/* RigoLLM 2026 — styles inspired by the ATC 2026 site (accent #f82249, Open Sans/Raleway) */

:root {
  --accent: #f82249;
  --accent-dark: #e0072f;
  --accent-light: #f94a6a;
  --navy: #112363;
  --ink: #060c22;
  --muted: #4b4f5c;
  --page-bg: #f6f7fd;
  --tint: #e9edfb;
  --tint-2: #e0e5fa;
  --white: #ffffff;
  --border: #e4e7f2;
  --nav-h: 66px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Open Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--muted);
  background: var(--page-bg);
  line-height: 1.65;
  font-size: 16px;
}

h1, h2, h3, h4, h5, .brand, .btn, .nav-links a {
  font-family: "Raleway", "Open Sans", sans-serif;
  color: var(--navy);
}

h1 { font-weight: 700; }
h2, h3 { font-weight: 700; }

a { color: var(--accent); text-decoration: none; transition: color .2s; }
a:hover { color: var(--accent-dark); }

img { max-width: 100%; }

.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background: rgba(255, 255, 255, 0.97);
  box-shadow: 0 2px 18px rgba(17, 35, 99, 0.08);
  z-index: 1000;
}
.nav {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  font-weight: 800;
  font-size: 24px;
  letter-spacing: .3px;
  color: var(--navy);
}
.brand span { color: var(--accent); }
.brand small {
  display: block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 1.5px;
  color: var(--muted);
  text-transform: uppercase;
  margin-top: -4px;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  list-style: none;
  margin: 0; padding: 0;
}
.nav-links a {
  font-size: 15px;
  font-weight: 600;
  color: var(--navy);
  position: relative;
}
.nav-links a:hover { color: var(--accent); }
.nav-links a.cta {
  background: var(--accent);
  color: #fff;
  padding: 9px 20px;
  border-radius: 50px;
}
.nav-links a.cta:hover { background: var(--accent-dark); }
.nav-toggle {
  display: none;
  background: none; border: none;
  font-size: 26px; color: var(--navy); cursor: pointer;
}

/* ---------- Hero ---------- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  color: #fff;
  position: relative;
  background:
    linear-gradient(120deg, rgba(9, 15, 45, 0.92) 0%, rgba(17, 35, 99, 0.82) 45%, rgba(224, 7, 47, 0.72) 100%),
    radial-gradient(circle at 78% 30%, rgba(248, 34, 73, 0.55), transparent 55%),
    #0b1130;
  padding-top: var(--nav-h);
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.05) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(circle at 70% 40%, #000 20%, transparent 75%);
  pointer-events: none;
}
.hero-inner { position: relative; z-index: 2; max-width: 820px; }
.hero .eyebrow {
  display: inline-block;
  font-family: "Raleway", sans-serif;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-size: 13px;
  color: #ffd2db;
  background: rgba(248, 34, 73, 0.25);
  border: 1px solid rgba(255,255,255,.25);
  padding: 7px 16px;
  border-radius: 50px;
  margin-bottom: 22px;
}
.hero h1 {
  color: #fff;
  font-size: clamp(34px, 6vw, 58px);
  line-height: 1.08;
  margin: 0 0 10px;
}
.hero h1 .accent { color: var(--accent-light); }
.hero .subtitle {
  font-size: clamp(17px, 2.4vw, 22px);
  color: #e8ebfb;
  font-weight: 400;
  margin: 0 0 26px;
  max-width: 680px;
}
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 30px;
  margin-bottom: 34px;
  font-size: 16px;
}
.hero-meta div { display: flex; align-items: center; gap: 9px; color: #fff; font-weight: 600; }
.hero-meta .dot { color: var(--accent-light); font-size: 20px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }

.btn {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 50px;
  font-weight: 700;
  font-size: 15px;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all .2s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); color: #fff; }
.btn-outline { background: transparent; color: #fff; border-color: rgba(255,255,255,.7); }
.btn-outline:hover { background: #fff; color: var(--navy); }

/* ---------- Sections ---------- */
section { padding: 84px 0; }
.section-alt { background: var(--white); }
.section-head { text-align: center; max-width: 720px; margin: 0 auto 52px; }
.section-head .kicker {
  color: var(--accent);
  font-weight: 700;
  font-family: "Raleway", sans-serif;
  letter-spacing: 2px;
  text-transform: uppercase;
  font-size: 14px;
}
.section-head h2 {
  font-size: clamp(28px, 4vw, 38px);
  margin: 8px 0 0;
  position: relative;
  display: inline-block;
  padding-bottom: 14px;
}
.section-head h2::after {
  content: "";
  position: absolute;
  left: 50%; bottom: 0;
  transform: translateX(-50%);
  width: 60px; height: 3px;
  background: var(--accent);
  border-radius: 3px;
}
.section-head p { margin-top: 16px; font-size: 17px; }

