:root {
  --blue: #149bd7;
  --ink: #102131;
  --line: #d8e2ea;
  --muted: #5c6b78;
  --paper: #ffffff;
  --wash: #edf5f9;
  --success: #167447;
  --warning: #a13a2d;
  --touch: 48px;
  --radius: 8px;
}

* { box-sizing: border-box; }

html,
body { width: 100%; min-height: 100%; margin: 0; color: var(--ink); background: var(--wash); font-family: Arial, Helvetica, sans-serif; }
button,
input,
select { font: inherit; }
button { min-height: var(--touch); }
body { min-height: 100dvh; }

@media (min-width: 861px) {
  html,
  body { height: 100%; overflow: hidden; }
  .mental-strategies-page .app { height: 100dvh; min-height: 0; }
}

.mental-strategies-page .app { min-height: 100dvh; display: grid; grid-template-rows: auto minmax(0, 1fr); }
.topbar { display: grid; grid-template-columns: minmax(220px, 1fr) auto; align-items: center; gap: 16px; min-height: 72px; padding: 12px 18px; color: #fff; background: #071018; }
.brand,
.top-actions,
.toolbar,
.toolbar-group,
.mental-stage-heading { display: flex; align-items: center; }
.brand { min-width: 0; gap: 14px; }
.brand-logo { display: inline-flex; border-radius: 6px; }
.brand-logo img { width: 142px; height: auto; display: block; }
.brand h1 { margin: 0; font-size: clamp(1.35rem, 2vw, 2.05rem); line-height: 1.05; }
.top-actions { justify-content: flex-end; gap: 8px; }
.icon-button,
.home-button { min-width: var(--touch); min-height: var(--touch); display: inline-grid; place-items: center; padding: 0 12px; border: 2px solid #263d51; border-radius: var(--radius); color: #fff; background: #122436; font-weight: 800; text-decoration: none; cursor: pointer; }
.icon-button { width: var(--touch); padding: 0; }
.icon-button:hover,
.icon-button:focus-visible,
.home-button:hover,
.home-button:focus-visible { border-color: #8fd8f3; background: var(--blue); color: #06111a; }
.icon { width: 24px; height: 24px; display: block; pointer-events: none; }

.mental-strategies-tool { min-height: 0; display: grid; grid-template-rows: auto minmax(0, 1fr); }
.mental-strategies-tool [hidden] { display: none !important; }
.mental-toolbar { z-index: 4; align-items: flex-end; gap: 10px; min-height: 64px; padding: 8px 14px; border-bottom: 1px solid var(--line); background: #fff; overflow: visible; }
.toolbar-group { gap: 8px; flex-wrap: wrap; }
.mental-toolbar .toolbar-group { align-items: flex-end; }
.mental-toolbar-actions { margin-left: auto; }
.control-group { display: inline-grid; gap: 2px; font-weight: 800; }
.control-label { color: var(--muted); font-size: .7rem; letter-spacing: .04em; text-transform: uppercase; }
.compact-select,
.mental-equation-entry select,
.mental-equation-entry input,
.mental-answer-region input { min-height: var(--touch); border: 1px solid #b9c9d5; border-radius: var(--radius); color: var(--ink); background: #fff; font-weight: 800; }
.compact-select { padding: 0 38px 0 12px; }
.mental-toolbar button,
.mental-toolbar summary,
.wide-button,
.mental-stage-action button,
.mental-answer-region button { min-height: var(--touch); display: inline-flex; align-items: center; justify-content: center; padding: 0 16px; border: 1px solid #b9c9d5; border-radius: var(--radius); color: var(--ink); background: #fff; font-weight: 800; cursor: pointer; }
.mental-toolbar button.primary,
.wide-button.primary,
.mental-answer-region button.primary { border-color: var(--blue); color: #fff; background: var(--blue); }
button:disabled { opacity: .45; cursor: not-allowed; }

