[hidden]{display:none!important}  /* the hidden attribute must win over component display rules (e.g. .tool-card{display:flex}) */
:root{
  --bg:#f5f7f6;--card:#fff;--ink:#14201b;--mute:#5d6b65;--line:#e1e7e4;
  --acc:#0b7a55;--acc2:#e7f4ee;--warn:#9a5b00;--warnbg:#fff5e0;--err:#b42318;--errbg:#fdecea;
  --r:12px;--sh:0 1px 2px rgba(16,24,20,.05),0 2px 10px rgba(16,24,20,.04);
  --mono:ui-monospace,"SF Mono",Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.6 -apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC",sans-serif}
a{color:var(--acc);text-decoration:none}a:hover{text-decoration:underline}
.wrap{max-width:1180px;margin:0 auto;padding:0 16px}
header.top{background:#0f2a21;color:#fff;position:sticky;top:0;z-index:20}
header.top .wrap{display:flex;align-items:center;gap:12px;height:52px}
header.top a{color:#fff}
.brand{font-weight:700;letter-spacing:.3px;display:flex;align-items:center;gap:8px;white-space:nowrap}
.brand i{display:inline-grid;place-items:center;width:26px;height:26px;border-radius:7px;background:#19a974;font-style:normal;font-size:14px}
header.top nav{margin-left:auto;display:flex;gap:16px;font-size:14px}
header.top nav a{opacity:.85}
.crumb{font-size:13px;color:var(--mute);margin:14px 0 4px}
.crumb a{color:var(--mute)}
h1{font-size:24px;line-height:1.3;margin:4px 0 6px}
.lead{color:var(--mute);margin:0 0 14px}
.tool-actions{display:flex;gap:8px;margin:0 0 14px;flex-wrap:wrap}
.btn{border:1px solid var(--line);background:#fff;border-radius:8px;padding:6px 12px;font:inherit;font-size:13px;cursor:pointer;color:var(--ink)}
.btn:hover{border-color:var(--acc);color:var(--acc)}
.grid{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:16px;align-items:start}
.col{display:flex;flex-direction:column;gap:16px;min-width:0}
.sticky{position:sticky;top:68px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--sh);padding:16px}
.card h2{font-size:15px;margin:0 0 12px;color:var(--ink);display:flex;align-items:center;gap:8px}
.card h2::before{content:"";width:4px;height:14px;border-radius:2px;background:var(--acc)}
/* schematic */
figure.sch{margin:0}
figure.sch .img{background:#fff;border:1px solid var(--line);border-radius:8px;overflow:auto;-webkit-overflow-scrolling:touch}
figure.sch img{display:block;width:100%;height:auto;min-width:420px;max-height:460px;object-fit:contain}
figure.sch figcaption{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center;font-size:12.5px;color:var(--mute);margin-top:8px}
figure.sch figcaption a{white-space:nowrap}
/* live CircuitJS simulation (src/core/sim.js) */
.sim-tabs{margin-bottom:10px}
.sim-frame{position:relative;width:100%;aspect-ratio:16/10;background:#000;border-radius:8px;overflow:hidden;border:1px solid var(--line)}
.sim-frame iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.sim-box:fullscreen{background:#000;display:flex;flex-direction:column}
.sim-box:fullscreen .sim-frame{flex:1;aspect-ratio:auto;border-radius:0;border:0}
.sim-box:fullscreen .sim-bar{padding:6px 10px;color:#ccc}
.sim-tap{position:absolute;inset:0;width:100%;border:0;background:#0f2a21;color:#fff;font:inherit;font-size:16px;cursor:pointer;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px}
.sim-tap small{font-size:12px;color:#a7c4b8}
.sim-bar{display:flex;flex-wrap:wrap;gap:6px 10px;align-items:center;font-size:12.5px;color:var(--mute);margin-top:8px}
.sim-bar span{flex:1 1 200px}
.sim-ext{border:1px dashed var(--line);border-radius:8px;padding:16px;display:flex;flex-direction:column;gap:10px;align-items:flex-start;font-size:14px}
.sim-ext p{margin:0}
.sim-ext small{color:var(--mute);font-size:12.5px}
@media (max-width:600px){.sim-frame{aspect-ratio:4/5}.sim-bar span{flex-basis:100%}}
.btn.primary{background:var(--acc);border-color:var(--acc);color:#fff}
.btn.primary:hover{color:#fff;text-decoration:none;filter:brightness(1.08)}
.kicad{display:inline-flex;align-items:center;gap:4px;background:#eef2ff;color:#3730a3;border-radius:5px;padding:1px 7px;font-weight:600}
/* modes */
.seg{display:flex;background:#eef1ef;border-radius:10px;padding:3px;gap:3px;overflow-x:auto;scrollbar-width:none}
.seg::-webkit-scrollbar{display:none}
.seg button{flex:1 0 auto;border:0;background:transparent;padding:8px 12px;border-radius:8px;font:inherit;font-size:14px;color:var(--mute);cursor:pointer;white-space:nowrap}
.seg button[aria-selected=true]{background:#fff;color:var(--acc);font-weight:600;box-shadow:0 1px 3px rgba(0,0,0,.08)}
#modes{margin-bottom:14px}
/* inputs */
.rows{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px 14px}
.row{display:flex;flex-direction:column;gap:5px;min-width:0}
.row label{font-size:13px;color:var(--mute)}
.row small{font-size:12px;color:var(--mute);line-height:1.4}
.row-inline{flex-direction:row;align-items:center;justify-content:space-between}
