/* ============================================================
   Chris Kapulkin — personal site
   Design language: "chalk on slate" — deep ink ground, chalk
   line-work drawn from cubical/simplicial cells and glued paths.
   Display: Fraunces (optical serif, high contrast).
   Body:    Spline Sans (humanist grotesque).
   Mono:    Spline Sans Mono (labels, arXiv ids, code).
   Accent:  a single warm ochre — used with restraint.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,500;9..144,600;9..144,900&family=Spline+Sans:wght@400;500;600&family=Spline+Sans+Mono:wght@400;500&display=swap');

:root{
  --ink:        #10141c;   /* near-black slate ground        */
  --ink-2:      #171d29;   /* raised panel                   */
  --ink-3:      #1f2736;   /* hover / border-lit             */
  --chalk:      #eef1f4;   /* primary text                   */
  --chalk-dim:  #a7b0bd;   /* secondary text                 */
  --chalk-faint:#6b7686;   /* captions, rules                */
  --ochre:      #e0a458;   /* single warm accent             */
  --ochre-deep: #c9863a;
  --teal:       #6fb6b2;   /* rarely: second complex colour  */
  --line:       #2a3446;   /* hairline rules                 */
  --focus:      #ffd089;

  --maxw: 1140px;
  --gutter: clamp(1.25rem, 4vw, 3rem);

  --step--1: clamp(0.82rem, 0.78rem + 0.2vw, 0.9rem);
  --step-0:  clamp(1rem, 0.96rem + 0.2vw, 1.075rem);
  --step-1:  clamp(1.2rem, 1.1rem + 0.5vw, 1.4rem);
  --step-2:  clamp(1.55rem, 1.35rem + 1vw, 2.05rem);
  --step-3:  clamp(2.1rem, 1.7rem + 2vw, 3.1rem);
  --step-4:  clamp(2.9rem, 2.1rem + 4vw, 5.2rem);
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

body{
  margin:0;
  background:var(--ink);
  color:var(--chalk);
  font-family:'Spline Sans',system-ui,sans-serif;
  font-size:var(--step-0);
  line-height:1.62;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}

/* faint blueprint grid behind everything */
body::before{
  content:"";
  position:fixed; inset:0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size:46px 46px;
  opacity:.13;
  pointer-events:none;
  z-index:0;
  mask-image:radial-gradient(ellipse 90% 70% at 50% 0%, #000 20%, transparent 80%);
}

a{color:var(--chalk);text-decoration:none}
a:focus-visible,button:focus-visible{
  outline:2px solid var(--focus);
  outline-offset:3px;
  border-radius:2px;
}

.wrap{max-width:var(--maxw);margin-inline:auto;padding-inline:var(--gutter);position:relative;z-index:1}

/* ---------- top nav ---------- */
.site-nav{
  position:sticky;top:0;z-index:50;
  backdrop-filter:blur(10px);
  background:color-mix(in srgb, var(--ink) 82%, transparent);
  border-bottom:1px solid var(--line);
}
.site-nav .wrap{
  display:flex;align-items:center;gap:1.5rem;
  min-height:64px;
}
.brand{
  font-family:'Fraunces',serif;
  font-weight:600;
  font-size:1.15rem;
  letter-spacing:.01em;
  display:flex;align-items:center;gap:.6rem;
  margin-right:auto;
}
.brand .glyph{width:26px;height:26px;flex:none}
.nav-links{display:flex;gap:.35rem;flex-wrap:wrap}
.nav-links a{
  font-size:var(--step--1);
  font-family:'Spline Sans Mono',monospace;
  letter-spacing:.02em;
  color:var(--chalk-dim);
  padding:.4rem .7rem;border-radius:6px;
  transition:color .18s, background .18s;
}
.nav-links a:hover{color:var(--chalk);background:var(--ink-2)}
.nav-links a[aria-current="page"]{color:var(--ochre)}
.nav-toggle{display:none}

@media (max-width:760px){
  .nav-toggle{
    display:inline-flex;margin-left:auto;
    background:var(--ink-2);border:1px solid var(--line);
    color:var(--chalk);border-radius:8px;padding:.5rem .7rem;
    font-family:'Spline Sans Mono',monospace;font-size:.8rem;cursor:pointer;
  }
  .brand{margin-right:0}
  .nav-links{
    display:none;width:100%;flex-direction:column;gap:.15rem;
    padding-bottom:.8rem;
  }
  .nav-links.open{display:flex}
  .site-nav .wrap{flex-wrap:wrap}
}

