/* =========================================================
   Spatial AI — course site
   Palette (RVP): navy #001524→#1A2A36 · orange #e8772e ·
   blue #1f6fb2 · soft gray #f6f7f8 · slate text
   ========================================================= */

:root{
  --navy-1:#001524; --navy-2:#1A2A36;
  --orange:#e8772e; --orange-dark:#d56a26;
  --blue:#1f6fb2;
  --bg:#f6f7f8; --ink:#1b2530; --ink-strong:#16202b;
  --muted:#5a6573; --muted-soft:#8b95a1; --faint:#c4cad2;
  --border:#e3e6ea; --border-soft:#edeff2;
  --mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace;
  --sans:'IBM Plex Sans',system-ui,-apple-system,sans-serif;
  --maxw:1080px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0; font-family:var(--sans); color:var(--ink);
  background:var(--bg); line-height:1.5;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;}
h1,h2,p,ul{margin:0;}

.wrap{max-width:var(--maxw);margin:0 auto;padding:0 28px;}

/* ---------- NAV ---------- */
.nav{
  position:sticky; top:0; z-index:50;
  background:rgba(246,247,248,.85);
  backdrop-filter:saturate(180%) blur(10px);
  -webkit-backdrop-filter:saturate(180%) blur(10px);
  border-bottom:1px solid var(--border);
}
.nav__inner{height:60px;display:flex;align-items:center;justify-content:space-between;gap:24px;}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;}
.brand__mark{width:20px;height:20px;border-radius:5px;background:var(--orange);}
.brand__name{font-weight:700;font-size:16px;letter-spacing:-.01em;color:var(--ink);}
.nav__links{display:flex;align-items:center;gap:26px;font-family:var(--mono);font-size:12.5px;}
.nav__links a{text-decoration:none;color:var(--muted);transition:color .12s;}
.nav__links a:hover{color:var(--blue);}

/* ---------- SECTIONS ---------- */
section{scroll-margin-top:80px;}
section + section, .section-divider{border-top:1px solid var(--border);}
.section-pad{padding:64px 28px;}
.sec-head{display:flex;align-items:center;gap:14px;margin-bottom:28px;}
.sec-bar{width:6px;height:26px;border-radius:3px;background:var(--orange);}
.sec-head h2{font-size:clamp(26px,3vw,34px);font-weight:700;letter-spacing:-.02em;color:var(--ink-strong);}
.eyebrow{font-family:var(--mono);font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted-soft);}

/* ---------- HERO ---------- */
.hero-wrap{padding:32px 28px 56px;}
.hero{
  position:relative; border-radius:16px; overflow:hidden;
  min-height:clamp(320px,40vw,420px);
  display:flex; flex-direction:column; justify-content:flex-end;
  background:linear-gradient(155deg,var(--navy-1) 0%,#0a1f30 55%,var(--navy-2) 100%);
  background-image:
    linear-gradient(to top, rgba(6,18,30,.85) 0%, rgba(6,18,30,.55) 45%, rgba(6,18,30,.35) 100%),
    url('figures/spatial_ai_banner.svg');
  background-size:cover; background-position:center;
  /* Swap the SVG for a photo by pointing this at e.g. figures/hero.jpg */
}
.hero__glow{position:absolute;pointer-events:none;}
.hero__glow--orange{top:-30%;right:-10%;width:60%;height:90%;
  background:radial-gradient(circle at 60% 40%, rgba(232,119,46,.55) 0%, rgba(232,119,46,.18) 35%, rgba(232,119,46,0) 70%);}
.hero__glow--blue{bottom:-35%;left:-12%;width:62%;height:95%;
  background:radial-gradient(circle at 40% 60%, rgba(31,111,178,.55) 0%, rgba(31,111,178,.18) 38%, rgba(31,111,178,0) 72%);}
.hero__inner{position:relative;z-index:2;padding:44px 48px;max-width:760px;}
.hero__eyebrow{font-family:var(--mono);font-size:13px;font-weight:500;letter-spacing:.06em;text-transform:uppercase;color:#f0a25a;}
.hero h1{margin-top:14px;font-size:clamp(44px,6.5vw,76px);font-weight:700;letter-spacing:-.03em;line-height:1.02;color:#fff;}
.hero__desc{margin-top:18px;max-width:600px;font-size:18px;line-height:1.6;color:rgba(255,255,255,.92);}

/* ---------- KEY FACTS ---------- */
.facts{display:flex;flex-wrap:wrap;margin-top:40px;border:1px solid var(--border);border-radius:14px;background:#fff;overflow:hidden;}
.fact{flex:1 1 160px;padding:18px 22px;border-right:1px solid var(--border-soft);}
.fact:last-child{border-right:0;}
.fact__k{font-family:var(--mono);font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted-soft);}
.fact__v{margin-top:6px;font-size:18px;font-weight:600;}
.fact__sub{display:block;margin-top:3px;font-family:var(--mono);font-size:12px;font-weight:400;color:var(--muted);}