.sym{font-family:"Times New Roman",serif;font-style:italic;font-weight:600;color:var(--ink);margin-right:6px;font-size:15px}
.field{display:flex;border:1px solid #cfd8d4;border-radius:9px;background:#fff;overflow:hidden;transition:border-color .15s,box-shadow .15s}
.field:focus-within{border-color:var(--acc);box-shadow:0 0 0 3px rgba(11,122,85,.13)}
.field input{flex:1;min-width:0;border:0;outline:0;padding:10px 11px;font:16px/1.2 var(--mono);background:transparent;color:var(--ink)}
.field .unit{border:0;border-left:1px solid var(--line);background:#f6f8f7;padding:0 10px;font:14px var(--mono);color:var(--mute);display:flex;align-items:center;min-width:44px;justify-content:center}
.field select.unit{appearance:none;-webkit-appearance:none;cursor:pointer;padding-right:20px;background:#f6f8f7 url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%235d6b65'/%3E%3C/svg%3E") no-repeat right 7px center;border-radius:0;outline:0}
.row>select{border:1px solid #cfd8d4;border-radius:9px;padding:10px 11px;font:15px inherit;background:#fff;color:var(--ink);width:100%;outline:0}
.row>select:focus{border-color:var(--acc)}
.sw{position:relative;width:44px;height:26px;flex:none}
.sw input{opacity:0;width:0;height:0}
.sw span{position:absolute;inset:0;background:#cfd8d4;border-radius:13px;transition:.2s;cursor:pointer}
.sw span::after{content:"";position:absolute;left:3px;top:3px;width:20px;height:20px;border-radius:50%;background:#fff;transition:.2s}
.sw input:checked+span{background:var(--acc)}
.sw input:checked+span::after{left:21px}
/* results */
#results{display:flex;flex-direction:column;gap:2px}
.res{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:baseline;gap:2px 12px;padding:9px 10px;border-radius:8px;cursor:copy;position:relative}
.res:hover{background:#f6f8f7}
.res .k{color:var(--mute);font-size:14px}
.res .v{font:600 16px/1.3 var(--mono);color:var(--ink);text-align:right;word-break:break-all}
.res small{flex-basis:100%;font-size:12px;color:var(--mute)}
.res.primary{background:var(--acc2)}
.res.primary .v{color:var(--acc);font-size:20px}
.res.bad .v{color:var(--err)}
.res.copied::after{content:"已复制";position:absolute;right:8px;top:-8px;background:#0f2a21;color:#fff;font-size:11px;padding:1px 6px;border-radius:4px}
.res-sec{font-size:12px;font-weight:600;color:var(--mute);letter-spacing:.5px;margin:10px 10px 2px;text-transform:uppercase}
.msg{margin:8px 0 0;padding:8px 11px;border-radius:8px;font-size:13.5px;line-height:1.5}
.msg.warn{background:var(--warnbg);color:var(--warn)}
.msg.err{background:var(--errbg);color:var(--err)}
.msg.info{background:#f1f5f3;color:var(--mute)}
/* content */
.formula{font-family:"Times New Roman",serif;font-size:17px;background:#fafbfa;border:1px solid var(--line);border-radius:8px;padding:10px 14px;overflow-x:auto;line-height:1.9}
.formula div{white-space:nowrap}
.prose{font-size:14.5px;color:#26332e}
.prose h3{font-size:15px;margin:16px 0 6px}
.prose p{margin:6px 0}
.prose ul{padding-left:20px;margin:6px 0}
.prose table,.tbl table{border-collapse:collapse;width:100%;font-size:13.5px}
.prose th,.prose td,.tbl th,.tbl td{border:1px solid var(--line);padding:6px 8px;text-align:left}
.prose th,.tbl th{background:#f6f8f7;font-weight:600}
.tbl{overflow-x:auto}
.tbl td{font-family:var(--mono);font-size:13px}
.chart svg{width:100%;height:auto;max-height:340px;font-size:12px}
.chart figcaption{display:none}
.chart .grid{stroke:#eef1ef}
.chart .axis{stroke:#9aa7a1}
.chart text{fill:#5d6b65;font-family:var(--mono);font-size:11px}
.chart .lbl{font-family:inherit;font-size:13px}
.chart .mk{fill:#0b7a55;font-weight:600}
.legend{display:flex;gap:14px;flex-wrap:wrap;font-size:12.5px;color:var(--mute);margin-top:4px}
.legend i{display:inline-block;width:14px;height:3px;border-radius:2px;margin-right:5px;vertical-align:middle}
.related{display:flex;flex-wrap:wrap;gap:8px}
.related a{border:1px solid var(--line);background:#fff;border-radius:999px;padding:4px 12px;font-size:13px}
footer{color:var(--mute);font-size:12.5px;padding:28px 0 40px;text-align:center}
/* home */
.hero{padding:26px 0 10px}
.hero h1{font-size:28px}
.search{display:flex;align-items:center;gap:8px;background:#fff;border:1px solid #cfd8d4;border-radius:12px;padding:0 14px;box-shadow:var(--sh);max-width:620px}
.search input{flex:1;border:0;outline:0;font:16px inherit;padding:13px 0;background:transparent;min-width:0}
.search kbd{font:12px var(--mono);border:1px solid var(--line);border-radius:4px;padding:1px 6px;color:var(--mute)}
.chips{display:flex;gap:8px;overflow-x:auto;padding:14px 0 6px;scrollbar-width:none}
.chips::-webkit-scrollbar{display:none}
.chip{flex:none;border:1px solid var(--line);background:#fff;border-radius:999px;padding:6px 13px;font:inherit;font-size:13.5px;cursor:pointer;color:var(--ink)}
