:root{color-scheme:dark;--bg:#101622;--panel:#171f2d;--canvas:#121a27;--line:#2a3548;--muted:#98a7bd;--text:#edf0f7;--accent:#b5afff;--accent-dark:#302f51;--mint:#71dfc1;--amber:#ffc880;--font:Inter,"Segoe UI","Microsoft YaHei",sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font);font-size:14px;line-height:1.6}button,input,select{font:inherit}button,select,input[type=range]{cursor:pointer}button,a,select,input{touch-action:manipulation}button{color:inherit}a{color:inherit;text-decoration:none}button{border:0}button:disabled{opacity:.35;cursor:not-allowed}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible{outline:2px solid var(--mint);outline-offset:4px}button:hover:not(:disabled){filter:brightness(1.14)}[hidden]{display:none!important}.topbar{height:80px;border-bottom:1px solid var(--line);display:flex;align-items:center;padding:0 28px;gap:24px;background:#111825}.brand{display:flex;align-items:center;gap:11px;font-size:19px;font-weight:750;letter-spacing:1.7px;line-height:1.2}.brand-mark{background:var(--accent);color:#161a2c;width:39px;height:39px;display:flex;justify-content:center;align-items:center;border-radius:11px;font-size:29px;letter-spacing:-5px;padding-right:5px}.brand-mark span{font-size:30px;color:#565181}.brand-light{font-weight:350;color:var(--accent)}.brand small{display:block;font-size:12px;font-weight:400;color:var(--muted);letter-spacing:3px;margin-top:4px}.topbar-note{color:var(--muted);margin-left:28px;font-size:14px}.topbar>.button{margin-left:auto}.button{display:inline-flex;justify-content:center;align-items:center;gap:8px;padding:9px 15px;border-radius:7px;background:#232d3e;border:1px solid #344056;white-space:nowrap;min-height:39px}.button.primary{background:var(--accent);color:#1b1a32;border-color:var(--accent);font-weight:650}.button.quiet{background:transparent;border-color:transparent;color:#b9c4d7}.button.small{padding:5px 10px;min-height:32px;font-size:13px}.button.danger{color:#ffb7b7;background:#3b2733;border-color:#5e3641}.topbar .quiet span{border:1px solid #75829a;border-radius:50%;width:18px;height:18px;line-height:17px;font-size:13px}.shell{display:grid;grid-template-columns:218px minmax(0,1fr);min-height:calc(100vh - 80px)}.sidebar{padding:31px 17px 20px;border-right:1px solid var(--line);display:flex;flex-direction:column;background:#111825}.eyebrow{font-size:11px;font-weight:600;letter-spacing:1.3px;color:var(--muted)}.sidebar>.eyebrow{padding-left:12px;font-size:12px}.nav-group{display:flex;align-items:center;justify-content:space-between;margin:26px 13px 10px;color:#8b9bb2;font-size:12px}.nav-group span{font-family:Consolas,monospace;color:#65728a}.algorithm{width:100%;display:flex;align-items:center;gap:12px;text-align:left;background:transparent;border:1px solid transparent;padding:13px 11px;margin:3px 0;border-radius:8px;color:#b2bed1;font-size:14px}.algorithm small{display:block;font-size:10px;letter-spacing:1.6px;color:#7f8da4;margin-top:2px}.algorithm-symbol{width:24px;font-size:25px;font-family:"Segoe UI Symbol",sans-serif;text-align:center;color:#8191ab;line-height:1}.algorithm.active{background:#292942;border-color:#424064;color:#dedbff}.algorithm.active small,.algorithm.active .algorithm-symbol{color:var(--accent)}.nav-active{width:5px;height:5px;margin-left:auto;border-radius:50%;background:transparent}.active .nav-active{background:var(--accent)}.sidebar-bottom{margin-top:auto;padding:65px 13px 4px}.sidebar-bottom strong{font-size:13px;font-weight:500;color:#bdc6d8}.sidebar-bottom p{font-size:12px;line-height:1.9;color:#7f8da4;margin:8px 