/* Flat Mono — neutral working surfaces, adapted from the shared design system. */
:root{color-scheme:light;--bg:#fafafa;--surface:#fff;--soft:#f5f5f5;--text:#111;--muted:#6b6b6b;--border:#e5e5e5;--strong:#cfcfcf;--success:#067647;--success-bg:#eef8f2;--danger:#b42318;--danger-bg:#fdeceb;--selection:#ddd}
:root[data-theme="dark"]{color-scheme:dark;--bg:#111;--surface:#191919;--soft:#232323;--text:#f5f5f5;--muted:#aaa;--border:#333;--strong:#555;--success:#8cdbb3;--success-bg:#1b3025;--danger:#ffb4aa;--danger-bg:#38211f;--selection:#494949}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.5 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans TC",Arial,sans-serif}button,input,select,textarea{font:inherit}button,a,select,input{touch-action:manipulation}a{color:var(--text);text-underline-offset:3px}button{min-height:44px;min-width:44px;padding:10px 14px;border:1px solid var(--strong);border-radius:0;background:var(--surface);color:var(--text);font-size:.88rem;font-weight:650;cursor:pointer}button:hover:not(:disabled){opacity:.72}button:disabled{opacity:.4;cursor:not-allowed}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:2px solid var(--text);outline-offset:2px}header{max-width:1440px;margin:auto;min-height:80px;padding:18px 24px;display:flex;align-items:center;gap:24px;border-bottom:1px solid var(--border)}.brand{display:flex;align-items:center;gap:12px;font-size:23px;font-weight:700;letter-spacing:-.03em;text-decoration:none;min-height:44px}.logo{display:grid;place-items:center;width:36px;height:36px;background:var(--text);color:var(--surface);font-family:monospace}.tag{font-size:12px;letter-spacing:.08em;font-weight:500;color:var(--muted);margin-left:4px}#runtime{margin-left:auto;font-size:13px;color:var(--muted)}.guide{display:inline-flex;align-items:center;min-height:44px;font-size:14px;text-decoration:none}.guide:hover{text-decoration:underline}#theme-toggle{white-space:nowrap}main{max-width:1440px;margin:auto;padding:28px 24px 20px}.workspace-heading{display:flex;align-items:center;justify-content:space-between;gap:24px;margin-bottom:20px}.eyebrow{font-size:12px;letter-spacing:.08em;color:var(--muted);font-weight:650}h1{font-size:1.6rem;line-height:1.12;font-weight:700;letter-spacing:-.03em;margin:6px 0}h2{font-size:1.05rem;letter-spacing:-.01em;margin:0;font-weight:700}h3{font-size:1rem;font-weight:650;margin:12px 0 8px}.actions{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.primary{background:var(--text);color:var(--surface);border-color:var(--text)}kbd{font:12px monospace;margin-left:16px;opacity:.75}.workbench{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,1fr);gap:16px}.panel{background:var(--surface);border:1px solid var(--border);overflow:hidden}.panel-bar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 18px;min-height:66px;border-bottom:1px solid var(--border)}.filename{font:14px monospace;white-space:nowrap}.python-mark{font-weight:700;margin-right:10px}.sample-label{display:flex;align-items:center;gap:8px;font-size:14px;color:var(--muted)}select{max-width:100%;min-height:44px;border:1px solid var(--strong);border-radius:0;background:var(--surface);color:var(--text);font-size:14px;padding:8px 10px}#editor{height:370px;background:var(--surface)}.cm-editor{height:100%;font-size:15px;background:var(--surface)!important;color:var(--text)!important}.cm-scroller{font-family:"SFMono-Regular",Consolas,monospace!important;line-height:1.8!important}.cm-editor .cm-gutters{background:var(--surface)!important;color:var(--muted)!important;border:0}.cm-editor .cm-content{padding:16px 0}.cm-editor .cm-activeLine,.cm-editor .cm-activeLineGutter{background:var(--soft)!important}.cm-editor .cm-trace-line{background:var(--success-bg)!important;border-left:3px solid var(--success)}.cm-editor .cm-cursor{border-left-color:var(--text)!important}.cm-editor .cm-selectionBackground{background:var(--selection)!important}.cm-editor .cm-panels,.cm-editor .cm-tooltip{background:var(--soft);color:var(--text);border-color:var(--strong)}.cm-editor .cm-search input,.cm-editor .cm-search button{background:var(--surface);color:var(--text);border:1px solid var(--strong);border-radius:0}.editor-foot{display:flex;justify-content:space-between;padding:8px 18px;font-size:12px;color:var(--muted);border-top:1px solid var(--border)}.input-box{padding:16px 18px;border-top:1px solid var(--border)}.input-box label{display:block;font-size:.88rem;font-weight:650;margin-bottom:8px}.input-box label span{font-size:12px;font-weight:400;color:var(--muted);margin-left:8px}textarea{display:block;width:100%;min-height:70px;resize:vertical;background:var(--surface);color:var(--text);border:1px solid