.dsa-main{max-width:1500px;margin:auto;padding:32px}.lesson-head h1{font-size:clamp(32px,4vw,52px)}.lesson-head p{max-width:860px}.split{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:start}.split.wide{grid-template-columns:1.2fr 1fr}.stacked{display:grid;gap:20px}.prose{color:var(--muted);font-size:15px;line-height:1.85}.prose h2,.prose h3{color:var(--ink);margin:0 0 12px}.prose ul,.prose ol{padding-left:20px}.prose li{margin:9px 0}.prose strong{color:var(--ink)}.prose pre{color:var(--cyan);padding:16px;background:var(--code);border:1px solid var(--line);border-radius:8px;margin:16px 0}.case-tabs{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:20px}.case-tabs button[aria-pressed=true]{border-color:var(--gold);color:var(--gold)}.tree-wrap{background:var(--code);border:1px solid var(--line);border-radius:12px;padding:16px;overflow:hidden}.tree-wrap svg{display:block;width:100%;height:auto;max-height:410px;min-height:150px}.tree-edge{stroke:var(--line);stroke-width:3}.tree-edge.path{stroke:var(--cyan);stroke-width:5}.tree-node circle{fill:var(--surface2);stroke:var(--faint);stroke-width:2}.tree-node text{fill:var(--ink);font:600 16px var(--mono);text-anchor:middle;dominant-baseline:central;pointer-events:none}.tree-node .node-id{fill:var(--muted);font:10px var(--mono)}.tree-node.active circle{stroke:var(--gold);stroke-width:4}.tree-node.path circle{fill:color-mix(in srgb,var(--cyan) 18%,var(--code));stroke:var(--cyan);stroke-width:3}.tree-node[role=button]{cursor:pointer;outline:none}.tree-node[role=button]:focus-visible circle{stroke:var(--gold);stroke-width:5}.tree-node[role=button]:hover circle{fill:var(--surface)}.tree-caption{font-size:12px;color:var(--muted);margin:12px 0 0;overflow-wrap:anywhere}.legend{display:flex;gap:16px;flex-wrap:wrap;font-size:11px;color:var(--muted);margin:12px 0}.legend b{font-size:16px;color:var(--gold)}.legend b.cyan{color:var(--cyan)}.manual-form{display:flex;gap:8px;align-items:center;flex-wrap:wrap;margin-top:20px}.manual-form label{width:100%;font-size:13px}.manual-form input,.custom-tree input{border:1px solid var(--line);background:var(--code);color:var(--ink);padding:10px;border-radius:8px;min-width:0}.manual-form input{width:150px}.small-note{font-size:12px;color:var(--muted);margin:12px 0}.path-readout{font:13px/1.7 var(--mono);padding:12px;background:var(--surface2);border-radius:8px;margin-top:12px;overflow-wrap:anywhere;min-height:46px}.draft-label{display:block;font-size:13px;margin:16px 0 8px}.approach{border:1px solid var(--line);border-radius:8px;min-height:150px;font:14px/1.7 var(--sans);padding:16px}.reveal{margin:20px 0}.reveal summary{padding:14px 16px;border:1px solid var(--line);border-radius:8px;color:var(--gold)}.reveal .prose{padding:20px 0}.trace-shell{margin-top:24px}.trace-toolbar{display:flex;align-items:end;gap:12px;justify-content:space-between;flex-wrap:wrap;padding:18px 20px;border-bottom:1px solid var(--line)}.trace-toolbar label,.custom-tree label{font-size:12px;color:var(--muted);display:block;margin-bottom:5px}.trace-toolbar