@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;600&family=Fraunces:ital,opsz,wght@0,9..144,300;0,9..144,700;1,9..144,300&family=DM+Sans:wght@300;400;500;600&display=swap');

/* Default theme: IEEE-style blue & white — white nav bar, IEEE Blue
   (#00629B) as the primary color, deep IEEE blue for dark bands. */
:root {
  --navy: #00467f;
  --navy-mid: #00558f;
  --navy-deep: #002855;
  --blue: #00629b;
  --blue-bright: #0072bc;
  --accent: #a6dcf5;
  --accent-dim: #6fc3ea;
  --teal: #0085ca;
  --teal-dim: #006fa8;
  --white: #ffffff;
  --section-alt: #eef4f9;
  --surface-muted: #f4f8fb;
  --gray-light: #dfe7ee;
  --gray: #a9b8c6;
  --gray-dark: #4b5563;
  --text: #13233a;
  /* nav bar */
  --nav-bg: #ffffff;
  --nav-fg: #1f3b57;
  --nav-fg-hover: #00629b;
  --nav-hover-bg: #eef4f9;
  --nav-border: #00629b;
  --nav-menu-bg: #ffffff;
  --nav-menu-line: #e3eaf1;
  --cta-bg: #00629b;
  --cta-fg: #ffffff;
  --cta-bg-hover: #00467f;
  --person-link: #0072bc;
  --radius: 3px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Secondary theme: the original COINS navy & gold, chosen with the nav
   theme switch (data-theme="classic" on <html>, see main.js). */
:root[data-theme="classic"] {
  --navy: #0a1628;
  --navy-mid: #132040;
  --navy-deep: #060f1f;
  --blue: #1a4fa3;
  --blue-bright: #2563eb;
  --accent: #e8c547;
  --accent-dim: #b8962c;
  --teal: #0ea5a0;
  --teal-dim: #0c8f8a;
  --white: #f5f4f0;
  --section-alt: #f0ede8;
  --surface-muted: #f8f6f2;
  --gray-light: #e8e6e1;
  --gray: #9ca3af;
  --text: #1c1c2e;
  --nav-bg: #0a1628;
  --nav-fg: #e8e6e1;
  --nav-fg-hover: #e8c547;
  --nav-hover-bg: rgba(255,255,255,0.05);
  --nav-border: #e8c547;
  --nav-menu-bg: #132040;
  --nav-menu-line: rgba(255,255,255,0.05);
  --cta-bg: #e8c547;
  --cta-fg: #0a1628;
  --cta-bg-hover: #b8962c;
  --person-link: #e8c547;
}

/* Default theme only: the white nav bar needs the (white) logo tinted IEEE
   blue, and people listings sit on white instead of a dark band. */
:root:not([data-theme="classic"]) .nav-logo img {
  filter: brightness(0) saturate(100%) invert(24%) sepia(98%) saturate(1900%) hue-rotate(186deg) brightness(90%);
}
:root:not([data-theme="classic"]) .section-people { background: var(--white); color: var(--text); }
:root:not([data-theme="classic"]) .section-people .role-title { color: var(--blue); border-bottom-color: var(--gray-light); }
:root:not([data-theme="classic"]) .section-people .person-card { background: var(--surface-muted); border-color: var(--gray-light); }
:root:not([data-theme="classic"]) .section-people .person-card:hover { border-color: var(--blue-bright); background: var(--white); }
:root:not([data-theme="classic"]) .section-people .person-name { color: var(--text); }
:root:not([data-theme="classic"]) .section-people .person-affil { color: var(--gray-dark); }
:root:not([data-theme="classic"]) .section-people .info-box p { color: var(--gray-dark) !important; }

/* ─── THEME SWITCH ────────────────────── */
/* scoped under .nav-links so it beats the generic nav-button rule */
.nav-links > li > .theme-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 34px; height: 34px; padding: 0; margin-left: 0.6rem;
  background: transparent; color: var(--nav-fg);
  border: 1px solid color-mix(in srgb, var(--nav-fg) 35%, transparent);
  border-radius: 50%; cursor: pointer;
  transition: color var(--transition), border-color var(--transition), transform var(--transition);
}
.nav-links > li > .theme-toggle:hover { color: var(--nav-fg-hover); border-color: var(--nav-fg-hover); background: transparent; }
.theme-toggle svg { width: 18px; height: 18px; transition: transform var(--transition); }
.theme-toggle[aria-checked="true"] svg { transform: rotate(180deg); }

