/* Academic palette in ACM colours: cool paper, ink, ACM blue + ACM-W purple, square corners, hairline rules */
:root{
  --paper:#f8f9fb;
  --paper-on-dark:#f0f6fc;
  --stone:#eef1f6;
  --ink:#0f1b2d;
  --ink-soft:#33415a;
  --muted:#5b6678;
  --hairline:#0f1b2d1f;
  --hairline-2:#0f1b2d38;
  --blue:#0067b8;        /* ACM blue */
  --blue-deep:#0b2f5e;   /* dark bands: hero, register */
  --blue-tint:#e3eefa;
  --purple:#4b1d8f;      /* ACM-W purple */
  --purple-tint:#ebe3f6;
  --sky:#8cc8f0;         /* accent on dark bands */
  --serif:"Forum",Georgia,"Times New Roman",serif;
  --sans:"Hanken Grotesk",system-ui,-apple-system,"Segoe UI",sans-serif;
  --max:1120px;
  --measure:64ch;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;background:var(--paper);color:var(--ink);
  font-family:var(--sans);font-size:17px;line-height:1.6;font-weight:400;
  -webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;
}
h1,h2,h3{font-family:var(--serif);font-weight:400;letter-spacing:-.01em;line-height:1.08}
h1 em,h2 em{font-style:normal;color:var(--blue)}
b,strong{font-weight:600}
a{color:inherit}
.wrap{max-width:var(--max);margin:0 auto;padding:0 24px}
.muted{color:var(--muted)}
.x{color:var(--blue)}

/* nav */
.nav{position:sticky;top:0;z-index:50;background:rgba(248,249,251,.94);
  backdrop-filter:blur(8px);border-bottom:1px solid var(--hairline)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:68px;gap:16px}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none}
.brand-logo{width:36px;height:36px;display:block}
.brand-txt{display:flex;flex-direction:column;line-height:1.15;font-family:var(--serif);font-size:19px}
.brand-txt em{font-family:var(--sans);font-style:normal;font-size:11px;letter-spacing:.08em;
  text-transform:uppercase;color:var(--muted);margin-top:3px}
.nav-links{display:flex;align-items:center;gap:26px}
.nav-links a{text-decoration:none;font-size:14.5px;font-weight:500;color:var(--ink-soft);transition:color .15s}
.nav-links a:hover{color:var(--blue)}
.nav-links a.btn{padding:10px 20px}
.nav-toggle{display:none;background:none;border:0;color:var(--ink);font-size:20px;cursor:pointer}

/* buttons — square, solid ACM blue or outlined */
.btn{display:inline-block;padding:13px 24px;text-decoration:none;font-weight:500;font-size:14.5px;
  letter-spacing:.02em;background:var(--blue);color:var(--paper);border:1px solid var(--blue);
  transition:background .15s,color .15s,border-color .15s}
.btn:hover{background:var(--blue-deep);border-color:var(--blue-deep)}
.btn-sm{padding:8px 16px;font-size:13.5px;color:var(--paper)!important}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--hairline-2)}
.btn-ghost:hover{background:transparent;border-color:var(--ink)}
.btn[aria-disabled="true"]{opacity:.7;cursor:not-allowed}

/* hero — dark navy band */
.hero{position:relative;overflow:hidden;padding:104px 0 92px;background:var(--blue-deep);color:var(--paper-on-dark)}
.grid-bg{position:absolute;inset:0;
  background-image:linear-gradient(rgba(240,246,252,.07) 1px,transparent 1px),linear-gradient(90deg,rgba(240,246,252,.07) 1px,transparent 1px);
  background-size:80px 80px;mask-image:linear-gradient(90deg,transparent 30%,#000)}
.hero-inner{position:relative}
.eyebrow,.kicker{font-family:var(--sans);font-size:11px;font-weight:500;letter-spacing:.16em;
  text-transform:uppercase;color:var(--blue);margin:0 0 20px}
.hero .eyebrow{color:var(--sky)}
.hero .eyebrow a{color:var(--paper-on-dark);text-underline-offset:3px}
.hero-title{display:flex;align-items:center;gap:32px;margin:0 0 26px}
.hero-logo{width:clamp(88px,11vw,148px);height:auto;flex:0 0 auto;display:block}
.hero .hero-title h1{margin:0}
.hero h1{font-size:clamp(38px,5.6vw,68px);line-height:1.06;margin:0 0 26px;color:var(--paper-on-dark)}
.hero h1 em{color:var(--sky)}
.lede{max-width:var(--measure);font-size:19px;line-height:1.7;color:rgba(240,246,252,.86);margin:0 0 40px}
.hero-meta{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));
  border-top:1px solid rgba(240,246,252,.28);margin-bottom:40px}
.hero-meta>div{padding:18px 20px 0 0;display:flex;flex-direction:column;gap:6px}
.hero-meta .k{font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--sky)}
.hero-meta .v{font-family:var(--serif);font-size:21px;line-height:1.2}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap}
.hero .btn{background:var(--paper-on-dark);color:var(--blue);border-color:var(--paper-on-dark)}
.hero .btn:hover{background:#fff;border-color:#fff}
.hero .btn-ghost{background:transparent;color:var(--paper-on-dark);border-color:rgba(240,246,252,.4)}
.hero .btn-ghost:hover{background:transparent;border-color:var(--paper-on-dark)}

