/* Practice and Check use the design-system 2.9 tokens from system.css. The two
   replaceable workspace hosts intentionally keep their own component boundaries. */

body.practice-check-active #offline-banner { display: none !important; }
.practice-check-view { --pc-max: 1040px; width: min(100%, var(--pc-max)); margin: 0 auto; padding-bottom: var(--space-8, 56px); }
.practice-check-view button, .practice-check-view textarea, .practice-check-view select { font-family: var(--display); }
.practice-check-view :where(button, textarea, select, summary):focus-visible,
.exercise-dialog :where(button, textarea):focus-visible,
.check-history-dialog :where(button, summary):focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

/* Product navigation */
.product-tabs .nav-btn { display: inline-flex; align-items: center; justify-content: center; gap: 7px; }
.product-tabs .nav-btn .ui-icon { display: none; width: 18px; height: 18px; }

/* Shared entry pages */
.pc-home { display: grid; gap: clamp(28px, 5vw, 54px); }
.pc-hero { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(300px, .85fr); align-items: end; gap: clamp(24px, 5vw, 64px); padding: clamp(24px, 4vw, 48px) 0 clamp(28px, 5vw, 56px); border-bottom: 1px solid var(--line); }
.pc-hero .editorial-title { max-width: 720px; margin-top: 9px; }
.pc-hero .page-lede { max-width: 650px; margin-top: 14px; }
.pc-eyebrow, .section-kicker, .submit-kicker { display: block; color: var(--subtle); font: 600 11px/1.2 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.pc-eyebrow { color: var(--accent); }
.pc-how { display: grid; gap: 0; margin: 0; padding: 0; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--panel); list-style: none; overflow: hidden; }
.pc-how li { display: grid; grid-template-columns: 34px 1fr; align-items: center; gap: 10px; min-height: 52px; padding: 10px 16px; }
.pc-how li + li { border-top: 1px solid var(--line); }
.pc-how b { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--panel-3); color: var(--accent); font: 600 12px var(--mono); }
.pc-how span { color: var(--text); font: 500 14px/1.35 var(--display); }
.format-strip { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.format-strip span { display: flex; align-items: center; gap: 9px; min-height: 48px; padding: 10px 12px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel); color: var(--muted); font: 500 13px/1.25 var(--display); }
.format-strip .ui-icon { width: 18px; height: 18px; color: var(--accent); }
.pc-subjects { margin-top: 0; }
.pc-subjects .section-bar { margin-bottom: 17px; }
.pc-subjects .section-bar h2 { margin-top: 5px; }
.pc-subject-grid { grid-template-columns: repeat(2, minmax(0, 1fr)) !important; gap: 12px !important; }
.pc-subject-card { position: relative; display: grid !important; grid-template-columns: 48px minmax(0, 1fr) auto !important; align-items: center; gap: 14px; min-height: 132px; padding: 18px !important; border: 1px solid var(--line) !important; border-radius: var(--radius-lg) !important; background: var(--panel) !important; color: var(--text); text-align: left; box-shadow: none !important; cursor: pointer; }
.pc-subject-card:hover { border-color: var(--field-line) !important; background: var(--panel-2) !important; transform: translateY(-1px); }
.pc-subject-card:disabled { cursor: default; opacity: .58; transform: none; }
.pc-subject-card .subject-monogram { width: 48px; height: 48px; border: 1px solid var(--line-2); border-radius: 14px; background: var(--panel-3); color: var(--accent); font: 600 12px var(--mono); }
.pc-subject-copy { min-width: 0; display: grid; gap: 5px; }
.pc-subject-copy strong { color: var(--text); font: 650 18px/1.2 var(--display); }
.pc-subject-copy em { overflow: hidden; color: var(--muted); font: 400 13px/1.35 var(--display); text-overflow: ellipsis; white-space: nowrap; }
.pc-subject-copy small { color: var(--subtle); font: 500 12px/1.35 var(--mono); }
.pc-subject-action { display: inline-flex; align-items: center; gap: 6px; align-self: end; color: var(--accent); font: 600 12px/1.2 var(--display); white-space: nowrap; }
.pc-subject-action .ui-icon { width: 16px; height: 16px; }
.usage-note, .pc-connectivity { align-items: center; gap: 10px; padding: 12px 14px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel-2); color: var(--muted); font: 500 13px/1.45 var(--display); }
.usage-note:not(.hidden), .pc-connectivity:not(.hidden) { display: flex; }
.pc-connectivity { margin-bottom: 16px; border-color: var(--warn); background: var(--warn-surface); color: var(--text); }
.pc-connectivity .ui-icon, .usage-note .ui-icon { flex: none; width: 18px; height: 18px; }

