.brief-panel { min-width: 0; padding: 22px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; }
.brief-panel .source-link { margin-top: 12px; }
.tools-intro { margin-bottom: 18px; }
.tools-intro p { font-size: 13px; color: var(--muted); margin-top: 3px; }
.preview-expand { min-height: 30px; padding: 0; font-size: 11px; white-space: nowrap; }
.preview-expand svg { width: 14px; height: 14px; }
.result-peek { display: none; }

/* Fit the workbench to the browser; shrink the whole case, never its contents. */
@media (min-width: 961px) and (min-height: 620px) {
  .work-shell { width: min(1440px,calc(100% - 48px)); height: 100dvh; display: grid; grid-template-rows: 52px minmax(0,1fr); }
  .work-shell .topbar { min-height: 0; gap: 20px; }
  .work-shell .brand-mark { width: 30px; height: 30px; border-radius: 9px; }
  .work-shell .brand-text { font-size: 15px; }
  .work-shell .brand-sub { font-size: 7px; }
  .work-shell .workspace { min-height: 0; padding: 12px 0 6px; display: grid; grid-template-rows: auto minmax(0,1fr) 28px; gap: 12px; }
  .work-shell .workspace-heading { margin: 0; align-items: center; gap: 16px; }
  .work-shell .workspace-heading > div:first-child { display: grid; grid-template-columns: auto 1fr; align-items: center; gap: 3px 14px; min-width: 0; }
  .work-shell .breadcrumb { grid-row: 1; font-size: 11px; }
  .work-shell .breadcrumb button { min-height: 26px; }
  .work-shell .workspace-heading h1 { grid-column: 2; grid-row: 1; margin: 0; font-size: 21px; line-height: 1.4; }
  .work-shell .workspace-heading p { grid-column: 2; font-size: 12px; color: var(--muted); }
  .work-shell .work-grid { min-height: 0; grid-template-columns: minmax(200px,.78fr) minmax(230px,1fr) minmax(320px,1.1fr); gap: 16px; align-items: stretch; }
  .work-shell .brief-panel { padding: 20px; }
  .work-shell .task-goal { margin: 0; padding: 0; border: 0; }
  .work-shell .task-goal h2 { font-size: 17px; line-height: 1.6; margin-top: 8px; }
  .work-shell .constraint-list { margin: 18px 0 0; padding-left: 17px; font-size: 12px; line-height: 1.8; }
  .work-shell .constraint-list li + li { margin-top: 10px; }
  .work-shell .hint { margin-top: 24px; padding: 12px; font-size: 12px; line-height: 1.7; }
  .work-shell .preview-panel { display: grid; grid-template-rows: auto minmax(0,1fr) auto; min-height: 0; }
  .work-shell .preview-panel > .panel-label { padding: 10px 14px 0; }
  .work-shell .conditions { padding: 6px 14px 0; gap: 6px; }
  .work-shell .condition-button { min-height: 34px; padding: 6px 9px; }
  .work-shell .preview-stage { container-type: size; min-height: 0; margin: 10px 12px; padding: 0; align-items: center; }
  .work-shell .preview-stage > .wx-preview { width: min(calc(var(--wx-base) * 1px),100cqw,calc(100cqh * var(--wx-base) / var(--wx-height,844))); flex: 0 0 auto; }
  .work-shell .preview-caption { padding: 0 12px 8px; font-size: 10px; }
  .work-shell .control-panel { min-height: 0; display: flex; flex-direction: column; padding: 18px; }
  .work-shell .tools-intro { margin: 0 0 18px; }
  .work-shell .controls { display: grid; gap: 18px; }
  .work-shell .control-group { margin: 0; padding: 0; border: 0; }
  .work-shell .control-label { margin-bottom: 7px; font-size: 12px; }
  .work-shell .option-group { gap: 6px; }
  .work-shell .option-group:has(> :nth-child(3):last-child) { grid-template-columns: repeat(3,minmax(0,1fr)); }
