:root{font-family:Inter,"Noto Sans TC","Microsoft JhengHei",system-ui,sans-serif;color:#1b2a39;background:#f7f5ef;font-synthesis:none}
*{box-sizing:border-box}
body{margin:0;min-width:320px}
button,input{font:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed;opacity:.48}
.page{max-width:1080px;margin:auto;padding:12px 20px 16px}
.intro{margin:0 0 8px}
.intro-header{display:flex;align-items:center;justify-content:space-between;gap:12px}
h1{font-size:clamp(24px,3vw,32px);font-weight:850;letter-spacing:-.045em;line-height:1.15;margin:0}
.lesson-title{margin:8px 0 4px;text-align:center;font-size:clamp(16px,1.8vw,20px);font-weight:800;letter-spacing:0;line-height:1.25;color:#294b51}
.intro p{margin:5px 0 0;color:#65737c;font-size:13px;line-height:1.35}
.lesson-nav{display:flex;flex-wrap:wrap;gap:5px;margin:7px 0 0;padding:5px;background:#f0dfd2;border:1px solid #d6b49c;border-radius:8px;font-size:12px}
.lesson-nav a{color:#78452f;text-decoration:none;padding:5px 10px;border-radius:5px;border:1px solid #d6b49c;background:#fff8ef;font-weight:700}
.lesson-nav a:hover{background:#fffdf8;border-color:#ac7254}
.lesson-nav a[aria-current="page"]{color:#fff;border-color:#934e36;background:#934e36;font-weight:800}
.lesson-nav a:focus-visible{outline:2px solid #e58f67;outline-offset:2px}
.language-tabs{display:inline-flex;flex:none;gap:2px;padding:3px;border:1px solid #dce3dc;border-radius:8px;background:#ecf1ec}
.language-tab{display:inline-flex;align-items:center;justify-content:center;min-width:60px;min-height:27px;padding:0 9px;border-radius:5px;text-decoration:none;color:#61736d;font-size:11px;font-weight:800}
.language-tab:hover{color:#1c4650;background:#f8fbf7}
.language-tab.active{color:#fff;background:#1c4650}
.language-tab:focus-visible{outline:2px solid #e58f67;outline-offset:2px}
.card{min-width:0;background:#fffefa;border:1px solid #e2e4df;border-radius:10px;box-shadow:0 3px 12px rgba(30,51,58,.03)}
.card h2{margin:0;font-size:14px;line-height:1.25;letter-spacing:-.02em}
.code-card{padding:8px 12px}
.code-table{width:100%;table-layout:fixed;border-collapse:separate;border-spacing:0}
.code-table th{width:50%;text-align:left;padding:0 5px 4px;font-weight:700}
.code-table tbody{counter-reset:line}
.code-line,.python-line{vertical-align:top;padding:1px 5px;border-radius:4px;white-space:pre-wrap;overflow-wrap:anywhere;font-family:"Cascadia Code","Consolas",monospace;font-size:12px;line-height:18px;transition:background .2s}
.code-line{position:relative;padding-left:30px}
.code-line:before{counter-increment:line;content:counter(line,decimal-leading-zero);position:absolute;left:5px;top:1px;display:inline-block;color:#a0aea5;min-width:18px;font-size:10px}
.code-line.indent{padding-left:47px}
.code-line.deep{padding-left:64px}
.code-table th:last-child,.python-line,.python-line.indent,.python-line.deep{padding-left:14px;border-left:1px solid #e5e9e2}
.python-line code{font:inherit}
.code-line.highlight,.python-line.highlight{background:#fff1e6;color:#a64d32;font-weight:700}
.code-line.done,.python-line.done{background:#ffd977;color:#573a00;font-weight:800}
.code-line.done:before{color:#755511}
.python-setup{margin:0 0 6px;font-family:"Cascadia Code","Consolas",monospace;font-size:11px;line-height:1.3;white-space:pre-wrap;overflow-wrap:anywhere;color:#748079}
.python-setup code{font:inherit}
.algorithm-note{margin:6px 2px 8px;font-size:11px;line-height:1.35;color:#6b7b72}