.tool-menu { position: relative; }
.tool-menu summary { list-style: none; }
.tool-menu summary::-webkit-details-marker { display: none; }
.tool-menu[open] summary { border-color: var(--blue); background: #eef8fc; }
.menu-panel { position: absolute; top: calc(100% + 8px); left: 0; z-index: 20; width: min(330px, calc(100vw - 28px)); max-height: min(480px, 72vh); overflow: auto; padding: 12px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; box-shadow: 0 14px 32px rgba(7, 16, 24, .18); }
.mental-questions-menu .menu-panel { left: 0; right: auto; }
.mental-teaching-panel { width: min(360px, calc(100vw - 28px)); }
.mental-teaching-panel fieldset { margin: 0; padding: 0; border: 0; }
.mental-menu-panel fieldset { margin: 0; padding: 0; border: 0; }
.mental-teaching-panel fieldset + fieldset { margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--line); }
.mental-menu-panel fieldset + fieldset { margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--line); }
.mental-teaching-panel legend,
.mental-menu-panel legend { margin-bottom: 5px; color: var(--muted); font-size: .78rem; font-weight: 900; text-transform: uppercase; }
.mental-menu-choice { min-height: 42px; display: flex; align-items: center; gap: 10px; padding: 7px 8px; border-radius: 6px; font-weight: 750; cursor: pointer; }
.mental-menu-choice:hover { background: #eef8fc; }
.mental-menu-choice input { width: 22px; height: 22px; margin: 0; accent-color: var(--blue); }

.mental-workspace { min-width: 0; min-height: 0; display: grid; grid-template-columns: minmax(310px, 360px) minmax(0, 1fr); gap: 12px; padding: 12px; overflow: auto; }
.mental-strategies-tool.is-editor-mode .mental-canvas { grid-column: 1 / -1; }
.mental-controls-panel,
.mental-canvas { min-width: 0; min-height: 0; border: 1px solid var(--line); border-radius: var(--radius); background: var(--paper); }
.mental-controls-panel { align-self: start; padding: 10px; display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.mental-stage:not(.mental-stage-action),
.mental-feedback { grid-column: 1 / -1; }
.mental-stage { padding: 11px; border: 1px solid var(--line); border-left: 4px solid #c4d1da; border-radius: var(--radius); background: #fff; }
.mental-stage[data-status="active"] { border-left-color: var(--blue); background: #f6fbfe; }
.mental-stage[data-status="complete"] { border-left-color: var(--success); }
.mental-stage[data-status="waiting"] { color: #657581; background: #f8fafb; }
.mental-stage-heading { align-items: flex-start; gap: 10px; }
.mental-stage-heading h2 { margin: 4px 0 0; font-size: 1rem; line-height: 1.2; }
.mental-stage-heading p { margin: 5px 0 0; color: var(--muted); font-size: .9rem; line-height: 1.35; }
.mental-stage-number { width: 30px; height: 30px; flex: 0 0 30px; display: inline-grid; place-items: center; border-radius: 6px; color: #fff; background: #718492; font-weight: 900; }
.mental-stage[data-status="active"] .mental-stage-number { background: var(--blue); }
.mental-stage[data-status="complete"] .mental-stage-number { background: var(--success); }
.mental-strategy-choices { margin: 10px 0 0; padding: 0; border: 0; }
.mental-choice { display: block; margin-top: 6px; cursor: pointer; }
.mental-choice input { position: absolute; opacity: 0; }
.mental-choice span { min-height: var(--touch); display: flex; align-items: center; padding: 9px 11px; border: 1px solid #b9c9d5; border-radius: var(--radius); color: var(--ink); background: #fff; line-height: 1.25; }
.mental-comparison-choices .mental-choice span { align-items: flex-start; flex-direction: column; gap: 3px; }
.mental-choice small { color: var(--muted); font-size: .78rem; font-weight: 650; }
.mental-choice:hover span,
.mental-choice input:focus-visible + span { border-color: var(--blue); outline: 3px solid rgba(20, 155, 215, .2); }
.mental-choice.is-selected span { border: 2px solid var(--blue); background: #eef8fc; }
.mental-stage > #mentalHint { min-height: var(--touch); width: 100%; margin-top: 9px; border: 1px solid #b9c9d5; border-radius: var(--radius); background: #fff; font-weight: 800; }
.mental-answer-region { margin-top: 10px; display: grid; grid-template-columns: minmax(0, 1fr) minmax(96px, .55fr) auto; gap: 8px; align-items: end; }
.mental-answer-region input { width: 100%; padding: 0 12px; font-size: 1.1rem; }
.mental-remainder-field { display: grid; gap: 3px; color: var(--muted); font-size: .72rem; font-weight: 850; }
.mental-remainder-field input { color: var(--ink); font-size: 1.1rem; }
.mental-stage-action { min-width: 0; }
.mental-strategies-tool.has-comparison-task #mentalStageCompare { grid-column: 1 / -1; }
.mental-strategies-tool.is-comparison-active #mentalStageChoose .mental-stage-heading p,
.mental-strategies-tool.is-comparison-active #mentalStageChoose .mental-strategy-choices,
.mental-strategies-tool.is-comparison-active #mentalStageChoose > #mentalHint,
.mental-strategies-tool.is-comparison-active #mentalStageCalculate .mental-answer-region,
.mental-strategies-tool.is-comparison-active #mentalStageReveal > button { display: none; }
.mental-strategies-tool.is-comparison-active .mental-stage:not(#mentalStageCompare) { padding: 5px 7px; }
.mental-strategies-tool.is-comparison-active #mentalStageCompare { padding: 7px; }
.mental-strategies-tool.is-comparison-active #mentalStageCompare > #mentalComparisonPrompt > p { margin: 6px 0; font-size: .86rem; }
.mental-strategies-tool.is-comparison-active #mentalStageCompare .mental-choice { margin-top: 4px; }
.mental-strategies-tool.is-comparison-active #mentalStageCompare .mental-choice span { padding: 6px 9px; line-height: 1.15; }
.mental-strategies-tool.is-comparison-active #mentalStageCompare .mental-choice small { font-size: .72rem; line-height: 1.15; }
.mental-strategies-tool.is-comparison-active #mentalStageCompare > button { margin-top: 6px; }
.mental-comparison-choices { margin: 8px 0 0; padding: 0; border: 0; }
.mental-stage-action .mental-stage-heading { align-items: center; }
.mental-stage-action button { width: 100%; margin-top: 10px; padding-inline: 8px; }
.mental-stage-action[data-status="active"] button { border-color: var(--blue); }
.mental-feedback { min-height: 46px; margin: 0; padding: 10px 12px; border-radius: var(--radius); background: #f4f7f9; font-weight: 800; line-height: 1.35; }
.mental-feedback:empty { min-height: 0; padding: 0; }
.mental-feedback[data-tone="correct"] { color: var(--success); background: #eef8f2; }
.mental-feedback[data-tone="incorrect"] { color: var(--warning); background: #fff4f2; }

