/* ============================================================
   STDC 60 — 60th Spring Topology and Dynamics Conference
   ============================================================ */

/* ── Variables ─────────────────────────────────────────────── */
:root {
  --scarlet:      #BA0C2F;
  --scarlet-dark: #8E0923;
  --charcoal:     #0C0D16;
  --charcoal-mid: #14172A;
  --gold:         #C4913A;
  --cream:        #F7F4EF;
  --surface:      #FFFFFF;
  --text:         #1A1918;
  --text-muted:   #5C5856;
  --border:       #DDD9D2;
}

/* ── Reset ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* ── Base ──────────────────────────────────────────────────── */
html { scroll-behavior: smooth; }

body {
  font-family: 'IBM Plex Serif', Georgia, 'Times New Roman', serif;
  font-size: 18px;
  line-height: 1.7;
  color: var(--text);
  background: var(--cream);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ── HEADER ────────────────────────────────────────────────── */
header {
  background-color: var(--charcoal);
  background-image:
    radial-gradient(ellipse 55% 90% at 8% 50%,  rgba(186, 12,  47, 0.14) 0%, transparent 60%),
    radial-gradient(ellipse 35% 60% at 92% 20%,  rgba(196,145,  58, 0.07) 0%, transparent 55%);
  border-bottom: 3px solid var(--scarlet);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.4);
}

.header-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0.9rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

/* Logo + brand */
.header-brand {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  flex-shrink: 0;
}

.logo-link {
  display: flex;
  align-items: center;
  flex-shrink: 0;
}

.site-logo {
  height: 54px;
  width: 54px;
  filter: invert(1) brightness(0.88);
  transition: opacity 0.2s ease;
}

.logo-link:hover .site-logo { opacity: 0.7; }

.header-text {
  display: flex;
  flex-direction: column;
  gap: 0.06rem;
}

.site-name {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 1.18rem;
  font-weight: 600;
  line-height: 1.28;
  letter-spacing: 0.01em;
  color: #F5F2EE;
  text-decoration: none;
  display: block;
  transition: color 0.15s;
}

.site-name:hover { color: #FFFFFF; }

.site-name sup {
  font-size: 0.55em;
  vertical-align: super;
  line-height: 0;
}

/* Navigation */
nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0;
}

nav a {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 0.96rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: #C8C2BB;
  text-decoration: none;
  padding: 0.55rem 0.8rem;
  position: relative;
  transition: color 0.15s ease;
}

nav a::after {
  content: '';
  position: absolute;
  bottom: 0.25rem;
  left: 0.8rem;
  right: 0.8rem;
  height: 1.5px;
  background: var(--scarlet);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.22s ease;
}

nav a:hover           { color: #FFFFFF; }
nav a:hover::after    { transform: scaleX(1); }

nav a.nav-active      { color: #FFFFFF; }
nav a.nav-active::after { transform: scaleX(1); }

/* ── MAIN ──────────────────────────────────────────────────── */
main {
  flex: 1;
  max-width: 860px;
  margin: 0 auto;
  padding: 3.5rem 2rem 5rem;
  animation: pageFadeUp 0.38s ease both;
}

@keyframes pageFadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── PAGE ARTICLE ──────────────────────────────────────────── */
.page-title {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 3rem;
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--charcoal);
  margin-bottom: 1.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
  position: relative;
}

/* Scarlet accent under the title bar */
.page-title::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 3.5rem;
  height: 3px;
  background: var(--scarlet);
}

/* ── TYPOGRAPHY ────────────────────────────────────────────── */
h2 {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 1.8rem;
  font-weight: 600;
  color: var(--charcoal);
  margin: 2.75rem 0 0.75rem;
  letter-spacing: -0.015em;
  line-height: 1.18;
}

h3 {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--charcoal);
  margin: 1.75rem 0 0.4rem;
  letter-spacing: -0.005em;
}

h4 {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-muted);
  margin: 1.25rem 0 0.3rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  font-size: 0.85rem;
}

p { margin-bottom: 1.1rem; }

a {
  color: var(--scarlet);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 0.15s;
}
a:hover { color: var(--scarlet-dark); }

ul, ol { margin: 0.5rem 0 1.25rem 1.75rem; }
li     { margin-bottom: 0.4rem; }

strong { font-weight: 600; }
em     { font-style: italic; }

blockquote {
  border-left: 3px solid var(--scarlet);
  padding: 0.75rem 1.5rem;
  margin: 1.75rem 0;
  color: var(--text-muted);
  font-style: italic;
}

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2.5rem 0;
}

/* ── HERO IDENTITY ─────────────────────────────────────────── */
.hero-identity {
  width: 520px;
  max-width: 100%;
  margin: 0 auto 3rem;
}

/* The sixty.svg + its blurred glow background */
.hero-sixty {
  position: relative;
  line-height: 0;      /* collapse inline whitespace under the img */
  margin-bottom: 0.6rem;
}