.lead { font-size: 18px; }

/* About */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: start; }
.principle-card {
  background: var(--tint);
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  padding: 22px 24px;
  margin-bottom: 18px;
}
.principle-card h4 { margin: 0 0 6px; color: var(--navy); }
.principle-card p { margin: 0; }

/* Topics — numbered list */
.topics-list {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: 820px;
}
.topics-list li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 2px;
  border-bottom: 1px solid var(--border);
}
.topics-list li:last-child { border-bottom: none; }
.topics-list .num {
  display: inline-flex;
  align-items: center; justify-content: center;
  width: 24px; height: 24px;
  flex-shrink: 0;
  border-radius: 6px;
  background: var(--tint);
  color: var(--accent);
  font-family: "Raleway", sans-serif;
  font-weight: 800;
  font-size: 13px;
}
.topics-list .txt {
  font-family: "Raleway", sans-serif;
  font-weight: 600;
  color: var(--navy);
  font-size: 15px;
  line-height: 1.35;
}

/* Call for papers */
.cfp-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 22px; }
.cat-card {
  background: var(--white);
  border-radius: 12px;
  padding: 28px 26px;
  border-top: 4px solid var(--accent);
  box-shadow: 0 8px 26px rgba(17, 35, 99, 0.07);
}
.cat-card h4 { margin: 0 0 4px; font-size: 19px; }
.cat-card .tag { color: var(--accent); font-weight: 700; font-size: 14px; }
.cat-card p { margin: 12px 0 0; }
.note {
  margin-top: 30px;
  background: var(--tint);
  border-radius: 10px;
  padding: 20px 24px;
  font-size: 15.5px;
}

/* Dates */
.dates-table {
  max-width: 720px;
  margin: 0 auto;
  background: var(--white);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 10px 30px rgba(17, 35, 99, 0.08);
}
.date-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 28px;
  border-bottom: 1px solid var(--border);
}
.date-row:last-child { border-bottom: none; }
.date-row.highlight { background: var(--tint); }
.date-row .label { font-weight: 600; color: var(--navy); font-family: "Raleway", sans-serif; }
.date-row .value {
  font-weight: 700;
  color: var(--accent);
  font-family: "Raleway", sans-serif;
  white-space: nowrap;
}
.tentative-note { text-align: center; margin-top: 18px; font-size: 14px; color: var(--muted); }

/* Format */
.format-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 22px; }
.format-card {
  text-align: center;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 30px 24px;
}
.format-card .ico {
  width: 56px; height: 56px;
  margin: 0 auto 16px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 26px; font-weight: 800;
  font-family: "Raleway", sans-serif;
}
.format-card h4 { margin: 0 0 8px; }
.format-card p { margin: 0; font-size: 15px; }

/* Organizers — name + affiliation list */
.org-list {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: 720px;
}
.org-list li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 2px;
  border-bottom: 1px solid var(--border);
}
.org-list li:last-child { border-bottom: none; }
.org-name {
  font-family: "Raleway", sans-serif;
  font-weight: 700;
  color: var(--navy);
  font-size: 17px;
}
.org-affil {
  color: var(--accent);
  font-weight: 600;
  font-size: 15px;
  text-align: right;
}
.primary-badge {
  display: inline-block;
  font-size: 11px; font-weight: 700;
  background: var(--tint); color: var(--accent);
  padding: 2px 9px; border-radius: 50px;
  margin-left: 8px; vertical-align: middle;
  font-family: "Raleway", sans-serif; letter-spacing: .5px;
}

/* Contact */
.contact-box {
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
  background: var(--white);
  border-radius: 14px;
  padding: 44px 32px;
  box-shadow: 0 10px 30px rgba(17, 35, 99, 0.08);
}
.contact-box h3 { margin: 0 0 6px; }
.contact-box .big-email { font-size: 16px; font-weight: 700; margin: 16px 0 6px; }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--ink);
  color: #c7cbe0;
  padding: 46px 0 26px;
  text-align: center;
}
.site-footer .fbrand { color: #fff; font-family: "Raleway", sans-serif; font-weight: 800; font-size: 22px; }
.site-footer .fbrand span { color: var(--accent-light); }
.site-footer p { margin: 10px 0; font-size: 14px; }
.site-footer a { color: #fff; font-weight: 600; }
.site-footer .copyright { margin-top: 20px; font-size: 13px; color: #8b90ab; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: var(--nav-h); left: 0; right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: #fff;
    box-shadow: 0 12px 24px rgba(17,35,99,.1);
    padding: 8px 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height .3s ease;
  }
  .nav-links.open { max-height: 460px; }
  .nav-links li { width: 100%; }
  .nav-links a { display: block; padding: 13px 24px; width: 100%; }
  .nav-links a.cta { border-radius: 0; text-align: left; }
  .about-grid { grid-template-columns: 1fr; }
}