var(--strong);border-radius:0;padding:10px 12px;font:14px/1.5 monospace}textarea::placeholder{color:var(--muted)}.pill{font-size:12px;color:var(--muted);border:1px solid var(--strong);padding:3px 8px;text-align:center}.transport{padding:16px 18px;background:var(--soft);border-bottom:1px solid var(--border)}.transport-top{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:10px}.transport-top>div{display:flex;gap:4px}#step-label{font:14px monospace;white-space:nowrap}.transport button{padding:6px;font-size:18px}#timeline{width:100%;height:28px;accent-color:var(--text);cursor:pointer;margin:0}#event-label{font-size:14px;color:var(--muted);margin-top:4px;overflow-wrap:anywhere}.scope-bar{display:flex;align-items:center;gap:10px;padding:14px 18px;font-size:14px;color:var(--muted)}.change-key{margin-left:auto;font-size:12px}.change-key:before{content:'';display:inline-block;width:7px;height:7px;background:var(--success);margin-right:7px}.variables{min-height:210px;max-height:350px;overflow:auto}.empty{text-align:center;max-width:330px;margin:24px auto;padding:0 18px;color:var(--muted)}.empty-symbol{font:24px monospace}.empty h3{color:var(--text)}.empty p{font-size:14px;margin:0}.variables table{border-collapse:collapse;width:100%;table-layout:fixed;font:14px/1.6 monospace}.variables th{text-align:left;background:var(--soft);color:var(--muted);font:650 12px/1.5 -apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;text-transform:uppercase;letter-spacing:.03em;padding:10px 16px;border-bottom:1px solid var(--strong)}.variables td{padding:10px 16px;border-bottom:1px solid var(--border);vertical-align:top;overflow-wrap:anywhere}.variables th:nth-child(1){width:27%}.variables th:nth-child(2){width:20%}.variables td:nth-child(2){color:var(--muted);font-size:12px}.variables tr.changed td:last-child{color:var(--success);background:var(--success-bg);font-weight:650}.stack-section{padding:14px 18px;border-top:1px solid var(--border)}.stack-section h3{font-size:12px;color:var(--muted);letter-spacing:.06em;margin:0 0 8px}#stack{font:12px/1.8 monospace;color:var(--muted)}.stack-frame{display:inline-block;background:var(--soft);border:1px solid var(--border);margin:2px 5px 2px 0;padding:2px 8px}.console-panel{grid-column:1/-1}.terminal-icon{margin-right:8px}#result-status{font-size:12px;color:var(--muted)}#console{margin:0;padding:18px 20px;min-height:120px;max-height:300px;overflow:auto;white-space:pre-wrap;overflow-wrap:anywhere;font:14px/1.7 monospace;color:var(--text);background:var(--surface)}#error{color:var(--danger);background:var(--danger-bg);border-top:1px solid var(--danger);padding:12px 18px;white-space:pre-wrap;font:14px/1.6 monospace}footer{padding:18px 0 0;color:var(--muted);font-size:12px}footer strong{color:var(--text);font-weight:650;margin:0 6px 0 18px}footer strong:first-child{margin-left:0}footer p{margin:8px 0 0}[hidden]{display:none!important}
@media(max-width:1100px){.transport-top{flex-wrap:wrap}.tag{display:none}}@media(max-width:900px){.guide{display:none}.workspace-heading{align-items:flex-start;flex-direction:column;gap:16px}.workbench{grid-template-columns:1fr}.console-panel{grid-column:1}.trace-panel{min-height:450px}}@media(max-width:600px){header{min-height:80px;padding:14px;flex-wrap:wrap;gap:10px}main{padding:20px 14px}#runtime{order:3;width:100%;margin:0}#theme-toggle{margin-left:auto}.brand{font-size:22px}.panel-bar{padding:12px}.sample-label{font-size:0}h2{font-size:1rem}.pill{max-width:140px}.input-box label span{display:block;margin:4px 0}.variables td,.variables th{padding:10px}kbd{display:none}.transport,.scope-bar{padding:14px}.transport-top{gap:10px}footer strong{margin-left:8px}.scope-bar{flex-wrap:wrap}}
/* Breakpoints are independent of trace highlighting and remain keyboard accessible. */
.cm-editor .breakpoint-gutter{width:28px}
.cm-editor .breakpoint-gutter .cm-gutterElement{padding:0;width:28px;display:flex;align-items:center;justify-content:center}
.cm-editor .breakpoint-marker{display:block;min-height:24px;min-width:24px;height:24px;width:24px;padding:0;border:0;background:transparent;color:var(--muted);font:16px/24px sans-serif;cursor:pointer}
.cm-editor .breakpoint-marker.is-set{color:var(--danger)}
.cm-editor .breakpoint-marker:focus-visible{outline-offset:-2px}
.breakpoint-bar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 18px;border-top:1px solid var(--border)}
.breakpoint-bar strong{display:block;font-size:14px;overflow-wrap:anywhere}.breakpoint-bar span{display:block;color:var(--muted);font-size:12px;margin-top:4px}.breakpoint-bar button{flex-shrink:0;font-size:12px}
#continue{margin:8px 0;width:100%}
@media(max-width:600px){.breakpoint-bar{padding:12px;flex-wrap:wrap}}