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'DM Sans', sans-serif;
  background: var(--white);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ─── NAV ─────────────────────────────── */
nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--nav-bg);
  border-bottom: 2px solid var(--nav-border);
  padding: 0 2rem;
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.nav-logo {
  display: flex; align-items: center; gap: 0.75rem;
  text-decoration: none; color: var(--nav-fg);
}
.nav-logo .logo-badge {
  background: var(--cta-bg); color: var(--cta-fg);
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 600; font-size: 0.7rem;
  padding: 2px 8px; letter-spacing: 0.1em;
  border-radius: 2px;
}
.nav-logo .logo-text {
  font-family: 'Fraunces', serif;
  font-size: 1.15rem; font-weight: 700;
  letter-spacing: 0.02em;
}
.nav-logo img { height: 34px; width: auto; }
.nav-links { display: flex; align-items: center; gap: 0; list-style: none; }
.nav-links > li { position: relative; }
.nav-links > li > a, .nav-links > li > button {
  display: flex; align-items: center; gap: 0.3rem;
  padding: 0 1rem; height: 64px;
  color: var(--nav-fg); text-decoration: none;
  font-size: 0.875rem; font-weight: 500; letter-spacing: 0.02em;
  background: none; border: none; cursor: pointer;
  transition: color var(--transition), background var(--transition);
  white-space: nowrap;
}
.nav-links > li > a:hover, .nav-links > li > button:hover,
.nav-links > li > a.active {
  color: var(--nav-fg-hover); background: var(--nav-hover-bg);
}
.dropdown { position: relative; }
.dropdown-menu {
  display: none; position: absolute; top: 100%; left: 0;
  background: var(--nav-menu-bg); border: 1px solid var(--nav-menu-line);
  border-top: 2px solid var(--nav-border); min-width: 220px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}
.dropdown:hover .dropdown-menu { display: block; }
.dropdown-menu a {
  display: block; padding: 0.75rem 1.25rem;
  color: var(--nav-fg); text-decoration: none;
  font-size: 0.85rem; border-bottom: 1px solid var(--nav-menu-line);
  transition: color var(--transition), background var(--transition);
}
.dropdown-menu a:hover { color: var(--nav-fg-hover); background: var(--nav-hover-bg); }
.nav-cta {
  margin-left: 0.75rem;
  background: var(--cta-bg) !important; color: var(--cta-fg) !important;
  font-weight: 600 !important; padding: 0.45rem 1.1rem !important;
  height: auto !important; border-radius: 2px;
  transition: background var(--transition) !important;
}
.nav-cta:hover { background: var(--cta-bg-hover) !important; }

.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; }
.hamburger span { display: block; width: 22px; height: 2px; background: var(--nav-fg); transition: var(--transition); }