0 22px}.tech-label{font-family:Consolas,monospace;font-size:10px;color:#65768e;letter-spacing:.7px}.mini-graph{display:flex;gap:6px;align-items:center;margin-bottom:14px}.mini-graph i{width:6px;height:6px;background:#62668b;border-radius:50%}.mini-graph i:nth-child(2){width:20px;height:1px;border-radius:0}.mini-graph i:nth-child(4){background:var(--mint)}main{padding:27px 29px 0;min-width:0;max-width:1800px;width:100%;margin:auto}.page-heading{display:flex;justify-content:space-between;gap:22px;align-items:center;margin-bottom:23px}.page-heading .eyebrow{font-size:12px;letter-spacing:.5px}.slash{margin:0 12px;color:#4e5c73}h1{font-size:27px;font-weight:650;letter-spacing:.3px;margin:8px 0 5px;line-height:1.5}h1 span{font-family:Consolas,monospace;color:var(--accent);font-size:16px;vertical-align:middle;font-weight:400;margin-left:10px;border:1px solid #42445f;padding:3px 8px;border-radius:5px}.page-heading p{color:var(--muted);font-size:14px;margin:0;max-width:680px}.complexity{white-space:nowrap;text-align:right;padding-left:20px}.complexity span{display:block;color:var(--muted);font-size:11px}.complexity strong{font-family:Consolas,monospace;font-size:20px;font-weight:400;color:var(--mint);display:block;margin-top:7px}.workspace{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:20px;align-items:start}.graph-column{min-width:0}.graph-panel,.playback-panel,.inspect-panel,.result-panel{border:1px solid var(--line);background:var(--panel);border-radius:10px;overflow:hidden}.panel-top{display:flex;justify-content:space-between;align-items:center;padding:16px 18px;gap:10px}.panel-top>div{display:flex;align-items:center;gap:9px}.panel-top strong{font-weight:550}.panel-dot{width:7px;height:7px;border:1px solid var(--accent);border-radius:2px;transform:rotate(45deg)}.subtle{font-size:12px;color:var(--muted);margin-left:7px}.chip{border:1px solid #364158;border-radius:4px;font-size:11px;color:#9eacc1;padding:2px 7px;white-space:nowrap}.graph-actions{display:flex;align-items:center;gap:7px;padding:0 14px 12px;border-bottom:1px solid var(--line)}select{background:#202a3b;border:1px solid #39465d;color:#dce3f1;border-radius:6px;padding:6px 24px 6px 10px;max-width:100%;min-height:33px}option{background:#1a2232}.select-label select{font-size:13px}.spacer{flex:1}.canvas-wrap{position:relative;height:clamp(345px,42vw,480px);overflow:hidden;background:var(--canvas)}#graphCanvas{display:block;width:100%;height:100%;touch-action:none}.canvas-badge{pointer-events:none;position:absolute;top:15px;left:18px;display:flex;align-items:center;gap:7px;color:#91a4bc;font-size:11px;letter-spacing:.6px}.status-dot{background:#8291a8;width:5px;height:5px;border-radius:50%}.is-playing .status-dot{background:var(--mint);box-shadow:0 0 10px #71dfc14a}.canvas-tools{position:absolute;left:50%;bottom:16px;transform:translateX(-50%);display:flex;align-items:center;gap:3px;background:#1b2535f5;border:1px solid #36435b;padding:5px;border-radius:9px;box-shadow:0 5px 22px #0005;white-space:nowrap}.tool{font-size:12px;padding:7px 9px;min-height:34px;background:transparent;color:#a9b7ce;border-radius:5px}.tool span{font-size:18px;vertical-align:-1px;line-height:1;margin-right:3px}.tool.active{color:#dedaff;background:#383653}.tool-separator{height:19px;width:1px;background:#3a4459;margin:0 3px}.empty-graph{pointer-events:none;position:absolute;top:40%;left:0;right:0;text-align:center;color:#acb9cd}.empty-graph strong{font-size:20px}.empty-graph p{font-size:13px}.canvas-footer{display:flex;align-items:center;justify-content:space-between;padding:12px 