/* ============================================================
   Design tokens — identical to the Cosmos Atlas page
   void #04060f · deep #0b1026 · ion #6be5ff · solar #ffb454
   plasma #ff5ea8 · starlight #e9efff · muted #93a0c4
   ============================================================ */
:root{
  --void:#04060f;
  --deep:#0b1026;
  --ion:#6be5ff;
  --solar:#ffb454;
  --plasma:#ff5ea8;
  --starlight:#e9efff;
  --muted:#93a0c4;
  --glass:rgba(14,20,44,.55);
  --glass-edge:rgba(120,160,255,.22);
  --ok:#5dffb0;
  --bad:#ff7a7a;
  --ease-zoom:cubic-bezier(.22,.9,.24,1);
  --rail:260px;          /* right-hand tab rail */
  --hud:96px;            /* header height */
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  min-height:100%;
  background:var(--void);
  color:var(--starlight);
  font-family:"Exo 2","Segoe UI",system-ui,-apple-system,sans-serif;
  -webkit-font-smoothing:antialiased;
  line-height:1.55;
}
a{color:var(--starlight);text-decoration:underline;text-decoration-color:rgba(233,239,255,.45);text-underline-offset:3px}
a:hover{text-decoration-color:var(--starlight)}
button,input,select,textarea{font-family:inherit;font-size:inherit;color:inherit}
button{background:none;border:none;cursor:pointer}
b,strong{color:var(--starlight);font-weight:600}

/* ---------- deep-space canvas (static stars, no meteors) ---------- */
#space{
  position:fixed;inset:0;overflow:hidden;z-index:0;pointer-events:none;
  background:
    radial-gradient(1200px 800px at 78% 18%, rgba(64,44,120,.35), transparent 60%),
    radial-gradient(1000px 700px at 12% 82%, rgba(20,60,110,.30), transparent 60%),
    radial-gradient(1400px 1000px at 50% 120%, rgba(8,14,40,.9), transparent 70%),
    linear-gradient(180deg,#03040c 0%, #060a1c 55%, #04060f 100%);
}
.starlayer{position:absolute;inset:0}
.starlayer .dot{position:absolute;border-radius:50%;background:#fff}
.starlayer .dot.tw{animation:twinkle 4s ease-in-out infinite}
@keyframes twinkle{0%,100%{opacity:.25}50%{opacity:1}}

/* ---------- HUD (header), as on Cosmos Atlas ---------- */
#hud{
  position:fixed;top:0;left:0;right:var(--rail);z-index:60;
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:16px 22px;
  pointer-events:none;
}
#hud>*{pointer-events:auto}
.brand{line-height:1.1}
.brand .t{
  display:block;
  font-weight:800;font-size:clamp(18px,2.1vw,26px);letter-spacing:.3em;text-transform:uppercase;
  color:var(--starlight);white-space:nowrap;
}
.brand .t,.brand .t:hover{text-decoration:none}
.brand p{font-size:13.5px;letter-spacing:.18em;text-transform:uppercase;color:var(--solar);margin-top:4px}
.hud-logos{display:flex;align-items:center;gap:22px}
.hud-logos img{height:44px;width:auto;opacity:.9}
.hud-logos img.purdue{height:26px}

/* ---------- right rail: readable tabs, stacked top → bottom ---------- */
#rail{
  position:fixed;top:0;right:0;bottom:0;width:var(--rail);z-index:65;
  display:flex;flex-direction:column;justify-content:center;gap:4px;
  padding:90px 14px 24px;
  background:var(--glass);border-left:1px solid var(--glass-edge);
  backdrop-filter:blur(22px) saturate(140%);-webkit-backdrop-filter:blur(22px) saturate(140%);
  box-shadow:-30px 0 80px rgba(0,0,0,.45);
}
#rail::before{
  content:"";position:absolute;inset:0 auto 0 0;width:1px;
  background:linear-gradient(180deg,transparent,var(--ion),var(--plasma),transparent);opacity:.5;
}
#rail .rail-eyebrow{font-size:12px;letter-spacing:.3em;text-transform:uppercase;color:var(--solar);padding:0 14px 10px}
#rail a{
  display:block;padding:12px 14px;border-radius:14px;text-decoration:none;
  border:1px solid transparent;transition:background .25s,border-color .25s,transform .15s;
}
#rail a b{
  display:block;font-size:15px;font-weight:800;letter-spacing:.22em;text-transform:uppercase;color:var(--starlight);
}
#rail a span{display:block;font-size:13px;color:var(--muted);letter-spacing:.08em;margin-top:3px}
#rail a:hover{background:rgba(30,50,100,.35);transform:translateX(-3px)}
#rail a.active{background:rgba(16,24,54,.75);border-color:rgba(120,200,255,.4);box-shadow:0 0 24px rgba(60,120,255,.15)}
#rail a.active b{color:#fff}
#rail .rail-foot{margin-top:auto;font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);padding:0 14px;opacity:.8}