/* ---------- ABOUT ---------- */
.about{display:grid;grid-template-columns:1.4fr 1fr;gap:48px;margin-top:52px;}
.about p{font-size:16px;line-height:1.7;color:#3f4856;}
.about p + p{margin-top:16px;}
.outcomes{list-style:none;padding:0;display:flex;flex-direction:column;gap:12px;}
.outcomes li{display:flex;gap:10px;font-size:15.5px;line-height:1.5;color:#3f4856;}
.outcomes li::before{content:"—";color:var(--orange);font-weight:700;}

/* ---------- CARDS GRID ---------- */
.cards{display:grid;gap:18px;}
.cards--4{grid-template-columns:repeat(4,1fr);}
.cards--2{grid-template-columns:repeat(2,1fr);}
.card{border:1px solid var(--border);border-radius:12px;background:#fff;padding:20px;}
.card__k{font-family:var(--mono);font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--muted-soft);}
.card__v{margin-top:10px;font-size:15.5px;font-weight:600;color:var(--ink);}
.card__sub{margin-top:3px;font-family:var(--mono);font-size:13px;color:var(--muted);}
.card__sub a{color:var(--blue);text-decoration:none;}
.card__sub a:hover{text-decoration:underline;}

/* ---------- SCHEDULE TABLE ---------- */
.note{margin-bottom:24px;font-size:14.5px;color:#6b7480;}
.note code{font-family:var(--mono);color:var(--blue);}
.table{border:1px solid var(--border);border-radius:12px;overflow:hidden;background:#fff;}
.row{display:grid;grid-template-columns:52px 124px minmax(190px,1.9fr) 96px minmax(180px,2fr) minmax(150px,1.35fr);}
.row > div{padding:14px 16px;border-right:1px solid var(--border-soft);}
.row > div:last-child{border-right:0;}
.row--head{background:var(--bg);}
.row--head > div{border-right:1px solid var(--border);font-family:var(--mono);font-size:11px;font-weight:600;letter-spacing:.04em;text-transform:uppercase;color:#6b7480;}
.row--body{border-top:1px solid var(--border-soft);}
.c-n{font-family:var(--mono);font-size:13px;color:#9aa3ae;}
.c-date{font-family:var(--mono);font-size:12.5px;color:var(--muted);white-space:nowrap;}
.c-topic{font-size:15px;font-weight:600;color:var(--ink);line-height:1.45;}
.c-readings{display:flex;flex-direction:column;gap:7px;}
.c-readings a{font-size:13.5px;line-height:1.4;color:var(--blue);text-decoration:none;}
.c-readings a:hover{text-decoration:underline;}
.c-assign{font-family:var(--mono);font-size:12.5px;line-height:1.45;color:#4b5563;}
.dash{color:var(--faint);}
.week{padding:10px 16px;background:#eaf3fa;border-top:1px solid #d2e6f4;border-left:3px solid var(--blue);
  font-family:var(--mono);font-size:11.5px;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--blue);}
.pdf{display:inline-flex;align-items:center;gap:5px;font-family:var(--mono);font-size:11.5px;font-weight:500;
  color:var(--blue);text-decoration:none;border:1px solid #bcdcef;background:#ecf5fb;padding:3px 8px;border-radius:6px;}
.pdf:hover{background:#dcecf8;}

/* ---------- GRADING ---------- */
.grade{display:grid;grid-template-columns:1.3fr 1fr;gap:48px;align-items:start;}
.bars{display:flex;flex-direction:column;gap:20px;}
.bar__top{display:flex;justify-content:space-between;align-items:baseline;margin-bottom:8px;}
.bar__label{font-size:15.5px;font-weight:600;color:var(--ink);}
.bar__pct{font-family:var(--mono);font-size:14px;color:var(--blue);}
.bar__track{height:8px;border-radius:99px;background:#eaecf0;overflow:hidden;}
.bar__fill{height:100%;background:var(--blue);border-radius:99px;}
.exam{border:1px solid var(--border);border-radius:12px;background:#fff;padding:22px;}
.exam p{margin-top:0;font-size:15px;line-height:1.65;color:#3f4856;}
.exam p + p{margin-top:14px;}

