/* RA10 BTEC IT AAQ — Revision Booklet reader + print styles
   Screen = mobile-responsive reader; Print = clean A4 booklet pages. */

:root {
  --bk-ink: #17202b;
  --bk-muted: #5b6472;
  --bk-brand: #d20000;
  --bk-brand-soft: #fbeaea;
  --bk-line: #d9dee6;
  --bk-paper: #ffffff;
  --bk-accent: #0f766e;
  --bk-gold: #b45309;
  --bk-slate: #334155;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: #eef0f4;
  color: var(--bk-ink);
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

/* ============ Reader chrome (screen only) ============ */
.bk-topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 10px 14px;
  background: #fff;
  border-bottom: 1px solid var(--bk-line);
  box-shadow: 0 2px 10px rgba(15,23,42,.06);
}
.bk-topbar .bk-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 800;
  letter-spacing: -.01em;
}
.bk-topbar .bk-brand img { width: 26px; height: 26px; border-radius: 7px; }
.bk-spacer { flex: 1; }
.bk-toolbar {
  display: flex;
  gap: 6px;
  align-items: center;
  flex-wrap: wrap;
}
.bk-select {
  padding: 7px 10px;
  border: 1px solid var(--bk-line);
  border-radius: 9px;
  background: #fff;
  color: var(--bk-ink);
  font-size: 13px;
  font-weight: 600;
}
.bk-btn {
  padding: 8px 13px;
  border: 1px solid var(--bk-line);
  border-radius: 9px;
  background: #fff;
  color: var(--bk-slate);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
}
.bk-btn:hover { background: #f4f6f8; }
.bk-btn.primary { background: var(--bk-brand); border-color: var(--bk-brand); color: #fff; }
.bk-btn.primary:hover { background: #a70000; }
.bk-btn.ghost { background: transparent; }
.bk-btn.active { background: #eef2ff; border-color: #6366f1; color: #4f46e5; }

/* ============ Reader viewport ============ */
.bk-stage {
  padding: 18px;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.bk-paper {
  width: 100%;
  max-width: 944px;
  background: var(--bk-paper);
  border-radius: 6px;
  box-shadow: 0 10px 30px rgba(15,23,42,.14);
  padding: 0;
  overflow: hidden;
}

/* ============ Booklet pages ============ */
.bk-page {
  position: relative;
  padding: 40px 48px;
  min-height: 1280px; /* approx A4 portrait ratio at 944px width */
  page-break-after: always;
  break-after: page;
}
.bk-page:last-child { page-break-after: auto; break-after: auto; }
.bk-page-hd {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  border-bottom: 2px solid var(--bk-ink);
  padding-bottom: 8px;
  margin-bottom: 16px;
}
.bk-page-num { font-size: 12px; font-weight: 700; color: var(--bk-muted); }
.bk-section-kicker {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--bk-brand);
  margin-bottom: 3px;
}
.bk-page h2 {
  margin: 0 0 4px;
  font-size: 26px;
  line-height: 1.15;
  letter-spacing: -.01em;
}
.bk-page h3 {
  margin: 16px 0 8px;
  font-size: 18px;
  line-height: 1.2;
}
.bk-page p { margin: 0 0 8px; line-height: 1.5; color: var(--bk-slate); }
.bk-lead { font-size: 14px; color: var(--bk-muted); }

