/* Layout: brand-led single page. Navy masthead bands top and bottom (as on the PiMath covers),
   cream page, Lora display with red small caps, a lattice-point motif as the one signature graphic. */
:root{
  --navy:#0F3065; --red:#A31E2D; --paper:#F8F7F2; --paper-2:#EFEDE4; --ink:#1A2233; --muted:#5A6378;
  --rule:#C9CDD6; --dot:#A5AEBE; --card:#FFFFFF; --on-navy:#FFFFFF; --on-navy-muted:#C9D2E3;
  --accent:var(--navy); --accent-2:var(--red);
  --display:"Lora", Georgia, "Times New Roman", serif;
  --body:"Source Sans 3", "Segoe UI", system-ui, -apple-system, sans-serif;
  --maxw:1120px;
}
@media (prefers-color-scheme: dark){ :root:not([data-theme="light"]){
  --paper:#0E1524; --paper-2:#141D30; --ink:#E7EAF1; --muted:#A3ACBF; --rule:#2C3850; --dot:#4A5874;
  --card:#162036; --accent:#9DB5E8; --accent-2:#E2737E; --on-navy:#FFFFFF; --on-navy-muted:#C9D2E3; color-scheme:dark }}
:root[data-theme="dark"]{
  --paper:#0E1524; --paper-2:#141D30; --ink:#E7EAF1; --muted:#A3ACBF; --rule:#2C3850; --dot:#4A5874;
  --card:#162036; --accent:#9DB5E8; --accent-2:#E2737E; --on-navy:#FFFFFF; --on-navy-muted:#C9D2E3; color-scheme:dark }

*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion: reduce){ html{scroll-behavior:auto} }
body{background:var(--paper);color:var(--ink);font-family:var(--body);font-size:1.0625rem;line-height:1.6;margin:0}
a{color:var(--accent)}
a:focus-visible,button:focus-visible,input:focus-visible{outline:2px solid var(--accent-2);outline-offset:3px;border-radius:2px}
h1,h2,h3{font-family:var(--display);color:var(--accent);text-wrap:balance;line-height:1.15;margin:0}
p{margin:0}
.wrap{max-width:var(--maxw);margin-inline:auto;padding-inline:clamp(16px,4vw,40px)}
.smallcaps{font-family:var(--display);font-variant:small-caps;letter-spacing:.08em;color:var(--accent-2);font-weight:600}
.eyebrow{font-family:var(--body);text-transform:uppercase;letter-spacing:.14em;font-size:.78rem;font-weight:700;color:var(--accent-2)}

/* masthead */
.topband{height:10px;background:var(--navy)}
header.site{position:sticky;top:env(safe-area-inset-top,0px);z-index:10;background:var(--paper);border-bottom:1px solid var(--rule)}
header.site .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;padding-block:12px;flex-wrap:wrap}
.brand{display:flex;flex-direction:column;text-decoration:none;line-height:1}
.brand b{font-family:var(--display);font-weight:700;font-size:1.9rem;color:var(--accent);letter-spacing:-.01em}
.brand span{font-family:var(--display);font-weight:600;font-size:.72rem;letter-spacing:.12em;color:var(--accent-2);text-transform:uppercase;margin-top:4px}
nav.main{display:flex;gap:clamp(10px,2vw,26px);flex-wrap:wrap;align-items:center}
nav.main a{text-decoration:none;color:var(--ink);font-weight:500;font-size:.98rem}
nav.main a:hover{color:var(--accent-2)}
.btn{display:inline-flex;align-items:center;gap:8px;font-family:var(--body);font-weight:600;font-size:1rem;padding:11px 20px;border-radius:3px;text-decoration:none;border:1.5px solid var(--accent);cursor:pointer}
.btn.solid{background:var(--navy);border-color:var(--navy);color:#fff}
.btn.solid:hover{background:var(--red);border-color:var(--red)}
.btn.solid.accent{background:var(--red);border-color:var(--red)}
.btn.solid.accent:hover{background:var(--navy);border-color:var(--navy)}
.btn.ghost{background:transparent;color:var(--accent)}
.btn.ghost:hover{border-color:var(--accent-2);color:var(--accent-2)}
nav.main .btn{padding:7px 14px;font-size:.92rem;color:#fff}

