:root {
  --cr-blue: #149bd7;
  --cr-blue-dark: #0c7fb1;
  --cr-ink: #102131;
  --cr-muted: #526676;
  --cr-line: #c8d8e2;
  --cr-surface: #ffffff;
  --cr-canvas: #edf5f9;
  --cr-success: #16734a;
  --cr-error: #a12828;
  --cr-hint: #8a5a00;
  --cr-touch: 48px;
}

* { box-sizing: border-box; }
html, body { min-height: 100%; }
body { margin: 0; color: var(--cr-ink); background: var(--cr-canvas); font-family: Arial, Helvetica, sans-serif; }
button, input { font: inherit; }
button { min-height: var(--cr-touch); }
.app { min-height: 100vh; display: grid; grid-template-rows: auto minmax(0, 1fr); }
.topbar { min-height: 72px; display: grid; grid-template-columns: minmax(250px, 1fr) auto; align-items: center; gap: 16px; padding: 11px 18px; color: #fff; background: #071018; }
.brand { min-width: 0; display: flex; align-items: center; gap: 14px; }
.brand-logo { display: inline-flex; border-radius: 6px; }
.brand h1 { margin: 0; font-size: clamp(1.3rem, 2vw, 2rem); line-height: 1.08; }
.top-actions { display: flex; align-items: center; justify-content: flex-end; gap: 8px; }
.icon-button, .home-button { min-width: var(--cr-touch); min-height: var(--cr-touch); display: inline-grid; place-items: center; padding: 0 14px; border: 2px solid #263d51; border-radius: 8px; color: #fff; background: #122436; font-weight: 800; text-decoration: none; cursor: pointer; }
.icon-button { width: var(--cr-touch); padding: 0; }
.icon-button:hover, .icon-button:focus-visible, .home-button:hover, .home-button:focus-visible { border-color: #8fd8f3; color: #06111a; background: var(--cr-blue); }
.icon { width: 24px; height: 24px; pointer-events: none; }

.cr-app { min-height: calc(100vh - 72px); display: grid; grid-template-rows: auto minmax(0, 1fr); background: var(--cr-canvas); }
.cr-toolbar { min-height: 66px; display: flex; align-items: center; gap: 10px; padding: 8px 14px; border-bottom: 1px solid var(--cr-line); background: #fff; overflow: visible; }
.cr-toolbar .toolbar-group { min-width: 0; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.cr-toolbar .toolbar-group.questions { margin-left: auto; justify-content: flex-end; }
.cr-toolbar-extra { display: contents; }
.cr-toolbar button, .cr-toolbar summary, .cr-actions button { min-height: var(--cr-touch); display: inline-flex; align-items: center; justify-content: center; padding: 0 15px; border: 1px solid #aebfca; border-radius: 8px; color: var(--cr-ink); background: #fff; font-weight: 800; cursor: pointer; }
.cr-toolbar button.primary, .cr-actions button.primary { border-color: var(--cr-blue-dark); color: #fff; background: var(--cr-blue); }
.cr-toolbar button:hover, .cr-toolbar button:focus-visible, .cr-toolbar summary:hover, .cr-toolbar summary:focus-visible, .cr-actions button:hover, .cr-actions button:focus-visible { border-color: var(--cr-blue-dark); box-shadow: 0 0 0 3px rgba(20, 155, 215, .18); }
.cr-menu { position: relative; }
.cr-menu > summary { list-style: none; }
.cr-menu > summary::-webkit-details-marker { display: none; }
.cr-menu[open] > summary { border-color: var(--cr-blue-dark); background: #eaf7fc; }
.cr-menu .menu-panel { position: absolute; z-index: 30; top: calc(100% + 7px); left: 0; width: min(310px, calc(100vw - 24px)); padding: 12px; border: 1px solid var(--cr-line); border-radius: 8px; background: #fff; box-shadow: 0 16px 38px rgba(7, 16, 24, .2); }
.cr-menu .cr-questions-menu { width: min(680px, calc(100vw - 24px)); display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
.cr-menu fieldset { display: grid; gap: 7px; margin: 0; padding: 0; border: 0; }
.cr-menu legend { margin-bottom: 5px; color: var(--cr-muted); font-size: .85rem; font-weight: 800; text-transform: uppercase; letter-spacing: .04em; }
.cr-menu label { min-height: 45px; display: flex; align-items: center; gap: 10px; padding: 8px 10px; border: 1px solid var(--cr-line); border-radius: 7px; cursor: pointer; }
.cr-menu label:has(input:checked) { border-color: var(--cr-blue-dark); background: #eaf7fc; }
.cr-menu input { width: 20px; height: 20px; }