/* ============ Cover ============ */
.bk-cover {
  display: flex;
  flex-direction: column;
  min-height: 1280px;
  text-align: center;
  justify-content: center;
  gap: 18px;
}
.bk-cover .bk-cover-band {
  padding: 10px 20px;
  border-top: 4px solid var(--bk-brand);
  border-bottom: 4px solid var(--bk-brand);
  display: inline-block;
  align-self: center;
}
.bk-cover .bk-cover-logo {
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--bk-brand);
}
.bk-cover h1 { font-size: 42px; margin: 6px 0; line-height: 1.05; letter-spacing: -.02em; }
.bk-cover .bk-cover-aim { font-size: 22px; color: var(--bk-accent); font-weight: 700; }
.bk-cover .bk-cover-sub { font-size: 15px; color: var(--bk-muted); max-width: 560px; margin: 0 auto; }
.bk-cover .bk-cover-meta { margin-top: 30px; font-size: 14px; color: var(--bk-slate); }
.bk-cover .bk-cover-fields {
  margin-top: 40px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px 40px;
  text-align: left;
  max-width: 560px;
  margin-inline: auto;
}
.bk-cover .bk-field { border-bottom: 1.5px solid var(--bk-line); padding-bottom: 4px; font-size: 12px; color: var(--bk-muted); }
.bk-cover .bk-field b { display: block; font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--bk-slateslate, var(--bk-slate)); }

/* ============ Checklist ============ */
.bk-checklist { list-style: none; margin: 0; padding: 0; }
.bk-checklist > li { margin: 0 0 12px; }
.bk-cl-group {
  font-weight: 800;
  font-size: 15px;
  padding: 8px 10px;
  background: var(--bk-brand-soft);
  border-left: 4px solid var(--bk-brand);
  border-radius: 4px;
}
.bk-cl-item {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 5px 2px 5px 12px;
  font-size: 14px;
  line-height: 1.45;
}
.bk-cl-item .bk-tick {
  flex: 0 0 16px;
  width: 16px;
  height: 16px;
  margin-top: 2px;
  border: 1.6px solid var(--bk-slate);
  border-radius: 3px;
}

/* ============ Definition boxes ============ */
.bk-def {
  border: 1px solid var(--bk-line);
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 14px;
}
.bk-def-hd {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  background: #f7f9fb;
  border-bottom: 1px solid var(--bk-line);
  font-weight: 700;
}
.bk-def-hd .bk-code { font-size: 12px; color: var(--bk-brand); font-weight: 800; }
.bk-def-body { padding: 12px 16px; }
.bk-def-body .bk-term { font-weight: 800; font-size: 15px; margin-bottom: 4px; }
.bk-lines { height: 30px; border-bottom: 1px dotted #c3c9d2; }
.bk-lines.tall { height: 44px; }

/* ============ Match-up ============ */
.bk-match { display: grid; grid-template-columns: 1fr 1fr; gap: 0 8px; }
.bk-match-col { display: grid; gap: 6px; align-content: start; }
.bk-match-item {
  display: flex;
  gap: 8px;
  align-items: flex-start;
  padding: 8px 10px;
  border: 1px solid var(--bk-line);
  border-radius: 7px;
  font-size: 13px;
  line-height: 1.35;
  min-height: 40px;
}
.bk-match-item .bk-k { flex: 0 0 auto; font-weight: 800; color: var(--bk-brand); }