.chip[aria-pressed=true]{background:var(--acc);color:#fff;border-color:var(--acc)}
.chip b{font-weight:400;opacity:.6;margin-left:3px}
.cat{margin:22px 0}
.cat>h2{font-size:17px;margin:0 0 10px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px}
.tcard{display:flex;flex-direction:column;gap:4px;background:#fff;border:1px solid var(--line);border-radius:var(--r);padding:13px 14px;color:var(--ink);transition:border-color .15s,transform .15s;min-height:84px}
.tcard:hover{border-color:var(--acc);text-decoration:none;transform:translateY(-1px)}
.tcard strong{font-size:15px;display:flex;align-items:center;gap:6px}
.tcard span{font-size:13px;color:var(--mute);line-height:1.45}
.tag{font-size:11px;font-weight:600;border-radius:4px;padding:0 5px;line-height:18px}
.tag.new{background:#e7f4ee;color:var(--acc)}
.tag.fix{background:#fff1e6;color:#b45309}
.tag.ext{background:#f1f5f9;color:#475569}
.tag.sch{background:#eef2ff;color:#3730a3}
#empty{color:var(--mute);padding:30px 0;text-align:center}
@media (max-width:860px){
  .grid{grid-template-columns:1fr}
  .sticky{position:static}
  h1{font-size:21px}
  .hero h1{font-size:23px}
}
@media (max-width:520px){
  .wrap{padding:0 12px}
  .rows{grid-template-columns:1fr}
  .card{padding:13px;border-radius:10px}
  header.top nav a.hide-s{display:none}
  .cards{grid-template-columns:1fr}
  .res .v{font-size:15px}
  .formula div{white-space:normal}
  .formula{font-size:16px}
  .seg{flex-wrap:wrap}
  .seg button{flex:1 1 auto;padding:7px 10px;font-size:13.5px}
  .chart text{font-size:12px}
  .res.primary .v{font-size:18px}
  figure.sch img{min-width:340px}
}
@media print{header.top,.tool-actions,footer{display:none}.grid{grid-template-columns:1fr}}

/* custom interactive tools */
.card.custom{padding:16px}
.calc-display{background:#0f2a21;color:#e8fff5;border-radius:10px;padding:12px 14px;font:18px/1.4 var(--mono);min-height:84px;word-break:break-all}
.calc-display .expr{color:#9fd9c2;font-size:15px;min-height:21px}
.calc-display .ans{font-size:26px;text-align:right}
.keys{display:grid;grid-template-columns:repeat(6,1fr);gap:6px;margin-top:10px}
.keys button{border:1px solid var(--line);background:#fff;border-radius:8px;padding:11px 0;font:15px var(--mono);cursor:pointer;color:var(--ink);touch-action:manipulation}
.keys button:active{background:var(--acc2)}
.keys button.op{background:#f1f5f3}
.keys button.eq{background:var(--acc);color:#fff;border-color:var(--acc)}
.toolbar{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin:10px 0}
.toolbar input[type=text],.toolbar select{border:1px solid #cfd8d4;border-radius:8px;padding:8px 10px;font:15px var(--mono);min-width:0}
.plot-wrap{position:relative;border:1px solid var(--line);border-radius:10px;overflow:hidden;background:#fff;touch-action:none}
.plot-wrap canvas{display:block;width:100%}
.flist{display:flex;flex-direction:column;gap:8px}
.frow{display:flex;gap:8px;align-items:center}
.frow i{width:12px;height:12px;border-radius:3px;flex:none}
.frow input{flex:1;min-width:0;border:1px solid #cfd8d4;border-radius:8px;padding:9px 10px;font:15px var(--mono)}
.frow button,.iconbtn{border:1px solid var(--line);background:#fff;border-radius:8px;width:36px;height:36px;cursor:pointer;flex:none;font-size:16px}
.hist{font:13px var(--mono);color:var(--mute);max-height:180px;overflow:auto;margin-top:10px}
.hist div{padding:4px 2px;border-bottom:1px dashed var(--line);cursor:pointer}
.out-box{background:#fafbfa;border:1px solid var(--line);border-radius:8px;padding:10px 12px;font:15px/1.6 var(--mono);overflow-x:auto;white-space:pre-wrap;word-break:break-word}
@media (max-width:520px){.keys{grid-template-columns:repeat(5,1fr)}.keys button{padding:12px 0}}

/* math tools */
.custom .seg{margin-bottom:12px}
.custom .seg button{min-height:40px}
.custom .btn{min-height:40px;padding:8px 14px;font-size:14px}
.custom .iconbtn{width:40px;height:40px}
.custom .chip{min-height:36px}
.custom .toolbar select{min-height:40px;max-width:100%}
.custom .mt-h{font-size:14px;margin:14px 0 6px;color:var(--mute)}
/* sci-calc */
.sc-grid{display:grid;grid-template-columns:minmax(0,520px) minmax(0,1fr);gap:20px;align-items:start}
.sc-in{width:100%;background:transparent;border:0;outline:0;color:#e8fff5;font:18px/1.4 var(--mono);padding:2px 0;caret-color:#7ef0c2}
.sc-in::placeholder{color:#6f9d8b;font-size:14px}
.calc-display .ans{min-height:36px;overflow-wrap:anywhere}
.calc-display .ans.pv{color:#9fd9c2;font-size:20px}
.calc-display .ans.err{color:#ffb4a8;font-size:14px;text-align:left;font-family:inherit}
.sc-extra{display:flex;flex-wrap:wrap;gap:4px 14px;justify-content:flex-end;font-size:12.5px;color:#9fd9c2;min-height:4px}
.sc-extra i{font-style:normal;color:#6f9d8b;margin-right:5px}