/* ─── HERO ───────────────────────────── */
.hero {
  background: var(--navy);
  background-image:
    radial-gradient(ellipse 80% 60% at 70% 40%, color-mix(in srgb, var(--blue) 40%, transparent) 0%, transparent 60%),
    radial-gradient(ellipse 50% 40% at 20% 80%, color-mix(in srgb, var(--teal) 20%, transparent) 0%, transparent 50%),
    url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.02'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  padding: 5rem 2rem 4rem;
  position: relative; overflow: hidden;
}
.hero::after {
  content: '';
  position: absolute; bottom: 0; left: 0; right: 0;
  height: 3px; background: linear-gradient(90deg, var(--teal), var(--accent), var(--blue-bright));
}
.hero-inner { max-width: 1200px; margin: 0 auto; position: relative; }
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 0.5rem;
  background: color-mix(in srgb, var(--accent) 15%, transparent); border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  color: var(--accent); font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem; letter-spacing: 0.12em; text-transform: uppercase;
  padding: 0.3rem 0.85rem; border-radius: 2px; margin-bottom: 1.5rem;
}
.hero-eyebrow::before { content: '◆'; font-size: 0.5rem; }
.hero h1 {
  font-family: 'Fraunces', serif;
  font-size: clamp(2.5rem, 5vw, 4.5rem);
  font-weight: 700; color: var(--white);
  line-height: 1.05; letter-spacing: -0.02em;
  margin-bottom: 1rem; max-width: 780px;
}
.hero h1 em { font-style: italic; color: var(--accent); }
.hero-subtitle {
  font-size: 1.15rem; color: var(--gray);
  max-width: 620px; margin-bottom: 2rem; line-height: 1.7;
}
.hero-meta {
  display: flex; flex-wrap: wrap; gap: 1.5rem; margin-bottom: 2.5rem;
}
.hero-meta-item {
  display: flex; align-items: center; gap: 0.6rem;
  color: var(--white); font-size: 0.95rem;
}
.hero-meta-item .icon {
  width: 36px; height: 36px; border-radius: 50%;
  background: rgba(255,255,255,0.08); border: 1px solid rgba(255,255,255,0.15);
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem; flex-shrink: 0;
}
.hero-meta-item strong { display: block; font-size: 1rem; color: var(--white); }
.hero-meta-item span { display: block; font-size: 0.8rem; color: var(--gray); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 1rem; }
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.75rem 1.75rem; border-radius: var(--radius);
  font-weight: 600; font-size: 0.9rem; text-decoration: none;
  transition: all var(--transition); cursor: pointer; border: 2px solid transparent;
  letter-spacing: 0.02em;
}
.btn-primary { background: var(--accent); color: var(--navy); }
.btn-primary:hover { background: var(--accent-dim); transform: translateY(-1px); box-shadow: 0 4px 20px color-mix(in srgb, var(--accent) 30%, transparent); }
.btn-outline { border-color: rgba(255,255,255,0.3); color: var(--white); }
.btn-outline:hover { border-color: var(--white); background: rgba(255,255,255,0.08); }
.btn-teal { background: var(--teal); color: var(--white); }
.btn-teal:hover { background: var(--teal-dim); transform: translateY(-1px); }
.btn-sm { padding: 0.5rem 1.1rem; font-size: 0.82rem; }

/* ─── COUNTDOWN ──────────────────────── */
.countdown-bar {
  background: var(--navy-mid); border-top: 1px solid rgba(255,255,255,0.08);
  padding: 1.25rem 2rem;
}
.countdown-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; flex-wrap: wrap; align-items: center; gap: 1.5rem;
}
.countdown-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem; letter-spacing: 0.1em; color: var(--gray);
  text-transform: uppercase; flex-shrink: 0;
}
.countdown-units { display: flex; gap: 1rem; }
.countdown-unit { text-align: center; }
.countdown-unit .num {
  display: block; font-family: 'IBM Plex Mono', monospace;
  font-size: 1.6rem; font-weight: 600; color: var(--accent); line-height: 1;
}
.countdown-unit .lbl {
  display: block; font-size: 0.7rem; color: var(--gray);
  text-transform: uppercase; letter-spacing: 0.08em; margin-top: 2px;
}
.countdown-divider {
  font-family: 'IBM Plex Mono', monospace; font-size: 1.2rem;
  color: var(--gray-dark); margin-bottom: 0.5rem;
}

/* ─── SECTIONS ───────────────────────── */
.section { padding: 4.5rem 2rem; }
.section-alt { background: var(--section-alt); }
.section-dark { background: var(--navy); color: var(--white); }
.section-inner { max-width: 1200px; margin: 0 auto; }

.section-tag {
  display: inline-block;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.72rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--blue-bright); margin-bottom: 0.75rem;
}
.section-dark .section-tag { color: var(--teal); }
h2.section-title {
  font-family: 'Fraunces', serif;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 700; line-height: 1.15;
  letter-spacing: -0.02em; margin-bottom: 1rem;
}
.section-lead { font-size: 1.1rem; color: var(--gray-dark); max-width: 680px; }
.section-dark .section-lead { color: var(--gray); }