.mental-canvas { position: relative; display: grid; grid-template-rows: auto minmax(0, 1fr); overflow: auto; }
.mental-prompt-panel { padding: clamp(16px, 2vw, 24px); border-bottom: 1px solid var(--line); }
.mental-prompt-label { color: var(--muted); font-size: .76rem; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.mental-prompt-panel h2 { max-width: 38ch; margin: 8px 0 0; font-size: clamp(1.35rem, 2.2vw, 2rem); line-height: 1.15; }
.mental-reasoning { min-height: 360px; display: grid; align-content: start; gap: 14px; padding: clamp(16px, 2vw, 24px); }
.mental-reasoning-placeholder { align-self: center; justify-self: center; max-width: 32ch; margin: auto; color: var(--muted); text-align: center; font-size: 1.05rem; line-height: 1.45; }
.mental-transformation ol { margin: 0; padding: 0; display: grid; gap: 8px; list-style: none; }
.mental-transformation li { min-height: var(--touch); display: flex; align-items: center; padding: 9px 13px; border-left: 4px solid var(--blue); border-radius: 0 var(--radius) var(--radius) 0; background: #f2f8fb; font-size: clamp(1.05rem, 1.8vw, 1.4rem); font-weight: 850; }
.mental-model-panel { min-height: 250px; overflow: auto; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
#mentalModelHost { width: 100%; min-height: 248px; display: grid; place-items: stretch; }
#mentalModelHost > * { width: 100%; max-width: none; }
#mentalModelHost figure { margin: 0; max-width: 100%; }
.mental-explanation { padding: 14px 16px; border-left: 4px solid #f4bd3c; border-radius: 0 var(--radius) var(--radius) 0; background: #fff8df; line-height: 1.5; }
.mental-explanation p { margin: 7px 0 0; }
.mental-related-link { color: #086c99; font-weight: 900; }
.mental-print-brand { display: none; }

.mental-custom-editor { width: min(760px, calc(100% - 32px)); align-self: start; justify-self: center; margin: 24px; padding: 18px; border: 1px solid var(--line); border-radius: var(--radius); background: #f7fbfd; }
.mental-custom-editor h2 { margin: 0 0 14px; }
.mental-equation-entry { display: grid; grid-template-columns: minmax(110px, 1fr) 84px minmax(110px, 1fr); gap: 10px; align-items: end; }
.mental-equation-entry label { display: grid; gap: 5px; font-weight: 800; }
.mental-equation-entry label > span { color: var(--muted); font-size: .8rem; }
.mental-equation-entry input,
.mental-equation-entry select { width: 100%; padding: 0 10px; font-size: 1.05rem; }
.mental-equation-entry .mental-third-toggle { grid-column: 1 / -1; min-height: var(--touch); display: flex; align-items: center; gap: 8px; }
.mental-third-toggle input { width: 24px; height: 24px; min-height: 0; }
.mental-equation-entry #mentalThirdField { grid-column: 1 / 3; }
.mental-equation-entry .wide-button { grid-column: 1 / -1; }
.mental-custom-feedback { min-height: 1.4em; margin: 9px 0 0; color: var(--muted); font-weight: 750; }
.mental-custom-summary { position: absolute; top: 12px; right: 12px; z-index: 2; }
.mental-custom-summary > span { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