  .work-shell .option-button { min-height: 40px; padding: 8px 5px; flex-direction: row; font-size: 12px; gap: 4px; }
  .work-shell .option-button svg { width: 12px; height: 12px; }
  .work-shell .control-help { font-size: 11px; line-height: 1.6; margin-top: 6px; }
  .work-shell .control-bottom { margin-top: auto; padding-top: 18px; }
  .work-shell .workspace-tools { padding-top: 12px; margin-top: 0; gap: 6px; }
  .work-shell .history-control { gap: 5px; }
  .work-shell .history-select { min-height: 36px; font-size: 10px; padding: 7px 22px 7px 8px; }
  .work-shell .workspace-tools .btn { min-height: 36px; padding: 7px 8px; font-size: 11px; gap: 4px; }
  .work-shell .workspace-tools .icon { width: 15px; height: 15px; }
  .work-shell .history-note { font-size: 10px; margin: 5px 0 10px; }
  .work-shell .check-button { min-height: 42px; padding: 9px 12px; }
  .work-shell .inline-feedback { display: none; }
  .work-shell .result-peek { display: flex; justify-content: space-between; gap: 6px; align-items: center; font-size: 11px; margin-top: 6px; }
  .work-shell .result-peek .text-button { min-height: 30px; font-size: 11px; }
  .work-shell .workspace-footer { margin: 0; padding: 0; font-size: 10px; align-items: center; }
  .work-shell .workspace-footer .text-button { min-height: 28px; padding: 0; font-size: 11px; }
  .result-dialog { width: min(920px,calc(100% - 48px)); }
  .result-dialog .dialog-header { padding: 18px 24px 0; }
  .result-dialog .dialog-body { padding: 12px 24px; }
  .result-dialog .dialog-actions { padding: 0 24px 18px; }
  .result-dialog .feedback { margin: 0; padding: 16px; }
  .result-dialog .check-list { display: grid; grid-template-columns: repeat(auto-fit,minmax(200px,1fr)); gap: 16px; margin-top: 14px; }
  .result-dialog .check-item { margin: 0; font-size: 12px; }
  .result-dialog .check-copy strong { font-size: 12px; }
  .result-dialog .feedback > p { font-size: 13px; }
  .result-dialog .trigger-card { margin-top: 12px; font-size: 12px; }
  .result-dialog .result-actions { margin-top: 12px; }
  .preview-dialog[open],.compare-dialog[open] { height: calc(100dvh - 48px); display: grid; grid-template-rows: auto minmax(0,1fr) auto; }
  .preview-dialog .dialog-header,.compare-dialog .dialog-header { padding: 16px 24px 0; }
  .preview-dialog .dialog-actions,.compare-dialog .dialog-actions { padding: 0 24px 16px; }
  .preview-dialog .dialog-body { min-height: 0; display: flex; flex-direction: column; gap: 10px; padding: 10px 24px; }
  .preview-dialog .quick-preview { flex: 1; min-height: 0; container-type: size; display: flex; justify-content: center; align-items: center; padding: 0; }
  .preview-dialog .quick-preview > .wx-preview { width: min(calc(var(--wx-base) * 1px),100cqw,calc(100cqh * var(--wx-base) / var(--wx-height,844))); flex: 0 0 auto; }
  .compare-dialog .dialog-body { min-height: 0; display: grid; grid-template-rows: auto auto minmax(0,1fr) auto; gap: 8px; padding: 8px 24px 12px; }
  .compare-dialog .compare-conditions,.compare-dialog .compare-note { margin: 0; }
  .compare-dialog .compare-grid { min-height: 0; align-items: stretch; }
  .compare-dialog .compare-column { min-height: 0; container-type: size; padding: 10px; }
  .compare-dialog .compare-label { margin-bottom: 10px; line-height: 20px; }
  .compare-dialog .compare-column > .wx-preview { width: min(calc(var(--wx-base) * 1px),100cqw,calc((100cqh - 32px) * var(--wx-base) / var(--wx-height,844))); }
}

