/* 蓝白课程视觉：清晰输入、输出与实验步骤；窄屏自动改单列。 */
/* 用自有标签代替随操作系统语言变化的文件按钮，保留原生可访问文件输入。 */
.upload{position:relative;cursor:pointer}.upload input[type=file]{position:absolute;inset:0;width:100%;height:100%;opacity:0;margin:0;cursor:pointer}.upload:focus-within{outline:3px solid #efac19;outline-offset:2px}
:root{--blue:#2460e9;--ink:#18283e;--muted:#57677e;--line:#dce5f2;--green:#157a57}*{box-sizing:border-box}body{margin:0;font:16px/1.6 Arial,sans-serif;color:var(--ink);background:#f3f6fb}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:wait;opacity:.55}a{color:var(--blue)}.shell{max-width:1280px;margin:auto;padding:0 28px}.topbar{display:flex;align-items:center;justify-content:space-between;padding:24px 0;border-bottom:1px solid var(--line)}.topbar div{display:flex;align-items:center;gap:18px}.brand{font-weight:800;letter-spacing:.12em;text-decoration:none}.brand span{font-size:12px;letter-spacing:0;margin-left:14px;color:var(--muted)}.topbar button,.output-head button{border:1px solid var(--line);background:white;padding:7px 12px;border-radius:7px}.hero{display:grid;grid-template-columns:1.35fr 1fr;gap:60px;padding:40px 0 30px;align-items:center}.eyebrow,.step{font-size:11px;letter-spacing:.15em;font-weight:bold;color:var(--blue)}h1{font-size:44px;line-height:1.12;letter-spacing:-.04em;margin:10px 0 16px}h2{font-size:23px;line-height:1.25;margin:9px 0 12px}h3{font-size:20px;margin:0 0 8px}p{margin:8px 0 14px}.lede{font-size:18px;color:var(--muted);max-width:520px}.hero aside{border-left:3px solid var(--blue);padding:6px 0 6px 24px}.hero aside strong{font-size:24px}.hero aside p{color:var(--muted)}.badges{display:flex;flex-wrap:wrap;gap:8px}.badges span{background:#e4ecff;color:#2855a1;font-size:11px;border-radius:30px;padding:4px 10px}.tabs{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin-bottom:12px}.tabs button{padding:17px 10px;border:1px solid var(--line);background:white;color:var(--muted);border-radius:12px;font-size:16px;font-weight:bold}.tabs button[aria-selected=true]{background:var(--blue);color:white;border-color:var(--blue)}.workspace{display:grid;grid-template-columns:350px minmax(0,1fr);background:white;border:1px solid var(--line);border-radius:16px;overflow:hidden}.controls{padding:25px;border-right:1px solid var(--line)}.muted{color:var(--muted);font-size:14px}.examples{display:flex;gap:7px;margin:20px 0;flex-wrap:wrap}.examples button{flex:1;min-width:64px;background:#f5f8fd;border:1px solid var(--line);border-radius:8px;padding:5px;font-size:11px;color:var(--ink)}.examples img{width:100%;height:64px;object-fit:cover;border-radius:5px}.upload{display:block;margin:10px 0;padding:9px 10px;border:1px dashed #a5b8d8;border-radius:7px;font-size:12px}.upload input{display:block;width:100%;font-size:11px;margin-top:6px}.setting{margin:20px 0}.setting label{display:flex;justify-content:space-between;font-size:13px;font-weight:bold}.setting p{font-size:12px;color:var(--muted)}.setting input{width:100%;accent-color:var(--blue)}.setting select{width:100%;padding:10px;border:1px solid var(--line);border-radius:7px;margin-top:8px}.primary{border:0;background:var(--blue);color:white;font-weight:bold;padding:13px;border-radius:8px;width:100%}#status{font-size:13px;color:var(--blue);min-height:40px}.model{font-size:11px;color:var(--muted)}.output{padding:25px;min-width:0}.output-head{display:flex;align-items:center;justify-content:space-between;gap:10px}.output-head button{font-size:11px}.canvases{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:14px}.canvases.single{grid-template-columns:1fr}.canvases figure{margin:0;text-align:center;min-width:0}.canvases figcaption{font-size:12px;color:var(--muted);margin-bottom:7px}canvas{max-width:100%;width:100%;height:auto;max-height:365px;object-fit:contain;border-radius:10px;background:#f1f4f8}.canvases.single canvas{max-height:420px}.result{margin:18px 0 0;padding:18px;border:1px solid #dce6f6;background:#f5f8ff;border-radius:10px;font-size:14px}.result .metric{font-size:30px;font-weight:bold;color:var(--blue)}.result .tag{display:inline-block;background:#e3f5ed;color:#145c45;padding:4px 10px;border-radius:5px;margin-right:6px}.result pre{white-space:pre-wrap;font:17px/1.5 Consolas,monospace}details{margin-top:15px;font-size:13px}details pre{white-space:pre-wrap;max-height:240px;overflow:auto;overflow-wrap:anywhere}.experiment{display:grid;grid-template-columns:1.6fr 1fr;gap:35px;padding:28px 0}.experiment h2{font-size:22px}.experiment p{color:var(--muted);font-size:14px}.answer{background:#eaf4ef;border-left:3px solid var(--green);padding:18px 22px;align-self:center}footer{border-top:1px solid var(--line);padding:20px 0 35px;color:var(--muted);font-size:12px}footer a{font-size:14px}.guide{max-width:850px;margin:30px auto}.guide section{background:white;border:1px solid var(--line);border-radius:12px;padding:26px;margin:16px 0}[hidden]{display:none!important}:focus-visible{outline:3px solid #efac19;outline-offset:3px}
@media(max-width:800px){.shell{padding:0 16px}.brand span{display:none}.topbar{font-size:12px}.hero{grid-template-columns:1fr;gap:18px;padding:28px 0}h1{font-size:37px}.hero aside{display:none}.workspace{grid-template-columns:1fr}.controls{border-right:0;border-bottom:1px solid var(--line)}.tabs button{font-size:12px;padding:13px 5px}.experiment{grid-template-columns:1fr;gap:10px}.output{padding:18px}.controls{padding:20px}.canvases{gap:8px}.output-head button{font-size:10px}.step{font-size:10px}}

/* 图库分组限制同时出现的按钮数量；不引入内层竖向滚动条或视口高度依赖。 */
.sample-library{margin-top:16px}.sample-library label{display:block;font-size:12px;font-weight:bold}
.sample-library select{width:100%;margin-top:5px;padding:7px;border:1px solid var(--line);border-radius:7px;background:white}
.sample-library p,.sample-note{font-size:11px;line-height:1.45;color:var(--muted)}
.examples{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:7px;margin:12px 0}
.examples button{min-width:0}.examples img{object-fit:contain;background:white}

/* 样例失败可独立重试；不锁住任务标签，也不创建额外的滚动区域。 */
.retry{width:100%;margin-top:9px;padding:8px 12px;border:1px solid var(--blue);border-radius:8px;color:var(--blue);background:white}