.sc-tog{flex:1}
.sc-tog[aria-pressed=true]{border-color:var(--acc);color:var(--acc)}
.keys.sc-keys{grid-template-columns:repeat(5,1fr);gap:6px}
.sc-keys button{min-height:44px;padding:0;font-size:15.5px}
.sc-keys button.num{font-weight:600;background:#fafbfa}
.sc-keys button.fn{font-size:14px}
.sc-hhead{display:flex;justify-content:space-between;align-items:center}
.hist.sc-hist{max-height:300px;font-size:13.5px}
.sc-hist div{display:flex;flex-direction:column;padding:7px 4px}
.sc-hist div:hover{background:#f6f8f7}
.sc-hist .e{color:var(--ink);word-break:break-all}
.sc-hist .r{color:var(--acc);text-align:right;word-break:break-all}
.sc-empty{cursor:default!important}
.sc-ex{display:flex;flex-wrap:wrap;gap:6px;margin-top:8px}
.sc-ex .chip,.cas-body .chip{font-family:var(--mono);font-size:12.5px}
/* function plot */
.fp-y{font:14px var(--mono);color:var(--mute);flex:none}
.fp-err{color:var(--err);display:block;padding-left:20px}
.fp-err:empty{display:none}
.custom .frow button{width:40px;height:40px}
.fp-tip{position:absolute;pointer-events:none;background:rgba(15,42,33,.92);color:#fff;font:12px var(--mono);padding:4px 8px;border-radius:6px;white-space:nowrap;z-index:2}
.fp-tip i{display:inline-block;width:8px;height:8px;border-radius:2px;margin-right:6px}
.fp-hint{font-size:12.5px;color:var(--mute)}
.fp-ana{display:flex;flex-direction:column;gap:8px}
.fp-row{border:1px solid var(--line);border-radius:8px;padding:8px 10px;font:13px/1.6 var(--mono);overflow-wrap:anywhere}
.fp-row b{display:block;font-weight:600;margin-bottom:2px}
.fp-row span{display:inline-block;min-width:3em;color:var(--mute);font-family:inherit}
/* geometry */
.geo-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);grid-template-rows:auto 1fr;grid-template-areas:"l r" "f r";gap:12px 16px;align-items:start}
.geo-l{grid-area:l}.geo-r{grid-area:r}.geo-f{grid-area:f}
.geo-sub{margin-bottom:12px;flex-wrap:wrap}
.geo-in{margin-bottom:12px}
.geo-in.geo-xy{grid-template-columns:repeat(2,minmax(0,1fr))}
.geo-out{display:flex;flex-direction:column;gap:2px}
.geo-fig{margin:6px 0 0;text-align:center}
.geo-fig svg{width:100%;max-width:380px;height:auto;background:#fafbfa;border:1px solid var(--line);border-radius:8px}
.geo-fig text{font:12px var(--mono);fill:#14201b}
.geo-fig text.v{font-weight:700;font-size:14px;fill:#0b7a55}
.geo-fig figcaption{font-size:12px;color:var(--mute)}
/* plot3d */
.p3-f{margin-bottom:4px}
.p3-range{grid-template-columns:repeat(4,minmax(0,1fr));margin-top:8px}
.p3-wrap{cursor:grab}
.p3-wrap:active{cursor:grabbing}
.p3-info{font-size:12.5px;color:var(--mute);margin-top:6px}
/* cas */
.cas-in{width:100%;border:1px solid #cfd8d4;border-radius:9px;padding:11px 12px;font:16px var(--mono);outline:0}
.cas-in:focus,.cas-ta:focus{border-color:var(--acc);box-shadow:0 0 0 3px rgba(11,122,85,.13)}
.cas-row{margin-top:10px;grid-template-columns:repeat(3,minmax(0,1fr))}
.cas-row>.row>select{min-height:42px}
.cas-go{background:var(--acc)!important;color:#fff!important;border-color:var(--acc)!important}
.cas-out .res-sec{margin:12px 0 4px}
.cas-out .out-box{font-size:16px}
.cas-out sup{font-size:.72em}
.cas-lin{display:grid;grid-template-columns:minmax(0,3fr) minmax(0,1fr);gap:12px}
.cas-ta{width:100%;border:1px solid #cfd8d4;border-radius:9px;padding:9px 10px;font:15px/1.5 var(--mono);outline:0;resize:vertical}
.cas-mat{border-collapse:collapse;font:14px var(--mono);border-left:2px solid #5d6b65;border-right:2px solid #5d6b65;display:block;overflow-x:auto;max-width:100%;width:max-content}
.cas-mat td{padding:3px 12px;text-align:right}
@media (max-width:760px){
  .sc-grid,.geo-grid{grid-template-columns:1fr}
  .geo-grid{grid-template-areas:"l" "r" "f";grid-template-rows:auto}
  .p3-range{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:520px){
  .card.custom{padding:12px}
  .cas-row{grid-template-columns:repeat(2,minmax(0,1fr))}
  .cas-lin{grid-template-columns:minmax(0,2fr) minmax(0,1fr)}
  .rows.geo-in{grid-template-columns:repeat(2,minmax(0,1fr))}
  .keys.sc-keys{grid-template-columns:repeat(5,1fr)}
  .sc-keys button{min-height:42px}
  .fp-hint{flex-basis:100%}
}
/* ===== CircuitJS case gallery (/cases/, scripts/build.mjs) ===== */
.hero-cases{display:flex;align-items:center;gap:6px 12px;flex-wrap:wrap;background:linear-gradient(90deg,#0f2a21,#145a41);color:#fff;border-radius:var(--r);padding:12px 16px;margin:4px 0 16px}
.hero-cases:hover{text-decoration:none;filter:brightness(1.08)}
.hero-cases b{font-size:16px}
.hero-cases span{font-size:13px;color:#cde5da;flex:1 1 220px}
.hero-cases i{font-style:normal;font-size:18px}
.cat h2 small{font-size:12px;color:var(--mute);font-weight:400;margin-left:6px}
.case-cards{grid-template-columns:repeat(auto-fill,minmax(220px,1fr))}
