/* ============================================================
   Harvard x Oxford Hackathon — one stylesheet for the page.
   Colours live in :root. Every pair below meets WCAG AA.
   ============================================================ */

:root{
  /* --- colour ---------------------------------------------
     Contrast ratios are measured against --void (#0A0A0A).
     Lime is a DARK-BACKGROUND colour only: on white it is 1.5:1
     and must never be used for text there. */
  --void:#0A0A0A;       /* page background */
  --panel:#111211;      /* cards */
  --panel-2:#171917;    /* raised cards, table rows */
  --line:#2A2D29;       /* hairlines */
  --line-2:#3D423B;     /* hairlines on raised cards */
  --field-line:#6B7266; /* form control borders       4.0:1 */
  --paper:#FFFFFF;      /* headings on dark          19.8:1 */
  --body:#D6D9D2;       /* body text on dark         13.9:1 */
  --muted:#A9ADA2;      /* captions, labels           8.7:1 */
  --lime:#C1E328;       /* accent. On dark 13.5:1; ink on lime 13.5:1 */
  --lime-dim:#8FA81E;   /* lime hairlines and hovers  7.3:1 */
  --ink:#0A0A0A;        /* text ON lime */
  --bronze:#F0A32A;     /* tier marker                8.4:1 */
  --silver:#B9BDB6;     /* tier marker                9.3:1 */
  --focus:#8AB4FF;      /* focus ring                 9.5:1 */

  --display:"Archivo",system-ui,sans-serif;
  --text:"Instrument Sans",system-ui,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,monospace;
  --pad:clamp(20px,5vw,64px);
  --head-h:68px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:calc(var(--head-h) + 16px)}
body{
  margin:0;background:var(--void);color:var(--body);
  font-family:var(--text);font-size:17px;line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block}
a{color:inherit}
/* long addresses must never push the page sideways */
a[href^="mailto:"]{overflow-wrap:anywhere}

/* --- accessibility floor ---------------------------------- */
.skip{
  position:absolute;left:12px;top:-80px;z-index:200;
  background:var(--lime);color:var(--ink);padding:14px 22px;border-radius:0 0 10px 10px;
  font-weight:700;text-decoration:none;transition:top .18s;
}
.skip:focus{top:0}
:focus-visible{outline:3px solid var(--focus);outline-offset:3px;border-radius:4px}
.vh{
  position:absolute;width:1px;height:1px;margin:-1px;padding:0;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}

.wrap{max-width:1240px;margin:0 auto;padding:0 var(--pad)}
h1,h2,h3,h4{font-family:var(--display);color:var(--paper);margin:0;line-height:1.02;letter-spacing:-.02em}
h1{font-weight:800}
h2,h3,h4{font-weight:700}
p{margin:0 0 1em}
.lede{font-size:clamp(17px,1.6vw,21px);color:var(--body);max-width:60ch}

/* --- buttons ---------------------------------------------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  min-height:48px;padding:12px 24px;border-radius:999px;
  font-family:var(--text);font-size:16px;font-weight:600;text-decoration:none;
  border:1.5px solid transparent;transition:background .16s,color .16s,border-color .16s;
}
.btn-fill{background:var(--lime);color:var(--ink)}
.btn-fill:hover{background:var(--paper)}
.btn-ghost{border-color:var(--line-2);color:var(--paper)}
.btn-ghost:hover{border-color:var(--lime);color:var(--lime)}
.btn-arrow{font-family:var(--mono);font-size:15px}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:32px}