16px 6px;gap:8px}.legend{display:flex;flex-wrap:wrap;gap:12px;color:#a3b1c7;font-size:11px}.legend span{display:flex;gap:5px;align-items:center}.legend-node{width:8px;height:8px;display:inline-block;border-radius:50%}.legend-node.idle{background:#26344a;border:1px solid #8396b5}.legend-node.queued{background:var(--accent)}.legend-node.current{background:var(--amber)}.legend-node.visited{background:var(--mint)}.text-button{font-size:12px;background:transparent;color:var(--muted);white-space:nowrap;padding:0}.edit-hint{color:#72829b;font-size:11px;padding:0 16px 12px}.playback-panel{margin-top:16px;padding:15px 18px}.run-config{display:flex;align-items:center;gap:16px;margin-bottom:16px}.run-config label{display:flex;align-items:center;gap:9px;font-size:12px;color:#a0aec5}.run-config select{min-width:60px;font-family:Consolas,var(--font);padding-top:3px;padding-bottom:3px}.playback-controls{display:flex;align-items:center;gap:9px}.icon-button{background:#222c3e;border:1px solid #364159;border-radius:6px;display:inline-flex;align-items:center;justify-content:center;width:33px;height:35px;font-size:18px;flex-shrink:0}.playback-controls .primary{min-width:115px;padding:8px 12px}.timeline{flex:1;min-width:60px;margin-left:8px}.timeline input{width:100%;height:4px;accent-color:var(--accent);display:block;margin:8px 0 10px}.timeline>div{display:flex;justify-content:space-between;font-size:10px;font-family:Consolas,var(--font);color:var(--muted);gap:5px}.step-message{margin-top:16px;border-top:1px solid var(--line);padding-top:13px;display:flex;align-items:flex-start;gap:10px;min-height:43px}.step-message>span{border:1px solid #5a5b8c;color:var(--accent);border-radius:50%;width:17px;height:17px;text-align:center;line-height:16px;font-family:Georgia,serif;font-size:12px;flex-shrink:0;margin-top:2px}.step-message p{margin:0;color:#bdc8db;font-size:13px;line-height:1.7}.inspector{display:flex;flex-direction:column;gap:16px}.inspect-panel{padding:17px 17px 15px}.inspect-heading{display:flex;justify-content:space-between;align-items:center;margin-bottom:17px}.inspect-heading h2,.insight h2{font-size:14px;font-weight:550;margin:0}.inspect-heading .eyebrow{font-size:9px;letter-spacing:1px;color:#8493ab}.metrics{display:grid;grid-template-columns:1fr 1fr;margin-bottom:17px}.metrics>div+div{border-left:1px solid var(--line);padding-left:19px}.metrics span{font-size:11px;color:#97a7be;display:block}.metrics strong{font-size:27px;line-height:1.6;font-family:Consolas,monospace;font-weight:400}.metrics small{font-size:13px;color:#6f839f}.structure-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px;color:#a6b5cb;font-size:11px;gap:10px}.structure-header small{font-size:10px;white-space:nowrap;color:#7f92ad}.structure-items{display:flex;flex-wrap:wrap;gap:6px;background:#111a28;border:1px dashed #354059;min-height:45px;border-radius:5px;padding:9px;margin-bottom:16px;max-height:138px;overflow:auto}.structure-item{padding:1px 9px;border:1px solid #514d7d;background:#292a44;color:#c5c0ff;font-family:Consolas,var(--font);font-size:12px;border-radius:4px}.structure-item:first-child{border-color:#9792ce}.placeholder{color:#697b95;font-size:12px;margin:auto}.table-scroll{max-height:252px;overflow:auto;scrollbar-width:thin;scrollbar-color:#3d4c66 transparent}table{border-collapse:collapse;width:100%;font-size:12px;text-align:left}thead{position:sticky;top:0;background:var(--panel)}th{color:#8497b2;font-weight:400;padding:6px 5px;border-bottom:1px solid #344158}td{padding:7px 5px;border-bottom:1px