/* ─── DATES TABLE ────────────────────── */
.dates-grid { margin-top: 2.5rem; display: grid; gap: 0; }
.date-row {
  display: grid; grid-template-columns: 2fr 1fr auto;
  align-items: center; gap: 1.5rem;
  padding: 1.1rem 1.25rem; border-bottom: 1px solid var(--gray-light);
  transition: background var(--transition);
}
.date-row:hover { background: color-mix(in srgb, var(--blue) 4%, transparent); }
.date-row:first-child { border-top: 2px solid var(--blue-bright); }
.date-event { font-weight: 500; }
.date-event small { display: block; color: var(--gray); font-size: 0.82rem; font-weight: 400; margin-top: 1px; }
.date-value { font-family: 'IBM Plex Mono', monospace; font-size: 0.88rem; color: var(--blue-bright); font-weight: 600; }
.date-badge {
  font-size: 0.7rem; padding: 0.2rem 0.6rem; border-radius: 20px;
  font-weight: 600; letter-spacing: 0.05em; white-space: nowrap;
}
.badge-open { background: #dcfce7; color: #166534; }
.badge-upcoming { background: #fef9c3; color: #854d0e; }
.badge-future { background: var(--gray-light); color: var(--gray-dark); }
.badge-passed { background: #f3f4f6; color: var(--gray); text-decoration: line-through; }

/* ─── TRACKS GRID ────────────────────── */
.cluster-section { margin-top: 2.5rem; }
.cluster-header {
  display: flex; align-items: center; gap: 1rem;
  margin-bottom: 1.25rem; padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--gray-light);
}
.cluster-num {
  font-family: 'IBM Plex Mono', monospace; font-size: 0.7rem;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--white); background: var(--blue);
  padding: 0.25rem 0.7rem; border-radius: 2px;
}
.cluster-title { font-family: 'Fraunces', serif; font-size: 1.2rem; font-weight: 700; }
.tracks-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1px; background: var(--gray-light); }
.track-card {
  background: var(--white); padding: 1.5rem;
  transition: background var(--transition);
}
.track-card:hover { background: var(--surface-muted); }
.track-num {
  font-family: 'IBM Plex Mono', monospace; font-size: 0.7rem;
  color: var(--blue-bright); font-weight: 600; margin-bottom: 0.5rem;
  letter-spacing: 0.06em;
}
.track-card h4 { font-size: 0.95rem; font-weight: 600; margin-bottom: 0.5rem; line-height: 1.3; }
.track-card p { font-size: 0.82rem; color: var(--gray-dark); line-height: 1.55; }
.track-keywords {
  margin-top: 0.75rem; display: flex; flex-wrap: wrap; gap: 0.3rem;
}
.kw {
  font-size: 0.68rem; background: var(--gray-light); color: var(--gray-dark);
  padding: 0.15rem 0.5rem; border-radius: 20px;
}

/* ─── COMMITTEE ──────────────────────── */
.committee-section { margin-top: 2.5rem; }
.committee-role {
  margin-bottom: 2.5rem;
}
.role-title {
  font-family: 'IBM Plex Mono', monospace; font-size: 0.78rem;
  text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--blue-bright); margin-bottom: 1rem;
  padding-bottom: 0.5rem; border-bottom: 1px solid var(--gray-light);
}
.section-dark .role-title { color: var(--teal); border-bottom-color: rgba(255,255,255,0.1); }
.people-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1rem; }
.person-card {
  padding: 1.25rem; background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.08); border-radius: var(--radius);
  transition: border-color var(--transition), background var(--transition);
}
.person-card:hover { border-color: color-mix(in srgb, var(--accent) 40%, transparent); background: rgba(255,255,255,0.08); }
.person-card.light {
  background: var(--white); border-color: var(--gray-light); color: var(--text);
}
.person-card.light:hover { border-color: var(--blue-bright); }
.person-avatar {
  width: 44px; height: 44px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--teal));
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 1rem; color: var(--white);
  margin-bottom: 0.75rem; flex-shrink: 0;
}
.person-photo {
  display: block; width: 96px; height: 96px; border-radius: 50%;
  object-fit: cover; margin-bottom: 0.85rem; flex-shrink: 0;
  border: 3px solid var(--accent); cursor: zoom-in;
  transition: transform var(--transition), box-shadow var(--transition);
}
.person-photo:hover, .person-photo:focus-visible {
  transform: scale(1.05); box-shadow: 0 6px 18px rgba(0,0,0,0.25); outline: none;
}
.person-name { font-weight: 600; font-size: 0.92rem; margin-bottom: 0.2rem; }
.person-affil { font-size: 0.8rem; color: var(--gray); line-height: 1.3; }
.section-dark .person-name { color: var(--white); }