.week-strip{display:flex;align-items:center;gap:24px;flex-wrap:wrap;margin-top:48px;padding-top:28px;
  border-top:1px solid rgba(240,246,252,.28)}
.week-strip .chip{width:132px;height:52px;padding:8px 14px;border:0}
.week-strip p{flex:1 1 360px;margin:0;font-size:15.5px;line-height:1.6;color:rgba(240,246,252,.86)}
.nowrap{white-space:nowrap}
.week-strip b{color:var(--paper-on-dark);font-weight:600}

/* sections */
.section{padding:96px 0;border-bottom:1px solid var(--hairline)}
.section.alt{background:var(--stone)}
.section h2{font-size:clamp(34px,4.6vw,52px);margin:0 0 16px}
.sub{color:var(--ink-soft);margin:0 0 40px;max-width:var(--measure)}
.cols{display:grid;grid-template-columns:1.15fr .85fr;gap:56px;align-items:start}
.col p{margin:0 0 18px;color:var(--ink-soft);max-width:var(--measure)}
.themes,.bullets{list-style:none;padding:0;margin:0;border-top:1px solid var(--hairline)}
.themes li,.bullets li{padding:14px 0 14px 22px;position:relative;color:var(--ink-soft);
  font-size:16px;border-bottom:1px solid var(--hairline)}
.themes li:before,.bullets li:before{content:"";position:absolute;left:0;top:25px;width:10px;height:1px;
  background:var(--blue)}
.themes strong{color:var(--ink)}

.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));margin-top:56px;
  border-top:1px solid var(--ink)}
.stat{padding:22px 20px 0 0}
.stat b{display:block;font-family:var(--serif);font-weight:400;font-size:52px;line-height:1;color:var(--blue)}
.stat span{display:block;margin-top:8px;font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}

/* agenda */
.agenda{list-style:none;margin:0;padding:0;border-top:1px solid var(--ink)}
.row{display:grid;grid-template-columns:170px 1fr;gap:24px;padding:24px 0;border-bottom:1px solid var(--hairline)}
.row .time{font-size:14px;font-weight:500;letter-spacing:.04em;color:var(--muted);white-space:nowrap;
  padding-top:4px;font-variant-numeric:tabular-nums}
.row h3{margin:6px 0 6px;font-size:25px}
.row .room{margin:0;font-size:13.5px;color:var(--muted)}
.row .people{margin:0 0 4px;font-size:15.5px;color:var(--ink-soft)}
.row .mod{margin:0 0 6px;font-size:14px;color:var(--muted)}
.row.break h3{font-family:var(--sans);font-size:15px;font-weight:500;color:var(--muted)}
.row.break{padding:16px 0}
.row.feature{border-left:2px solid var(--blue);padding-left:20px;margin-left:-22px}
.row.parallel{background:var(--blue-tint);border-left:2px solid var(--blue);padding-left:20px;margin-left:-22px}
.tag{display:inline-block;font-size:10.5px;letter-spacing:.14em;text-transform:uppercase;font-weight:600;
  padding:4px 9px;border:1px solid var(--hairline-2);color:var(--muted)}
.tag-key{background:var(--blue);border-color:var(--blue);color:var(--paper)}
.tag-panel{background:var(--purple-tint);border-color:var(--purple-tint);color:var(--purple)}
.tag-parallel{background:var(--paper);border-color:var(--blue);color:var(--blue)}

/* people */
.people-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:0;
  border-top:1px solid var(--hairline);border-left:1px solid var(--hairline)}
.person{padding:28px 26px;border-right:1px solid var(--hairline);border-bottom:1px solid var(--hairline);
  background:var(--paper);transition:background .18s;text-align:center}
.person:hover{background:#fff}
.person{position:relative}
.person h3 a{text-decoration:none}
.person h3 a:after{content:"";position:absolute;inset:0}  /* whole card is the link */
.person:hover h3 a{color:var(--blue)}
.avatar{width:148px;height:148px;border-radius:50%;margin:0 auto 22px;background:var(--blue-tint);color:var(--blue);
  display:grid;place-items:center;font-family:var(--serif);font-size:32px}
.avatar:after{content:attr(data-initials)}
img.avatar{display:block;object-fit:cover;background:var(--stone)}
.person h3{margin:0 0 8px;font-size:24px}
.person .role{margin:0 0 12px;font-size:14px;color:var(--muted)}
.person.tbd{background:transparent}
.person.tbd h3,.person.tbd .avatar{opacity:.6}