solid #263146;color:#a9b9d0;font-family:Consolas,var(--font)}tbody tr:last-child td{border-bottom:0}td:first-child{color:#e0e6f2;font-weight:600}td:last-child{font-size:10px;font-family:var(--font)}tr.node-current td{color:var(--amber);background:#ffc88008}tr.node-visited td:last-child{color:var(--mint)}tr.node-frontier td:last-child{color:var(--accent)}.code-panel{padding-bottom:0}.code-panel .inspect-heading{margin-bottom:13px}#pseudocode{list-style:none;margin:0 -17px;padding:0;counter-reset:line}#pseudocode li{position:relative;counter-increment:line;padding:7px 13px 7px 38px;font-size:11px;line-height:1.7;color:#91a4c0;white-space:pre-wrap;border-left:2px solid transparent}#pseudocode li:before{content:counter(line,decimal-leading-zero);position:absolute;left:12px;color:#5d708e;font:10px/1.9 Consolas,monospace}#pseudocode li.highlight{background:#302f4e;border-left-color:var(--accent);color:#dedaff}#pseudocode li.highlight:before{color:#a39adf}.code-note{font-size:10px;color:#7c8ea8;border-top:1px solid var(--line);padding:11px 0;margin-top:10px}.insight{display:flex;gap:12px;background:#1b2533;border-color:#2e4350}.insight-icon{color:var(--mint);font-size:20px;line-height:1.3}.insight h2{font-size:12px;color:#b9d7d6;margin-bottom:6px}.insight p{font-size:12px;color:#94a8bc;margin:0;line-height:1.9}.result-panel{margin-top:16px;padding:15px 18px;border-color:#396057;background:#172c2d}.result-label{font-size:11px;color:var(--mint)}.result-panel h2{font:600 20px/1.5 var(--font);margin:5px 0;overflow-wrap:anywhere}.result-panel p{font-size:13px;color:#a6c2c0;margin:0}.page-footer{display:flex;justify-content:space-between;gap:15px;color:#647793;font-size:10px;letter-spacing:.4px;padding:21px 0}.page-footer b{font-weight:400;margin:0 9px;color:#455772}dialog{background:#1a2332;border:1px solid #43516a;color:var(--text);border-radius:12px;padding:25px;max-width:520px;width:calc(100% - 32px);box-shadow:0 30px 90px #0007}dialog::backdrop{background:#050910bd;backdrop-filter:blur(4px)}.dialog-title{display:flex;align-items:center;justify-content:space-between;gap:15px}.dialog-title h2{font-size:19px;margin:0}.dialog-title .icon-button{border:0;background:transparent}dialog p{color:#a9b9cf;font-size:14px;line-height:1.9}.field{display:flex;flex-direction:column;gap:8px;color:#d1d8e5;margin-top:20px}.field input{background:#111a29;border:1px solid #465873;padding:11px 13px;border-radius:6px;color:var(--text);font-size:17px}.dialog-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:23px}.help-dialog{max-width:790px}.help-lead{font-size:16px!important}.help-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin:27px 0}.help-steps article>span{font:26px Consolas,monospace;color:var(--accent)}.help-steps h3{font-size:15px;font-weight:550}.help-steps p,.help-note p{font-size:13px}.help-note{background:#131d2c;border:1px solid var(--line);padding:16px;border-radius:8px;margin-bottom:23px}.help-note strong{font-size:14px}.help-note p:last-child{margin-bottom:0}.toast{position:fixed;bottom:25px;left:50%;transform:translateX(-50%);z-index:20;background:#e2dcff;color:#1c2131;padding:11px 22px;border-radius:8px;box-shadow:0 5px 35px #0006;max-width:calc(100% - 30px);font-size:14px}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@media(min-width:1550px){main{padding:32px 36px 0}.workspace{grid-template-columns:minmax(0,1fr) 340px;gap:24px}.canvas-wrap{height:530px}.inspector{gap:18px}.table-scroll{max-height:300px}#pseudocode li{font-size:12px;padding-top:9px;padding-bottom:9px}}