/* ─── PROGRAM ────────────────────────── */
.program-day-tabs { display: flex; gap: 0; margin-bottom: 0; border-bottom: 2px solid var(--gray-light); }
.day-tab {
  padding: 0.75rem 1.5rem; font-weight: 600; font-size: 0.88rem;
  cursor: pointer; border: none; background: none; color: var(--gray-dark);
  border-bottom: 3px solid transparent; margin-bottom: -2px;
  transition: all var(--transition);
}
.day-tab.active { color: var(--blue-bright); border-bottom-color: var(--blue-bright); }
.day-tab:hover { color: var(--blue-bright); }
.day-content { display: none; padding-top: 1.5rem; }
.day-content.active { display: block; }
.session-block { margin-bottom: 1.25rem; }
.session-time {
  font-family: 'IBM Plex Mono', monospace; font-size: 0.78rem;
  color: var(--blue-bright); font-weight: 600; margin-bottom: 0.4rem;
}
.session-card {
  padding: 1.1rem 1.25rem; border-left: 3px solid var(--blue);
  background: var(--white); border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}
.session-card.keynote { border-left-color: var(--accent); }
.session-card.break { border-left-color: var(--gray); background: var(--surface-muted); }
.session-card.special { border-left-color: var(--teal); }
.session-title { font-weight: 600; font-size: 0.92rem; margin-bottom: 0.25rem; }
.session-speaker { font-size: 0.82rem; color: var(--gray-dark); }
.session-speaker em { font-style: normal; color: var(--blue); font-weight: 500; }

/* ─── VENUE ──────────────────────────── */
.venue-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 3rem; align-items: start; margin-top: 2rem; }
.venue-info h3 { font-family: 'Fraunces', serif; font-size: 1.5rem; margin-bottom: 0.5rem; }
.venue-address { color: var(--gray-dark); margin-bottom: 1.5rem; line-height: 1.8; }
.venue-map {
  background: var(--gray-light); border-radius: var(--radius);
  overflow: hidden; height: 320px; position: relative;
}
.venue-map iframe { width: 100%; height: 100%; border: none; }
.hotels-list { margin-top: 1.5rem; }
.hotels-list h4 { font-size: 0.9rem; font-weight: 600; margin-bottom: 0.75rem; color: var(--gray-dark); text-transform: uppercase; letter-spacing: 0.05em; }
.hotel-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.6rem 0; border-bottom: 1px solid var(--gray-light);
  font-size: 0.88rem;
}
.hotel-item:last-child { border-bottom: none; }
.hotel-stars { color: var(--accent-dim); }

/* ─── REGISTRATION ───────────────────── */
.reg-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.reg-card {
  border: 2px solid var(--gray-light); border-radius: var(--radius);
  padding: 1.75rem; position: relative; transition: border-color var(--transition);
}
.reg-card:hover { border-color: var(--blue-bright); }
.reg-card.featured { border-color: var(--accent); }
.reg-card.featured::before {
  content: 'Most Common';
  position: absolute; top: -1px; right: 1.5rem;
  background: var(--accent); color: var(--navy);
  font-size: 0.7rem; font-weight: 700; padding: 0.2rem 0.75rem;
  border-radius: 0 0 4px 4px; letter-spacing: 0.05em;
}
.reg-type { font-family: 'IBM Plex Mono', monospace; font-size: 0.78rem; color: var(--blue); font-weight: 600; text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 0.5rem; }
.reg-price { font-family: 'Fraunces', serif; font-size: 2.2rem; font-weight: 700; line-height: 1; margin-bottom: 0.25rem; }
.reg-price sup { font-size: 1rem; vertical-align: super; font-family: 'DM Sans', sans-serif; }
.reg-note { font-size: 0.8rem; color: var(--gray); margin-bottom: 1.25rem; }
.reg-features { list-style: none; margin-bottom: 1.5rem; }
.reg-features li { font-size: 0.85rem; padding: 0.35rem 0; display: flex; gap: 0.5rem; align-items: flex-start; }
.reg-features li::before { content: '✓'; color: var(--teal); font-weight: 700; flex-shrink: 0; }