/* Subject workspace and scope */
.pc-subject-workspace, .check-subject-workspace { display: grid; gap: 28px; }
.pc-workspace-head { display: grid; grid-template-columns: auto minmax(0, 1fr); align-items: start; gap: 16px 20px; padding: 8px 0 26px; border-bottom: 1px solid var(--line); }
.pc-workspace-title { min-width: 0; }
.pc-workspace-title h1 { margin: 4px 0 5px; color: var(--text); font: 650 clamp(28px, 4vw, 44px)/1.05 var(--display); letter-spacing: -.035em; }
.pc-workspace-title p { margin: 0; color: var(--muted); font: 400 15px/1.45 var(--display); }
.back-chip { display: inline-flex; align-items: center; justify-content: center; gap: 6px; min-height: var(--touch, 44px); padding: 0 12px; border: 1px solid var(--line); border-radius: 999px; background: var(--panel); color: var(--muted); font: 600 13px var(--display); cursor: pointer; }
.back-chip:hover { color: var(--text); border-color: var(--field-line); }
.back-chip .ui-icon { width: 16px; height: 16px; }
.check-workspace-head { grid-template-columns: auto minmax(0, 1fr) auto; }
.workspace-head-actions { display: flex; align-items: center; gap: 10px; }
.workspace-head-actions .btn { min-height: var(--touch, 44px); }
.draft-status { display: inline-flex; align-items: center; gap: 6px; color: var(--subtle); font: 500 12px/1.3 var(--display); white-space: nowrap; }
.draft-status .ui-icon { width: 15px; height: 15px; color: var(--good); }
.scope-card { display: grid; grid-template-columns: minmax(210px, .7fr) minmax(0, 1.3fr); align-items: center; gap: 24px; padding: 20px; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--panel); }
.scope-card-copy h2 { margin: 5px 0 7px; color: var(--text); font: 650 19px/1.2 var(--display); }
.scope-summary { margin: 0; color: var(--muted); font: 400 13px/1.45 var(--display); }
.scope-picker { display: flex; flex-wrap: wrap; gap: 8px; }
.scope-choice { position: relative; display: inline-flex; align-items: center; gap: 8px; min-height: var(--touch, 44px); padding: 9px 14px 9px 12px; border: 1px solid var(--field-line); border-radius: 999px; background: var(--bg); color: var(--muted); font: 500 14px/1.2 var(--display); cursor: pointer; }
.scope-choice::before { content: ""; width: 14px; height: 14px; border: 1px solid var(--field-line); border-radius: 50%; box-shadow: inset 0 0 0 3px var(--bg); }
.scope-choice:hover { border-color: var(--accent); color: var(--text); }
.scope-choice.is-active { border-color: var(--accent); background: var(--panel-3); color: var(--text); }
.scope-choice.is-active::before { border-color: var(--accent); background: var(--accent); }
.scope-choice small { color: var(--subtle); font: 500 11px var(--mono); }