@media(max-width:1200px){.shell{grid-template-columns:190px minmax(0,1fr)}.sidebar{padding-left:10px;padding-right:10px}main{padding:23px 20px 0}.workspace{grid-template-columns:minmax(0,1fr) 280px;gap:15px}.complexity{display:none}.algorithm{gap:8px;font-size:13px}.graph-actions{gap:2px;padding-left:9px;padding-right:9px}.button.small{padding:5px 7px}.canvas-wrap{height:420px}.canvas-footer{align-items:flex-start}.legend{gap:8px}.playback-panel{padding:13px}.playback-controls{gap:6px}.timeline{margin-left:2px}.subtle{font-size:11px;margin-left:2px}.panel-top{padding:14px 12px}.canvas-tools .tool{padding:7px}.page-footer{font-size:9px}}
@media(max-width:1000px){.shell{grid-template-columns:170px minmax(0,1fr)}.workspace{grid-template-columns:minmax(0,1fr)}.inspector{display:grid;grid-template-columns:1fr 1fr;align-items:start}.inspector .insight{grid-column:1/-1}.sidebar{padding-top:26px}.algorithm-symbol{display:none}.algorithm{padding:11px 9px}.sidebar-bottom{padding-left:10px}.canvas-wrap{height:450px}.topbar-note{display:none}.table-scroll{max-height:240px}.page-heading p{max-width:600px}.graph-actions .button.small{padding:5px 10px}}
@media(max-width:700px){.topbar{height:68px;padding:0 16px}.brand{font-size:16px}.brand-mark{width:34px;height:34px;font-size:25px}.brand small{font-size:10px}.topbar .button{font-size:12px;padding:7px}.shell{display:block}.sidebar{padding:10px 13px;border-right:0;border-bottom:1px solid var(--line);overflow:auto}.sidebar>.eyebrow,.nav-group,.sidebar-bottom{display:none}#algorithmNav{display:flex;gap:5px;width:max-content}.algorithm{width:auto;min-width:88px;font-size:12px;margin:0;padding:8px 10px}.algorithm small{font-size:9px;margin-top:2px}.nav-active{display:none}main{padding:20px 13px 0}.page-heading{margin-bottom:16px}h1{font-size:23px;margin-top:6px}h1 span{font-size:13px}.page-heading p{font-size:13px}.page-heading .eyebrow{font-size:10px}.canvas-wrap{height:395px}.graph-actions{flex-wrap:wrap;gap:3px}.graph-actions select{max-width:127px}.graph-actions .button.small{font-size:11px;padding:5px 7px}.graph-actions .spacer{min-width:0}.graph-actions #imageBtn{margin-left:auto}.panel-top{padding:12px}.subtle{font-size:10px}.chip{font-size:10px}.panel-top strong{font-size:13px}.canvas-tools{bottom:13px}.tool{font-size:11px!important}.tool span{font-size:16px}.canvas-footer{padding:12px 10px 6px}.legend{font-size:10px;gap:7px}.edit-hint{padding-left:10px}.playback-panel{padding:13px 11px}.playback-controls{gap:6px;flex-wrap:wrap}.playback-controls .primary{min-width:117px}.timeline{min-width:90px;margin-left:4px}.icon-button{width:29px;height:34px;font-size:16px}.run-config{gap:12px}.run-config label{font-size:11px;gap:6px}.run-config select{min-width:48px;padding-left:6px}.inspector{grid-template-columns:1fr}.inspector .insight{grid-column:auto}.table-scroll{max-height:265px}.inspect-heading .eyebrow{font-size:10px}#pseudocode li{font-size:13px;padding-top:8px;padding-bottom:8px}.code-note{font-size:11px}.structure-header{font-size:12px}.metrics span{font-size:12px}table{font-size:13px}.page-footer{flex-direction:column;gap:5px;padding:18px 2px;font-size:10px}.help-steps{grid-template-columns:1fr;gap:10px}.help-steps article>span{font-size:21px}.help-steps h3{display:inline;margin-left:12px}.help-steps p{margin-top:6px}.dialog-actions{gap:7px;flex-wrap:wrap}dialog{padding:19px}.dialog-actions .button{font-size:13px;padding:8px 12px}}
@media(prefers-reduced-motion:no-preference){button{transition:background .16s,border-color .16s,filter .16s}.algorithm{transition:background .2s}.toast{animation:toast-in .2s ease-out}@keyframes toast-in{from{opacity:0;transform:translate(-50%,6px)}to{opacity:1;transform:translate(-50%,0)}}}