/* ─── PAGE HERO ──────────────────────── */
.page-hero {
  background: var(--navy);
  padding: 3.5rem 2rem 3rem;
  border-bottom: 3px solid var(--accent);
}
.page-hero-inner { max-width: 1200px; margin: 0 auto; }
.page-hero h1 {
  font-family: 'Fraunces', serif;
  font-size: clamp(1.8rem, 3.5vw, 3rem);
  font-weight: 700; color: var(--white); margin-top: 0.75rem;
  letter-spacing: -0.02em;
}
.page-hero p { color: var(--gray); max-width: 620px; margin-top: 0.75rem; }
.breadcrumb {
  display: flex; align-items: center; gap: 0.5rem;
  font-size: 0.8rem; color: var(--gray);
}
.breadcrumb a { color: var(--gray); text-decoration: none; }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb::before { content: ''; }
.breadcrumb-sep { color: var(--gray-dark); }

/* ─── INFO BOXES ─────────────────────── */
.info-box {
  border-left: 4px solid var(--blue-bright); padding: 1rem 1.25rem;
  background: color-mix(in srgb, var(--blue-bright) 6%, transparent); border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.5rem 0;
}
.info-box.warning { border-left-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, transparent); }
.info-box.success { border-left-color: var(--teal); background: color-mix(in srgb, var(--teal) 6%, transparent); }
.info-box strong { display: block; margin-bottom: 0.25rem; font-size: 0.9rem; }
.info-box p { font-size: 0.88rem; color: var(--gray-dark); margin: 0; }

/* ─── FOOTER ─────────────────────────── */
footer {
  background: var(--navy-deep); color: var(--gray);
  padding: 3rem 2rem 1.5rem;
  border-top: 3px solid var(--navy-mid);
}
.footer-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 2.5rem;
  padding-bottom: 2rem; border-bottom: 1px solid rgba(255,255,255,0.06);
}
.footer-brand p { font-size: 0.85rem; line-height: 1.7; margin-top: 0.75rem; max-width: 280px; }
.footer-col h5 {
  font-family: 'IBM Plex Mono', monospace; font-size: 0.72rem;
  letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--white); margin-bottom: 1rem;
}
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 0.5rem; }
.footer-col ul li a { color: var(--gray); text-decoration: none; font-size: 0.85rem; transition: color var(--transition); }
.footer-col ul li a:hover { color: var(--accent); }
.footer-bottom {
  max-width: 1200px; margin: 1.5rem auto 0;
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem;
  font-size: 0.8rem; color: #4b5563;
}
.footer-ieee {
  display: flex; align-items: center; gap: 0.5rem;
  font-family: 'IBM Plex Mono', monospace; font-size: 0.72rem; letter-spacing: 0.1em;
  color: var(--gray);
}
.ieee-badge {
  background: #00629b; color: white;
  padding: 2px 8px; border-radius: 2px; font-weight: 700; font-size: 0.75rem;
}

/* ─── STATS BAR ──────────────────────── */
.stats-bar {
  background: var(--blue); padding: 2rem;
}
.stats-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; text-align: center;
}
.stat-item .stat-num {
  font-family: 'Fraunces', serif; font-size: 2.4rem;
  font-weight: 700; color: var(--white); line-height: 1;
}
.stat-item .stat-lbl {
  font-size: 0.8rem; color: rgba(255,255,255,0.7); margin-top: 0.25rem;
  text-transform: uppercase; letter-spacing: 0.06em;
}

/* ─── SPONSORS ───────────────────────── */
.sponsor-logos { display: flex; flex-wrap: wrap; align-items: center; gap: 2rem; margin-top: 1.5rem; }
.sponsor-logo {
  background: rgba(255,255,255,0.08); border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius); padding: 0.75rem 1.5rem;
  color: var(--gray); font-family: 'IBM Plex Mono', monospace;
  font-size: 0.85rem; font-weight: 600; letter-spacing: 0.08em;
}
.sponsor-logo-img {
  height: 56px; width: auto; max-width: 180px; object-fit: contain;
  background: #fff; border-radius: var(--radius); padding: 0.6rem 1rem;
}