/* hero */
.hero .wrap{display:grid;grid-template-columns:1.15fr .85fr;gap:clamp(24px,5vw,64px);align-items:center;padding-block:clamp(40px,7vw,88px) clamp(32px,5vw,56px)}
.hero h1{font-size:clamp(2.5rem,6vw,4.4rem);font-weight:700;letter-spacing:-.015em;margin-top:14px}
.hero h1 em{font-style:italic;font-weight:500;color:var(--accent-2)}
.hero .lede{font-size:1.2rem;color:var(--muted);max-width:34em;margin-top:20px}
.hero .lede strong{color:var(--ink);font-weight:600}
.cta-row{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}
.hero-art{position:relative;min-width:0}
.hero-art canvas{width:100%;max-width:440px;aspect-ratio:1/1;display:block;margin-inline:auto}
.hero-art figcaption{font-family:var(--display);font-style:italic;color:var(--muted);text-align:center;font-size:.95rem;margin-top:6px}
.facts{border-block:1px solid var(--rule)}
.facts ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(4,1fr)}
.facts li{padding:18px 16px;border-left:1px solid var(--rule);min-width:0}
.facts li:first-child{border-left:0;padding-left:0}
.facts b{display:block;font-family:var(--display);font-size:1.25rem;color:var(--accent)}
.facts small{color:var(--muted);font-size:.92rem}

section.block{padding-block:clamp(56px,8vw,96px)}
section.alt{background:var(--paper-2)}
.sec-head{display:grid;gap:10px;max-width:44em;margin-bottom:36px}
.sec-head h2{font-size:clamp(1.9rem,3.6vw,2.6rem)}
.sec-head p{color:var(--muted);font-size:1.1rem}
.rule-title{display:flex;align-items:center;gap:14px}
.rule-title::after{content:"";flex:1;height:2px;background:var(--navy);opacity:.9}

/* pillars */
.pillars{display:grid;grid-template-columns:repeat(3,1fr);gap:clamp(20px,3vw,40px)}
.pillar{border-top:3px solid var(--navy);padding-top:18px;min-width:0}
.pillar:nth-child(2){border-top-color:var(--red)}
.pillar h3{font-size:1.5rem;margin-bottom:8px}
.pillar p{color:var(--muted)}
.diff{display:grid;grid-template-columns:repeat(2,1fr);gap:18px 48px;margin-top:48px}
.diff div{min-width:0}
.diff h3{font-family:var(--body);font-size:1.05rem;color:var(--ink);font-weight:700;margin-bottom:4px}
.diff p{color:var(--muted)}

/* courses */
.filters{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:28px}
.chip{font-family:var(--body);font-size:.92rem;font-weight:600;padding:7px 14px;border-radius:999px;border:1.5px solid var(--rule);background:transparent;color:var(--ink);cursor:pointer}
.chip[aria-pressed="true"]{background:var(--navy);border-color:var(--navy);color:#fff}
.chip:hover{border-color:var(--accent)}
.courses{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:20px}
.course{background:var(--card);border:1px solid var(--rule);border-radius:4px;padding:22px 22px 20px;display:flex;flex-direction:column;gap:10px;min-width:0}
.course .track{font-size:.76rem;text-transform:uppercase;letter-spacing:.12em;font-weight:700;color:var(--accent-2)}
.course h3{font-size:1.3rem}
.course p{color:var(--muted);font-size:.98rem}
.course .seq{display:flex;flex-wrap:wrap;gap:6px;margin-top:auto;padding-top:6px}
.course .seq span{font-size:.82rem;font-weight:600;padding:3px 9px;border-radius:3px;background:var(--paper-2);color:var(--ink);border:1px solid var(--rule)}
.note{margin-top:22px;color:var(--muted);font-style:italic;font-family:var(--display)}