.cr-workspace { min-width: 0; min-height: 0; display: grid; grid-template-columns: minmax(0, 1.45fr) minmax(310px, .75fr); grid-template-rows: auto minmax(0, 1fr) auto; gap: 10px; padding: 10px 12px 12px; }
.cr-task-header { grid-column: 1 / -1; display: flex; align-items: baseline; gap: 14px; padding: 8px 14px; border: 1px solid var(--cr-line); border-radius: 8px; background: #fff; }
.cr-task-header span { flex: 0 0 auto; color: var(--cr-blue-dark); font-weight: 800; }
.cr-task-header h2 { margin: 0; font-size: clamp(1.15rem, 2vw, 1.65rem); line-height: 1.2; }
.cr-reasoning-panel, .cr-response-panel { min-width: 0; min-height: 0; border: 1px solid var(--cr-line); border-radius: 8px; background: #fff; box-shadow: 0 5px 18px rgba(20, 58, 80, .07); }
.cr-reasoning-panel { display: grid; align-content: center; gap: 10px; padding: clamp(10px, 1.6vw, 20px); overflow: hidden; }
.cr-sentence-model { height: clamp(120px, 16vh, 210px); min-height: 0; display: grid; place-items: stretch; }
.cr-sentence-model figure, .cr-sentence-model .diagram-frame, .cr-sentence-model svg { width: 100%; max-width: none; min-height: 0; height: 100%; margin: 0; }
.cr-reasoning-panel.is-sentence-only .cr-sentence-model { height: clamp(210px, 34vh, 320px); }
.cr-sentence-model .comparison-sentence-visual text { font-weight: 800; }
.cr-support { display: grid; gap: 8px; }
.cr-support-model { height: clamp(218px, 28vh, 270px); min-height: 0; display: grid; place-items: stretch; overflow: hidden; }
.cr-support-model figure, .cr-support-model .diagram-frame, .cr-support-model svg { width: 100%; max-width: none; height: 100%; min-height: 0; margin: 0; }
.cr-hint, .cr-reveal { padding: 10px 12px; border: 1px solid #e0b550; border-radius: 7px; background: #fff8e6; line-height: 1.4; }
.cr-reveal { border-color: #79bd9c; background: #edf9f3; }
.cr-reveal strong { display: block; font-size: clamp(1.05rem, 1.8vw, 1.35rem); }
.cr-reveal p { margin: 6px 0 0; }

.cr-response-panel { display: grid; align-content: start; gap: 12px; padding: 14px; overflow: auto; }
.cr-response-group, .cr-reason-group { min-width: 0; margin: 0; padding: 0; border: 0; }
.cr-response-group legend, .cr-reason-group legend { margin-bottom: 8px; font-weight: 800; }
.cr-choice-row { display: flex; gap: 8px; flex-wrap: wrap; }
.cr-symbol-choices button { flex: 1 1 72px; min-height: 58px; border: 2px solid var(--cr-line); border-radius: 8px; color: var(--cr-ink); background: #fff; font-size: 1.65rem; font-weight: 800; cursor: pointer; }
.cr-symbol-choices button[aria-pressed="true"] { border-color: var(--cr-blue-dark); color: #05394f; background: #dff4fc; box-shadow: inset 0 0 0 2px #fff; }
.cr-number-response { display: grid; gap: 7px; font-weight: 800; }
.cr-number-response input { width: min(100%, var(--cr-number-capacity, 12ch)); min-width: 7ch; min-height: 58px; padding: 8px 12px; border: 2px solid #8ca8b9; border-radius: 8px; color: var(--cr-ink); background: #fff; font-size: clamp(1.25rem, 2.5vw, 1.7rem); font-weight: 800; font-variant-numeric: tabular-nums; }
.cr-number-response input:focus { border-color: var(--cr-blue-dark); outline: 3px solid rgba(20, 155, 215, .18); }
.cr-reason-options { display: grid; gap: 8px; }
.cr-reason-options label { min-height: 48px; display: grid; grid-template-columns: 22px minmax(0, 1fr); align-items: start; gap: 9px; padding: 9px 10px; border: 1px solid var(--cr-line); border-radius: 7px; background: #fff; line-height: 1.3; cursor: pointer; }
.cr-reason-options label:has(input:checked) { border-color: var(--cr-blue-dark); background: #edf8fc; }
.cr-reason-options input { width: 20px; height: 20px; margin: 1px 0 0; }
.cr-actions { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; }
.cr-feedback { grid-column: 1 / -1; min-height: 48px; display: flex; align-items: center; margin: 0; padding: 10px 14px; border: 1px solid var(--cr-line); border-radius: 8px; background: #fff; font-weight: 800; line-height: 1.3; }
.cr-feedback[data-tone="success"] { border-color: #68b18d; color: var(--cr-success); background: #edf9f3; }
.cr-feedback[data-tone="error"] { border-color: #d99a9a; color: var(--cr-error); background: #fff2f2; }
.cr-feedback[data-tone="hint"] { border-color: #e0b550; color: var(--cr-hint); background: #fff8e6; }
.visually-hidden { position: absolute !important; width: 1px !important; height: 1px !important; padding: 0 !important; margin: -1px !important; overflow: hidden !important; clip: rect(0, 0, 0, 0) !important; white-space: nowrap !important; border: 0 !important; }