/* ---------- section scaffolding ---------- */
section{position:relative;z-index:1;padding-block:clamp(3rem,7vw,6rem)}
.eyebrow{
  font-family:'Spline Sans Mono',monospace;
  font-size:var(--step--1);
  letter-spacing:.22em;text-transform:uppercase;
  color:var(--ochre);
  display:flex;align-items:center;gap:.7rem;
  margin:0 0 1.1rem;
}
.eyebrow::before{content:"";width:26px;height:1px;background:var(--ochre);opacity:.7}

h1,h2,h3{font-family:'Fraunces',serif;font-weight:600;line-height:1.05;margin:0}
h1{font-size:var(--step-4);font-weight:500;letter-spacing:-.02em}
h2{font-size:var(--step-3);letter-spacing:-.01em}
h3{font-size:var(--step-1);font-weight:600}
p{margin:0 0 1rem}
.lead{font-size:var(--step-1);color:var(--chalk-dim);font-weight:400;line-height:1.5}

.section-head{max-width:60ch;margin-bottom:2.5rem}

/* ---------- hero ---------- */
.hero{padding-top:clamp(2.5rem,6vw,5rem);overflow:hidden}
.hero-grid{
  display:grid;grid-template-columns:1.15fr .85fr;
  gap:clamp(2rem,5vw,4rem);align-items:center;
}
@media (max-width:900px){.hero-grid{grid-template-columns:1fr}}

/* prospective students: text + larger figure side by side */
.prospective-grid{
  display:grid;grid-template-columns:minmax(0,0.9fr) minmax(0,1.1fr);
  gap:clamp(2rem,4vw,3.5rem);align-items:start;
}
.prospective-grid .figure-frame{position:sticky;top:88px}
@media (max-width:860px){
  .prospective-grid{grid-template-columns:1fr}
  .prospective-grid .figure-frame{position:static;margin-top:.5rem}
}
.hero h1 .accent{color:var(--ochre);font-style:italic;font-weight:400}
.hero .role{
  font-family:'Spline Sans Mono',monospace;
  color:var(--chalk-dim);font-size:var(--step--1);
  letter-spacing:.04em;margin-top:1.4rem;
}
.hero .role strong{color:var(--chalk);font-weight:500}
.hero-cta{display:flex;gap:.8rem;flex-wrap:wrap;margin-top:2rem}

.btn{
  display:inline-flex;align-items:center;gap:.5rem;
  font-family:'Spline Sans Mono',monospace;font-size:var(--step--1);
  letter-spacing:.02em;
  padding:.7rem 1.15rem;border-radius:8px;
  border:1px solid var(--line);
  transition:transform .15s, border-color .18s, background .18s;
}
.btn.primary{background:var(--ochre);color:#20160a;border-color:var(--ochre);font-weight:500}
.btn.primary:hover{background:var(--ochre-deep);border-color:var(--ochre-deep)}
.btn.ghost{color:var(--chalk-dim)}
.btn.ghost:hover{color:var(--chalk);border-color:var(--ink-3);background:var(--ink-2)}
.btn:hover{transform:translateY(-1px)}

/* the hero figure frame */
.figure-frame{
  position:relative;border:1px solid var(--line);border-radius:16px;
  background:linear-gradient(160deg,var(--ink-2),var(--ink));
  padding:1.1rem;
}
.figure-frame figcaption{
  font-family:'Spline Sans Mono',monospace;font-size:.72rem;
  color:var(--chalk-faint);letter-spacing:.04em;
  margin-top:.7rem;display:flex;justify-content:space-between;
}
.figure-frame svg{display:block;width:100%;height:auto}

/* photo slot (swap in a real photo) */
.photo-slot{
  position:relative;border:1px dashed var(--chalk-faint);
  border-radius:12px;aspect-ratio:4/5;overflow:hidden;
  display:flex;align-items:center;justify-content:center;
  background:var(--ink-2);
}
.photo-slot img{width:100%;height:100%;object-fit:cover;display:block}
.photo-slot .hint{
  font-family:'Spline Sans Mono',monospace;font-size:.72rem;
  color:var(--chalk-faint);text-align:center;padding:1rem;line-height:1.5;
}

/* photo image in hero */
.hero-photo{
  border:1px solid var(--line);border-radius:16px;overflow:hidden;
  background:var(--ink-2);aspect-ratio:4/5;
}
.hero-photo img{width:100%;height:100%;object-fit:cover;object-position:center 15%;display:block}

