.lesson-intro{padding:38px 0 28px;max-width:850px}.lesson-intro h1{font-size:clamp(33px,4.3vw,53px);margin:10px 0 20px}.task-description{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:28px 32px;margin-bottom:28px}.task-description h2{font-size:22px;margin-bottom:14px}.task-description p{max-width:850px}.example{padding:15px 18px;background:var(--soft);border-radius:9px;font:14px/1.7 ui-monospace,monospace;white-space:pre-wrap}.approach-nav{display:flex;gap:24px;margin-bottom:30px;font-size:14px}.approach-nav a{text-decoration:underline;text-underline-offset:5px}.approach{border-top:1px solid var(--line);padding:38px 0 50px}.approach h2{font-size:30px;margin-bottom:15px}.approach .explanation{max-width:860px;color:var(--muted)}.workspace{display:grid;grid-template-columns:minmax(0,.95fr) minmax(0,1.05fr);gap:22px;align-items:start;margin:26px 0}.code-pane{position:sticky;top:calc(var(--header) + 20px);border:1px solid var(--line);border-radius:14px;background:#f1f6fd;overflow:hidden}.pane-heading{padding:13px 18px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);font-size:12px;color:var(--muted)}pre[data-code]{margin:0;padding:18px 10px;overflow:auto;max-height:480px;line-height:1.9;font-size:12px}pre[data-code] code{font-size:inherit}pre[data-code] span{display:block;width:max-content;min-width:100%;padding:0 7px;border-left:2px solid transparent}pre[data-code] .current{background:#d5e8ff;border-color:var(--primary)}.demo{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:22px;min-width:0}.demo h3{font-size:18px;margin-bottom:18px}.inputs{display:grid;grid-template-columns:minmax(0,1fr) 90px;gap:10px;align-items:end}.inputs label{font-size:12px;font-weight:600;display:grid;gap:6px}.inputs input{min-width:0;width:100%;border:1px solid #bdcde4;background:var(--paper);border-radius:7px;padding:9px 10px;color:var(--ink);font-size:14px}.inputs button{grid-column:1/-1;justify-self:start}.inputs button,.controls button{font-size:12px;border:1px solid var(--line);background:var(--paper);border-radius:7px;padding:9px 13px;min-height:40px}.inputs button:hover,.controls button:hover:not(:disabled){border-color:var(--primary)}.controls button.primary{background:var(--primary);border-color:var(--primary);color:#fff}.help{font-size:12px;color:var(--muted);margin:10px 0}.stage{position:relative;padding-top:30px;margin:20px 0 10px}.boxes{display:grid;grid-template-columns:repeat(auto-fit,minmax(48px,1fr));gap:34px 8px}.cell{text-align:center;min-width:0}.value{border:1px solid #c6d9ee;background:#edf4fc;border-radius:8px;padding:10px 2px;font-size:14px;font-variant-numeric:tabular-nums;overflow-wrap:anywhere;transition:background .25s}.index{font-size:11px;color:var(--muted);margin-top:4px}.left .value{background:#d2e5ff;border-color:var(--blue)}.right .value{background:#ead9f6;border-color:var(--purple)}.found .value{background:#d5efd7;border-color:var(--success)}.pointer{position:absolute;left:0;top:0;font-size:12px;font-weight:700;white-space:nowrap;transition:transform .4s ease}.pointer-a{color:var(--blue)}.pointer-b{color:var(--purple)}.result{min-height:105px;font-size:13px;margin:16px 0}.expression{font:13px/1.7 ui-monospace,monospace;overflow-wrap:anywhere;margin-bottom:10px}.controls{display:flex;flex-wrap:wrap;gap:7px}.error{color:#b42318;font-size:13px}.complexity{display:grid;grid-template-columns:1fr 1fr;gap:24px;padding:20px 24px;background:var(--soft);border-radius:12px;font-size:14px}.complexity h3{font-size:15px;margin-bottom:10px}.complexity p{margin:0;color:var(--muted)}.sort-note{font-size:13px;color:var(--muted);padding:16px 0 0}.task-pin{position:fixed;top:calc(var(--header) + 14px);right:24px;z-index:35;border:1px solid #a0bbdf;border-radius:12px;background:var(--highlight);color:var(--ink);box-shadow:0 5px 20px #182c4b15;padding:10px 16px;display:flex;gap:18px;align-items:center;text-align:left}.task-pin span{display:grid;font-size:12px;line-height:1.4}.task-pin strong{font-size:13px}.task-pin .pin-icon{font-size:21px}.task-dialog{border:1px solid var(--line);padding:0;border-radius:18px;background:var(--surface);color:var(--ink);max-width:640px;width:calc(100% - 36px);max-height:80dvh;overflow:auto;box-shadow:0 24px 80px #132e4b38}.task-dialog::backdrop{background:#112542a6;backdrop-filter:blur(3px)}.dialog-header{position:sticky;top:0;display:flex;justify-content:space-between;gap:20px;align-items:center;padding:20px 24px;background:var(--surface);border-bottom:1px solid var(--line)}.dialog-header h2{font-size:21px}.dialog-header button{font:14px system-ui;background:var(--soft);border:1px solid var(--line);border-radius:7px;padding:8px 12px}.dialog-body{padding:24px}.dialog-body p{font-size:15px}.dialog-help{font-size:12px!important;color:var(--muted);margin:20px 0 0}.lesson-footer{padding-bottom:40px;font-size:12px;color:var(--muted)}[hidden]{display:none!important}@media(min-width:1500px){.task-pin{right:calc((100vw - 1460px)/2)}}@media(max-width:900px){.workspace{grid-template-columns:1fr}.code-pane{position:static}pre[data-code]{max-height:260px}.complexity{grid-template-columns:1fr;gap:18px}.task-pin{right:14px}.demo{padding:20px}.lesson-intro{padding-top:28px}}@media(max-width:640px){.task-description{padding:20px}.approach h2{font-size:25px}.task-pin{top:calc(var(--header) + 8px);padding:8px 12px}.task-pin span{font-size:11px}.task-pin strong{font-size:12px}.lesson-intro h1{font-size:35px}.inputs input{font-size:16px}.controls button{min-height:44px}.dialog-header{padding:16px}.dialog-header h2{font-size:18px}.dialog-body{padding:20px}}@media(prefers-reduced-motion:reduce){.pointer,.value{transition:none}}