/* taste */
.taste{display:grid;grid-template-columns:1fr 1fr;gap:clamp(24px,5vw,64px);align-items:start}
.taste>div{min-width:0}
.formula{font-family:var(--display);font-size:clamp(1.4rem,3vw,2rem);color:var(--accent);padding:22px 0;border-block:1px solid var(--rule);margin-block:16px 18px;overflow-x:auto;white-space:nowrap}
.frac{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;line-height:1.1;font-size:.8em;margin-inline:2px}
.frac>span:first-child{border-bottom:1.5px solid currentColor;padding-inline:3px}
.proofs{list-style:none;padding:0;margin:0;display:grid;gap:10px}
.proofs li{padding-left:18px;position:relative;color:var(--muted)}
.proofs li::before{content:"";position:absolute;left:0;top:.65em;width:7px;height:7px;background:var(--accent-2);border-radius:50%}
.proofs b{color:var(--ink)}
.lab{background:var(--card);border:1px solid var(--rule);border-radius:4px;padding:22px}
.lab label{font-weight:600;display:flex;justify-content:space-between;gap:12px}
.lab input[type=range]{width:100%;accent-color:var(--red);margin-block:10px 18px}
.readout{display:grid;grid-template-columns:auto 1fr;gap:6px 16px;font-variant-numeric:tabular-nums;font-size:.98rem}
.readout dt{color:var(--muted)}
.readout dd{margin:0;font-family:ui-monospace,"SF Mono",Menlo,monospace;text-align:right}
.bar{height:8px;background:var(--paper-2);border-radius:4px;margin-top:16px;overflow:hidden;border:1px solid var(--rule)}
.bar i{display:block;height:100%;background:var(--navy);width:0}
.ask{margin-top:18px;font-family:var(--display);font-style:italic;color:var(--accent)}

/* research */
.research{display:grid;grid-template-columns:1.1fr .9fr;gap:clamp(24px,5vw,64px)}
.research>div{min-width:0}
.research p+p{margin-top:14px}
.areas{list-style:none;padding:0;margin:0;columns:2;column-gap:28px}
.areas li{break-inside:avoid;padding:9px 0;border-bottom:1px solid var(--rule);font-weight:500}
.thm{margin-top:26px;background:var(--card);border:1px solid var(--rule);border-left:4px solid var(--navy);padding:18px 20px;border-radius:2px}
.thm .lbl{font-weight:700;color:var(--ink)}
.thm .lbl i{font-weight:400}
.thm p{margin-top:6px;color:var(--muted)}

/* class format */
.format{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.format div{min-width:0;padding-top:14px;border-top:1px solid var(--rule)}
.format b{display:block;font-family:var(--display);color:var(--accent);font-size:1.15rem;margin-bottom:4px}
.format p{color:var(--muted);font-size:.97rem}

/* instructor */
.bio{display:grid;grid-template-columns:280px 1fr;gap:clamp(24px,5vw,56px);align-items:start}
.bio>div{min-width:0}
.bio img{width:100%;max-width:280px;aspect-ratio:1/1;object-fit:cover;border-radius:3px;display:block;border:1px solid var(--rule)}
.bio h3{font-size:1.9rem}
.bio .role{color:var(--muted);margin-top:4px}
.creds{list-style:none;padding:0;margin:20px 0 0;display:grid;grid-template-columns:1fr 1fr;gap:0 32px}
.creds li{padding:9px 0;border-bottom:1px solid var(--rule);font-size:.98rem;min-width:0}
.creds li span{display:block;color:var(--muted);font-size:.86rem}

/* fit + aid */
.fit{display:grid;grid-template-columns:1fr 1fr;gap:clamp(24px,5vw,56px)}
.fit>div{min-width:0}
.fit h3{font-size:1.45rem;margin-bottom:12px}
.fit ul{margin:0;padding-left:1.1em;color:var(--muted);display:grid;gap:6px}
.fit p{color:var(--muted)}
.aid{background:var(--navy);color:var(--on-navy);border-radius:4px;padding:28px}
.aid h3{color:#fff}
.aid p{color:var(--on-navy-muted)}

/* apply */
.steps{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(3,1fr);gap:24px;counter-reset:s}
.steps li{counter-increment:s;min-width:0}
.steps li::before{content:counter(s);display:grid;place-items:center;width:40px;height:40px;border-radius:50%;border:2px solid var(--accent-2);color:var(--accent-2);font-family:var(--display);font-weight:700;font-size:1.15rem;margin-bottom:12px}
.steps b{display:block;font-size:1.1rem;margin-bottom:4px}
.steps p{color:var(--muted)}
.contact{margin-top:40px;display:flex;flex-wrap:wrap;align-items:center;gap:12px 18px;padding:20px 22px;border:1px solid var(--rule);border-radius:4px;background:var(--card)}
.contact .addr{font-family:var(--display);font-size:1.25rem;color:var(--accent);user-select:all;word-break:break-all}
.contact small{color:var(--muted);flex-basis:100%}