/* ---------- page layout ---------- */
#page{position:relative;z-index:1;padding:calc(var(--hud) + 28px) var(--rail) 60px 0}
main{max-width:1000px;margin:0 auto;padding:0 40px}
.page-head{margin-bottom:26px}
.eyebrow{font-size:13px;letter-spacing:.3em;text-transform:uppercase;color:var(--solar);margin-bottom:8px}
h1.title{font-size:clamp(32px,4vw,48px);font-weight:800;letter-spacing:.04em;line-height:1.15}
.sub{margin-top:8px;font-size:18px;color:var(--solar);font-style:italic}
h2{font-size:15px;font-weight:800;letter-spacing:.24em;text-transform:uppercase;color:var(--solar);margin:30px 0 12px}
h3{font-size:21px;font-weight:800;letter-spacing:.04em;margin:0 0 6px}
p{margin:0 0 14px;font-size:17.5px;line-height:1.65;color:var(--starlight)}
p.muted,.muted{color:var(--muted)}
ul.list{margin:0 0 14px 20px;font-size:17.5px;line-height:1.6}
ul.list li{margin:4px 0}
.rule{height:1px;background:linear-gradient(90deg,transparent,var(--muted),transparent);opacity:.5;margin:26px 0}
.hint{font-size:13.5px;letter-spacing:.24em;text-transform:uppercase;color:var(--muted);display:flex;align-items:center;gap:10px;justify-content:center;margin:26px 0 0}
.hint::before,.hint::after{content:"";width:46px;height:1px;background:linear-gradient(90deg,transparent,var(--muted));display:block}
.hint::after{transform:scaleX(-1)}

/* glass panel (like the dashboard) */
.panel{
  border:1px solid var(--glass-edge);border-radius:18px;
  background:var(--glass);
  backdrop-filter:blur(22px) saturate(140%);-webkit-backdrop-filter:blur(22px) saturate(140%);
  box-shadow:0 20px 60px rgba(0,0,0,.4);
  padding:22px 24px;
}
.panel + .panel{margin-top:16px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media (max-width:760px){.grid2{grid-template-columns:1fr}}

/* tags (like the node tags) */
.tag a{text-decoration:none}
.tag a:hover{text-decoration:underline}
.tags{display:flex;flex-wrap:wrap;gap:10px 22px;margin:16px 0 4px}
.tag b{display:block;font-size:15px;font-weight:800;letter-spacing:.2em;text-transform:uppercase;color:var(--starlight)}
.tag span{display:block;font-size:13.5px;color:var(--solar);letter-spacing:.1em;margin-top:3px}
.tag.ion b,.tag.solar b,.tag.plasma b{color:var(--starlight)}

/* pill buttons (like the zoom-out button) */
.pill{
  display:inline-flex;align-items:center;gap:12px;
  padding:13px 26px;border-radius:999px;
  border:1px solid rgba(150,210,255,.45);
  background:linear-gradient(120deg,rgba(12,22,52,.8),rgba(30,16,50,.8));
  backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  font-weight:800;font-size:14.5px;letter-spacing:.22em;text-transform:uppercase;
  color:var(--starlight);text-decoration:none!important;cursor:pointer;
  box-shadow:0 0 30px rgba(107,229,255,.25), inset 0 0 22px rgba(107,229,255,.08);
  transition:box-shadow .3s,transform .15s;
}
.pill:hover{box-shadow:0 0 46px rgba(107,229,255,.5),inset 0 0 22px rgba(107,229,255,.15)}
.pill.solar{border-color:rgba(233,239,255,.45);box-shadow:0 0 30px rgba(233,239,255,.18),inset 0 0 22px rgba(233,239,255,.06)}
.pill[disabled]{opacity:.6;cursor:wait}
.pill svg{width:17px;height:17px;stroke:var(--ion);fill:none;stroke-width:2;stroke-linecap:round}
.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}