/* organizing team */
.group-title{font-family:var(--sans);font-size:11px;font-weight:500;letter-spacing:.16em;text-transform:uppercase;
  color:var(--muted);margin:40px 0 18px}
.organizers{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));
  column-gap:32px;border-top:1px solid var(--hairline)}
.organizers li{border-bottom:1px solid var(--hairline)}
.organizers a{display:block;padding:14px 0;font-family:var(--serif);font-size:21px;text-decoration:none;transition:color .15s}
.organizers a:hover{color:var(--blue)}
.people-grid.chairs{
  grid-template-columns:repeat(auto-fit,minmax(250px,300px));
  justify-content:center;
  width:fit-content;max-width:100%;margin:0 auto;
  gap:1px;background:var(--hairline);border:1px solid var(--hairline)}
.chairs .person{border:0}

/* cards + logos */
.card{border:1px solid var(--hairline-2);border-top:2px solid var(--blue);padding:28px;background:var(--paper)}
.card h3{margin:0 0 12px;font-size:26px}
.card p{margin:0 0 14px;color:var(--ink-soft)}
/* logo chips — official marks are mostly dark-on-transparent, so they sit on white */
.chip{display:flex;align-items:center;justify-content:center;background:#fff;border:1px solid var(--hairline);padding:12px 18px;
  width:172px;height:64px;overflow:hidden;flex:0 0 auto}
.chip img{max-width:100%;max-height:100%;width:auto;height:auto;object-fit:contain;display:block}
.chip img.tight{max-height:72%}
.chip-bleed{padding:0;width:64px;background:transparent;border:0}
.chip-bleed img{width:100%;height:100%}
.chip-bleed img.round{border-radius:50%}
.chip-lg{height:88px;width:100%;margin-bottom:20px}
.chip-lg.chip-bleed{width:88px}
.chip-empty{background:transparent;border:1px dashed var(--hairline-2);color:var(--muted);
  font-size:11px;letter-spacing:.16em;text-transform:uppercase}



.logos{display:flex;flex-wrap:wrap;justify-content:center;gap:20px}
.logos>.logo-card{flex:0 1 calc((100% - 40px)/3);min-width:240px}
.logo-card{display:block;border:1px solid var(--hairline-2);padding:26px;background:var(--paper);
  text-decoration:none;transition:border-color .18s}
.logo-card{text-align:center}
.logo-card .chip{margin-left:auto;margin-right:auto}
a.logo-card:hover{border-color:var(--blue)}
.logo-card b{display:block;font-family:var(--serif);font-weight:400;font-size:26px;line-height:1.25}
.logo-card .meta{display:block;font-size:14px;color:var(--muted)}
.logo-card.placeholder{border-style:dashed;background:transparent}

.sponsor-cta{margin-top:36px;text-align:center}

/* cta — navy band to bookend the hero */
.cta{background:var(--blue-deep);color:var(--paper-on-dark);text-align:center;border-bottom:0}
.cta-inner{max-width:660px;margin:0 auto}
.cta h2{color:var(--paper-on-dark)}
.cta .hero-cta{justify-content:center}
.cta p{color:rgba(240,246,252,.86);margin:0 0 30px}
.cta .btn{background:var(--paper-on-dark);color:var(--blue);border-color:var(--paper-on-dark)}
.cta .btn-ghost{background:transparent;color:var(--paper-on-dark);border-color:rgba(240,246,252,.4)}
.cta .btn-ghost:hover{border-color:var(--paper-on-dark)}

/* footer */
.footer{padding:48px 0;background:var(--ink);color:var(--paper-on-dark)}
.footer-inner{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap;align-items:center}
.footer b{font-family:var(--serif);font-weight:400;font-size:22px}
.footer p{margin:6px 0 0;font-size:14px}
.footer .muted{color:rgba(240,246,252,.6)}
.footer-links{display:flex;gap:22px;flex-wrap:wrap}
.footer-links a{font-size:14px;color:rgba(240,246,252,.7);text-decoration:none}
.footer-links a:hover{color:var(--paper-on-dark)}

@media(max-width:860px){
  .cols{grid-template-columns:1fr;gap:32px}
  .row{grid-template-columns:1fr;gap:6px}
  .row.feature,.row.parallel{margin-left:0}
  .nav-links{position:absolute;top:68px;left:0;right:0;flex-direction:column;align-items:flex-start;
    gap:0;background:var(--paper);border-bottom:1px solid var(--hairline);padding:8px 24px 18px;display:none}
  .nav-links.open{display:flex}
  .nav-links a{padding:10px 0}
  .nav-toggle{display:block}
  .hero{padding:72px 0 64px}
  .hero-title{gap:18px}
  .section{padding:72px 0}
}
@media(max-width:560px){
  .hero-title{flex-direction:column;align-items:flex-start}
}