/* winter term feature */
section.term{background:var(--navy);color:var(--on-navy)}
section.term .eyebrow{color:#F2B8BF}
section.term h2{color:#fff}
section.term .sec-head p{color:var(--on-navy-muted)}
section.term .rule-title::after{background:#fff;opacity:.5}
.term-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:20px}
.term-grid>.term-card{grid-column:span 2}
.term-grid>.term-card.full{grid-column:1 / -1}
.term-card .fee{display:flex;justify-content:space-between;align-items:baseline;gap:12px;font-size:.9rem;color:var(--muted)}
.term-card .fee b{font-family:var(--display);font-size:1.35rem;color:var(--accent);font-variant-numeric:tabular-nums}
.term-card .fee b.tbd{font-size:1.05rem;color:var(--muted);font-style:italic;font-weight:500}
.term-card{background:var(--card);color:var(--ink);border-radius:4px;padding:24px;display:flex;flex-direction:column;gap:10px;min-width:0}
.term-card .track{font-size:.76rem;text-transform:uppercase;letter-spacing:.12em;font-weight:700;color:var(--accent-2)}
.term-card h3{font-size:1.35rem}
.term-card p{color:var(--muted);font-size:.98rem}
.term-card .pre{margin-top:auto;padding-top:12px;border-top:1px solid var(--rule);font-size:.9rem;color:var(--ink)}
.term-card .pre b{font-weight:700}
.term-cta{display:flex;flex-wrap:wrap;align-items:center;gap:14px 20px;margin-top:28px}
.term-cta .btn.solid{background:#fff;border-color:#fff;color:#0F3065}
.term-cta .btn.solid:hover{background:var(--red);border-color:var(--red);color:#fff}
.term-cta small{color:var(--on-navy-muted)}
@media (max-width:900px){.term-grid{grid-template-columns:1fr}.term-grid>.term-card,.term-grid>.term-card.full{grid-column:auto}}


/* student publications */
.pubs{margin-top:clamp(40px,6vw,64px)}
.pubs h3{font-size:1.5rem;margin-bottom:6px}
.pubs .key{color:var(--muted);font-size:.95rem;margin-bottom:18px}
.pubs h4{font-family:var(--body);font-size:.78rem;text-transform:uppercase;letter-spacing:.14em;color:var(--accent-2);margin:22px 0 4px}
.pubs ol{list-style:none;margin:0;padding:0}
.pubs li{padding:12px 0;border-bottom:1px solid var(--rule);display:grid;grid-template-columns:4.2em 1fr;gap:4px 16px}
.pubs li .yr{font-family:var(--display);font-weight:600;color:var(--accent);font-variant-numeric:tabular-nums}
.pubs li div{min-width:0}
.pubs .t{color:var(--ink)}
.pubs .a{color:var(--muted);font-size:.95rem}
.pubs .a b{color:var(--ink);font-weight:700}
.pubs .j{color:var(--muted);font-size:.95rem;font-style:italic}
.pubs a{word-break:break-word}
.pubs ul.honors{margin:0;padding:0;list-style:none}
.pubs ul.honors li{padding:10px 0;border-bottom:1px solid var(--rule);color:var(--muted)}
.pubs ul.honors b{color:var(--ink)}


footer.site{background:var(--navy);color:var(--on-navy)}
footer.site .wrap{display:flex;flex-wrap:wrap;justify-content:space-between;gap:18px;padding-block:36px}
footer.site .n{font-family:var(--display);font-size:1.35rem}
footer.site small{color:var(--on-navy-muted);display:block;letter-spacing:.04em}
footer.site em{font-family:var(--display);color:var(--on-navy-muted)}