/* Practice session */
.workspace-stats { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--line); gap: 1px; }
.workspace-stats > div { min-width: 0; padding: 15px 18px; background: var(--panel); }
.workspace-stats span { display: block; color: var(--subtle); font: 600 10px/1.2 var(--mono); letter-spacing: .09em; text-transform: uppercase; }
.workspace-stats strong { display: block; margin-top: 6px; color: var(--text); font: 650 25px/1 var(--display); }
.exercises-section { display: grid; gap: 14px; }
.exercises-section .section-bar { align-items: end; }
.practice-next-card { grid-column: 1 / -1; display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 18px; padding: 20px; border: 1px solid var(--accent); border-radius: var(--radius-lg); background: linear-gradient(125deg, var(--panel-2), var(--panel)); }
.practice-next-card-copy { min-width: 0; }
.practice-next-card strong { display: block; margin: 5px 0; color: var(--text); font: 650 19px/1.25 var(--display); }
.practice-next-card p { margin: 0; color: var(--muted); font: 400 13px/1.45 var(--display); }
.exercise-list { overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--panel); }
.exercise-row { display: grid; grid-template-columns: 34px minmax(0, 1fr) auto; align-items: center; gap: 14px; width: 100%; min-height: 74px; padding: 14px 16px; border: 0; background: transparent; color: inherit; text-align: left; cursor: pointer; }
.exercise-row + .exercise-row { border-top: 1px solid var(--line); }
.exercise-row:hover { background: var(--panel-2); }
.exercise-number { display: grid; place-items: center; width: 32px; height: 32px; border: 1px solid var(--line); border-radius: 50%; color: var(--subtle); font: 600 11px var(--mono); }
.exercise-row.is-solved .exercise-number { border-color: var(--good); color: var(--good); }
.exercise-row-copy { min-width: 0; display: grid; gap: 4px; }
.exercise-row-copy strong { color: var(--text); font: 600 15px/1.35 var(--display); }
.exercise-row-copy small { color: var(--subtle); font: 400 12px/1.35 var(--display); }
.exercise-row-action { display: inline-flex; align-items: center; gap: 5px; color: var(--accent); font: 600 12px var(--display); white-space: nowrap; }
.exercise-row-action .ui-icon { width: 15px; height: 15px; }
.state-panel, .skeleton-list { padding: 18px; }
.state-panel { display: grid; justify-items: start; gap: 10px; color: var(--muted); font: 400 14px/1.5 var(--display); }
.state-panel strong { color: var(--text); }
.skeleton-list { display: grid; gap: 12px; }
.skeleton-line { height: 54px; border-radius: var(--radius-sm); background: linear-gradient(90deg, var(--panel-2), var(--panel-3), var(--panel-2)); background-size: 200% 100%; animation: pc-shimmer 1.3s linear infinite; }
@keyframes pc-shimmer { to { background-position: -200% 0; } }

/* Check workspace */
.workspace-section { display: grid; gap: 14px; }
.workspace-section-bar { margin-bottom: 0; }
.check-workspace { min-height: 560px; border: 1px solid var(--line); border-radius: var(--radius-lg); background: var(--panel); overflow: clip; }
.workspace-mode-switch { display: grid; grid-template-columns: repeat(4, 1fr); gap: 4px; padding: 6px; border-bottom: 1px solid var(--line); background: var(--bg); }
.workspace-mode { display: flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 8px 12px; border: 1px solid transparent; border-radius: var(--radius-sm); background: transparent; color: var(--muted); font: 600 14px/1.2 var(--display); cursor: pointer; }
.workspace-mode .ui-icon { width: 18px; height: 18px; }
.workspace-mode:hover { color: var(--text); background: var(--panel-2); }
.workspace-mode.is-active { border-color: var(--line-2); background: var(--panel); color: var(--text); box-shadow: 0 1px 7px rgba(0,0,0,.12); }
.instructions-details { margin: 16px 20px 0; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel-2); }
.instructions-details summary { display: flex; align-items: center; justify-content: space-between; min-height: var(--touch, 44px); padding: 9px 13px; color: var(--muted); cursor: pointer; list-style: none; }
.instructions-details summary::-webkit-details-marker { display: none; }
.instructions-details summary span { display: inline-flex; align-items: center; gap: 8px; }
.instructions-details summary b { font: 600 13px var(--display); }
.instructions-details summary small { color: var(--subtle); font: 500 11px var(--mono); }
.instructions-details summary .ui-icon { width: 16px; height: 16px; }
.instructions-details[open] summary { border-bottom: 1px solid var(--line); color: var(--text); }
.check-instructions-field { margin: 0; padding: 12px; }
.check-instructions-field textarea { min-height: 76px; }
.workspace-stage { min-height: 350px; padding: 20px; }
.workspace-pane { position: relative; min-width: 0; }
.workspace-module-state { display: flex; align-items: center; justify-content: center; gap: 10px; min-height: 300px; color: var(--muted); font: 500 13px var(--display); }
.workspace-fallback { display: grid; gap: 10px; }
.workspace-fallback .notice-inline { margin: 0; }
.workspace-pane-label { display: grid; gap: 3px; margin-bottom: 10px; }
.workspace-pane-label strong { color: var(--text); font: 600 14px var(--display); }
.workspace-pane-label span { color: var(--subtle); font: 400 12.5px/1.4 var(--display); }
.workspace-textarea { width: 100%; min-height: 250px; padding: 15px 16px; border: 1px solid var(--field-line); border-radius: var(--radius-md); background: var(--bg); color: var(--text); font: 400 16px/1.6 var(--display); resize: vertical; }
.workspace-textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); outline: 0; }
.input-counter { position: absolute; right: 11px; bottom: 9px; padding: 3px 6px; border-radius: 5px; background: var(--bg); color: var(--subtle); font: 500 10px var(--mono); }