/* Version 2: experiment controls and two independent teaching views. */
.lab-controls{display:flex;flex-wrap:wrap;align-items:center;gap:10px;margin:0 0 16px;padding:12px 14px;background:#182233;border:1px solid var(--line);border-radius:9px}
.lab-controls label{display:flex;align-items:center;gap:8px;font-size:12px;color:#b3c4db}
select{max-width:100%;background:#111b2a;color:#e0e9f8;border:1px solid #43536d;border-radius:5px;padding:7px}
.save-status{font-size:11px;color:#8ac9b9;margin-left:auto}.notice{padding:12px 16px;border:1px solid #796044;background:#362d22;color:#ffdaa0;border-radius:8px;font-size:13px;line-height:1.7}
.graph-pair{display:grid;grid-template-columns:minmax(0,1fr);gap:16px}.graph-panel{min-width:0}.graph-actions{flex-wrap:wrap;row-gap:5px}.graph-actions select{max-width:175px}.graph-actions #exportFormat{max-width:125px;font-size:11px}.graph-actions .spacer{min-width:0}
.workspace.compare-mode{grid-template-columns:minmax(0,1fr)}.compare-mode .graph-pair{grid-template-columns:repeat(2,minmax(0,1fr));align-items:start}.compare-mode .inspector{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));align-items:start}.compare-mode .canvas-wrap{height:430px}.compare-mode .graph-actions{min-height:84px}.compare-canvas{margin-top:84px}
.compare-body{padding:14px 18px}.compare-message{font-size:13px;line-height:1.8;color:#c6d7ed;min-height:48px}.compare-hint{font-size:12px;line-height:1.7;color:#a0b3cd}.mono{font:12px/1.9 Consolas,"Microsoft YaHei",monospace;color:#b5c6dd;overflow-wrap:anywhere}.compare-code{padding:0;list-style-position:inside;font:12px/1.9 Consolas,"Microsoft YaHei",monospace;color:#97abc8}.compare-code li{padding:3px 7px;border-left:2px solid transparent}.compare-code .highlight{color:#e5dfff;background:#302f4e;border-left-color:#b5afff}
.operation-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.operation-grid span{font-size:11px;line-height:1.7;color:#95acc8}.operation-grid b{display:block;font:600 18px/1.5 Consolas,monospace;color:#d5e5fc}.operation-grid .zero{opacity:.65}.inspect-panel .code-note{line-height:1.8}.node-affected td{color:#ff9dab!important;background:#50273355}
#structureContent{overflow:auto;max-height:55vh;padding:16px;background:#101a29;border:1px solid #34455d;border-radius:7px;color:#c6daf7;font:13px/1.9 Consolas,"Microsoft YaHei",monospace}.field textarea{color:#d6e4fa;background:#101a29;border:1px solid #536984;border-radius:6px;padding:12px;font:12px/1.8 Consolas,monospace;resize:vertical}.field select{width:100%}.sidebar-bottom{position:static;margin-top:35px}.sidebar{display:block}#graphCanvas{touch-action:none}.canvas-wrap canvas{width:100%;height:100%}button:disabled{cursor:not-allowed;opacity:.45}
@media(max-width:1100px){.compare-mode .graph-pair{grid-template-columns:minmax(0,1fr)}.compare-canvas{margin-top:0}.compare-mode .graph-actions{min-height:0}.compare-mode .canvas-wrap{height:400px}.compare-mode .inspector{grid-template-columns:1fr 1fr}}
@media(max-width:700px){.lab-controls{gap:8px;padding:10px}.lab-controls label{flex-wrap:wrap}.lab-controls select{font-size:12px;max-width:175px}.save-status{width:100%;margin-left:0}.compare-mode .inspector{grid-template-columns:minmax(0,1fr)}.graph-actions select{max-width:150px}.graph-actions #exportFormat{max-width:110px}.compare-body{padding:12px}.compare-mode .canvas-wrap{height:380px}.notice{font-size:12px}.sidebar-bottom{display:none}}