/* ============ Cloze (fill the gaps) + word bank + tables ============ */
.bk-cloze { line-height: 1.9; font-size: 15px; color: var(--bk-ink); margin-bottom: 14px; }
.bk-cloze .ans { color: var(--bk-accent); font-weight: 800; }
.bk-blank {
  display: inline-block;
  min-width: 110px;
  border-bottom: 1.6px solid var(--bk-ink);
  margin: 0 3px;
  padding: 0 4px;
}
.bk-wordbank {
  border: 2px solid var(--bk-brand);
  border-radius: 10px;
  padding: 12px 14px;
  margin-bottom: 18px;
  background: var(--bk-brand-soft);
}
.bk-wordbank-label {
  display: block;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--bk-brand);
  margin-bottom: 8px;
}
.bk-wordbank-chips { display: flex; flex-wrap: wrap; gap: 6px 8px; }
.bk-word-chip {
  display: inline-block;
  padding: 3px 10px;
  border: 1px solid #d9a1a1;
  border-radius: 999px;
  background: #fff;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--bk-ink);
}
/* ============ Design workshop workspace ============ */
.bk-scenario {
  border: 2px solid var(--bk-ink);
  border-left: 6px solid var(--bk-brand);
  border-radius: 8px;
  padding: 12px 16px;
  margin-bottom: 14px;
  font-size: 13.5px;
  line-height: 1.5;
  background: #fafafa;
}
.bk-scenario-aud { display: block; margin-top: 4px; color: var(--bk-muted); font-style: italic; }
.bk-task { font-weight: 700; font-size: 14.5px; color: var(--bk-ink); margin-bottom: 12px; }
.bk-grid-pad {
  min-height: 780px;
  margin: 16px 0;
  border: 2px dashed #b6bdc7;
  border-radius: 10px;
  background:
    linear-gradient(to right, #eef1f4 1px, transparent 1px),
    linear-gradient(to bottom, #eef1f4 1px, transparent 1px),
    #fff;
  background-size: 24px 24px;
}
.bk-table-lines {
  min-height: 780px;
  margin: 16px 0;
  border: 2px solid #b6bdc7;
  border-radius: 10px;
  background: repeating-linear-gradient(to bottom, #fff, #fff 34px, #d5dae2 35px);
}
.bk-table-lines::before {
  content: '';
  display: block;
  height: 34px;
  background: repeating-linear-gradient(to right, transparent, transparent 33%, #d5dae2 33%, #d5dae2 calc(33% + 1px));
}
.bk-table { width: 100%; border-collapse: collapse; margin: 10px 0 16px; font-size: 13.5px; }
.bk-table th, .bk-table td { border: 1px solid var(--bk-line); padding: 7px 9px; text-align: left; vertical-align: top; }
.bk-table th { background: #f7f9fb; font-size: 12px; text-transform: uppercase; letter-spacing: .04em; }
.bk-table .ans { color: var(--bk-accent); font-weight: 700; }

/* ============ MCQ ============ */
.bk-mcq { margin: 0 0 12px; padding: 12px 16px; border: 1px solid var(--bk-line); border-radius: 8px; }
.bk-mcq .bk-q { font-weight: 700; font-size: 14px; margin-bottom: 8px; }
.bk-mcq ol { list-style: none; margin: 0; padding: 0; }
.bk-mcq li { display: flex; gap: 10px; align-items: flex-start; padding: 4px 0; font-size: 13.5px; }
.bk-mcq .bk-letter { flex: 0 0 20px; width: 20px; height: 20px; border: 1.5px solid var(--bk-slate); border-radius: 50%; display: grid; place-items: center; font-size: 11px; font-weight: 800; }
.bk-qn { color: var(--bk-brand); font-weight: 800; margin: 14px 0 6px; font-size: 14px; }
.bk-answer-lines { border-bottom: 1px solid #d5dae2; height: 26px; }

/* ============ Diagram box ============ */
.bk-draw-box {
  border: 2px dashed #b6bdc7;
  border-radius: 10px;
  min-height: 300px;
  margin: 12px 0;
  padding: 10px;
  color: var(--bk-muted);
  font-size: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: repeating-linear-gradient(0deg, transparent, transparent 27px, #eef1f4 28px);
}
/* ============ Model-answer diagrams (mermaid + scaffolds) ============ */
.bk-diagram-media {
  margin: 10px 0 4px;
  background: #fff;
  border: 1px solid #dce3ea;
  border-radius: 8px;
  padding: 12px;
  overflow-x: auto;
  text-align: center;
}
.bk-diagram-media svg { max-width: 100%; height: auto; }
.bk-mermaid {
  margin: 10px 0 4px;
  background: #fff;
  border: 1px solid #dce3ea;
  border-radius: 8px;
  padding: 12px;
  overflow-x: auto;
  text-align: center;
}
.bk-mermaid svg { max-width: 100%; height: auto; }
.bk-mermaid.failed { display: none; }
.bk-wireframe-model { border: 1px solid #dce3ea; border-radius: 8px; overflow: hidden; margin-top: 8px; }
.bk-wf-row {
  display: flex;
  align-items: center;
  padding: 0 14px;
  border-bottom: 1px solid #e7ecf1;
  background: #fafbfc;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--bk-slate);
}
.bk-wf-row:nth-child(odd) { background: #f3f6f9; }
.bk-form-model { border: 1px solid #dce3ea; border-radius: 8px; overflow: hidden; margin-top: 8px; }
.bk-form-row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  padding: 8px 14px;
  border-bottom: 1px solid #e7ecf1;
  font-size: 13px;
}
.bk-form-row:last-child { border-bottom: none; }
.bk-form-field { font-weight: 700; min-width: 140px; }
.bk-form-type { color: var(--bk-muted); }
.bk-form-req { font-size: 10.5px; font-weight: 800; color: #b45309; background: #fff3e0; border-radius: 999px; padding: 1px 7px; }
.bk-form-val { font-size: 10.5px; font-weight: 700; color: #0f766e; background: #e6f6f3; border-radius: 999px; padding: 1px 7px; }