/* --- header ----------------------------------------------- */
.site-head{
  position:sticky;top:0;z-index:100;
  background:rgba(10,10,10,.92);border-bottom:1px solid var(--line);
  backdrop-filter:saturate(160%) blur(10px);
}
.head-in{display:flex;align-items:center;gap:16px;min-height:var(--head-h)}
.brand{
  display:flex;align-items:baseline;gap:9px;text-decoration:none;margin-right:auto;
  min-height:44px;padding-top:14px;
  font-family:var(--display);font-weight:800;font-size:16px;letter-spacing:.01em;
  color:var(--paper);text-transform:uppercase;
}
.brand .x{color:var(--lime)}
.brand span.sub{
  font-family:var(--mono);font-size:11px;font-weight:400;letter-spacing:.14em;
  color:var(--muted);text-transform:uppercase;
}
.menu-btn{
  display:none;align-items:center;gap:9px;min-height:44px;padding:10px 16px;
  background:none;border:1.5px solid var(--line-2);border-radius:999px;
  color:var(--paper);font:600 15px/1 var(--text);cursor:pointer;
}
.bars,.bars::before,.bars::after{
  display:block;width:16px;height:2px;background:currentColor;content:"";
}
.bars{position:relative}
.bars::before{position:absolute;top:-5px}
.bars::after{position:absolute;top:5px}
.mainnav ul{display:flex;align-items:center;gap:6px;list-style:none;margin:0;padding:0}
.mainnav a{
  display:flex;align-items:center;min-height:44px;padding:8px 14px;border-radius:999px;
  text-decoration:none;color:var(--body);font-size:15px;font-weight:500;
}
.mainnav a:hover{color:var(--lime)}
.mainnav a[aria-current="page"]{color:var(--lime)}
.mainnav .nav-cta a[aria-current="page"]{background:var(--paper);color:var(--ink)}
.mainnav .nav-cta a{background:var(--lime);color:var(--ink);font-weight:600;padding:8px 20px}
.mainnav .nav-cta a:hover{background:var(--paper);color:var(--ink)}

/* --- section furniture ------------------------------------ */
section{padding:clamp(64px,9vw,120px) 0;border-top:1px solid var(--line)}
.eyebrow{
  display:flex;align-items:center;gap:14px;
  font-family:var(--mono);font-size:11px;letter-spacing:.18em;text-transform:uppercase;
  color:var(--lime);margin:0 0 22px;
}
.eyebrow::after{
  content:"";flex:1;height:1px;background:linear-gradient(90deg,var(--lime-dim),transparent);
}
.sec-head{max-width:70ch;margin-bottom:clamp(36px,5vw,60px)}
.sec-head h2{font-size:clamp(30px,4.4vw,52px);margin-bottom:18px}
.sec-head p{color:var(--muted);max-width:62ch}

/* --- hero ------------------------------------------------- */
.hero{
  border-top:0;position:relative;overflow:hidden;
  padding:clamp(56px,8vw,96px) 0 clamp(56px,7vw,88px);
}
.hero::before{
  content:"";position:absolute;inset:-40% -20% auto -20%;height:120%;
  background:radial-gradient(60% 55% at 22% 30%,rgba(193,227,40,.16),transparent 70%);
  pointer-events:none;
}
.hero .wrap{position:relative}
.hero h1{font-size:clamp(42px,8.4vw,104px);letter-spacing:-.035em;margin:0 0 26px}
.hero h1 em{font-style:normal;color:var(--lime)}
.kicker{
  font-family:var(--display);font-weight:800;font-size:clamp(15px,2vw,20px);
  letter-spacing:.06em;text-transform:uppercase;color:var(--paper);margin:0 0 20px;
}
.kicker .x{color:var(--lime);margin:0 6px}
.facts{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:14px 34px;
  list-style:none;margin:44px 0 0;padding:26px 0 0;border-top:1px solid var(--line);
}
.facts li{font-family:var(--mono);font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);padding:6px 0}
.facts b{display:block;font-family:var(--display);font-size:19px;letter-spacing:0;color:var(--paper);text-transform:none}

/* --- pull quote / mission --------------------------------- */
.pull{
  font-family:var(--display);font-weight:700;color:var(--paper);margin:0;
  font-size:clamp(26px,4vw,46px);line-height:1.08;letter-spacing:-.02em;max-width:20ch;
}
.pull em{font-style:normal;color:var(--lime)}
.split{display:grid;grid-template-columns:1.05fr .95fr;gap:clamp(28px,5vw,64px);align-items:start}

