:root{--navy:#061b3a;--blue:#1265e8;--ink:#10213f;--muted:#64748b;--line:#dbe4f0;--bg:#f5f8fc;--green:#0ea566}
*{box-sizing:border-box}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,sans-serif;color:var(--ink);background:var(--bg);display:grid;grid-template-columns:270px 1fr;min-height:100vh}
.sidebar{background:linear-gradient(180deg,#061b3a,#08254c);color:white;padding:30px 22px;position:sticky;top:0;height:100vh}
.brand{display:flex;align-items:center;gap:12px}.mark,.bot{display:grid;place-items:center;border:2px solid #59c8ff;border-radius:50%;font-weight:900}.mark{width:48px;height:48px;font-size:25px}.brand strong{display:block;font-size:30px;letter-spacing:.04em}.brand span{display:block;color:#71a8ff;font-size:14px;font-weight:800}.tagline{color:#55ddb0;margin:12px 0 28px}
nav{display:grid;gap:8px}.nav{border:0;background:transparent;color:#d8e5f7;text-align:left;padding:13px;border-radius:10px;font-size:15px}.nav.active,.nav:hover{background:#1265e8;color:white}.promise{position:absolute;bottom:28px;left:22px;right:22px;border:1px solid #31557e;border-radius:14px;padding:16px;display:grid;gap:6px}.promise span{font-size:12px;color:#c6d5e8}
main{padding:32px;max-width:1450px;width:100%;margin:auto}header{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}h1{margin:0;font-size:28px}header p{margin:7px 0;color:var(--muted)}.status{display:flex;gap:10px}.status span,.badge{background:white;border:1px solid var(--line);box-shadow:0 4px 16px #10213f0c;border-radius:12px;padding:10px 14px;font-weight:700}
.panel{background:white;border:1px solid var(--line);border-radius:18px;padding:20px;margin-bottom:18px;box-shadow:0 7px 24px #10213f0a}.panel h2{font-size:18px;margin:0 0 16px}
.courses{display:grid;grid-template-columns:1fr 1fr;gap:14px}.course{border:1px solid var(--line);background:white;border-radius:14px;padding:16px;display:flex;align-items:center;gap:16px;text-align:left}.course.selected{border:2px solid var(--blue);background:#f8fbff}.course b{display:grid;place-items:center;width:58px;height:58px;border-radius:12px;background:var(--blue);color:white;font-size:28px}.course:nth-child(2) b{background:var(--green)}.course strong,.course small{display:block}.course strong{font-size:17px}.course small{color:var(--muted);margin-top:5px}
.modes{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}.mode{border:1px solid var(--line);background:white;border-radius:14px;padding:17px 10px;display:grid;gap:8px;place-items:center}.mode i{font-style:normal;font-size:27px}.mode small{color:var(--muted)}.mode.selected{outline:2px solid #7c3aed;background:#fbf9ff}
.coach{padding:0;overflow:hidden}.coach-head{display:flex;align-items:center;gap:14px;padding:18px 20px;border-bottom:1px solid var(--line)}.bot{width:46px;height:46px;background:#092852;color:#56e0b2}.coach-head h2{margin:0 0 3px}.coach-head p{margin:0;color:var(--muted);font-size:13px}.badge{margin-left:auto;font-size:12px;padding:7px 10px}.badge.demo{color:#a16207;background:#fff8df}.badge.live{color:#047857;background:#e9fff6}
.chat{min-height:260px;max-height:430px;overflow:auto;padding:22px;background:#fbfdff}.message{max-width:76%;padding:13px 15px;border-radius:15px;margin:0 0 12px;white-space:pre-wrap}.message p{margin:5px 0 0;line-height:1.55}.assistant{background:#eaf3ff;border:1px solid #cce1ff}.user{margin-left:auto;background:#102d58;color:white}.message.error{background:#fff1f2;border:1px solid #fecdd3;color:#991b1b}
.quick{display:flex;gap:9px;padding:12px 20px;border-top:1px solid var(--line)}.quick button{background:white;border:1px solid var(--line);border-radius:10px;padding:9px 12px;font-weight:650}
#composer{display:grid;grid-template-columns:1fr 46px 50px;gap:9px;padding:0 20px 18px}textarea{resize:vertical;min-height:54px;border:1px solid #9fc1ee;border-radius:14px;padding:14px;font:inherit;outline:none}.attach,#send{display:grid;place-items:center;border-radius:14px;border:1px solid var(--line);background:white;font-size:20px;cursor:pointer}#send{background:var(--blue);color:white;border:0}.fine{font-size:11px;color:var(--muted);padding:0 20px 18px;margin:0}
.preview{position:relative;margin:0 20px 12px;width:max-content;max-width:220px}.preview img{display:block;max-width:220px;max-height:140px;border-radius:12px;border:1px solid var(--line)}.preview button{position:absolute;right:-8px;top:-8px;border:0;background:#111827;color:white;border-radius:50%;width:24px;height:24px}.hidden{display:none}
.bottom-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.mini{margin:0}.mini h3{margin-top:0}.mini progress{width:100%}footer{text-align:center;background:#eaf3ff;border:1px solid #cfe0f4;border-radius:14px;padding:18px;margin-top:18px}
@media(max-width:950px){body{display:block}.sidebar{position:relative;height:auto}.promise{display:none}.sidebar nav{grid-template-columns:repeat(3,1fr)}main{padding:18px}.modes{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.sidebar{padding:18px}.sidebar nav{display:none}.brand strong{font-size:24px}header{display:block}.status{margin-top:12px}.courses,.bottom-grid{grid-template-columns:1fr}.modes{grid-template-columns:1fr 1fr}.message{max-width:92%}.quick{overflow:auto}.quick button{white-space:nowrap}#composer{grid-template-columns:1fr 42px 44px}}

.graph-panel{
  margin:16px 20px;
  padding:16px;
  background:#fff;
  border:1px solid var(--line);
  border-radius:14px;
  box-shadow:0 8px 24px rgba(16,33,63,.08);
}

.graph-panel.hidden{
  display:none;
}

.graph-header{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:12px;
  margin-bottom:12px;
  font-size:16px;
}

#graphEquation{
  color:var(--muted);
  font-size:14px;
}

#graphCanvas{
  width:100%;
  height:420px;
  min-height:320px;
  border:1px solid var(--line);
  border-radius:12px;
  overflow:hidden;
  background:#fff;
}

@media(max-width:600px){
  .graph-panel{
    margin:12px;
    padding:12px;
  }

  #graphCanvas{
    height:340px;
  }
}