/* Fallback code workspace; Agent B may replace #code-workspace-host at runtime. */
.ide-card { overflow: hidden; border: 1px solid var(--line-2); border-radius: var(--radius-md); background: #0b0e0b; }
.ide-tabbar { display: flex; align-items: center; gap: 10px; min-height: 50px; padding: 7px 10px; border-bottom: 1px solid var(--line-2); background: var(--panel-2); }
.ide-file-tab { display: inline-flex; align-items: center; gap: 7px; padding: 7px 10px; border-radius: 7px; background: #0b0e0b; color: #d8ecd2; font: 500 12px var(--mono); }
.ide-file-tab .ui-icon { width: 14px; height: 14px; }
.ide-language-picker { display: flex; align-items: center; gap: 6px; margin-left: auto; color: var(--subtle); font: 600 10px var(--mono); letter-spacing: .06em; text-transform: uppercase; }
.ide-language-picker select { min-height: 36px; padding: 5px 27px 5px 8px; border: 1px solid var(--line-2); border-radius: 6px; background-color: var(--bg); color: var(--text); font: 13px var(--display); text-transform: none; letter-spacing: normal; }
.ide-editor { display: block; width: 100%; min-height: 300px; padding: 17px 18px; border: 0; background: #0b0e0b; color: #d8ecd2; caret-color: #ddebce; font: 14px/1.65 var(--mono); tab-size: 4; white-space: pre; resize: vertical; }
.ide-editor:focus { outline: 1px solid var(--accent); outline-offset: -1px; }
.ide-editor::placeholder { color: #536050; }
.ide-console { max-height: 240px; overflow: auto; padding: 13px 17px; border-top: 1px solid #2a3029; background: #070907; color: var(--muted); font: 12.5px/1.55 var(--mono); white-space: pre-wrap; word-break: break-word; }
.ide-console.status-ok { color: var(--good); }
.ide-console.status-error { color: var(--bad-ink); }
.ide-console.status-pending { color: var(--subtle); }
.stdin-details { margin-top: 12px; }
.stdin-details summary { min-height: var(--touch, 44px); padding: 10px 2px; color: var(--muted); font: 500 13px var(--display); cursor: pointer; }
.stdin-details textarea { min-height: 90px; margin-top: 6px; font-family: var(--mono); }

/* Fallback ink workspace; Agent B may replace #ink-workspace-host at runtime. */
.sketchpad-card { padding: 13px; border: 1px solid var(--line-2); border-radius: var(--radius-md); background: var(--panel-2); }
.sketchpad-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 11px; }
.pen-size-group, .sketchpad-actions { display: flex; gap: 7px; }
.pen-size { display: grid; place-items: center; width: var(--touch, 44px); height: var(--touch, 44px); border: 1px solid var(--field-line); border-radius: 9px; background: var(--bg); cursor: pointer; }
.pen-size:hover, .pen-size.is-active { border-color: var(--accent); background: var(--panel-3); }
.pen-dot { display: block; border-radius: 50%; background: var(--text); }
.sketchpad-surface { position: relative; overflow: hidden; border: 1px solid #d8d5c6; border-radius: 7px; background-color: #faf8ef; background-image: linear-gradient(#e8e4d5 1px, transparent 1px), linear-gradient(90deg, #e8e4d5 1px, transparent 1px); background-size: 28px 28px; box-shadow: inset 0 0 30px rgba(31,36,28,.06); }
#check-canvas { display: block; width: 100%; height: auto; aspect-ratio: 3 / 2; touch-action: none; cursor: crosshair; }
.sketchpad-hint { margin: 10px 2px 0; color: var(--subtle); font: 400 12.5px/1.45 var(--display); }