/* --- cards ------------------------------------------------ */
.grid{display:grid;gap:16px}
.g2{grid-template-columns:repeat(2,1fr)}
.g3{grid-template-columns:repeat(3,1fr)}
.g4{grid-template-columns:repeat(4,1fr)}
.g5{grid-template-columns:repeat(5,1fr)}
.card{
  background:var(--panel);border:1px solid var(--line);border-radius:16px;
  padding:clamp(20px,2.4vw,30px);
}
.card h3{font-size:20px;margin-bottom:10px}
.card p{color:var(--muted);margin:0;font-size:15.5px}
.card p + p{margin-top:.8em}
.num{
  display:flex;align-items:center;justify-content:center;flex:none;width:34px;height:34px;
  border:1.5px solid var(--lime);border-radius:50%;margin:0;
  font-family:var(--mono);font-size:13px;color:var(--lime);
}
/* Number and heading sit on one row. The min-height keeps the body copy of
   every card in a row starting at the same line, whether the heading wraps or not. */
.card-top{
  display:flex;align-items:center;gap:14px;
  min-height:62px;margin-bottom:16px;
}
.card-top h3{margin:0}

/* --- challenge list --------------------------------------- */
.chal{border-top:1px solid var(--line);margin:0;padding:0}
.chal > div{
  display:grid;grid-template-columns:minmax(190px,26%) 1fr;gap:8px 32px;
  padding:22px 0;border-bottom:1px solid var(--line);
}
.chal dt{font-family:var(--display);font-weight:700;font-size:19px;color:var(--paper)}
.chal dd{margin:0;color:var(--muted)}

/* --- timeline --------------------------------------------- */
.stage{position:relative;background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:clamp(20px,2.2vw,28px)}
.stage .when{font-family:var(--mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--lime);margin:0 0 12px}
.stage h3{font-size:19px;margin-bottom:12px}
.stage p{font-size:15.5px;color:var(--muted);margin:0 0 16px}
.stage ul{margin:0 0 18px;padding-left:18px;color:var(--body);font-size:15px}
.stage li{margin-bottom:5px}
.out{
  margin-top:auto;padding-top:16px;border-top:1px solid var(--line);
  font-size:14.5px;color:var(--body);
}
.out b{
  display:block;font-family:var(--mono);font-size:10.5px;letter-spacing:.14em;
  text-transform:uppercase;color:var(--muted);margin-bottom:6px;font-weight:400;
}
.stage{display:flex;flex-direction:column}
/* --- judging criteria ------------------------------------- */
.judged{
  display:grid;grid-template-columns:minmax(160px,18%) 1fr;align-items:center;gap:18px 32px;
  margin-top:20px;padding:24px clamp(20px,2.4vw,30px);
  background:var(--panel);border:1px solid var(--line);border-radius:16px;
}
.judged h3{
  margin:0;font-family:var(--mono);font-weight:400;font-size:11px;letter-spacing:.18em;
  text-transform:uppercase;color:var(--lime);
}
.judged ul{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:0;padding:0;list-style:none}
.judged li{
  display:flex;align-items:center;gap:10px;min-height:56px;
  padding:12px 18px;border:1px solid var(--line-2);border-radius:12px;
  font-family:var(--display);font-weight:700;font-size:16px;color:var(--paper);
}
.judged li::before{
  content:"";flex:none;width:8px;height:8px;border-radius:50%;background:var(--lime);
}

