto; font-style: italic; }
.pg-foot-budget { font-family: var(--font-mono); white-space: nowrap; }

/* ── GUIDANCE NOTES (hidden until toggled) ────────────────────── */
.note {
  border-left: 3px solid var(--crit);
  background: color-mix(in srgb, var(--crit) 9%, #fff);
  padding: 6px 9px;
  font-size: 10.5px;
  line-height: 1.4;
  color: var(--ink-soft);
  border-radius: 0 3px 3px 0;
  display: none;
}
.note b {
  display: block;
  font-size: 9px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: color-mix(in srgb, var(--crit) 65%, #000);
  margin-bottom: 2px;
}
body.show-notes .note { display: block; }

/* ── PRINT: real A4, one page per sheet ───────────────────────── */
@page { size: A4 portrait; margin: 0; }
@media print {
  body { display: block; height: auto; overflow: visible; background: #fff; }
  .ia-bar, .skip-link { display: none; }
  .ia-scroller { overflow: visible; }
  .ia-track { display: block; width: auto; padding: 0; zoom: 1 !important; }
  .ia-page {
    width: 210mm; height: 297mm;
    box-shadow: none; border-radius: 0;
    break-after: page; page-break-after: always;
  }
  .ia-page.is-landscape { width: 297mm; height: 210mm; }
  .note { display: none !important; }
}

/* ── LAYOUT HELPERS INSIDE A PAGE ─────────────────────────────── */
.cols2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; align-items: start; }
.cols2.uneven { grid-template-columns: 1.15fr 1fr; }
.cols2.grow { flex: 1 1 auto; min-height: 0; }
.col { display: flex; flex-direction: column; gap: 11px; min-height: 0; }
.blk { display: flex; flex-direction: column; }
.blk.grow { flex: 1 1 auto; min-height: 0; }
.stack { display: flex; flex-direction: column; gap: 11px; }
.stack.grow { flex: 1 1 auto; min-height: 0; }

/* ── DRAFTED CONTENT vs EVIDENCE STILL TO COME ────────────────────
   Black upright text is written. Grey italic is a placeholder waiting
   on a photograph, a measurement or a test result. */
.field-val { flex: 1 1 auto; color: var(--ink); }
.field-val.strong { font-weight: 600; }
.prose.written { color: var(--ink); font-style: normal; }
.ann-text.written { color: var(--ink); font-style: normal; border-bottom: none; }
.pg-foot-notes.written { font-style: normal; color: var(--ink-soft); }