/* File workspace */
.check-dropzone { display: grid !important; justify-items: center; gap: 6px; min-height: 300px; padding: 34px 20px !important; border: 1px dashed var(--field-line) !important; border-radius: var(--radius-md) !important; background: var(--bg) !important; text-align: center; cursor: pointer; }
.check-dropzone:hover, .check-dropzone.dragging { border-color: var(--accent) !important; background: var(--panel-2) !important; }
.check-dropzone input { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }
.dropzone-icon { display: grid; place-items: center; width: 52px; height: 52px; margin-bottom: 4px; border-radius: 16px; background: var(--panel-3); color: var(--accent); }
.dropzone-icon .ui-icon { width: 24px; height: 24px; }
.check-dropzone strong { color: var(--text); font: 650 17px var(--display); }
.check-dropzone > span:not(.dropzone-icon) { color: var(--muted); font: 400 13px var(--display); }
.check-dropzone small { margin-top: 8px; color: var(--subtle); font: 400 12px/1.45 var(--display); }
.file-summary { display: flex; align-items: center; gap: 12px; margin-top: 12px; padding: 13px 14px; border: 1px solid var(--line-2); border-radius: var(--radius-sm); background: var(--panel-2); }
.file-summary > .ui-icon { flex: none; width: 22px; height: 22px; color: var(--accent); }
.file-summary div { min-width: 0; }
.file-summary strong, .file-summary span { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.file-summary strong { color: var(--text); font: 600 14px/1.3 var(--display); }
.file-summary span { margin-top: 3px; color: var(--subtle); font: 400 12px var(--display); }
.file-summary .icon-btn { flex: none; margin-left: auto; }

/* Submit, progress, rate-limit and offline states */
.check-error { margin: 0 20px 14px; }
.check-submit-dock { position: static; z-index: 5; display: flex; align-items: center; justify-content: space-between; gap: 18px; min-height: 82px; padding: 14px 20px; border-top: 1px solid var(--line); background: color-mix(in srgb, var(--panel) 94%, transparent); backdrop-filter: blur(12px); }
.check-submit-dock small { display: block; margin-top: 4px; color: var(--subtle); font: 400 12px/1.3 var(--display); }
#check-submit-btn { min-width: 220px; }
.check-progress { align-items: flex-start; gap: 16px; margin: 0 20px 18px; padding: 18px; border: 1px solid var(--line-2); border-radius: var(--radius-md); background: var(--panel-2); }
.check-progress:not(.hidden) { display: flex; }
.progress-orbit { flex: none; display: grid; place-items: center; width: 42px; height: 42px; border: 1px solid var(--line-2); border-radius: 50%; }
.progress-orbit span { width: 18px; height: 18px; border: 2px solid var(--line-2); border-top-color: var(--accent); border-radius: 50%; animation: pc-spin .8s linear infinite; }
@keyframes pc-spin { to { transform: rotate(360deg); } }
.check-progress strong { display: block; color: var(--text); font: 650 16px/1.3 var(--display); }
.check-progress p { margin: 4px 0 11px; color: var(--muted); font: 400 13px/1.45 var(--display); }
.check-progress ol { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 9px; padding: 0; list-style: none; }
.check-progress li { padding: 5px 8px; border-radius: 999px; background: var(--bg); color: var(--subtle); font: 500 11px var(--display); }
.check-progress li.is-active { background: var(--panel-3); color: var(--text); }
.check-progress li.is-done::before { content: "✓ "; color: var(--good); }
#check-progress-time { color: var(--subtle); font: 500 11px var(--mono); }
.request-state { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 12px; padding: 14px; border: 1px solid var(--line-2); border-radius: var(--radius-sm); background: var(--panel-2); color: var(--muted); }
.request-state .ui-icon { width: 20px; height: 20px; color: var(--warn); }
.request-state strong { display: block; color: var(--text); font: 600 14px var(--display); }
.request-state p { margin: 4px 0 0; font: 400 13px/1.5 var(--display); }