/* --- tiers ------------------------------------------------ */
.tier{
  display:flex;flex-direction:column;background:var(--panel-2);
  border:1.5px solid var(--line-2);border-radius:16px;padding:24px 22px;
}
.tier-community{border-color:var(--lime-dim)}
.tier-bronze{border-color:var(--bronze)}
.tier-silver{border-color:var(--silver)}
.tier-gold{border-color:var(--lime)}
.tier .name{
  display:flex;align-items:center;gap:10px;
  font-family:var(--display);font-weight:800;font-size:13px;letter-spacing:.1em;
  text-transform:uppercase;color:var(--lime);margin:0 0 18px;
}
.tier .name span{
  display:flex;align-items:center;justify-content:center;width:26px;height:26px;flex:none;
  border:1.5px solid currentColor;border-radius:50%;font-family:var(--mono);font-size:12px;
}
.tier-bronze .name{color:var(--bronze)}
.tier-silver .name{color:var(--silver)}
.tier .price{font-family:var(--display);font-weight:800;color:var(--paper);font-size:clamp(25px,2.4vw,31px);letter-spacing:-.02em;margin:0}
.tier .price .alt{
  display:block;margin-top:6px;
  font-family:var(--text);font-weight:500;font-size:16px;letter-spacing:0;color:var(--muted);
}
.tier ul{
  margin:18px 0 0;padding:18px 0 0;list-style:none;border-top:1px solid var(--line-2);
  color:var(--body);font-size:15px;
}
.tier li{margin-bottom:6px}
/* --- sponsor logo wall ------------------------------------ */
/* Sponsor logos are supplied as dark artwork on white, so the tiles are white
   rather than the page black — otherwise the logos disappear. */
.logos{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:16px;
  margin:0;padding:0;list-style:none;
}
.logos li{
  display:flex;align-items:center;justify-content:center;min-height:132px;padding:24px 28px;
  background:var(--paper);border:1px solid var(--line-2);border-radius:16px;
}
.logos li span{ /* until a logo file arrives, the name stands in for it */
  font-family:var(--display);font-weight:700;font-size:19px;letter-spacing:-.01em;
  color:var(--ink);text-align:center;
}
.logos img{max-height:68px;width:auto;object-fit:contain}

/* --- offer list (beyond the hackathon) -------------------- */
.offer{display:grid;grid-template-columns:minmax(200px,24%) 1fr;gap:10px 32px;padding:26px 0;border-bottom:1px solid var(--line)}
.offer:first-of-type{border-top:1px solid var(--line)}
.offer h3{font-size:22px}
.offer ul{margin:0;padding-left:18px;color:var(--muted)}
.offer li{margin-bottom:6px}

.caveat{
  margin:28px 0 0;max-width:62ch;color:var(--muted);font-size:15px;
}

/* --- people ----------------------------------------------- */
.person{display:flex;gap:20px;align-items:flex-start}
.person .initials{
  display:flex;align-items:center;justify-content:center;flex:none;width:64px;height:64px;
  border-radius:50%;border:1.5px solid var(--lime);color:var(--lime);
  font-family:var(--display);font-weight:800;font-size:20px;letter-spacing:.02em;
}
.person h3{font-size:21px;margin-bottom:6px}
.person p{margin:0;color:var(--muted);font-size:15.5px}
/* email links are targets, not prose — keep them 44px tall */
.person p a{display:inline-flex;align-items:center;min-height:44px}

/* --- closing call to action ------------------------------- */
.close-cta{background:var(--panel);border-radius:24px;padding:clamp(32px,5vw,64px);border:1px solid var(--line)}
.close-cta h2{font-size:clamp(28px,4vw,46px);margin-bottom:16px}
.close-cta .lede{color:var(--muted)}
.cta-cards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:36px}
.cta-card{
  display:flex;flex-direction:column;gap:12px;background:var(--void);
  border:1px solid var(--line-2);border-radius:16px;padding:24px;
}
.cta-card h3{font-size:19px}
.cta-card p{color:var(--muted);font-size:15px;margin:0 0 6px}
.cta-card .btn{align-self:flex-start;margin-top:auto}

.contact{
  margin-top:32px;padding-top:28px;border-top:1px solid var(--line-2);
}
.contact h3{font-size:19px;margin-bottom:10px}
.contact p{margin:0;color:var(--muted);max-width:62ch;font-size:15.5px}

