:root{
  --bg:#0b1220; --panel:#111a2e; --panel2:#0f172a; --border:#1e293b;
  --text:#e2e8f0; --muted:#94a3b8; --accent:#38bdf8;
  --sin:#38bdf8; --cos:#a78bfa; --tan:#fbbf24; --csc:#f472b6; --sec:#34d399; --cot:#fb923c;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif}
a{color:var(--accent)}
.topbar{display:flex;justify-content:space-between;align-items:flex-start;gap:16px;padding:20px 20px 12px;max-width:1440px;margin:0 auto}
.topbar h1{margin:0;font-size:28px;letter-spacing:-.02em}
.subtitle{margin:6px 0 0;color:var(--muted);font-size:14px}
.formula-inline{background:#1e293b;padding:2px 8px;border-radius:999px;color:#e2e8f0;font-family:ui-monospace,monospace;font-size:13px}
.top-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
.toggle{display:flex;gap:6px;align-items:center;background:var(--panel);border:1px solid var(--border);padding:8px 10px;border-radius:999px;font-size:13px;cursor:pointer}
button{background:#1e293b;color:var(--text);border:1px solid #334155;padding:8px 12px;border-radius:8px;cursor:pointer;font-weight:600}
button:hover{background:#263449}
.layout{max-width:1440px;margin:0 auto;display:grid;grid-template-columns:340px 1fr;gap:16px;padding:8px 16px 20px}
@media(max-width:960px){.layout{grid-template-columns:1fr}}
.controls{display:flex;flex-direction:column;gap:14px}
.control-card,.panel{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:16px}
.control-card h2,.panel h2{margin:0 0 8px;font-size:15px;letter-spacing:.02em;text-transform:uppercase;color:#cbd5e1}
.hint{color:var(--muted);font-size:13px;line-height:1.5;margin:6px 0 0}
.param{margin-top:16px;padding-top:14px;border-top:1px solid var(--border)}
.param:first-of-type{border-top:none;padding-top:4px}
.param-head{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:6px}
.param-head label{font-weight:600;font-size:14px}
.param-head input[type=number]{width:84px;background:#020617;border:1px solid #334155;color:var(--text);border-radius:8px;padding:7px 8px}
input[type=range]{width:100%;accent-color:var(--accent)}
.param-desc{color:var(--muted);font-size:12.5px;line-height:1.45;margin-top:4px}
.equation-box{margin-top:16px;background:#020617;border:1px solid var(--border);border-radius:10px;padding:12px}
.eq-label{font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.eq{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:13.5px;margin-top:6px;word-break:break-word}
.eq-sub{color:var(--muted);font-size:12.5px;margin-top:6px}
.theta-readout{display:flex;gap:8px;align-items:center;font-weight:700;margin:10px 0}
.dot{color:var(--muted)}
.btn-row,.preset-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.preset-row button{padding:6px 9px;font-size:13px}
.values-table{width:100%;border-collapse:collapse;font-size:13.5px;margin-top:8px}
.values-table th{text-align:left;color:var(--muted);font-weight:600;padding:6px 6px;border-bottom:1px solid var(--border)}
.values-table td{padding:7px 6px;border-bottom:1px solid #1e293b}
.toggles-grid{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.toggles-grid label{display:flex;gap:8px;align-items:center;background:#020617;border:1px solid var(--border);padding:8px 10px;border-radius:8px;font-size:13.5px;cursor:pointer}
.content{display:flex;flex-direction:column;gap:16px;min-width:0}
.panel-head{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:10px}
.badge{background:#020617;border:1px solid var(--border);color:var(--muted);padding:5px 9px;border-radius:999px;font-size:12px}
canvas{width:100%;height:auto;display:block;background:#020617;border:1px solid var(--border);border-radius:10px}
.legend{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.legend span{display:inline-flex;gap:6px;align-items:center;font-size:13px;background:#020617;border:1px solid var(--border);padding:5px 8px;border-radius:999px}
.legend i{width:10px;height:10px;border-radius:50%;display:inline-block}
.unit-wrap{display:grid;grid-template-columns:420px 1fr;gap:16px;align-items:start}
@media(max-width:760px){.unit-wrap{grid-template-columns:1fr}}
#unitCircle{max-width:420px}
.unit-legend{display:flex;flex-direction:column;gap:8px;font-size:14px;line-height:1.5}
.swatch{width:11px;height:11px;border-radius:50%;display:inline-block;margin-right:6px;vertical-align:middle}
.identity-list{margin:8px 0 0;padding-left:18px;color:var(--muted);font-size:13.5px;line-height:1.7}
.section-head h2{margin:4px 0 4px;font-size:18px}
.section-head p{margin:0;color:var(--muted);font-size:13.5px}
.cards-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin-top:12px}
@media(max-width:1100px){.cards-grid{grid-template-columns:1fr}}
.func-card{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:14px;overflow:hidden}
.func-card header{display:flex;justify-content:space-between;align-items:flex-start;gap:10px}
.func-title{font-size:17px;font-weight:800}
.func-formula{font-family:ui-monospace,monospace;color:var(--muted);font-size:12.5px;margin-top:2px}
.func-value{font-weight:800;font-size:14px;white-space:nowrap}
.func-meta{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-top:10px}
.func-meta div{background:#020617;border:1px solid var(--border);border-radius:8px;padding:8px}
.func-meta dt{font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.func-meta dd{margin:3px 0 0;font-size:13px;font-weight:600}
.func-note{color:var(--muted);font-size:12.5px;line-height:1.5;margin-top:10px}
.lesson-text{color:var(--muted);font-size:13.5px;line-height:1.65;margin:8px 0 0}
.lesson p{color:#cbd5e1;font-size:14.5px;line-height:1.7;margin:0 0 10px}
.lesson p:last-child{margin-bottom:0}
.display-math{overflow-x:auto;overflow-y:hidden;padding:2px 0;color:#e2e8f0}
.display-math .katex-display{margin:6px 0}
.katex{font-size:1.04em}
.eq .katex{font-size:1.05em}
.func-note .katex,.param-desc .katex{font-size:1em}