@media (min-width: 961px) and (min-height: 620px) and (max-height: 760px) {
  .work-shell .control-panel,.work-shell .brief-panel { padding: 16px; }
  .work-shell .tools-intro { margin-bottom: 12px; }
  .work-shell .controls { gap: 12px; }
  .work-shell fieldset.control-group { position: relative; padding-left: 84px; }
  .work-shell .control-label { position: absolute; left: 0; top: 9px; width: 76px; margin: 0; line-height: 20px; }
  .work-shell .control-help { margin-left: -84px; }
  .work-shell .option-button { position: relative; font-size: 11px; }
  .work-shell .option-button svg { position: absolute; top: 4px; right: 4px; width: 9px; height: 9px; }
  .work-shell .control-bottom { padding-top: 10px; }
  .work-shell .hint { margin-top: 16px; }
}

@media (min-width: 961px) and (max-width: 1180px) and (min-height: 620px) {
  .work-shell .brief-panel { min-height: 0; padding: 14px; }
  .work-shell .task-goal h2 { font-size: 15px; line-height: 1.5; }
  .work-shell .constraint-list { margin-top: 12px; line-height: 1.6; }
  .work-shell .constraint-list li + li { margin-top: 6px; }
  .work-shell .hint { margin-top: 12px; padding: 10px; line-height: 1.6; }
  .work-shell .brief-panel .source-link { min-height: 32px; margin-top: 8px; }
}

/* Narrow screens retain readable document flow and the quick-preview action. */
@media (max-width: 960px), (max-height: 619px) {
  .work-grid { grid-template-columns: minmax(0,1fr) minmax(0,1fr); }
  .brief-panel { grid-column: 1 / -1; }
}
@media (max-width: 720px) {
  .work-grid { grid-template-columns: minmax(0,1fr); }
}

/* Keep the explanatory labels and one result action inside a short desktop. */
@media(min-width:961px) and (min-height:620px) and (max-height:760px) {
 .workspace[data-task-id="actions"] .controls {gap:8px;}
 .workspace[data-task-id="actions"] .control-help {line-height:1.5;margin-top:4px;}
 .workspace[data-task-id="actions"] .tools-intro {margin-bottom:8px;}
 .workspace[data-task-id="actions"] .control-bottom {padding-top:4px;}
}

/* The working view keeps the current task and one pair of history actions. */
.work-background {flex:none;white-space:nowrap;}
.workspace-tools {display:flex;justify-content:flex-end;gap:8px;margin-bottom:12px;}
.workspace-tools > .btn {flex:0 0 auto;min-width:86px;}
.workspace-footer {justify-content:flex-end;}
.preview-stage > .phone-preview {align-self:stretch;}
@media(min-width:961px) and (min-height:620px) {
 .work-shell .preview-stage {display:flex;align-items:stretch;}
 .work-shell .preview-stage > .phone-preview {height:100%;}
 .work-shell .workspace-tools {display:flex;justify-content:flex-end;margin-bottom:10px;}
 .preview-dialog .quick-preview > .phone-preview {height:100%;}
 .compare-dialog .compare-column > .phone-preview {height:calc(100% - 32px);}
}
@media(max-width:720px) {
 .workspace-heading {align-items:flex-start;}
 .workspace-heading > div:first-child {min-width:0;}
 .work-background {font-size:13px;gap:4px;}
 .work-background .icon {width:16px;height:16px;}
}

/* The selected exercises share one list; this number is the item's position. */
.task-crumb {display:flex;align-items:center;gap:8px;flex-wrap:wrap;}

/* Preserve the fixed phone preview; improve only labels and actions around it. */
.work-shell .control-label,.work-shell .option-button { font-size: 13px; }
.work-shell .control-help,.work-shell .history-note,.work-shell .preview-caption { font-size: 12px; color: var(--muted); }
.work-shell .workspace-tools .btn { font-size: 13px; min-height: 40px; }
.work-shell .check-button { font-size: 14px; min-height: 46px; }
.work-shell .option-button { border-radius: var(--radius-control); }
.work-shell .workspace-footer,.work-shell .workspace-footer .text-button { font-size: 12px; }
.work-shell .option-button:not(.selected) { color: var(--muted); }
.work-shell .option-button:focus-visible { outline-color: var(--ink); }