/* ---------- ASSIGNMENTS ---------- */
.assign{border:1px solid var(--border);border-radius:12px;background:#fff;padding:22px;display:flex;flex-direction:column;}
.assign__top{display:flex;justify-content:space-between;align-items:baseline;gap:12px;}
.assign__title{font-size:17px;font-weight:700;color:var(--ink-strong);}
.assign__meta{font-family:var(--mono);font-size:11.5px;color:var(--muted-soft);white-space:nowrap;}
.assign p{margin:10px 0 16px;font-size:14.5px;line-height:1.6;color:var(--muted);}
.btn{margin-top:auto;align-self:flex-start;display:inline-flex;align-items:center;gap:5px;font-family:var(--mono);
  font-size:12px;text-decoration:none;padding:5px 11px;border-radius:7px;}
.btn--blue{color:var(--blue);border:1px solid #bcdcef;background:#ecf5fb;}
.btn--blue:hover{background:#dcecf8;}
.btn--orange{color:#fff;border:1px solid var(--orange);background:var(--orange);}
.btn--orange:hover{background:var(--orange-dark);}
.assign--project{border-color:#f0cbab;background:#fdf4ec;}
.assign--project p{color:#3f4856;}
.assign--project .assign__meta{color:#b3601f;}

/* ---------- TEACHING STAFF ---------- */
.staff{display:flex;flex-wrap:wrap;justify-content:center;gap:18px;}
.person{flex:0 1 300px;border:1px solid var(--border);border-radius:12px;background:#fff;padding:24px;
  display:flex;flex-direction:column;align-items:center;text-align:center;}
.person__photo{width:108px;height:108px;border-radius:50%;object-fit:cover;
  background:#eef0f2;border:1px solid var(--border);}
.person__photo--ph{display:flex;align-items:center;justify-content:center;
  border-style:dashed;border-color:var(--faint);color:var(--muted-soft);
  font-family:var(--mono);font-size:12px;letter-spacing:.04em;text-transform:uppercase;}
.person__name{margin-top:16px;font-size:16.5px;font-weight:700;color:var(--ink-strong);}
.person__role{margin-top:5px;font-family:var(--mono);font-size:11px;letter-spacing:.05em;
  text-transform:uppercase;color:var(--orange-dark);}
.person__mail{margin-top:9px;font-family:var(--mono);font-size:12.5px;}
.person__mail a{color:var(--blue);text-decoration:none;}
.person__mail a:hover{text-decoration:underline;}

/* ---------- FOOTER ---------- */
.footer{border-top:1px solid var(--border);background:#eef0f2;}
.footer__inner{padding:32px 28px;display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;align-items:center;}
.footer__brand{display:flex;align-items:center;gap:10px;}
.footer__brand .brand__mark{width:16px;height:16px;border-radius:4px;}
.footer__brand .brand__name{font-size:14px;}
.footer__tag{font-family:var(--mono);font-size:12px;color:#9aa3ae;}
.footer__legal{font-family:var(--mono);font-size:12px;color:var(--muted-soft);text-align:right;line-height:1.6;}

/* ---------- RESPONSIVE ---------- */
@media (max-width:880px){
  .about,.grade{grid-template-columns:1fr;gap:32px;}
  .cards--4{grid-template-columns:repeat(2,1fr);}
  .nav__links{display:none;}
}
@media (max-width:760px){
  /* schedule becomes stacked cards */
  .row--head{display:none;}
  .row{grid-template-columns:1fr;}
  .row > div{border-right:0;border-bottom:1px solid var(--border-soft);}
  .row > div:last-child{border-bottom:0;}
  .row > div::before{content:attr(data-label);display:block;font-family:var(--mono);font-size:10px;
    letter-spacing:.06em;text-transform:uppercase;color:var(--muted-soft);margin-bottom:4px;}
  .cards--2,.cards--4,.staff{grid-template-columns:1fr;}
  .hero__inner{padding:32px 24px;}
  .video-compare-container,.video-frame{width:100%;}
}

/* ===== DEMO (mesh vs 3DGS slider) ===== */
.video-compare-container{
  width:72%; max-width:820px; margin:0 auto; position:relative; display:block;
  line-height:0; border-radius:14px; overflow:hidden;
  border:1px solid var(--border-soft); box-shadow:0 10px 30px rgba(10,31,48,.10);
  cursor:ew-resize;
}
.video-compare-container .video{width:100%; height:auto; position:relative; top:0; left:0;}
.video-compare-container .videoMerge{
  position:relative; top:0; left:0; z-index:10; width:100%; display:block;
  margin:0 auto; background-size:cover;
}
.demo-caption{margin-top:14px; text-align:center; font-family:var(--mono);
  font-size:13px; color:var(--muted);}
.demo-caption a{color:var(--blue); text-decoration:none;}
.demo-caption a:hover{text-decoration:underline;}
.demo-intro{max-width:680px; margin-left:auto; margin-right:auto; text-align:center;}
.demo-subhead{margin:40px 0 4px; text-align:center; font-size:20px; font-weight:600;}
.demo-sub{margin:0 auto 16px; max-width:620px; text-align:center;
  font-size:14.5px; line-height:1.55; color:var(--muted);}
.video-frame{
  width:72%; max-width:820px; margin:0 auto; line-height:0;
  border-radius:14px; overflow:hidden;
  border:1px solid var(--border-soft); box-shadow:0 10px 30px rgba(10,31,48,.10);
}
.video-frame .demo-video{width:100%; height:auto; display:block;}