.case-card{padding:10px 12px 12px;min-width:0}
.case-card .thumb{display:block;height:120px;background:#fff;border:1px solid var(--line);border-radius:8px;overflow:hidden;margin-bottom:6px}
.case-card .thumb img{width:100%;height:100%;object-fit:contain;padding:4px;display:block}
.case-card .thumb i{display:grid;place-items:center;height:100%;font-style:normal;font-size:12px;color:var(--mute);background:#f6f8f7}
.case-card strong{flex-wrap:wrap}
.tag.lv1{background:#e7f4ee;color:var(--acc)}
.tag.lv2{background:#eef2ff;color:#3730a3}
.tag.lv3{background:#fff1e6;color:#b45309}
.case-tags{display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center;font-size:12.5px;color:var(--mute);margin:-4px 0 14px}
.case-tags code{font:12px var(--mono);background:#eef1ef;border-radius:4px;padding:0 5px}
.case-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:16px;align-items:start}
.case-grid figure.sch img{min-width:0;max-height:520px}
.case-links a{max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.case-nav{display:grid;grid-template-columns:1fr auto 1fr;gap:10px;align-items:stretch;margin:18px 0 6px}
.case-nav a{background:#fff;border:1px solid var(--line);border-radius:10px;padding:8px 12px;font-size:14px;min-width:0;overflow:hidden;text-overflow:ellipsis}
.case-nav a small{display:block;font-size:12px;color:var(--mute)}
.case-nav .up{align-self:center;font-size:13px}
.case-nav .nx{text-align:right}
.case-gpl{font-size:12px;color:var(--mute);margin:14px 0 4px}
@media (max-width:860px){.case-grid{grid-template-columns:1fr}}
@media (max-width:520px){
  .case-cards{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}
  .case-card .thumb{height:88px}
  .case-card strong{font-size:14px}
  .case-nav{grid-template-columns:1fr 1fr}.case-nav .up{display:none}
}
/* ===== end case gallery ===== */

/* LTspice netlist tab / download */
.spice-box{display:flex;flex-direction:column;gap:10px}
.spice-hint{margin:0;font-size:13.5px;color:var(--mute);line-height:1.7}
.spice-acts{display:flex;gap:8px;flex-wrap:wrap}
.spice-net{margin:0;max-height:420px;overflow:auto;background:#0f1419;color:#d6e2ee;border-radius:8px;padding:12px 14px;font:12.5px/1.55 ui-monospace,SFMono-Regular,Consolas,monospace;white-space:pre}
.spice-dl{display:flex;flex-wrap:wrap;align-items:center;gap:6px 12px;margin-top:12px}
.spice-dl small{color:var(--mute);font-size:12.5px}

/* case sources */
.tag.src{font-style:normal;font-size:11px;padding:1px 6px;border-radius:4px;margin-left:4px;vertical-align:1px;background:#eef3ff;color:#2f55a4}
.tag.src-esim{background:#fff3e6;color:#9a5300}.tag.src-kicad{background:#eaf2ff;color:#1f4fa3}.tag.src-adi{background:#f1e9ff;color:#5b2ea6}
.src-chips{margin-bottom:6px;align-items:center}.src-chips>span{font-size:13px;color:var(--mute);margin-right:4px}
.ext-sim{display:flex;flex-direction:column;gap:10px;font-size:14px}.ext-sim p{margin:0;line-height:1.7}.ext-ok{color:#2c7a4b;font-size:12.5px}

/* =================================================================== layout v2: tools / cases separation */
:root{--g:#16703f;--g2:#0f5a32;--gl:#e9f5ee;--gl2:#f3faf6;--bd:#dfe8e3;--ink2:#2b3a33}
body{background:#f6f8f7}
.ic{flex:none;vertical-align:-3px}
/* header */
header.top{background:#fff;color:var(--ink);border-bottom:1px solid var(--bd);box-shadow:0 1px 0 rgba(0,0,0,.02)}
header.top .wrap{height:64px;gap:20px}
header.top a{color:var(--ink)}
.brand{gap:10px}
.brand i{width:38px;height:38px;border-radius:9px;background:var(--g);color:#fff}
.brand-name{display:flex;flex-direction:column;line-height:1.05}
.brand-name b{font-size:19px;color:var(--g2);letter-spacing:1px}
.brand-name small{font-size:12px;color:var(--mute);font-weight:500;letter-spacing:.5px}
.brand-sub{font-weight:500;color:var(--mute);font-size:14px;border-left:1px solid var(--bd);padding-left:12px;margin-left:2px}
header.top .mainnav{margin:0 auto;gap:34px;font-size:15px;font-weight:600}
header.top .mainnav a{opacity:1;color:var(--ink2)}
header.top .mainnav a:hover{color:var(--g);text-decoration:none}
.back{border:1.5px solid var(--g);border-radius:8px;padding:7px 14px;font-size:14px;font-weight:600;color:var(--g)!important;display:inline-flex;gap:6px;align-items:center;white-space:nowrap}
.back:hover{background:var(--gl);text-decoration:none}
/* tools / cases switch */
.switch{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:18px 0 6px}
.switch a{position:relative;display:flex;align-items:center;justify-content:center;gap:16px;padding:14px 18px;border:1px solid var(--bd);border-radius:10px;background:#fff;color:var(--ink);text-decoration:none}
.switch a:hover{border-color:var(--g)}
.switch a .ic{color:var(--g)}
.switch b{display:flex;align-items:center;gap:10px;font-size:19px}