/* Reserve a header row so the task shortcut never covers lesson controls. */
.lesson-page{--header:140px}.lesson-page .nav-inner{height:76px}.lesson-toolbar{height:64px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-top:1px solid var(--line)}.toolbar-title{font-size:11px;font-weight:700;letter-spacing:.09em}.toolbar-title span{font-weight:400;letter-spacing:0;color:var(--muted);margin-left:10px}.lesson-toolbar .task-pin{position:static;box-shadow:none;padding:7px 13px;border-radius:8px}.task-pin span{font-size:11px}.task-pin strong{font-size:12px}@media(max-width:640px){.lesson-page{--header:168px}.lesson-page .nav-inner{height:104px}.toolbar-title span{display:none}.lesson-toolbar .task-pin{padding:6px 10px}}
@media(max-width:900px){.workspace .code-pane{position:static}.workspace pre[data-code]{max-height:170px}.workspace .pane-heading{padding:9px 14px}}

@media(max-width:1000px){.lesson-page{--header:178px}.lesson-page .nav-inner{height:114px}}

.solution-video{width:100%;aspect-ratio:16/9;margin:24px 0 0;border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--soft)}.solution-video iframe{display:block;width:100%;height:100%;border:0}.video-link{margin:10px 0 24px;font-size:13px}.video-link a{color:var(--primary);text-decoration:underline;text-underline-offset:4px}

.lesson-page .notes-content{padding-top:28px}.lesson-toolbar h1.toolbar-title{font-size:14px;margin:0;letter-spacing:0;font-weight:600}.approach .complexity{margin:22px 0}.approach .complexity+p.explanation{margin-top:20px}
.lesson-toolbar .toolbar-title,.lesson-toolbar .task-pin{min-width:0;overflow-wrap:anywhere}.lesson-toolbar .task-pin>span:first-child{min-width:0}.example{overflow-wrap:anywhere}

.pattern-intro{padding:0 0 24px!important;border-top:0}.pattern-intro h1{font-size:34px;line-height:1.25;margin:0 0 14px}.pattern-intro h2{font-size:18px;margin:20px 0 10px}.pattern-intro p{max-width:800px}.pattern-examples{padding-left:22px;margin:0}.pattern-examples li{margin:7px 0}.pattern-examples a{text-decoration:underline;text-underline-offset:3px}.lesson-toolbar{justify-content:flex-end}.lesson-toolbar:has(.task-pin[hidden]){display:none}.lesson-page:has(.task-pin[hidden]){--header:76px}@media(max-width:1000px){.lesson-page:has(.task-pin[hidden]){--header:114px}}