/* Verdict: shape and language carry the outcome; colour is secondary. */
.verdict-card { margin: 0 20px 20px; }
.verdict-hero { display: grid; grid-template-columns: 44px minmax(0, 1fr); gap: 13px; padding: 18px; border: 1px solid var(--line-2); border-radius: var(--radius-md); background: var(--panel-2); }
.verdict-symbol { display: grid; place-items: center; width: 44px; height: 44px; border: 1px solid var(--line-2); border-radius: 50%; color: var(--muted); font: 700 19px var(--display); }
.verdict-correct .verdict-symbol { border-color: var(--good); color: var(--good); }
.verdict-partial .verdict-symbol { border-color: var(--warn); color: var(--warn); }
.verdict-incorrect .verdict-symbol { border-color: var(--bad); color: var(--bad-ink); }
.verdict-label { display: block; color: var(--subtle); font: 600 10px var(--mono); letter-spacing: .09em; text-transform: uppercase; }
.verdict-hero h3 { margin: 3px 0 5px; color: var(--text); font: 650 20px/1.2 var(--display); }
.verdict-hero p { margin: 0; color: var(--muted); font: 400 14px/1.55 var(--display); }
.verdict-groups { display: grid; gap: 12px; margin-top: 12px; }
.verdict-group { padding: 15px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel); }
.verdict-group h4 { display: flex; align-items: center; gap: 7px; margin: 0 0 10px; color: var(--text); font: 650 14px var(--display); }
.verdict-group h4 .ui-icon { width: 16px; height: 16px; }
.verdict-items { display: grid; gap: 10px; margin: 0; padding: 0; list-style: none; }
.verdict-item { position: relative; padding-left: 15px; }
.verdict-item::before { content: ""; position: absolute; top: 7px; left: 0; width: 6px; height: 6px; border-radius: 50%; background: var(--line-2); }
.severity-error::before { background: var(--bad); }
.severity-warn::before { background: var(--warn); }
.severity-info::before { background: var(--good); }
.verdict-item strong { display: block; color: var(--text); font: 600 13.5px/1.35 var(--display); }
.verdict-item p { margin: 3px 0 0; color: var(--muted); font: 400 13px/1.5 var(--display); }
.verdict-fix { margin-top: 6px !important; color: var(--accent) !important; }
.verdict-next { margin-top: 12px; padding: 15px; border: 1px dashed var(--line-2); border-radius: var(--radius-sm); }
.verdict-next h4 { margin: 0; color: var(--text); font: 650 14px var(--display); }
.verdict-next ol { margin: 8px 0 0; padding-left: 20px; color: var(--muted); font: 400 13px/1.55 var(--display); }
.verdict-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }

/* History */
.check-history-section { display: grid; gap: 13px; padding-top: 4px; }
.check-history-list { display: grid; gap: 8px; }
.check-history-row { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 8px; width: 100%; min-height: 66px; padding: 6px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel); color: inherit; }
.check-history-row:hover { border-color: var(--field-line); background: var(--panel-2); }
.check-history-open { display: grid; grid-template-columns: 38px minmax(0, 1fr) auto; align-items: center; gap: 11px; min-width: 0; min-height: 52px; padding: 5px 7px; border: 0; background: transparent; color: inherit; text-align: left; cursor: pointer; }
.history-delete { flex: none; width: var(--touch, 44px); height: var(--touch, 44px); color: var(--subtle); }
.history-delete:hover { color: var(--bad-ink); }
.history-mode-icon { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 10px; background: var(--panel-3); color: var(--accent); }
.history-mode-icon .ui-icon { width: 17px; height: 17px; }
.check-history-copy { min-width: 0; display: grid; gap: 3px; }
.check-history-copy strong { overflow: hidden; color: var(--text); font: 600 13.5px/1.35 var(--display); text-overflow: ellipsis; white-space: nowrap; }
.check-history-copy small { color: var(--subtle); font: 400 11.5px/1.35 var(--display); }
.outcome-badge { padding: 5px 8px; border: 1px solid var(--line-2); border-radius: 999px; color: var(--muted); font: 600 10px var(--mono); white-space: nowrap; }
.outcome-badge.verdict-correct { border-color: var(--good); }
.outcome-badge.verdict-partial { border-color: var(--warn); }
.outcome-badge.verdict-incorrect { border-color: var(--bad); }