/* ---------- notes: numbered expandable cards (Cosmos "mission briefing" cards) ---------- */
.q{
  border:1px solid rgba(120,160,255,.16);border-radius:16px;
  background:rgba(10,16,40,.45);
  margin-bottom:12px;overflow:hidden;
  transition:border-color .3s,box-shadow .3s;
}
.q.open{border-color:rgba(120,200,255,.4);box-shadow:0 0 24px rgba(60,120,255,.15)}
.q-head{
  width:100%;display:flex;gap:12px;align-items:flex-start;text-align:left;
  padding:14px 16px;color:inherit;
}
.q-head:focus-visible{outline:2px solid var(--ion);outline-offset:-2px;border-radius:16px}
.q-num{
  flex:none;width:32px;height:32px;border-radius:50%;
  display:grid;place-items:center;
  font-size:13px;font-weight:800;color:#071022;
  background:#fff;
  box-shadow:0 0 12px rgba(233,239,255,.45);
}
.q.solar .q-num{background:#fff}
.q-text{font-size:18px;font-weight:600;line-height:1.45;flex:1;color:var(--starlight)}
.q-text small{display:block;font-weight:400;font-size:14.5px;color:var(--solar);margin-top:2px;letter-spacing:.04em}
.q-caret{flex:none;margin-top:6px;transition:transform .35s;color:var(--muted);font-size:13px}
.q.open .q-caret{transform:rotate(180deg)}
.q-panel{max-height:0;overflow:hidden;transition:max-height .5s var(--ease-zoom)}
.q-inner{padding:2px 18px 18px 62px}
.q-inner p:last-child,.q-inner ul:last-child{margin-bottom:0}

/* fact note: plasma bar (Cosmos ".fact") */
.fact{
  font-size:15.5px;line-height:1.55;color:var(--muted);
  border-left:2px solid var(--plasma);
  padding:6px 0 6px 12px;margin:10px 0;
}
.fact b{color:var(--starlight)}
.fact.ion{border-left-color:var(--ion)}
.fact.solar{border-left-color:var(--solar)}

/* centred fact (Cosmos ".popup-fact") */
.popup-fact{padding:14px 22px 4px;text-align:center;font-size:19px;line-height:1.65;color:var(--starlight)}

/* captioned media (Cosmos ".fig-media" + ".popup-cap") */
.fig{display:flex;flex-direction:column;border:1px solid rgba(150,200,255,.25);border-radius:16px;overflow:hidden;background:#05081a}
.fig img{display:block;width:100%;flex:1;object-fit:contain;background:#05081a}
.fig figcaption{
  font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);
  padding:8px 14px;background:rgba(8,12,30,.7);border-top:1px solid rgba(120,160,255,.15);line-height:1.5;
}
.fig figcaption a{color:var(--starlight)}

/* Purdue wordmark inline after the lecturer's name */
.purdue-inline{display:inline-block;vertical-align:middle;margin-left:10px;text-decoration:none}
.purdue-inline img{height:1.3em;width:auto;display:block;opacity:.95}

/* ---------- lecturer ---------- */
.lecturer{display:grid;grid-template-columns:230px 1fr;gap:24px;align-items:start}
.lecturer .portrait{border-radius:16px;overflow:hidden;border:1px solid rgba(150,200,255,.25);box-shadow:0 0 40px rgba(70,110,255,.22)}
.lecturer .portrait img{display:block;width:100%}
@media (max-width:640px){.lecturer{grid-template-columns:1fr}.lecturer .portrait{max-width:220px}}