.instructions-dialog { width: min(680px, calc(100vw - 32px)); max-height: min(760px, calc(100vh - 32px)); padding: 0; border: 0; border-radius: var(--radius); color: var(--ink); box-shadow: 0 24px 64px rgba(7, 16, 24, .35); }
.instructions-dialog::backdrop { background: rgba(7, 16, 24, .58); }
.instructions-header { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 16px 18px; color: #fff; background: #071018; }
.instructions-header h2 { margin: 0; }
.instructions-body { padding: 18px; line-height: 1.55; overflow: auto; }
.instructions-body li { margin: 7px 0; }
.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; }
button:focus-visible,
select:focus-visible,
input:focus-visible,
a:focus-visible,
summary:focus-visible { outline: 4px solid rgba(20, 155, 215, .35); outline-offset: 3px; }

@media (max-width: 860px) {
  html,
  body { height: auto; overflow: auto; }
  .mental-strategies-page .app { display: block; }
  .topbar { grid-template-columns: 1fr; }
  .top-actions { justify-content: flex-start; flex-wrap: wrap; }
  .mental-strategies-tool { display: block; }
  .mental-toolbar { align-items: stretch; flex-direction: column; }
  .mental-toolbar-actions { margin-left: 0; }
  .toolbar-group > button,
  .toolbar-group > details { flex: 1 1 145px; }
  .tool-menu summary { justify-content: center; }
  .mental-questions-menu .menu-panel { left: 0; right: auto; }
  .mental-workspace { grid-template-columns: 1fr; overflow: visible; }
  .mental-controls-panel { grid-template-columns: 1fr 1fr; }
  .mental-canvas { min-height: 520px; }
}

@media (max-width: 560px) {
  .brand { align-items: flex-start; flex-direction: column; gap: 8px; }
  .toolbar-group { width: 100%; }
  .control-group { width: 100%; }
  .compact-select { width: 100%; }
  .mental-workspace { padding: 8px; }
  .mental-equation-entry { grid-template-columns: 1fr 74px; }
  .mental-equation-entry label:nth-child(3) { grid-column: 1 / -1; }
  .mental-equation-entry #mentalThirdField { grid-column: 1 / -1; }
  .mental-answer-region { grid-template-columns: 1fr; }
  .mental-controls-panel { grid-template-columns: 1fr; }
  .mental-stage,
  .mental-feedback { grid-column: 1; }
}

@page { size: A4 landscape; margin: 8mm; }
@media print {
  html,
  body { width: 100%; height: auto; min-height: 0; overflow: visible; background: #fff; }
  .topbar,
  .mental-toolbar,
  .mental-controls-panel,
  .mental-custom-editor,
  .mental-custom-summary,
  .instructions-dialog { display: none !important; }
  .mental-strategies-page .app,
  .mental-strategies-tool,
  .mental-workspace { display: block; width: 100%; min-height: 0; height: auto; padding: 0; }
  .mental-canvas { height: 174mm; border: 0; overflow: hidden; }
  .mental-prompt-panel { padding: 4mm 5mm; }
  .mental-prompt-panel h2 { max-width: none; font-size: 16pt; }
  .mental-reasoning { min-height: 0; padding: 4mm 5mm 13mm; gap: 3mm; }
  .mental-reasoning-placeholder { display: none; }
  .mental-transformation li { min-height: 0; padding: 2mm 3mm; font-size: 11.5pt; }
  .mental-model-panel,
  #mentalModelHost { min-height: 68mm; overflow: hidden; }
  .mental-explanation { padding: 3mm 4mm; font-size: 10pt; }
  .mental-print-brand { height: 12mm; display: flex; align-items: center; justify-content: space-between; padding-top: 2mm; font-size: 9pt; font-weight: 800; }
  .mental-print-logo { width: 42mm; height: 9mm; object-fit: contain; object-position: left center; }
}