@media (max-width:900px){
  .hero .wrap,.taste,.research,.fit{grid-template-columns:1fr}
  .hero-art canvas{max-width:340px}
  .facts ul{grid-template-columns:repeat(2,1fr)}
  .facts li:nth-child(3){border-left:0;padding-left:0}
  .format{grid-template-columns:repeat(2,1fr)}
  .bio{grid-template-columns:1fr}
}
@media (max-width:640px){
  nav.main a:not(.btn):not(.keep){display:none}
  .pillars,.diff,.steps,.creds{grid-template-columns:1fr}
  .areas{columns:1}
  .format{grid-template-columns:1fr}
  .facts li{padding-left:0;border-left:0}
}

/* ---------- course track pages ---------- */
.crumbs{font-size:.9rem;color:var(--muted);margin-bottom:14px}
.crumbs a{color:var(--muted)}
.page-hero .wrap{padding-block:clamp(40px,6vw,72px) clamp(28px,4vw,44px)}
.page-hero h1{font-size:clamp(2.2rem,5vw,3.4rem);font-weight:700;margin-top:10px}
.page-hero .lede{font-size:1.15rem;color:var(--muted);max-width:44em;margin-top:16px}
.track-course{display:grid;grid-template-columns:1fr 300px;gap:clamp(20px,4vw,48px);padding-block:36px;border-top:1px solid var(--rule)}
.track-course:first-child{border-top:0;padding-top:0}
.track-course>div{min-width:0}
.track-course h2{font-size:clamp(1.6rem,3vw,2.1rem)}
.track-course .desc{margin-top:12px;color:var(--ink)}
.track-course .desc+.desc{margin-top:12px}
.topics{display:flex;flex-wrap:wrap;gap:6px;margin-top:16px;padding:0;list-style:none}
.topics li{font-size:.86rem;font-weight:600;padding:4px 10px;border-radius:3px;background:var(--paper-2);border:1px solid var(--rule)}
.facts-card{background:var(--card);border:1px solid var(--rule);border-radius:4px;padding:20px;align-self:start;display:grid;gap:12px}
.facts-card dl{margin:0;display:grid;gap:10px}
.facts-card dt{font-size:.76rem;text-transform:uppercase;letter-spacing:.12em;font-weight:700;color:var(--accent-2)}
.facts-card dd{margin:2px 0 0;color:var(--ink)}
.badge{display:inline-block;font-size:.78rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;padding:4px 10px;border-radius:999px;background:var(--navy);color:#fff}
.facts-card .badge{justify-self:start}
.badge.quiet{background:transparent;color:var(--muted);border:1px solid var(--rule)}
.howbox{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.howbox div{min-width:0;padding-top:12px;border-top:1px solid var(--rule)}
.howbox b{display:block;font-family:var(--display);color:var(--accent);font-size:1.1rem;margin-bottom:4px}
.howbox p{color:var(--muted);font-size:.96rem}
.tracks{display:flex;flex-wrap:wrap;gap:10px}
.tracks a{text-decoration:none;font-weight:600;padding:9px 16px;border:1.5px solid var(--rule);border-radius:3px;color:var(--ink)}
.tracks a:hover{border-color:var(--accent-2);color:var(--accent-2)}
.more{font-weight:600;font-size:.95rem;text-decoration:none}
.more:hover{text-decoration:underline}
.topic-list{columns:2;column-gap:32px;padding-left:1.1em;color:var(--muted)}
.topic-list li{break-inside:avoid;margin-bottom:6px}
@media (max-width:900px){.track-course{grid-template-columns:1fr}.howbox{grid-template-columns:repeat(2,1fr)}}
@media (max-width:640px){.howbox{grid-template-columns:1fr}.topic-list{columns:1}}

/* Announcement bar at top of homepage */
.announce{background:var(--paper-2);border-bottom:1px solid var(--rule);border-left:4px solid var(--accent-2)}
.announce .wrap{display:flex;align-items:center;justify-content:space-between;gap:8px 20px;flex-wrap:wrap;padding-block:12px}
.announce p{margin:0;font-size:1rem;color:var(--ink)}
.announce .tag{display:inline-block;background:var(--red);color:#fff;font-weight:700;font-size:.75rem;letter-spacing:.08em;text-transform:uppercase;padding:2px 8px;border-radius:3px;margin-right:6px;vertical-align:2px}
.announce a{font-weight:600;color:var(--accent);text-decoration:none;white-space:nowrap}
.announce a:hover{color:var(--accent-2);text-decoration:underline}