select{max-width:100%;padding:8px;border-radius:8px;color:var(--ink);background:var(--code);border:1px solid var(--line)}.trace-buttons{display:flex;gap:6px;align-items:center;flex-wrap:wrap}.custom-tree{display:flex;gap:8px;flex-wrap:wrap;padding:0 20px 18px;border-bottom:1px solid var(--line)}.custom-tree label{width:100%;margin-top:12px}.custom-tree input{flex:1;font:12px var(--mono)}.custom-tree p{width:100%;font-size:12px;color:var(--red)}.trace-grid{display:grid;grid-template-columns:1.05fr 1fr;gap:20px;padding:20px}.trace-status{padding:16px 20px;border-bottom:1px solid var(--line);background:var(--surface2)}.trace-status .eyebrow{margin-bottom:5px}.trace-status p{min-height:50px;font-size:14px}.trace-status input{width:100%;accent-color:var(--gold);margin:12px 0}.metrics{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:14px 0}.metric{border:1px solid var(--line);padding:12px;border-radius:8px;background:var(--code)}.metric small{display:block;color:var(--muted);font-size:11px}.metric strong{font:22px var(--mono);color:var(--gold)}.code-lines{list-style:none;margin:0;padding:14px 0;background:var(--code);border:1px solid var(--line);border-radius:10px;overflow:auto}.code-lines li{padding:3px 14px 3px 42px;position:relative;font:12px/1.8 var(--mono);white-space:pre;min-width:max-content;border-left:3px solid transparent}.code-lines li::before{content:attr(data-line);position:absolute;left:12px;color:var(--faint);font-size:10px}.code-lines li.active{border-left-color:var(--gold);background:color-mix(in srgb,var(--gold) 13%,var(--code));color:var(--gold)}.table-scroll{overflow:auto;border:1px solid var(--line);border-radius:8px;margin-top:12px}table{width:100%;border-collapse:collapse;text-align:left;font:11px/1.6 var(--mono)}th,td{padding:9px 10px;border-bottom:1px solid var(--line);white-space:nowrap}th{color:var(--muted);background:var(--code)}tr:last-child td{border-bottom:0}tbody tr:last-child{color:var(--gold)}caption{text-align:left;padding:10px;color:var(--muted);font:12px var(--sans)}.trace-grid h3{margin:20px 0 8px;font-size:14px}.returned{font:12px/1.8 var(--mono);color:var(--cyan);overflow-wrap:anywhere}.comparison{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:20px 0}.comparison article{border:1px solid var(--line);padding:20px;border-radius:10px}.comparison strong{display:block;font-size:22px;color:var(--gold)}.quiz{margin:16px 0}.quiz button{display:block;margin:8px 0;text-align:left;justify-content:flex-start;width:100%}.solution-code{padding:20px;background:var(--code);border:1px solid var(--line);border-radius:10px;max-height:600px;overflow:auto}.test-list{padding:0;list-style:none}.test-list li{border-bottom:1px solid var(--line);padding:10px 0;font:12px var(--mono)}#storage-notice{position:fixed;bottom:12px;left:12px;right:12px;padding:12px;background:var(--surface2);border:1px solid var(--red);z-index:50}.topbar{height:auto;min-height:72px;padding-top:12px;padding-bottom:12px;flex-wrap:wrap}.stages button{font-size:13px}.topnav a{font-size:11px}