.algorithm-note span{color:#89938d}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 190px;gap:8px;align-items:start}
.stage{padding:10px}
.control-box{padding:7px 8px;background:#f5f7f3;border:1px solid #e6ebe6;border-radius:7px}
.control-row{display:flex;align-items:flex-end;gap:6px;flex-wrap:wrap}
.field{display:flex;flex:1;flex-direction:column;gap:3px;min-width:100px;max-width:140px}
.field label{font-size:11px;font-weight:800;color:#62716f}
.field input{height:32px;width:100%;border:1px solid #ccd7d2;border-radius:6px;background:#fff;padding:0 9px;color:#1a3040;font-weight:700;outline:none}
.field input:focus{border-color:#478b84;box-shadow:0 0 0 2px #cfe6dd}
.btn{height:32px;border-radius:6px;padding:0 9px;display:inline-flex;align-items:center;justify-content:center;gap:5px;font-size:12px;font-weight:800;border:1px solid #d9e0da;background:#fff;color:#29414b;transition:background .15s,border-color .15s}
.btn:hover:not(:disabled){border-color:#8fa9a1}
.btn-primary{background:#1c4650;border-color:#1c4650;color:#fff}
.btn-primary:hover:not(:disabled){background:#285a62}
.btn svg{width:13px;height:13px;stroke:currentColor;fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
.control-tip{display:none;margin:5px 0 0;font-size:11px;line-height:1.3}
.control-tip.error{display:block;color:#bc5d4a}
.array-settings{display:flex;align-items:center;flex-wrap:wrap;gap:6px;margin-top:6px;padding-top:6px;border-top:1px solid #dbe4dd;font-size:11px}
.array-settings label{font-weight:800;color:#62716f}
.array-settings input{width:64px;height:28px;border:1px solid #ccd7d2;border-radius:5px;background:#fff;padding:0 6px;font-weight:700;color:#1a3040}
.array-settings input:focus{outline:2px solid #478b84;outline-offset:1px}
.array-settings .btn{height:28px;flex:none;font-size:11px}
.size-hint{color:#71807d;font-size:10px}
.array-area{margin-top:8px}
.array-caption{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:3px}
.array-caption strong{font-size:12px}
.step-counter{background:#edf3f1;color:#497069;padding:3px 7px;border-radius:5px;font-size:11px;font-weight:800;white-space:nowrap}
.array-board{display:grid;grid-template-columns:35px minmax(0,1fr);gap:4px;padding-top:3px;width:100%;min-width:0}
.array-labels{display:flex;flex-direction:column;gap:4px;font-size:10px;color:#788b83}
.array-row-label{height:69px;display:grid;grid-template-rows:18px 34px;align-items:center}
.array-labels strong{font-size:10px}
.array{display:grid;grid-template-columns:repeat(var(--array-columns,10),minmax(0,1fr));column-gap:2px;row-gap:4px;width:100%;min-width:0}
.slot{min-width:0;text-align:center}
.slot-index{height:18px;font-size:10px;color:#8c9997;font-weight:800}
.slot-value{height:34px;border:1px solid #dce4df;border-radius:5px;background:#f7f9f6;display:grid;place-items:center;font-size:clamp(10px,2.1vw,17px);letter-spacing:-.045em;font-weight:750;transition:background .2s,color .2s,border-color .2s}
.slot.active .slot-index{color:#d2734e}
.slot.active .slot-value{background:#fff0e5;border-color:#e58f67;color:#a64d32}
.slot.miss .slot-value{color:#aeb8b3;background:#f6f7f4}
.slot.hit .slot-value{background:#daf1e7;border-color:#54a68b;color:#22765c}
.slot-marker{height:15px;margin-top:2px;font-size:13px;font-weight:800;color:#df7a58}
.slot.hit .slot-marker{color:#26926d}
.array-foot{border-top:1px dashed #e2e7e2;padding-top:5px;margin-top:2px;display:flex;align-items:center;gap:6px;flex-wrap:wrap;font-size:10px;color:#7e8c8a}