.instructions-dialog { width: min(680px, calc(100vw - 28px)); max-height: min(760px, calc(100vh - 28px)); padding: 0; border: 0; border-radius: 9px; color: var(--cr-ink); background: #fff; box-shadow: 0 24px 65px rgba(7, 16, 24, .36); }
.instructions-dialog::backdrop { background: rgba(7, 16, 24, .6); }
.instructions-header { min-height: 64px; display: flex; align-items: center; justify-content: space-between; gap: 14px; padding: 10px 14px; color: #fff; background: #071018; }
.instructions-header h2 { margin: 0; }
.instructions-body { padding: 16px 18px; line-height: 1.5; overflow: auto; }
.instructions-body h3 { margin: 18px 0 6px; }
.instructions-body p, .instructions-body ul { margin-top: 6px; }

@media (min-width: 901px) {
  .cr-app { height: calc(100vh - 72px); overflow: hidden; }
  .cr-reasoning-panel.has-guidance:not(.is-sentence-only) .cr-sentence-model { height: 98px; }
}

@media (max-width: 900px) {
  .app, .cr-app { display: block; min-height: 0; }
  .topbar { grid-template-columns: 1fr; }
  .top-actions { justify-content: flex-start; flex-wrap: wrap; }
  .cr-toolbar { align-items: stretch; flex-direction: column; }
  .cr-toolbar .toolbar-group.questions { margin-left: 0; justify-content: flex-start; }
  .cr-toolbar .cr-menu, .cr-toolbar button { flex: 1 1 140px; }
  .cr-toolbar summary { width: 100%; }
  .cr-workspace { display: grid; grid-template-columns: 1fr; grid-template-rows: auto auto auto auto; }
  .cr-task-header, .cr-feedback { grid-column: 1; }
  .cr-reasoning-panel, .cr-response-panel { overflow: visible; }
}

@media (max-width: 520px) {
  .topbar { padding: 10px 12px; }
  .brand { gap: 9px; }
  .brand h1 { font-size: 1.2rem; }
  .top-actions { gap: 6px; }
  .home-button { padding-inline: 10px; }
  .cr-toolbar { padding: 8px; }
  .cr-toolbar .toolbar-group { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); width: 100%; }
  .cr-toolbar .toolbar-group.questions { grid-template-columns: 1fr; }
  .cr-toolbar .cr-menu, .cr-toolbar button { min-width: 0; width: 100%; }
  .cr-menu .menu-panel { position: fixed; top: auto; left: 8px; right: 8px; width: auto; }
  .cr-menu .cr-questions-menu { max-height: calc(100vh - 120px); grid-template-columns: 1fr; overflow: auto; }
  .cr-task-header { display: grid; gap: 5px; }
  .cr-workspace { padding: 8px; }
  .cr-reasoning-panel, .cr-response-panel { padding: 10px; }
  .cr-sentence-model { height: 125px; }
  .cr-actions { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  .cr-app * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}

@media print {
  @page { size: A4 landscape; margin: 8mm; }
  html, body, .app, .cr-app { width: 100%; min-height: 0 !important; height: auto !important; background: #fff !important; }
  .topbar, .cr-toolbar, .cr-response-panel, .cr-feedback, .instructions-dialog, .classroom-tools-layer, .annotation-toolbar, .setup-share-dialog { display: none !important; }
  .cr-workspace { display: block; padding: 0 0 13mm; }
  .cr-task-header { margin-bottom: 4mm; border: 0; padding: 0; }
  .cr-reasoning-panel { min-height: 142mm; display: grid; align-content: center; gap: 4mm; overflow: hidden; border: 1px solid #9eb1bd; box-shadow: none; padding: 7mm; break-inside: avoid; }
  .cr-sentence-model, .cr-sentence-model .diagram-frame, .cr-sentence-model svg { min-height: 50mm; }
  .cr-support-model, .cr-support-model .diagram-frame, .cr-support-model svg { min-height: 48mm; max-height: 60mm; }
}