/* Dialogs */
.exercise-dialog { width: min(650px, calc(100% - 28px)); max-height: min(820px, calc(100dvh - 28px)); overflow: auto; }
.exercise-dialog .dialog-mini-head { align-items: flex-start; }
.exercise-position { display: block; margin-top: 5px; color: var(--subtle); font: 500 11px var(--mono); }
.exercise-prompt { margin: 16px 0; padding: 15px; border-left: 3px solid var(--accent); background: var(--panel-2); color: var(--text); font: 500 16px/1.55 var(--display); }
.exercise-dialog .field { margin-bottom: 14px; }
.exercise-dialog textarea { min-height: 150px; }
.exercise-actions { position: sticky; z-index: 2; bottom: -1px; display: flex; align-items: center; justify-content: flex-end; gap: 9px; margin: 4px -2px 0; padding: 12px 2px 2px; background: var(--panel); }
.exercise-dialog .verdict-card { margin: 16px 0 0; }
.check-history-dialog { width: min(700px, calc(100% - 28px)); max-height: min(820px, calc(100dvh - 28px)); overflow: auto; }
.check-history-dialog .verdict-card { margin: 16px 0 0; }
.history-instructions { margin: 14px 0 0; padding: 12px; border-radius: var(--radius-sm); background: var(--panel-2); color: var(--muted); font: 400 13px/1.5 var(--display); }

@media (max-width: 1000px) {
  .pc-hero { grid-template-columns: 1fr; align-items: start; }
  .pc-how { grid-template-columns: repeat(3, 1fr); }
  .pc-how li { grid-template-columns: 30px minmax(0, 1fr); }
  .pc-how li + li { border-top: 0; border-left: 1px solid var(--line); }
  .check-workspace-head { grid-template-columns: auto 1fr; }
  .workspace-head-actions { grid-column: 2; justify-content: flex-start; }
  .scope-card { grid-template-columns: 1fr; }
}

/* Keep the phone/tablet navigation reachable. */
@media (max-width: 850px) {
  .exercise-dialog .icon-btn, .exercise-dialog .btn { min-width: var(--touch, 44px); min-height: var(--touch, 44px); }
  .product-tabs { position: fixed; z-index: 60; left: 0; right: 0; bottom: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); width: 100%; height: auto; margin: 0; padding: 0 0 env(safe-area-inset-bottom); border-top: 1px solid var(--line-2); background: color-mix(in srgb, var(--panel) 96%, transparent); backdrop-filter: blur(14px); }
  .product-tabs .nav-btn { flex-direction: column; gap: 4px; min-height: 60px; padding: 7px 3px 6px; border: 0; border-top: 2px solid transparent; color: var(--subtle); font: 600 10px/1 var(--mono); letter-spacing: .04em; }
  .product-tabs .nav-btn .ui-icon { display: block; }
  .product-tabs .nav-btn.active { border-top-color: var(--accent); background: var(--panel-2); color: var(--text); }
  .study-workbench { padding-bottom: calc(76px + env(safe-area-inset-bottom)); }
  body.drawer-open .product-tabs { z-index: 40; }
  .practice-check-view { width: 100%; }
  .pc-hero { padding-top: 12px; }
  .pc-subject-grid { grid-template-columns: 1fr !important; }
  .check-submit-dock { position: sticky; bottom: calc(60px + env(safe-area-inset-bottom)); }
}