.legend-dot{width:6px;height:6px;display:inline-block;border-radius:50%;margin-left:5px}
.legend-dot:first-child{margin-left:0}
.legend-dot.current{background:#e58f67}
.legend-dot.compared{background:#bec9c4}
.legend-dot.found{background:#62ad90}
.feedback{display:flex;align-items:center;gap:9px;margin-top:8px;padding:8px 10px;border-radius:7px;background:#f9f5ef;min-height:47px}
.feedback-icon{width:28px;height:28px;flex:none;border-radius:7px;display:grid;place-items:center;background:#f4e8dc;color:#c27556;font-size:19px;font-weight:700}
.feedback.match{background:#edf7f0}
.feedback.match .feedback-icon{background:#d8eee0;color:#288465}
.feedback.end{background:#1c4650;border:2px solid #dfaa49;box-shadow:0 2px 8px #1c465026}
.feedback.end .feedback-icon{background:#ffd977;color:#573a00}
.feedback.end .feedback-title{color:#fff;font-size:15px}
.feedback.end .feedback-copy{color:#e3f0ef}
.feedback-title{font-size:12px;font-weight:800;margin-bottom:2px;line-height:1.3}
.feedback-copy{color:#71807d;font-size:11px;line-height:1.3}
.side{min-width:0}
.state-card{padding:10px}
.state-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:5px;margin-top:7px}
.state-item{padding:7px;background:#f7f9f6;border:1px solid #e7ece7;border-radius:6px;min-width:0}
.state-label{font-size:10px;color:#8b9995;font-weight:700;margin-bottom:3px;line-height:1.3}
.state-value{font-family:"Cascadia Code","Consolas",monospace;font-size:15px;font-weight:800}
.state-value.true{color:#18805d}
.state-value.false{color:#a96a55}
.state-value.output{background:#ffd977;color:#573a00;border-radius:4px;padding:3px 5px;display:inline-block}
.state-item.result-item{background:#ffe3a0;border:2px solid #cf941e;box-shadow:0 2px 5px #996b151a;padding:6px}
.result-item .state-label{color:#78520b;font-weight:800}
.result-item .state-value{color:#573a00;font-size:21px;line-height:1.1;font-weight:900}
.result-item .state-value.output{background:transparent;padding:0}
.mini-note{font-size:10px;color:#87948f;line-height:1.3;margin:7px 0 0}
.footer{margin-top:8px;font-size:10px;color:#85918e}
@media(max-width:760px){
  .page{padding:10px 14px 12px}
  .layout{grid-template-columns:minmax(0,1fr) 174px}
  .code-table th:last-child,.python-line,.python-line.indent,.python-line.deep{padding-left:10px}
  .field{min-width:95px;max-width:110px}
  .btn{font-size:11px;padding:0 7px}
  .slot-value{font-size:12px}
}
@media(max-width:519px){
  .layout{grid-template-columns:minmax(0,1fr)}
  .state-grid{grid-template-columns:repeat(4,minmax(0,1fr));margin-top:5px}
  .state-card{padding:8px 10px}
  .code-line,.python-line,.python-setup{font-size:11px}
}
@media(max-width:479px){
  .intro-header{align-items:flex-start;gap:8px}
  h1{font-size:23px}
  .language-tab{min-width:48px;padding:0 6px;font-size:10px}
  .intro p{font-size:12px}
  .code-line,.python-line,.python-setup{font-size:10px}
  .code-line{padding-left:20px}
  .code-line:before{left:2px;min-width:14px;font-size:9px}
  .code-line.indent{padding-left:28px}
  .code-line.deep{padding-left:36px}
  .code-table th:last-child,.python-line,.python-line.indent,.python-line.deep{padding-left:6px}
  .stage{padding:8px}
  .field{min-width:100%;max-width:none}
  .btn{flex:1}
  .state-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .array-board{grid-template-columns:32px minmax(0,1fr);gap:3px}
  .slot-value{font-size:10px}
}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation-duration:.01ms!important;transition-duration:.01ms!important}}