.switch em{font-style:normal;font-size:14px;background:var(--gl);color:var(--g);border-radius:99px;padding:1px 10px}
.switch small{display:block;color:var(--mute);font-size:13.5px;margin-top:2px}
.switch a[aria-current=page]{background:var(--g);border-color:var(--g);color:#fff}
.switch a[aria-current=page] .ic,.switch a[aria-current=page] small{color:#e2f2e8}
.switch a[aria-current=page] em{background:#fff;color:var(--g)}
.switch a[aria-current=page]::after{content:"";position:absolute;left:50%;bottom:-9px;margin-left:-9px;border:9px solid transparent;border-bottom:0;border-top-color:var(--g)}
/* hero */
.hero2{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:18px 40px;align-items:center;margin:18px 0 20px;padding:24px 32px;border-radius:14px;
  background:radial-gradient(120% 140% at 100% 0,#d9efe2 0,rgba(217,239,226,0) 55%),linear-gradient(90deg,#eef7f1,#f6fbf8)}
.hero-title h1{font-size:34px;margin:0;letter-spacing:1px}
.hero-title p{margin:4px 0 0;color:var(--mute);font-size:15px}
.hero-search{display:flex;max-width:640px;box-shadow:0 2px 8px rgba(20,60,40,.06);border-radius:10px}
.hero-search label{flex:1;display:flex;align-items:center;gap:10px;background:#fff;border:1.5px solid var(--bd);border-right:0;border-radius:10px 0 0 10px;padding:0 14px;color:var(--mute)}
.hero-search label:focus-within{border-color:var(--g)}
.hero-search input{flex:1;border:0;outline:0;font:inherit;font-size:15px;padding:12px 0;background:transparent;min-width:0;color:var(--ink)}
.hero-search button{white-space:nowrap;border:0;background:var(--g);color:#fff;font:inherit;font-weight:700;padding:0 30px;border-radius:0 10px 10px 0;cursor:pointer}
.hero-search button:hover{background:var(--g2)}
.hero-sub{display:flex;flex-wrap:wrap;align-items:center;gap:8px 12px;margin-top:12px;font-size:14px}
.hero-sub>span:first-child{font-weight:600}
.hero-sub i{font-style:normal;color:var(--mute)}
.pill{border:1px solid #bfdcc9;background:#fff;border-radius:7px;padding:3px 14px;color:var(--g);font-size:14px}
.pill:hover{background:var(--gl);text-decoration:none}
.src-count{color:var(--ink2)}.src-count b{color:var(--g)}
.hero-count{margin:0;color:var(--mute);font-size:14px;white-space:nowrap}
/* browse layout */
.browse{display:grid;grid-template-columns:230px minmax(0,1fr);gap:20px;align-items:start}
.panel{background:#fff;border:1px solid var(--bd);border-radius:12px}
.side{background:#fff;border:1px solid var(--bd);border-radius:12px;padding:14px 10px;position:sticky;top:80px}
.side h2{font-size:18px;margin:4px 8px 10px;display:flex;align-items:center;gap:8px}
.side nav{display:flex;flex-direction:column}
.side nav a{display:flex;align-items:center;gap:12px;padding:10px 12px;border-radius:8px;color:var(--ink2);font-size:15px;border-bottom:1px solid #f0f3f1}
.side nav a b{margin-left:auto;font-weight:500;font-size:12px;color:var(--mute)}
.side nav a .ic{color:#506159}
.side nav a:hover{background:var(--gl2);text-decoration:none}
.side nav a[aria-current=true]{background:var(--gl);color:var(--g);font-weight:700;box-shadow:inset 4px 0 0 var(--g)}
.side nav a[aria-current=true] .ic{color:var(--g)}
.browse-main{display:flex;flex-direction:column;gap:16px;min-width:0}
/* tool cards */
.tool-sec{padding:18px 20px}
.tool-sec h2{font-size:20px;margin:0 0 14px;padding-left:12px;border-left:4px solid var(--g);line-height:1.2}
.tool-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.tool-card{border:1px solid var(--bd);border-radius:10px;display:flex;flex-direction:column;transition:border-color .15s,box-shadow .15s}
.tool-card:hover{border-color:#9ccbb0;box-shadow:0 4px 14px rgba(20,80,50,.07)}
.tool-main{display:flex;gap:14px;padding:16px 16px 8px;color:var(--ink);flex:1}
.tool-main:hover{text-decoration:none}
.tool-ic{flex:none;width:62px;height:62px;border-radius:10px;background:var(--gl);color:var(--g);display:grid;place-items:center}
.tool-txt{display:flex;flex-direction:column;gap:4px;min-width:0}
.tool-txt strong{font-size:16px;line-height:1.35}
.tool-txt>span:not(.tool-tags){color:var(--mute);font-size:13.5px;line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.tool-tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:4px}
.tag.grp{background:#f1f4f2;color:#4d5c55;border:1px solid #e3e9e5}
.tool-foot{display:flex;justify-content:space-between;align-items:center;padding:6px 16px 14px 16px;font-weight:700;font-size:14.5px}
.tool-foot a{display:inline-flex;align-items:center;gap:4px;color:var(--g)}
.tool-foot a.rel{color:#2f63b8;font-weight:600;font-size:13.5px}
.ext-strip{display:flex;align-items:center;gap:20px;padding:14px 20px;flex-wrap:wrap}
.ext-strip h2{font-size:16px;margin:0;display:flex;align-items:center;gap:10px;white-space:nowrap}
.ext-strip div{display:flex;flex-wrap:wrap;gap:6px 22px;margin-left:auto}