/* --- forms ------------------------------------------------ */
/* Every control has a real <label for>. Placeholder text is never used
   as a label. The forms post straight to Google Forms, so with JavaScript
   off they still submit — Google shows its own confirmation page. */
.form{max-width:720px;margin:0}
.field{margin:0 0 28px}
.field > label,.field legend{
  display:block;margin:0 0 10px;padding:0;
  font-family:var(--display);font-weight:700;font-size:17px;color:var(--paper);
}
.req,.opt-tag{
  font-family:var(--mono);font-weight:400;font-size:11px;letter-spacing:.14em;
  text-transform:uppercase;color:var(--muted);margin-left:8px;
}
.req{color:var(--lime)}
.hint{margin:-4px 0 10px;color:var(--muted);font-size:14.5px}
.field fieldset{border:0;margin:0;padding:0}

.form input[type=text],.form input[type=email],.form input[type=url],.form textarea{
  display:block;width:100%;min-height:52px;padding:13px 16px;
  background:var(--panel-2);color:var(--paper);
  border:1.5px solid var(--field-line);border-radius:10px;
  font-family:var(--text);font-size:16px;line-height:1.5;
}
.form textarea{min-height:132px;resize:vertical}
.form input::placeholder,.form textarea::placeholder{color:var(--muted)}

.opts{display:grid;gap:8px}
.opt{
  display:flex;align-items:center;gap:14px;min-height:52px;padding:10px 16px;
  background:var(--panel);border:1.5px solid var(--line-2);border-radius:10px;
  color:var(--body);font-size:16px;cursor:pointer;
}
.opt:hover{border-color:var(--field-line)}
.opt input{flex:none;width:21px;height:21px;margin:0;accent-color:var(--lime)}
.opt-other{margin-top:10px}
.opt-other label{
  display:block;margin:0 0 8px;color:var(--muted);font-size:14.5px;font-family:var(--text);font-weight:400;
}

.form-actions{display:flex;flex-wrap:wrap;align-items:center;gap:16px;margin-top:36px}
.form-actions .btn{border:0;cursor:pointer;font-family:var(--text)}
.form-actions p{margin:0;color:var(--muted);font-size:14.5px}
.btn[disabled]{opacity:.5;cursor:not-allowed}

.form-error{
  margin:0 0 24px;padding:16px 20px;border-radius:12px;
  border:1.5px solid var(--bronze);color:var(--paper);background:var(--panel);
}
.thanks{
  padding:clamp(24px,3vw,36px);background:var(--panel);
  border:1.5px solid var(--lime);border-radius:16px;
}
.thanks h2{font-size:clamp(24px,3vw,32px);margin-bottom:12px}
.thanks p{color:var(--body);margin-bottom:0}
.thanks p + p{margin-top:.8em}

/* --- form page furniture ---------------------------------- */
.page-head{padding:clamp(48px,7vw,80px) 0 clamp(28px,4vw,44px);border-top:0}
.page-head h1{font-size:clamp(34px,5.6vw,64px);letter-spacing:-.03em;margin-bottom:20px}
.form-layout{display:grid;grid-template-columns:1.1fr .9fr;gap:clamp(32px,5vw,72px);align-items:start}
.aside{
  position:sticky;top:calc(var(--head-h) + 24px);
  background:var(--panel);border:1px solid var(--line);border-radius:16px;
  padding:clamp(22px,2.6vw,30px);
}
.aside h2{font-size:20px;margin-bottom:14px}
.aside h3{font-size:15px;margin:22px 0 8px}
.aside p,.aside li{color:var(--muted);font-size:15px}
.aside p{margin:0 0 .8em}
.aside ul{margin:0;padding-left:18px}
.aside li{margin-bottom:6px}
.aside .btn{margin-top:8px}
/* the "not the right form?" links are navigation, so give them a real target */
.aside p a{display:inline-flex;align-items:center;min-height:44px}