/* Auto-scrolling logo strip on a white shelf, used for the sponsor/partner
   logo row. Content is duplicated once in the markup so the loop is seamless;
   the duplicate is aria-hidden. Edges fade to transparent via a mask. */
.logo-marquee {
  background: #fff; border-radius: var(--radius);
  overflow: hidden; padding: 1.75rem 0; margin-top: 1.5rem;
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
}
.logo-marquee-track {
  display: flex; align-items: center; gap: 3rem; width: max-content;
  animation: logo-marquee-scroll 30s linear infinite;
}
.logo-marquee:hover .logo-marquee-track { animation-play-state: paused; }
.logo-marquee-track img {
  height: 48px; width: auto; max-width: 160px; object-fit: contain; flex-shrink: 0;
}
.logo-marquee-track .sponsor-logo {
  background: var(--surface-muted); border-color: var(--gray-light); color: var(--gray-dark);
  flex-shrink: 0;
}
@keyframes logo-marquee-scroll {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

/* ─── UTILITY ────────────────────────── */
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.text-sm { font-size: 0.875rem; }
.text-muted { color: var(--gray-dark); }
a { color: var(--blue-bright); }
a:hover { color: var(--blue); }

/* ─── MOBILE ─────────────────────────── */
@media (max-width: 900px) {
  .nav-links { display: none; flex-direction: column; gap: 0; position: absolute; top: 64px; left: 0; right: 0; background: var(--nav-bg); border-bottom: 2px solid var(--nav-border); z-index: 99; }
  .nav-links.open { display: flex; }
  .nav-links > li > a, .nav-links > li > button { height: auto; padding: 0.9rem 1.5rem; width: 100%; border-bottom: 1px solid var(--nav-menu-line); }
  .nav-links > li > .theme-toggle { width: 34px; margin: 0.75rem 1.5rem; }
  .dropdown-menu { position: static; display: none; background: rgba(255,255,255,0.04); border: none; box-shadow: none; }
  .dropdown.open .dropdown-menu { display: block; }
  .hamburger { display: flex; }
  nav { position: relative; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .venue-grid { grid-template-columns: 1fr; }
  .stats-inner { grid-template-columns: repeat(2, 1fr); }
  .date-row { grid-template-columns: 1fr; gap: 0.5rem; }
}
@media (max-width: 600px) {
  .footer-inner { grid-template-columns: 1fr; }
  .hero { padding: 3rem 1.25rem 2.5rem; }
  .section { padding: 3rem 1.25rem; }
  .stats-inner { grid-template-columns: repeat(2, 1fr); }
  .reg-grid { grid-template-columns: 1fr; }
}

/* ─── PHOTO GALLERY ──────────────────────────────────────── */
.venue-gallery {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  grid-template-rows: 240px 240px;
  gap: 6px;
  border-radius: 6px;
  overflow: hidden;
  margin-top: 2rem;
}
.venue-gallery .photo-item {
  overflow: hidden; position: relative; cursor: pointer;
}
.venue-gallery .photo-item:first-child {
  grid-row: 1 / 3;
}
.venue-gallery .photo-item img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 0.5s cubic-bezier(0.4,0,0.2,1);
  display: block;
}
.venue-gallery .photo-item:hover img { transform: scale(1.05); }
.venue-gallery .photo-item .photo-caption {
  position: absolute; bottom: 0; left: 0; right: 0;
  background: linear-gradient(transparent, rgba(0,0,0,0.6));
  color: #fff; font-size: 0.75rem; padding: 1rem 0.75rem 0.5rem;
  opacity: 0; transition: opacity 0.3s;
}
.venue-gallery .photo-item:hover .photo-caption { opacity: 1; }

/* Lightbox */
.lightbox {
  display: none; position: fixed; inset: 0; z-index: 999;
  background: rgba(0,0,0,0.92); align-items: center; justify-content: center;
}
.lightbox.open { display: flex; }
.lightbox img { max-width: 90vw; max-height: 85vh; object-fit: contain; border-radius: 4px; }
.lightbox.person-lightbox img { max-height: 75vh; border-radius: 8px; }
.lightbox-close {
  position: absolute; top: 1.5rem; right: 1.5rem;
  color: #fff; font-size: 2rem; cursor: pointer; line-height: 1;
  background: none; border: none;
}
.lightbox-caption {
  position: absolute; bottom: 1.5rem; left: 50%; transform: translateX(-50%);
  color: rgba(255,255,255,0.7); font-size: 0.85rem;
}