#run-results,#custom-results{white-space:pre-wrap;overflow-wrap:anywhere}
.playground{margin-top:24px}.playground textarea{border:1px solid var(--line);border-radius:8px;margin-bottom:16px}.playground #custom-tests{min-height:210px}.playground h3{margin-top:24px}
.tree-node.active circle{stroke:var(--gold);stroke-width:4}
.trace-shell{overflow:visible}.trace-toolbar{position:sticky;top:72px;z-index:10;background:var(--surface);border-radius:12px 12px 0 0}.trace-grid>div{min-width:0}.trace-grid .tree-wrap svg{max-height:290px}
@media(max-width:1100px){.trace-toolbar{top:0}}
@media(max-width:1000px){.split,.split.wide,.trace-grid{grid-template-columns:1fr}.dsa-main{padding:24px}.trace-grid .code-lines{max-height:360px}.tree-wrap svg{max-height:360px}}
@media(max-width:600px){.dsa-main{padding:20px 12px}.panel-pad,.trace-grid{padding:16px}.stages button{font-size:10px}.stage-number{width:20px;height:20px}.topnav{justify-content:flex-start}.topnav a{font-size:10px;padding:6px}.topbar{padding:12px}.lesson-head h1{font-size:34px}.comparison{grid-template-columns:1fr}.trace-toolbar{padding:16px}.trace-toolbar>div{max-width:100%}.tree-wrap{padding:8px}.trace-status{padding:16px}.custom-tree{padding:0 16px 16px}.code-lines li{font-size:11px}.trace-buttons button{font-size:11px;padding:9px}.panel-label{padding:12px 16px}}
/* Shared lesson catalog and state views. */
.catalog-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,280px),1fr));gap:18px}.catalog-category{margin:30px 0}.lesson-card{display:block;padding:24px;color:var(--ink);text-decoration:none}.lesson-card:hover{border-color:var(--gold)}.lesson-card h3{font-size:1.35rem;margin:10px 0}.lesson-card p{line-height:1.7}#lesson-search{width:100%;padding:14px;font:inherit;border:1px solid var(--line);border-radius:12px;background:var(--surface);color:var(--ink)}.visual-array{display:flex;flex-wrap:wrap;gap:7px;list-style:none;padding:0}.visual-array li{min-width:48px;border:1px solid currentColor;border-radius:7px;padding:8px;text-align:center}.visual-array small,.visual-array strong{display:block}.visual-array small{opacity:.65}.structure-view{overflow:auto;padding:12px;max-height:600px}.structure-view svg{display:block;width:100%;height:auto;min-width:240px;max-height:none}.edge-label{fill:var(--muted);font-size:12px}.pointer-strip{display:flex;flex-wrap:wrap;gap:12px;margin:12px 0}.pointer-strip span{padding:8px;border:1px solid currentColor;border-radius:8px}.state-changed{background:rgba(98,217,206,.12)}.visual-grid td{text-align:center;min-width:36px;border:1px solid currentColor}.panel-pad dd{margin:6px 0 18px;line-height:1.65}.panel-pad pre,.solution-code{overflow:auto;max-width:100%}#run-results{white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.8;margin:14px 0}.trace-grid>div{min-width:0}#custom-tests{width:100%;min-height:170px}#trace-example{max-width:100%}#trace-scrub{width:100%}#variables td{white-space:pre-wrap;overflow-wrap:anywhere;max-width:30ch}#source{max-height:760px;overflow:auto}#source li.active{position:relative}.catalog-grid .panel{margin:0}#prediction{width:100%}