/* ============ Exam technique / model answer ============ */
.bk-tip {
  background: #fff8f1;
  border: 1px solid #f5d9b5;
  border-left: 5px solid var(--bk-gold);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 12px 0;
  font-size: 13.5px;
  line-height: 1.5;
}
.bk-tip b:first-child { color: var(--bk-gold); }
.bk-model {
  background: #f0fbf9;
  border: 1px solid #bfe6de;
  border-left: 5px solid var(--bk-accent);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 12px 0;
  font-size: 13.5px;
  line-height: 1.55;
}
.bk-model b:first-child { color: var(--bk-accent); }
.bk-marks { font-size: 12px; color: var(--bk-muted); margin-top: 6px; }
.bk-marks .mk { display: inline-block; background: var(--bk-brand-soft); color: var(--bk-brand); border-radius: 4px; padding: 1px 6px; font-weight: 700; }

/* ============ Assignment task structure (units 3 & 4) ============ */
.bk-taskcard {
  border: 1px solid var(--bk-line);
  border-radius: 9px;
  margin-bottom: 14px;
  overflow: hidden;
}
.bk-taskcard-hd {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  background: #f7f9fb;
  border-bottom: 1px solid var(--bk-line);
}
.bk-tasknum {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--bk-brand);
  color: #fff;
  font-weight: 800;
  font-size: 14px;
}
.bk-taskcard-hd strong { display: block; font-size: 14.5px; }
.bk-taskaim { font-size: 12px; color: var(--bk-muted); font-weight: 700; }
.bk-tasksteps { margin: 0; padding: 10px 14px 10px 34px; font-size: 13.5px; line-height: 1.55; }
.bk-tasksteps li { margin-bottom: 4px; }
.bk-distinction {
  margin: 0;
  padding: 10px 14px;
  background: #f6f0ff;
  border-top: 1px solid #e2d4ff;
  font-size: 13px;
  line-height: 1.5;
}
.bk-distinction b { color: #6d28d9; }

/* Solutions watermark */
.bk-solutions-badge {
  position: absolute;
  top: 26px;
  right: -34px;
  transform: rotate(36deg);
  background: var(--bk-accent);
  color: #fff;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .1em;
  text-transform: uppercase;
  padding: 6px 40px;
  opacity: .55;
}

/* ============ Print ============ */
@media print {
  body { background: #fff; }
  .bk-topbar, .bk-toolbar, .bk-btn, .bk-select { display: none !important; }
  .bk-stage { padding: 0; }
  .bk-paper { max-width: none; box-shadow: none; border-radius: 0; }
  .bk-page { min-height: auto; padding: 0; margin: 0; page-break-after: always; }
  .bk-page { width: 100%; }
}

/* ============ Mobile ============ */
@media (max-width: 640px) {
  .bk-stage { padding: 10px; }
  .bk-page { padding: 26px 20px; min-height: auto; }
  .bk-cover { min-height: auto; }
  .bk-cover h1 { font-size: 30px; }
  .bk-match { grid-template-columns: 1fr; }
  .bk-cover .bk-cover-fields { grid-template-columns: 1fr; }
  .bk-topbar { gap: 6px; }
  .bk-btn { padding: 7px 10px; }
}