/* Blurred copy rendered behind via pseudo-element.
   inset: -12% gives the blur room to spread without clipping. */
.hero-sixty::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('/logo/sixty.svg') center / contain no-repeat;
  filter: drop-shadow(0 0 4px black) drop-shadow(0 0 4px black) drop-shadow(0 0 4px black) blur(10px);
  opacity: 0.4;
  pointer-events: none;
  z-index: 0;
}

.hero-sixty-img {
  display: block;
  width: 100%;
  height: auto;
  position: relative;
  z-index: 1;
}

/* "STDC 2027" — bold; JS scales font-size to fill image width */
.hero-abbr {
  display: block;
  width: 100%;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-weight: 700;
  font-size: 2.8rem;   /* pre-JS fallback */
  line-height: 1;
  color: var(--charcoal);
  white-space: nowrap; /* prevents wrap so scrollWidth is accurate */
  letter-spacing: -0.01em;
}

/* Conference name — regular weight; JS scales font-size to fill image width */
.hero-name {
  display: block;
  width: 100%;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-weight: 400;
  font-size: 1.12rem;  /* pre-JS fallback */
  line-height: 1.3;
  color: var(--charcoal);
  white-space: nowrap;
}

.hero-name sup {
  font-size: 0.55em;
  vertical-align: super;
  line-height: 0;
}

/* ── TRACK CARDS ───────────────────────────────────────────── */
ul.tracks {
  list-style: none;
  margin: 1.25rem 0 1.75rem;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.9rem;
}

ul.tracks li {
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: 3px solid var(--scarlet);
  padding: 1rem 1.25rem;
  border-radius: 2px;
  transition: box-shadow 0.22s ease, transform 0.22s ease;
}

ul.tracks li:hover {
  box-shadow: 0 6px 28px rgba(0, 0, 0, 0.09);
  transform: translateY(-3px);
}

.track-name {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--charcoal);
  line-height: 1.3;
  margin-bottom: 0.3rem;
}

.organizers {
  font-size: 0.8rem;
  font-style: italic;
  color: var(--text-muted);
}

/* ── TABLES ────────────────────────────────────────────────── */
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  margin: 1.25rem 0 1.75rem;
}

th {
  text-align: left;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  border-bottom: 2px solid var(--border);
  padding: 0.5rem 0.75rem 0.5rem 0;
}

td {
  padding: 0.65rem 0.75rem 0.65rem 0;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

tr:last-child td { border-bottom: none; }
tr:hover td      { background: rgba(186, 12, 47, 0.025); }

/* ── FOOTER ────────────────────────────────────────────────── */
footer {
  background: var(--charcoal-mid);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding: 2rem;
}

.footer-inner {
  max-width: 1120px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.footer-conference {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 1rem;
  color: #D8D2CB;
  margin-bottom: 0.2rem;
}

.footer-conference sup {
  font-size: 0.55em;
  vertical-align: super;
  line-height: 0;
}

.footer-venue {
  font-size: 0.82rem;
  color: #B0AAA3;
  margin-bottom: 0.2rem;
}

.footer-contact {
  font-size: 0.82rem;
}

.footer-contact a {
  color: #B0AAA3;
  text-decoration: none;
}

.footer-contact a:hover {
  color: #E8E2DB;
}

/* ── MARY ELLEN RUDIN AWARD ────────────────────────────────── */
.mer-award {
  overflow: hidden; /* clearfix for float */
}

.mer-photo {
  float: right;
  margin: 0.25rem 0 1rem 2rem;
  width: 200px;
  flex-shrink: 0;
}

.mer-photo img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 2px;
}

.mer-photo figcaption {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 0.78rem;
  color: var(--text-muted);
  text-align: center;
  margin-top: 0.4rem;
  font-style: italic;
}

@media (max-width: 480px) {
  .mer-photo {
    float: none;
    margin: 0 auto 1.25rem;
    width: 160px;
  }
}

/* ── MATH ──────────────────────────────────────────────────── */
.math.display {
  overflow-x: auto;
  margin: 1.25rem 0;
}

/* ── RESPONSIVE ────────────────────────────────────────────── */
@media (max-width: 820px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    padding: 0.8rem 1.25rem;
    gap: 0.75rem;
  }

  nav {
    justify-content: flex-start;
  }

  nav a {
    padding: 0.4rem 0.65rem;
    font-size: 0.88rem;
  }

  main {
    padding: 2.25rem 1.25rem 3.5rem;
  }

  .page-title { font-size: 2.2rem; }

  ul.tracks { grid-template-columns: 1fr; }


}

@media (max-width: 480px) {
  .site-logo { height: 42px; width: 42px; }
  .site-name  { font-size: 1.02rem; }
  nav a       { font-size: 0.82rem; padding: 0.35rem 0.5rem; }
  .page-title { font-size: 1.85rem; }
  h2          { font-size: 1.5rem; }
}