#helper-event{max-width:100%;width:100%}.structure-subview{margin:16px 0}.structure-subview h4{margin:8px 0}

.panel-pad select{border:1px solid var(--line);border-radius:8px;background:var(--surface2);color:var(--ink);padding:10px;max-width:100%;margin:8px 0}#source{position:relative}.visual-array li{border-color:var(--line);background:var(--code)}

.histogram-view{overflow-x:auto;margin:1rem 0}.histogram-view svg{display:block;width:100%;min-width:260px;max-height:300px}.histogram-bar rect{fill:var(--gold);opacity:.35;stroke:currentColor}.histogram-bar.active rect{opacity:.85}.histogram-bar text{fill:currentColor;font-size:13px;text-anchor:middle}.histogram-bar .bar-index{opacity:.7}.histogram-candidate{fill:#4ddac622;stroke:#20bba7;stroke-width:3;stroke-dasharray:6 3}.visual-grid .cell-selected{background:#4ddac633;box-shadow:inset 0 0 0 2px #20bba7}.visual-grid .cell-current{outline:3px solid #e8ad29;outline-offset:-4px}

.visual-grid .block-right{border-right-width:3px}.visual-grid .block-bottom{border-bottom-width:3px}.tree-edge.edge-active{stroke:var(--gold);stroke-width:5}

.coordinate-view{overflow:auto}.coordinate-view svg{width:100%;min-width:320px;max-width:620px;display:block}.coordinate-axis{fill:none;stroke:var(--muted);stroke-width:1}.coordinate-view text{fill:var(--ink);font:12px ui-monospace,monospace;text-anchor:middle}.coordinate-point circle{fill:var(--ink);stroke:var(--bg);stroke-width:2}.coordinate-point.active circle{fill:var(--gold)}.coordinate-point.selected circle{fill:var(--cyan)}.coordinate-rectangle{fill:rgba(84,210,200,.15);stroke:var(--cyan);stroke-width:2}

.worked-examples{display:grid;gap:20px}.worked-examples>.panel{margin:0}.worked-example>h3{font-size:21px;margin:0 0 22px}.example-flow{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:28px}.example-flow>section{min-width:0}.example-flow>section+section{border-left:1px solid var(--line);padding-left:28px}.example-label{margin:0 0 16px!important;font-size:12px!important;letter-spacing:.06em;text-transform:uppercase;color:var(--muted)!important}.input-data{margin-top:14px;font-size:12px}.input-data summary{cursor:pointer;color:var(--muted)}.answer-summary{border-left:3px solid var(--cyan);padding:12px 16px;margin:18px 0 0;background:var(--code);border-radius:0 8px 8px 0}.answer-summary>strong{font-size:11px;text-transform:uppercase;letter-spacing:.1em;margin-right:10px}.answer-summary>code{font-size:15px;color:var(--cyan);overflow-wrap:anywhere;white-space:pre-wrap}.answer-summary>p{margin:8px 0 0;line-height:1.7}.diagram-caption{font-size:11px;color:var(--muted);margin:4px 12px 12px}.structure-view{padding:10px 8px;max-height:440px}.structure-view svg{max-height:380px;margin:0 auto}.structure-subview h4{font-size:12px;margin:14px 0 8px;color:var(--muted)}.visual-array{gap:6px;margin:10px 0;padding:0}.visual-array li{border-color:var(--line);background:var(--code);min-width:40px;padding:6px 9px;font-size:13px}.visual-array small{font-size:10px}.visual-array strong{font-weight:500}.worked-walkthrough{margin-top:24px;padding-top:20px;border-top:1px solid var(--line)}.walkthrough-controls{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-top:14px}.walkthrough-controls span{color:var(--muted);font-size:12px}.walkthrough-note{min-height:2.5em}.walkthrough-title{margin:0 0 12px;font-size:15px}
@media(max-width:760px){.example-flow{grid-template-columns:1fr;gap:20px}.example-flow>section+section{border-left:0;border-top:1px solid var(--line);padding:20px 0 0}.worked-example>h3{font-size:18px}.structure-view svg{max-height:320px}}

.visual-grid{width:max-content;max-width:100%;table-layout:auto}.visual-grid td{padding:9px 14px}.visual-grid tbody tr:last-child{color:var(--ink)}.visual-grid.square-grid{width:auto;table-layout:fixed}.visual-grid.square-grid td{width:var(--cell-size);min-width:var(--cell-size);height:var(--cell-size);padding:0}.visual-grid caption{line-height:1.5}.example-flow .table-scroll{margin:0 0 12px}

.table-scroll:has(.visual-grid){width:fit-content;max-width:100%}

.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}

.visual-grid.square-grid td{font-size:13px}

.structure-disclosure{margin:12px 0}.structure-disclosure>summary{cursor:pointer;color:var(--cyan);font-size:13px;padding:8px 0}.structure-disclosure>.table-scroll{margin-top:8px}

.mobile-pan-hint{display:none}.structure-view:focus-visible{outline:2px solid var(--gold);outline-offset:2px}@media(max-width:600px){.mobile-pan-hint{display:inline}}