/* --- footer ----------------------------------------------- */
.site-foot{border-top:1px solid var(--line);padding:56px 0 72px;color:var(--muted);font-size:15px}
.foot-in{
  display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));
  gap:32px;align-items:start;
}
.site-foot a{color:var(--body)}
.site-foot a:hover{color:var(--lime)}
.site-foot h2{font-size:20px;margin-bottom:12px}
.site-foot ul{list-style:none;margin:0;padding:0}
.site-foot li{margin-bottom:0}
.site-foot li a{display:inline-flex;align-items:center;min-height:44px}
.fine{margin-top:40px;padding-top:24px;border-top:1px solid var(--line);font-size:13.5px}

/* --- line up the insides of cards, not just their edges ----
   Each card in a row borrows the parent grid's rows, so headings, prices,
   lists and output blocks start at the same height in every card in that row —
   however the text happens to wrap at the current width. The row counts below
   are the number of direct children each card has: change the markup, change
   the span. Browsers without subgrid fall back to the rules above, where the
   cards still align top and bottom. */
@supports (grid-template-rows:subgrid){
  #aims .grid > .card,
  #sponsors .g3 > .card{display:grid;grid-row:span 2;grid-template-rows:subgrid}
  .stage{display:grid;grid-row:span 5;grid-template-rows:subgrid}
  .tier{display:grid;grid-row:span 3;grid-template-rows:subgrid}
  .card-top{min-height:0}   /* the shared rows do this job now */
  .out{margin-top:0}
}

/* --- scroll reveal (progressive enhancement) -------------- */
.rv{opacity:1}
.js .rv{opacity:0;transform:translateY(14px)}
.js .rv.in{opacity:1;transform:none;transition:opacity .5s ease,transform .5s ease}

/* --- narrow widths ---------------------------------------- */
@media (max-width:1080px){
  .g5{grid-template-columns:repeat(2,1fr)}
  .g4{grid-template-columns:repeat(2,1fr)}
  .cta-cards{grid-template-columns:1fr}
  .judged{grid-template-columns:1fr;gap:14px}
  .form-layout{grid-template-columns:1fr}
  .aside{position:static}
  .judged ul{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:900px){
  /* No JavaScript: the header wraps and every link stays visible and tappable.
     It also stops sticking, so the taller header does not eat the screen. */
  .site-head{position:static}
  .head-in{flex-wrap:wrap;padding-bottom:10px}
  .mainnav{flex-basis:100%}
  .mainnav ul{flex-wrap:wrap;gap:2px 4px}
  .mainnav a{padding:10px 10px}
  .mainnav .nav-cta a{padding:10px 18px}

  /* With JavaScript: collapse it behind the menu button. */
  .js-nav .site-head{position:sticky;top:0}
  .js-nav .menu-btn{display:inline-flex}
  .js-nav .head-in{flex-wrap:nowrap;padding-bottom:0}
  .js-nav .mainnav{
    position:absolute;left:0;right:0;top:100%;display:none;
    background:var(--panel);border-bottom:1px solid var(--line);padding:8px var(--pad) 20px;
    box-shadow:0 20px 44px rgba(0,0,0,.65);
  }
  .js-nav .mainnav.open{display:block}
  .js-nav .mainnav ul{flex-direction:column;align-items:stretch;gap:2px}
  .js-nav .mainnav a{min-height:48px;padding:12px 4px}
  .js-nav .mainnav .nav-cta a{justify-content:center;margin-top:10px}
  .split{grid-template-columns:1fr}
  .g2{grid-template-columns:1fr}
  .g3{grid-template-columns:1fr 1fr}
  .offer{grid-template-columns:1fr;gap:12px}
}
@media (max-width:680px){
  .g2,.g3,.g4,.g5{grid-template-columns:1fr}
  .card-top{min-height:0}
  .judged ul{grid-template-columns:1fr}
  .chal > div{grid-template-columns:1fr;gap:6px}
  .facts{gap:0 24px}
  .btn{width:100%}
  .cta-row .btn{width:100%}
  .brand span.sub{display:none}
}

/* --- reduced motion --------------------------------------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .js .rv{opacity:1;transform:none}
  *{transition-duration:.001ms !important;animation-duration:.001ms !important}
}