.ext-strip a{display:inline-flex;align-items:center;gap:6px;font-size:14px;color:#2f63b8}
.ext-strip a b{color:var(--ink2);font-weight:500;margin-right:2px}
.cross{display:flex;align-items:center;justify-content:center;gap:10px;margin:20px 0 6px;padding:14px;border-radius:12px;background:#eef3f0;color:var(--ink2);font-size:15px}
.cross b{color:var(--g);display:inline-flex;align-items:center;gap:4px}
.cross .ic{color:var(--g)}
.cross:hover{text-decoration:none;background:var(--gl)}
#empty.panel{padding:30px;text-align:center;color:var(--mute)}
/* case library */
.filters{display:flex;flex-wrap:wrap;align-items:center;gap:10px}
.filters select{appearance:none;-webkit-appearance:none;font:inherit;font-size:14px;color:var(--ink2);background:#fff url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23455' stroke-width='2.5'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E") no-repeat right 12px center;border:1px solid var(--bd);border-radius:8px;padding:8px 36px 8px 14px;cursor:pointer}
.filters select:focus{outline:2px solid #bfdcc9;border-color:var(--g)}
.filters .sp{flex:1}
.filters .total{font-size:14px;color:var(--mute)}.filters .total b{color:var(--g);font-size:16px}
.tool-filter{margin:0;padding:10px 14px;border-radius:8px;background:#eef4fb;color:#244f8f;font-size:14px}
.tool-filter button{border:0;background:none;color:#244f8f;font:inherit;cursor:pointer;margin-left:8px;text-decoration:underline}
.case-grid-list{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.case-card{background:#fff;border:1px solid var(--bd);border-radius:12px;overflow:hidden;display:flex;flex-direction:column;transition:border-color .15s,box-shadow .15s}
.case-card:hover{border-color:#9ccbb0;box-shadow:0 4px 16px rgba(20,80,50,.08)}
.case-card[hidden]{display:none}
.tag{font-style:normal}
.case-thumb{display:flex;align-items:center;justify-content:center;height:190px;overflow:hidden;background:#fbfcfb;border-bottom:1px solid #eef2ef;
  background-image:linear-gradient(#f0f4f1 1px,transparent 1px),linear-gradient(90deg,#f0f4f1 1px,transparent 1px);background-size:16px 16px;padding:10px}
.case-thumb img{width:100%;height:100%;object-fit:contain}
.case-thumb i{color:var(--mute);font-style:normal;font-size:13px}
.case-body{padding:14px 16px 14px;display:flex;flex-direction:column;gap:6px;flex:1}
.case-body h3{font-size:17px;margin:0;line-height:1.35}.case-body h3 a{color:var(--ink)}
.case-body p{margin:0;color:var(--mute);font-size:13.5px;line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.case-tags{display:flex;flex-wrap:wrap;gap:6px;align-items:center}
.case-tags .tag{margin:0}
.tag.res{background:#eef4fb;color:#2c5ea8;border:1px solid #d6e4f6}
.tag.src{border:1px solid #c9d9f3}.tag.src-circuitjs{background:#eef3ff;color:#2f55a4}
.tag.cat{background:#f1f4f2;color:#4d5c55}
.case-tags .en{font-size:12.5px;color:var(--mute)}
.case-body .more{margin-top:auto;padding-top:4px;font-weight:700;font-size:14.5px;display:inline-flex;align-items:center;gap:4px;color:var(--g)}
.list-foot{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:10px;color:var(--mute);font-size:13px}
.list-foot>span{display:inline-flex;gap:6px;align-items:center}
.pager{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.pager button{min-width:40px;height:38px;border:1px solid var(--bd);background:#fff;border-radius:8px;font:inherit;font-size:14px;cursor:pointer;padding:0 12px;color:var(--ink2)}
.pager button:hover{border-color:var(--g);color:var(--g)}
.pager button[aria-current=page]{background:var(--g);border-color:var(--g);color:#fff;font-weight:700}
.pager span{color:var(--mute);padding:0 2px}
.notices{margin-top:18px}
/* case page */
.case-page .crumb{margin-top:16px}
.case-head{display:flex;gap:20px;align-items:flex-end;justify-content:space-between;margin:2px 0 16px}
.case-head h1{font-size:30px;margin:0 0 6px}
.case-head .lead{margin:0 0 10px}
.case-acts{display:flex;gap:10px;flex-wrap:wrap;justify-content:flex-end;flex:none}
.btn{display:inline-flex;align-items:center;gap:8px;border-radius:8px;padding:9px 16px;font-size:14.5px;font-weight:600;color:var(--ink2);text-decoration:none}
.btn:hover{text-decoration:none}
.btn.primary{background:var(--g);border-color:var(--g);color:#fff}.btn.primary:hover{background:var(--g2);color:#fff}
.btn.wide{width:100%;justify-content:center;padding:11px}
.case-layout{display:grid;grid-template-columns:minmax(0,1fr) 380px;gap:20px;align-items:start}
.case-main{display:flex;flex-direction:column;gap:16px;min-width:0}
.tabbar{display:flex;align-items:center;border-bottom:1px solid var(--bd);padding:0 16px}
.tabbar [role=tablist]{display:flex;gap:4px}
.tabbar [role=tab]{border:0;background:none;font:inherit;font-size:15.5px;padding:13px 20px 11px;cursor:pointer;color:var(--ink2);border-bottom:3px solid transparent;margin-bottom:-1px}