/* Optional checked visual decisions reuse the course's ink/cyan/gold palette. */
/* Grid's automatic min-content width must not stretch narrow lesson panels. */
.learning-exercises,.learning-exercises>div,.learning-panel,.learning-panel .panel-pad{min-width:0}
.learning-exercises{display:grid;gap:20px;margin-bottom:24px}.learning-panel{margin:0}.learning-panel h3{margin:0 0 10px}.learning-panel p{line-height:1.7}.learning-panel .visual-array li:has(button){padding:0}.learning-panel .visual-array button{display:grid;gap:6px;min-width:48px;min-height:52px;padding:8px 12px;border:0;background:transparent;color:var(--ink)}.visual-array li.cell-selected{border-color:var(--cyan);background:color-mix(in srgb,var(--cyan) 18%,var(--code))}.visual-array li.cell-current{outline:2px solid var(--gold)}.learning-choices{display:flex;flex-wrap:wrap;gap:10px;margin:16px 0}.learning-choices button[aria-pressed=true]{border-color:var(--cyan);background:color-mix(in srgb,var(--cyan) 18%,var(--code))}.learning-selection{font:13px/1.7 var(--mono);padding:12px;background:var(--code);border-left:3px solid var(--cyan);overflow-wrap:anywhere}.learning-panel input{max-width:100%;box-sizing:border-box;padding:12px;border:1px solid var(--line);border-radius:8px;color:var(--ink);background:var(--code)}[data-learning-feedback][data-pass=true]{color:var(--cyan)}[data-learning-feedback][data-pass=false]{color:var(--gold)}[data-learning-reveal]{margin-top:18px}.learning-panel .visual-array button:focus-visible,.learning-choices button:focus-visible{outline:3px solid var(--gold);outline-offset:3px}
.interactive-grid { max-width:100%; overflow:auto; }
.learning-choices button { min-width:44px; min-height:44px; }
.interactive-grid .visual-grid { width:max-content; min-width:0; }
.interactive-grid .visual-grid td { padding:0; min-width:48px; height:48px; }
.interactive-grid button { min-width:44px; min-height:44px; width:100%; border:0; border-radius:0; background:transparent; color:inherit; padding:8px; }
.interactive-grid button:focus-visible { outline:3px solid var(--gold); outline-offset:-3px; }
.histogram-water { fill:color-mix(in srgb,var(--cyan) 42%,transparent); stroke:var(--cyan); stroke-width:1.5; }

.node-value-legend{margin:12px 0;min-width:0}.node-value-legend>p{font-size:.8rem;opacity:.75;margin:0 0 8px}.node-value-legend ul{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,220px),1fr));gap:8px;list-style:none;margin:0;padding:0}.node-value-legend li{display:flex;gap:10px;align-items:flex-start;padding:8px 10px;border:1px solid var(--line);border-radius:8px;min-width:0}.node-value-legend li.active{border-color:var(--gold)}.node-value-legend li>strong{flex-shrink:0}.node-value-legend li>span{overflow-wrap:anywhere;min-width:0;font-family:monospace;font-size:.85rem}.node-value-legend small{display:block;font-family:inherit;opacity:.7;margin-bottom:3px}

.visual-array li{max-width:100%;box-sizing:border-box}.visual-array strong{white-space:normal;overflow-wrap:anywhere;min-width:0}

.disk-stack-view{max-width:100%;min-width:0}.disk-stack-view svg{display:block;width:100%;max-width:430px;height:auto}.disk-stack-view rect{fill:color-mix(in srgb,var(--cyan) 25%,var(--surface));stroke:var(--cyan);stroke-width:1.5}.disk-stack-view line{stroke:var(--muted);stroke-width:1;stroke-dasharray:3 3}.disk-stack-view ol{padding-left:24px;font:12px/1.8 var(--mono);overflow-wrap:anywhere}