.award-list--solo{max-width:640px}
.award-list--solo li{padding:.7rem 0;border-bottom:1px solid var(--line)}
.award-list--solo li:first-child{border-top:1px solid var(--line)}

/* ---------- awards strip ---------- */
.awards{
  display:grid;grid-template-columns:auto 1fr;gap:1.5rem;align-items:center;
  background:var(--ink-2);border:1px solid var(--line);border-radius:14px;
  padding:1.4rem 1.6rem;
}
.awards .medal{
  width:96px;height:96px;border-radius:10px;object-fit:cover;
  border:1px solid var(--line);flex:none;
}
.award-list{display:flex;flex-direction:column;gap:.55rem;margin:0;padding:0;list-style:none}
.award-list li{display:flex;flex-wrap:wrap;gap:.5rem;align-items:baseline}
.award-list .yr{font-family:'Spline Sans Mono',monospace;font-size:.76rem;color:var(--ochre);min-width:64px}
.award-list .nm{font-weight:500}
.award-list .org{color:var(--chalk-faint);font-size:.9rem}
@media (max-width:560px){
  .awards{grid-template-columns:1fr}
  .awards .medal{width:72px;height:72px}
}

/* ---------- research areas ---------- */
.area-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);border:1px solid var(--line);border-radius:14px;overflow:hidden}
.area{
  background:var(--ink);padding:1.5rem 1.4rem;color:var(--chalk);text-decoration:none;
  transition:background .2s;position:relative;
  display:flex;align-items:center;min-height:120px;
}
.area::after{content:"→";position:absolute;top:1.1rem;right:1.2rem;color:var(--ochre);opacity:0;transform:translateX(-4px);transition:opacity .2s,transform .2s;font-family:'Spline Sans Mono',monospace}
.area:hover{background:var(--ink-2)}
.area:hover::after{opacity:1;transform:none}
.area h3{margin:0;font-size:1.08rem;line-height:1.3}
@media (max-width:900px){.area-grid{grid-template-columns:repeat(2,1fr)}}
@media (max-width:520px){.area-grid{grid-template-columns:1fr}}

.award-link{color:inherit;text-decoration:underline;text-underline-offset:3px;text-decoration-color:color-mix(in srgb,var(--ochre) 40%,transparent)}
.award-link:hover{text-decoration-color:var(--ochre);color:var(--ochre)}

/* ---------- publications ---------- */
.pub-list{display:flex;flex-direction:column;gap:0;border-top:1px solid var(--line)}
.pub{
  display:grid;grid-template-columns:auto 1fr auto;gap:1.2rem;
  padding:1.4rem 0;border-bottom:1px solid var(--line);
  align-items:start;
}
.pub .yr{
  font-family:'Spline Sans Mono',monospace;font-size:.82rem;
  color:var(--ochre);padding-top:.2rem;white-space:nowrap;
}
.pub .body h3{font-size:1.08rem;font-family:'Fraunces',serif;font-weight:600;line-height:1.25;margin-bottom:.35rem}
.pub .body .meta{color:var(--chalk-dim);font-size:.9rem}
.pub .body .authors{color:var(--chalk-faint)}
.pub .body .auth{color:var(--chalk-dim);text-decoration:underline;text-underline-offset:2px;text-decoration-color:color-mix(in srgb,var(--chalk-faint) 50%,transparent)}
.pub .body .auth:hover{color:var(--ochre);text-decoration-color:var(--ochre)}
.pub .links{display:flex;gap:.4rem;flex-wrap:wrap;justify-content:flex-end;padding-top:.15rem}
.tag{
  font-family:'Spline Sans Mono',monospace;font-size:.72rem;letter-spacing:.03em;
  color:var(--chalk-dim);border:1px solid var(--line);border-radius:5px;
  padding:.2rem .5rem;transition:.15s;white-space:nowrap;
}
.tag:hover{color:var(--ochre);border-color:var(--ochre)}
@media (max-width:680px){
  .pub{grid-template-columns:1fr;gap:.5rem}
  .pub .links{justify-content:flex-start}
}