.tabbar [role=tab][aria-selected=true]{color:var(--g);font-weight:700;border-bottom-color:var(--g)}
.tabbar .fs{margin-left:auto;border:0;background:none;font:inherit;font-size:14px;cursor:pointer;display:inline-flex;gap:6px;align-items:center;color:var(--ink2)}
.case-view>[data-panel],.case-info>[data-panel]{padding:16px}
.case-view figure.sch{margin:0}
.case-view .sch .img{min-height:260px}
.case-info .prose{font-size:14.5px}
.parts{border-collapse:collapse;width:100%;max-width:520px;font-size:14px}
.parts th,.parts td{border-bottom:1px solid #edf1ee;padding:7px 10px;text-align:left}
.parts th{color:var(--mute);font-weight:600;font-size:13px}
.parts td:first-child{font-family:var(--mono);width:110px}
.hint{color:var(--mute);font-size:13px}
.files{list-style:none;margin:0;padding:0}
.files li{display:flex;justify-content:space-between;gap:10px;padding:9px 4px;border-bottom:1px solid #edf1ee;font-size:14.5px;flex-wrap:wrap}
.files a{display:inline-flex;align-items:center;gap:8px;font-weight:600}
.files code{color:var(--mute);font-size:12.5px}
.spice-note{font-size:13.5px;color:var(--mute);margin:10px 0 0}
.case-side{display:flex;flex-direction:column;gap:16px}
.side-card{padding:18px 20px}
.side-card h2{font-size:18px;margin:0 0 12px;padding-bottom:12px;border-bottom:1px solid var(--bd);display:flex;align-items:center;gap:10px}
.side-card h2 .ic{color:var(--g)}
.side-card ul{margin:0;padding-left:20px;font-size:15px;line-height:1.8}
.side-card li::marker{color:var(--g)}
.steps{list-style:none;margin:0;padding:0;counter-reset:s}
.steps li{counter-increment:s;display:flex;gap:12px;align-items:flex-start;padding:6px 0;font-size:15px;line-height:1.6}
.steps li::before{content:counter(s);flex:none;width:24px;height:24px;border-radius:50%;border:1.5px solid #9ccbb0;color:var(--g);display:grid;place-items:center;font-size:13px;font-weight:700;margin-top:1px}
.side-card.cta{background:var(--gl);border-color:#cfe6d8}
.side-card.cta h2{border-bottom-color:#cfe6d8}
.side-card.cta p{margin:0 0 14px;color:var(--ink2);font-size:14.5px}
.more-tools{display:flex;flex-wrap:wrap;gap:6px 14px;margin-top:10px;font-size:13.5px}
.case-foot{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;margin:18px 0 4px}
.case-foot p{margin:0;font-size:14px;color:var(--ink2)}
.case-foot nav{display:flex;gap:10px}
.case-foot .btn.next{border-color:var(--g);color:var(--g)}
.case-page .case-gpl{font-size:12px}
/* footer */
footer{background:var(--g2);color:#e6f3ec;margin-top:28px;padding:18px 0 16px;text-align:center}
footer .wrap{display:flex;flex-direction:column;gap:4px}
footer b{font-size:17px;letter-spacing:1.5px;color:#fff}
footer small{font-size:12px;color:#a9cdb8}
/* responsive */
@media (max-width:1080px){
  .tool-grid,.case-grid-list{grid-template-columns:repeat(2,minmax(0,1fr))}
  .case-layout{grid-template-columns:minmax(0,1fr) 320px}
  .hero2{grid-template-columns:1fr;gap:12px}
  .hero-count{white-space:normal}
}
@media (max-width:860px){
  header.top .mainnav{display:none}
  header.top .wrap{justify-content:space-between}
  .browse{grid-template-columns:minmax(0,1fr)}
  .side{min-width:0}
  .side{position:static;padding:8px}
  .side h2{display:none}
  .side nav{flex-direction:row;overflow-x:auto;gap:6px;scrollbar-width:none}
  .side nav a{white-space:nowrap;border:1px solid var(--bd);border-radius:99px;padding:6px 12px;font-size:14px}
  .side nav a b{margin-left:4px}
  .side nav a[aria-current=true]{box-shadow:none;border-color:var(--g)}
  .case-layout{grid-template-columns:1fr}
  .case-head{flex-direction:column;align-items:stretch}
  .case-acts{justify-content:flex-start}
}
@media (max-width:600px){
  .brand-sub,.brand-name small{display:none}
  .back{padding:6px 10px;font-size:13px}
  .switch{gap:8px;margin-top:12px}
  .switch a{padding:10px 8px;gap:8px;flex-direction:column;text-align:center}
  .switch b{font-size:16px;justify-content:center}
  .switch small{font-size:12px}
  .hero2{padding:18px;margin-top:14px}
  .hero-title h1{font-size:26px}
  .hero-search button{padding:0 16px}
  .tool-grid,.case-grid-list{grid-template-columns:1fr}
  .tool-sec{padding:14px}
  .ext-strip div{margin-left:0}
  .filters select{flex:1 1 calc(50% - 5px);min-width:0;width:0}
  .filters .total{flex-basis:100%}
  .filters .sp{display:none}
  .case-head h1{font-size:24px}
  .case-acts .btn{flex:1 1 auto;justify-content:center}
  .tabbar{padding:0 6px}.tabbar [role=tab]{padding:12px 12px 10px}
}

/* ---------- embed mode (iframe on www.eetree.cn): no own header / footer, see src/assets/embed.js ---------- */
.embed header.top,.embed body>footer{display:none}
.embed .switch{margin-top:12px}
.embed .side{top:12px}
.embed .sticky{top:12px}
.embed body{padding-bottom:20px}