*{box-sizing:border-box}
body{margin:0;font-family:Arial,Helvetica,sans-serif;background:#f4f6f8;color:#1f2933}
.topbar{background:white;border-bottom:1px solid #d8dee5;padding:18px 22px}
.brand{display:flex;justify-content:space-between;align-items:flex-start;gap:18px;flex-wrap:wrap}
.brand h1{margin:0;font-size:30px}
.subtitle{margin:5px 0 0;color:#667788}
.mode-badge{padding:7px 10px;border:1px solid #d2dbe3;border-radius:999px;background:#f7f9fb;color:#607080;font-size:13px}
.equation-banner{margin-top:15px;padding:12px 14px;border:1px solid #dfe6eb;border-radius:8px;background:#fafcfd}
.formula{font-size:20px;font-weight:700}
.formula-note{margin-top:5px;color:#667788;font-size:13px}
.top-controls{display:flex;flex-wrap:wrap;gap:16px;align-items:flex-start;margin-top:16px}
button{font-size:16px;padding:9px 15px;background:white;border:1px solid #b8c1cc;border-radius:7px;cursor:pointer}
button:hover{background:#edf2f6}
label{display:flex;flex-direction:column;gap:6px;color:#52616f;font-size:14px}
.help{font-size:11px;line-height:1.3;color:#7a8792;max-width:190px}
input,select{font-size:15px}
#durationInput{width:92px;padding:5px}
.clock-box{min-width:160px;padding:7px 11px;border:1px solid #d4dce3;border-radius:7px;background:#f8fafb}
.clock-box span,.clock-box strong,.clock-box small{display:block}
.clock-box span{font-size:12px;color:#6d7985}
.clock-box strong{margin-top:4px;font-size:16px}
.clock-box small{margin-top:3px;color:#7c8994}
main{padding:22px}
.teaching-strip{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:18px;padding:12px 14px;border:1px solid #d8dee5;background:white;border-radius:10px;font-size:13px;color:#52616f}
.network-layout{display:grid;grid-template-columns:300px minmax(580px,1fr) 250px;gap:18px}
.panel,.plot-panel,.analysis-panel,.footer-learning{background:white;border:1px solid #d8dee5;border-radius:10px;padding:18px}
.panel h2,.plot-panel h2,.analysis-panel h2,.footer-learning h2{margin-top:0}
.section-explain,.small-text,.plot-panel p,.analysis-panel p{color:#71808e;font-size:13px;line-height:1.45}
.mini-formula{display:inline-block;padding:7px 9px;border-radius:6px;background:#f6f8fa;border:1px solid #e3e8ec;font-family:Georgia,serif;font-size:15px;margin:5px 0 12px}
.input-row{background:#fafcfd;border:1px solid #dfe5ea;border-radius:7px;padding:10px;margin-top:12px}
.input-row strong{display:block;margin-bottom:10px}
.input-grid{display:grid;grid-template-columns:1fr 1fr;gap:7px}
.input-grid .wide{grid-column:1/-1}
.input-grid input,.input-grid select{width:100%;padding:6px;border:1px solid #ccd5dc;border-radius:5px}
.hidden-header{display:flex;justify-content:space-between;align-items:flex-start;gap:18px}
.hidden-buttons{display:flex;align-items:center;gap:12px}
.hidden-buttons button{width:42px;padding:8px;font-size:22px}
.initial-state-section{margin-top:18px;padding-top:14px;border-top:1px solid #e5eaee}
.initial-state-section h3{margin:0 0 7px;font-size:15px}
.initial-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(100px,1fr));gap:8px}
.initial-grid input{width:100%;padding:6px;border:1px solid #ccd5dc;border-radius:5px}
#networkSvg{width:100%;display:block;min-height:390px;margin-top:15px;border-top:1px solid #edf1f4;border-bottom:1px solid #edf1f4}
.connection-control{margin-top:15px}
.connection-control h3{margin:0 0 6px;font-size:15px}
.connection-control p{margin:5px 0;color:#667788}
.connection-control input{width:70%}
#outputValues{margin-top:18px}
.output-box{padding:12px;border:1px solid #dbe2e8;border-radius:7px;margin-bottom:10px;background:#fafcfd;font-size:18px}
.teach-box{margin-top:14px;border:1px solid #dfe5ea;border-radius:7px;background:#fbfcfd;padding:9px 11px}
.teach-box summary{cursor:pointer;font-weight:700;color:#40505d}
.teach-box p{margin:8px 0;font-size:13px;color:#5f6d78}
.analysis-panel{margin-top:18px}
.analysis-header{display:flex;justify-content:space-between;align-items:flex-end;gap:18px;flex-wrap:wrap}
.analysis-controls{display:flex;gap:14px;align-items:flex-end;flex-wrap:wrap}
.analysis-explain-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:14px}
.explain-card{padding:10px 12px;background:#f8fafb;border:1px solid #e2e7eb;border-radius:7px}
.explain-card p{margin-bottom:0}
.analysis-results{display:grid;grid-template-columns:1fr 1fr 1.4fr;gap:14px;margin-top:16px}
.analysis-card{background:#fafcfd;border:1px solid #dfe5ea;border-radius:8px;padding:12px}
.analysis-card h3{margin:0 0 8px;font-size:15px}
.plot-layout{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-top:18px}
.trajectory-header{display:flex;justify-content:space-between;align-items:flex-start;gap:20px}
.pca-status{font-size:12px;color:#73808c;margin:-6px 0 10px}
.trajectory-legend{display:flex;gap:16px;flex-wrap:wrap;margin-bottom:10px;font-size:12px;color:#667788}
.dot{display:inline-block;width:10px;height:10px;border-radius:50%;margin-right:5px}
.dot.green{background:#5a9f68}.dot.black{background:#1f2933}
.cross-red{display:inline-block;color:#b23a48;font-size:18px;font-weight:700;line-height:10px;margin-right:4px}
canvas{width:100%;height:auto;background:white;border:1px solid #e0e5e9}
.edge{cursor:pointer}
.node-label{font-size:14px;pointer-events:none}
.footer-learning{margin-top:18px}
.summary-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}
.summary-grid>div{padding:11px;background:#f8fafb;border:1px solid #e2e7eb;border-radius:7px;font-size:13px;line-height:1.4}
@media(max-width:1100px){.network-layout,.plot-layout,.analysis-results,.analysis-explain-grid,.teaching-strip,.summary-grid{grid-template-columns:1fr}}


/* ===== Final visual polish ===== */
a, button, select, input { transition: all .14s ease; }
button:focus-visible, select:focus-visible, input:focus-visible, a:focus-visible {
  outline: 2px solid rgba(49,93,143,.45);
  outline-offset: 2px;
}
button:hover { transform: translateY(-1px); }
section, .plot-card, .network-panel, .weights-panel {
  backdrop-filter: blur(1px);
}