/* filter chips */
.filters{display:flex;gap:.5rem;flex-wrap:wrap;margin-bottom:1.8rem}
.chip{
  font-family:'Spline Sans Mono',monospace;font-size:.78rem;
  background:var(--ink-2);border:1px solid var(--line);color:var(--chalk-dim);
  padding:.4rem .8rem;border-radius:20px;cursor:pointer;transition:.15s;
}
.chip:hover{color:var(--chalk);border-color:var(--ink-3)}
.chip[aria-pressed="true"]{background:var(--ochre);color:#20160a;border-color:var(--ochre);font-weight:500}

/* ---------- generic cards ---------- */
.card{
  background:var(--ink-2);border:1px solid var(--line);border-radius:12px;
  padding:1.5rem;transition:border-color .2s, transform .2s;
}
.card:hover{border-color:var(--ink-3);transform:translateY(-2px)}
.card h3{margin-bottom:.5rem}
.card .meta{font-family:'Spline Sans Mono',monospace;font-size:.76rem;color:var(--ochre);letter-spacing:.04em}
.card p{color:var(--chalk-dim);font-size:.93rem;margin:.5rem 0 0}
.grid-2{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:1rem}
.grid-3{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:1rem}

/* people / supervision list */
.roster{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:1px;background:var(--line);border:1px solid var(--line);border-radius:12px;overflow:hidden}
.person{background:var(--ink);padding:1.1rem 1.2rem;transition:background .18s}
.person:hover{background:var(--ink-2)}
.person .name{font-family:'Fraunces',serif;font-size:1.02rem;font-weight:600}
.person .kind{font-family:'Spline Sans Mono',monospace;font-size:.72rem;color:var(--chalk-dim);margin-top:.2rem;letter-spacing:.02em}
.person a.name:hover{color:var(--ochre)}

/* timeline (talks / honours) */
.timeline{border-left:1px solid var(--line);margin-left:.5rem;padding-left:1.5rem;display:flex;flex-direction:column;gap:1.5rem}
.tl-item{position:relative}
.tl-item::before{content:"";position:absolute;left:calc(-1.5rem - 5px);top:.55rem;width:9px;height:9px;border-radius:50%;background:var(--ink);border:1.5px solid var(--ochre)}
.tl-item .when{font-family:'Spline Sans Mono',monospace;font-size:.76rem;color:var(--ochre);letter-spacing:.03em}
.tl-item .what{margin-top:.2rem}
.tl-item .what strong{font-weight:500}
.tl-item .where{color:var(--chalk-dim);font-size:.92rem}

/* prose blocks */
.prose{max-width:68ch}
.prose p{color:var(--chalk-dim)}
.prose a{color:var(--ochre);text-decoration:underline;text-underline-offset:3px;text-decoration-color:color-mix(in srgb,var(--ochre) 40%,transparent)}
.prose a:hover{text-decoration-color:var(--ochre)}
.prose ul{color:var(--chalk-dim);padding-left:1.1rem}
.prose li{margin-bottom:.4rem}

/* ---------- footer ---------- */
.site-foot{border-top:1px solid var(--line);padding-block:2.5rem;margin-top:2rem}
.site-foot .wrap{display:flex;flex-wrap:wrap;gap:1.5rem;justify-content:space-between;align-items:flex-start}
.site-foot .col h4{font-family:'Spline Sans Mono',monospace;font-size:.74rem;letter-spacing:.1em;text-transform:uppercase;color:var(--chalk-faint);margin:0 0 .6rem}
.site-foot a{color:var(--chalk-dim);font-size:.9rem;display:block;padding:.15rem 0}
.site-foot a:hover{color:var(--ochre)}
.site-foot .fine{font-family:'Spline Sans Mono',monospace;font-size:.72rem;color:var(--chalk-faint)}

/* reveal-on-scroll */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .6s ease, transform .6s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}}

.pagetitle{padding-top:clamp(2.5rem,5vw,4rem);padding-bottom:1rem}

/* secondary tab bar (media sections) */
.subnav{display:flex;gap:.4rem;flex-wrap:wrap;margin-top:1.5rem}
.subnav a{
  font-family:'Spline Sans Mono',monospace;font-size:var(--step--1);
  letter-spacing:.02em;color:var(--chalk-dim);
  padding:.45rem .9rem;border:1px solid var(--line);border-radius:20px;
  transition:color .15s,border-color .15s,background .15s;
}
.subnav a:hover{color:var(--chalk);border-color:var(--ink-3);background:var(--ink-2)}
.subnav a[aria-current="page"]{background:var(--ochre);color:#20160a;border-color:var(--ochre);font-weight:500}

hr.rule{border:none;border-top:1px solid var(--line);margin:0}