@media (max-width: 640px) {
  .practice-check-view { --mobile-gutter: 16px; padding-bottom: 24px; }
  .pc-home { gap: 27px; }
  .pc-hero { gap: 21px; padding: 8px 0 25px; }
  .pc-hero .editorial-title { margin-top: 7px; font-size: clamp(31px, 10vw, 42px); }
  .pc-hero .page-lede { margin-top: 10px; font-size: 15px; line-height: 1.48; }
  .pc-how { grid-template-columns: 1fr; }
  .pc-how li { min-height: 46px; padding: 8px 12px; }
  .pc-how li + li { border-top: 1px solid var(--line); border-left: 0; }
  .format-strip { display: flex; flex-wrap: wrap; gap: 6px; }
  .format-strip span { flex: 1 1 calc(50% - 3px); min-height: 42px; padding: 8px 10px; }
  .pc-subject-card { min-height: 118px; padding: 15px !important; grid-template-columns: 42px minmax(0, 1fr) !important; }
  .pc-subject-card .subject-monogram { width: 42px; height: 42px; }
  .pc-subject-action { grid-column: 1; justify-self: start; }
  .pc-workspace-head, .check-workspace-head { grid-template-columns: 1fr; gap: 12px; padding-top: 0; }
  .pc-workspace-head .back-chip { justify-self: start; }
  .workspace-head-actions { grid-column: 1; flex-wrap: wrap; }
  .workspace-head-actions .btn { flex: 1; }
  .draft-status { order: 2; width: 100%; }
  .scope-card { gap: 13px; padding: 14px; }
  .scope-picker { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .scope-choice { justify-content: flex-start; width: 100%; border-radius: var(--radius-sm); }
  .scope-choice:first-child { grid-column: 1 / -1; }
  .scope-choice span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .workspace-stats > div { padding: 13px 11px; }
  .workspace-stats span { min-height: 25px; font-size: 9px; }
  .workspace-stats strong { font-size: 22px; }
  .exercises-section .section-bar { align-items: flex-start; }
  .exercises-section .section-note { display: none; }
  .practice-next-card { grid-template-columns: 1fr; padding: 16px; }
  .practice-next-card .btn { width: 100%; }
  .exercise-row { grid-template-columns: 30px minmax(0, 1fr); gap: 10px; min-height: 76px; padding: 12px; }
  .exercise-row-action { grid-column: 2; }
  .workspace-mode-switch { position: sticky; z-index: 4; top: 0; grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .workspace-mode { flex-direction: column; gap: 4px; min-height: 58px; padding: 6px 2px; font-size: 10.5px; }
  .workspace-mode .ui-icon { width: 17px; height: 17px; }
  .instructions-details { margin: 12px 12px 0; }
  .workspace-stage { min-height: 320px; padding: 14px 12px; }
  .workspace-textarea { min-height: 245px; font-size: 16px; }
  .ide-tabbar { flex-wrap: wrap; }
  .ide-language-picker { order: 3; width: 100%; margin-left: 0; }
  .ide-language-picker select { flex: 1; }
  .ide-editor { min-height: 330px; padding: 14px 12px; font-size: 13px; }
  .sketchpad-card { padding: 9px; }
  .sketchpad-toolbar { align-items: flex-start; }
  .sketchpad-actions .btn { width: 44px; padding: 0; font-size: 0; }
  .sketchpad-actions .btn .ui-icon { margin: 0; }
  #check-canvas { aspect-ratio: 4 / 5; }
  .check-dropzone { min-height: 320px; }
  .check-error, .check-progress, .verdict-card { margin-left: 12px; margin-right: 12px; }
  .check-submit-dock { align-items: stretch; min-height: auto; padding: 10px 12px calc(10px + env(safe-area-inset-bottom)); }
  .check-submit-dock > div { display: none; }
  #check-submit-btn { width: 100%; min-width: 0; min-height: 50px; }
  .check-history-section .section-note { display: none; }
  .check-history-open { grid-template-columns: 38px minmax(0, 1fr); }
  .check-history-open .outcome-badge { grid-column: 2; justify-self: start; }
  .outcome-badge { grid-column: 2; justify-self: start; }
  .exercise-dialog { max-height: calc(100dvh - 12px); width: calc(100% - 12px); padding: 18px 16px; }
  .exercise-actions { bottom: 0; flex-wrap: wrap; padding-bottom: calc(7px + env(safe-area-inset-bottom)); }
  .exercise-actions .btn { flex: 1 1 auto; min-height: var(--touch, 44px); }
  .exercise-actions #exercise-next-btn { flex-basis: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  .practice-check-view *, .exercise-dialog * { scroll-behavior: auto !important; animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; }
}