/* ─── KEYNOTE CARDS ──────────────────────────────────────── */
.keynote-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem; margin-top: 1.5rem;
}
.keynote-card {
  border: 1px solid var(--gray-light); border-radius: 4px;
  overflow: hidden; transition: border-color var(--transition), box-shadow var(--transition);
}
.keynote-card:hover { border-color: var(--blue-bright); box-shadow: 0 4px 20px color-mix(in srgb, var(--blue) 10%, transparent); }
.keynote-card-header {
  background: var(--navy); padding: 1.5rem;
  display: flex; gap: 1rem; align-items: flex-start;
}
.keynote-photo {
  width: 72px; height: 72px; border-radius: 50%;
  object-fit: cover; border: 3px solid var(--accent); flex-shrink: 0;
}
.keynote-avatar {
  width: 72px; height: 72px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--teal));
  display: flex; align-items: center; justify-content: center;
  font-size: 1.6rem; color: white; flex-shrink: 0;
  border: 3px solid var(--accent);
}
.keynote-meta { color: var(--white); }
.keynote-meta .name { font-family: 'Fraunces', serif; font-size: 1.1rem; font-weight: 700; margin-bottom: 0.25rem; }
.keynote-meta .affil { font-size: 0.8rem; color: var(--gray); }
.keynote-meta .slot { font-family: 'IBM Plex Mono', monospace; font-size: 0.72rem; color: var(--accent); margin-top: 0.4rem; letter-spacing: 0.06em; }
.keynote-card-body { padding: 1.25rem; }
.keynote-card-body .talk-title { font-weight: 600; font-size: 0.95rem; margin-bottom: 0.5rem; color: var(--text); }
.keynote-card-body .abstract { font-size: 0.84rem; color: var(--gray-dark); line-height: 1.65; }
.tba-badge {
  display: inline-block; background: var(--gray-light); color: var(--gray-dark);
  font-family: 'IBM Plex Mono', monospace; font-size: 0.68rem; padding: 0.2rem 0.6rem;
  border-radius: 20px; letter-spacing: 0.06em; margin-bottom: 0.5rem;
}

/* ─── TUTORIAL / COMPETITION / PHD CARDS ────────────────── */
.event-card {
  border: 1px solid var(--gray-light); border-radius: 4px; padding: 1.75rem;
  transition: border-color var(--transition);
}
.event-card:hover { border-color: var(--blue-bright); }
.event-card .event-type {
  font-family: 'IBM Plex Mono', monospace; font-size: 0.7rem;
  text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--teal); margin-bottom: 0.5rem;
}
.event-card h3 { font-family: 'Fraunces', serif; font-size: 1.1rem; margin-bottom: 0.5rem; }
.event-card .presenter { font-size: 0.85rem; color: var(--blue); font-weight: 500; margin-bottom: 0.75rem; }
.event-card p { font-size: 0.88rem; color: var(--gray-dark); line-height: 1.65; }
.event-card .meta-row { display: flex; gap: 1.5rem; margin-top: 1rem; flex-wrap: wrap; }
.event-card .meta-item { font-size: 0.82rem; color: var(--gray-dark); }
.event-card .meta-item strong { color: var(--text); }
.event-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 1.5rem; margin-top: 1.5rem; }

/* ─── PROGRAM MENU UPDATES ───────────────────────────────── */
.nav-links > li > a.active, .nav-links > li.active > button { color: var(--nav-fg-hover); }

/* ─── MOBILE GALLERY ─────────────────────────────────────── */
@media (max-width: 800px) {
  .venue-gallery {
    grid-template-columns: 1fr 1fr;
    grid-template-rows: 160px 160px 160px;
  }
  .venue-gallery .photo-item:first-child { grid-row: 1; }
}
@media (max-width: 500px) {
  .venue-gallery { grid-template-columns: 1fr; grid-template-rows: auto; }
  .venue-gallery .photo-item { height: 200px; }
  .venue-gallery .photo-item:first-child { grid-row: auto; }
}