/* ---------- programme table ---------- */
.tt{width:100%;border-collapse:collapse;font-size:17px}
.tt td{padding:9px 8px;border-top:1px solid rgba(120,160,255,.12);vertical-align:top;color:var(--starlight)}
.tt tr:first-child td{border-top:none}
.tt td.t{white-space:nowrap;color:var(--starlight);font-weight:800;width:140px;font-variant-numeric:tabular-nums;letter-spacing:.04em}
.tt td.b{color:var(--muted);font-style:italic}
.day-head{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin-bottom:8px}
.day-head h3{margin:0}
.day-head span{font-size:13px;letter-spacing:.3em;text-transform:uppercase;color:var(--solar)}

/* ---------- venue ---------- */
.map{position:relative;min-height:380px;border-radius:16px;overflow:hidden;border:1px solid rgba(150,200,255,.25);box-shadow:0 0 40px rgba(70,110,255,.15);background:#05081a}
.map iframe{position:absolute;inset:0;width:100%;height:100%;border:0;filter:saturate(.85) contrast(1.05)}
.addr{font-size:17.5px;line-height:1.6}
.addr b{display:block;font-weight:800;letter-spacing:.04em}

/* ---------- form ---------- */
form{display:grid;grid-template-columns:1fr 1fr;gap:14px 16px}
.f{display:flex;flex-direction:column;gap:6px}
.f.full{grid-column:1/-1}
label{font-size:12.5px;font-weight:600;letter-spacing:.22em;text-transform:uppercase;color:var(--muted)}
label .req{color:var(--starlight)}
input[type=text],input[type=email],select,textarea{
  width:100%;padding:11px 13px;border-radius:11px;
  background:rgba(16,24,54,.5);border:1px solid rgba(120,160,255,.2);color:var(--starlight);
  outline:none;transition:border-color .25s,background .25s;font-size:16.5px;
}
input:focus,select:focus,textarea:focus{border-color:var(--starlight);background:rgba(30,50,100,.5)}
textarea{min-height:100px;resize:vertical}
.choices{display:flex;flex-direction:column;gap:8px}
.choice{
  display:flex;align-items:center;gap:10px;
  border:1px solid rgba(120,160,255,.2);border-radius:11px;
  background:rgba(16,24,54,.5);padding:10px 13px;
  font-size:16.5px;line-height:1.4;color:var(--starlight);cursor:pointer;
  text-transform:none;letter-spacing:0;font-weight:400;
  transition:border-color .25s,background .25s,transform .15s;
}
.choice:hover{border-color:var(--starlight);background:rgba(30,50,100,.5);transform:translateX(3px)}
.choice:has(input:checked){border-color:var(--starlight);background:rgba(30,50,100,.5)}
.choice input{accent-color:#fff;width:15px;height:15px;flex:none}
.form-foot{grid-column:1/-1;display:flex;align-items:center;gap:16px;flex-wrap:wrap;margin-top:6px}
#form-status{font-size:14px;letter-spacing:.14em;text-transform:uppercase}
#form-status.ok{color:var(--ok)}
#form-status.bad{color:var(--bad)}
.hp{position:absolute;left:-9999px;opacity:0;height:0;width:0}
@media (max-width:640px){form{grid-template-columns:1fr}}

/* ---------- footer ---------- */
footer{margin-top:40px;font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);line-height:1.8;opacity:.85}
footer a{color:var(--muted)}

/* ---------- responsive ---------- */
@media (max-width:960px){
  :root{--rail:0px;--hud:170px}
  #hud{right:0;flex-direction:column;align-items:flex-start;gap:10px;background:linear-gradient(180deg,rgba(4,6,15,.95),rgba(4,6,15,0))}
  #rail{
    top:auto;bottom:0;left:0;right:0;width:auto;height:66px;
    flex-direction:row;justify-content:flex-start;gap:4px;padding:0 10px;
    overflow-x:auto;border-left:none;border-top:1px solid var(--glass-edge);scrollbar-width:none;
  }
  #rail::-webkit-scrollbar{display:none}
  #rail::before,#rail .rail-eyebrow,#rail .rail-foot{display:none}
  #rail a{padding:8px 12px;white-space:nowrap;flex:none;align-self:center}
  #rail a b{font-size:13px;letter-spacing:.14em}
  #rail a span{display:none}
  #page{padding:calc(var(--hud) + 10px) 0 90px}
  main{padding:0 16px}
}
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01s !important;animation-iteration-count:1 !important;transition-duration:.2s !important}
}