/* ============================================================
   IEEE SCPEC — Conference Website Styles
   Simple, professional layout in IEEE blue
   ============================================================ */
@import url("https://fonts.googleapis.com/css2?family=Source+Serif+4:opsz,wght@8..60,500;8..60,600&display=swap");

:root {
  /* Heading font + color — change these two lines to restyle all titles */
  --heading-font: "Source Serif 4", Georgia, "Times New Roman", serif;
  --heading-color: #00629b;
  --blue: #00629b;       /* IEEE blue */
  --blue-dark: #003a5d;
  --blue-light: #e8f1f7;
  --accent: #f2a900;
  --text: #222b36;
  --muted: #5f6b78;
  --border: #dfe5eb;
  --bg-alt: #f6f8fa;
  --max: 1100px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  line-height: 1.65;
  background: #fff;
  display: flex; flex-direction: column; min-height: 100vh;
}
main { flex: 1; }
a { color: var(--blue); }
a:hover { color: var(--blue-dark); }
.container { width: min(var(--max), 92%); margin: 0 auto; }

/* ---------- Top bar + header ---------- */
.topbar { background: var(--blue-dark); color: #cfe0ee; font-size: 0.85rem; }
.topbar .container { display: flex; justify-content: space-between; padding: 0.35rem 0; gap: 1rem; flex-wrap: wrap; }
.topbar a { color: #fff; text-decoration: none; }

.site-header { background: #fff; position: sticky; top: 0; z-index: 10; box-shadow: 0 2px 8px rgba(0,0,0,0.08); }
.site-header > .container { display: flex; align-items: center; justify-content: space-between; min-height: 76px; gap: 1rem; }
.navbar { background: var(--blue); }
.brand { text-decoration: none; color: var(--blue-dark); line-height: 1.2; }
.brand strong { display: block; font-family: var(--heading-font); font-weight: 600; font-size: 1.5rem; color: var(--heading-color); }
h1, h2, h3, h4 { font-family: var(--heading-font); font-weight: 600; }
.brand span { font-size: 0.85rem; color: var(--muted); }

.nav { display: flex; list-style: none; flex-wrap: wrap; }
.nav a {
  display: block; padding: 0.75rem 1rem; white-space: nowrap;
  text-decoration: none; color: #fff; font-weight: 500; font-size: 0.95rem;
  border-bottom: 3px solid transparent;
}
.nav a:hover { background: rgba(255,255,255,0.12); color: #fff; }
.nav a.active { background: var(--blue-dark); border-bottom-color: var(--accent); color: #fff; }
.nav-toggle { display: none; background: none; border: 1px solid var(--border); border-radius: 4px; padding: 0.4rem 0.7rem; font-size: 1.1rem; cursor: pointer; }

/* ---------- Banner ---------- */
.banner {
  background: linear-gradient(120deg, var(--blue-dark) 0%, var(--blue) 100%);
  color: #fff; padding: 4.5rem 0;
}
.banner h1 { font-size: clamp(1.9rem, 4.5vw, 2.9rem); line-height: 1.2; font-weight: 500; margin-bottom: 0.75rem; }
.banner .sub { font-size: 1.15rem; color: #d6e6f2; }
.banner .meta { margin-top: 1.25rem; font-size: 1.05rem; font-weight: 600; }
.banner .meta span { display: inline-block; margin-right: 1.75rem; }
.banner .actions { margin-top: 2rem; display: flex; gap: 0.75rem; flex-wrap: wrap; }

.page-title { background: var(--blue-light); border-bottom: 1px solid var(--border); padding: 2.25rem 0; }
.page-title h1 { color: var(--heading-color); font-size: 2.1rem; font-weight: 500; }
.page-title p { color: var(--muted); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; padding: 0.7rem 1.4rem; border-radius: 4px;
  background: var(--accent); color: #1b1b1b; font-weight: 700; text-decoration: none;
  border: 2px solid var(--accent);
}
.btn:hover { filter: brightness(0.93); color: #1b1b1b; }
.btn-ghost { background: transparent; color: #fff; border-color: rgba(255,255,255,0.7); }
.btn-ghost:hover { background: rgba(255,255,255,0.1); color: #fff; }
.btn-blue { background: var(--blue); border-color: var(--blue); color: #fff; }
.btn-blue:hover { color: #fff; }

/* ---------- Layout ---------- */
.section { padding: 3.5rem 0; }
.section-alt { background: var(--bg-alt); }
.layout { display: grid; grid-template-columns: 1fr 300px; gap: 3rem; align-items: start; }
h2 { color: var(--heading-color); font-size: 1.6rem; margin: 2rem 0 0.75rem; }
h2:first-child { margin-top: 0; }
h3 { color: var(--heading-color); font-size: 1.2rem; margin: 1.5rem 0 0.5rem; }
p + p { margin-top: 0.9rem; }
.content ul, .content ol { padding-left: 1.4rem; margin: 0.5rem 0 1rem; }
.content li { margin-bottom: 0.35rem; }

/* Sidebar box */
.sidebar { position: sticky; top: 100px; }
.box { border: 1px solid var(--border); border-top: 4px solid var(--blue); border-radius: 4px; padding: 1.25rem 1.4rem; background: #fff; }
.box + .box { margin-top: 1.25rem; }
.box h3 { margin-top: 0; font-size: 1.15rem; }
.dates { list-style: none; }
.dates li { padding: 0.6rem 0; border-bottom: 1px solid var(--border); }
.dates li:last-child { border-bottom: 0; }
.dates .d { display: block; font-weight: 600; color: var(--blue); }
.dates .l { font-size: 0.92rem; color: var(--muted); }

/* Tables */
table { width: 100%; border-collapse: collapse; margin: 1rem 0 1.5rem; }
th, td { text-align: left; padding: 0.85rem 1rem; border-bottom: 1px solid var(--border); }
th { background: var(--blue); color: #fff; font-weight: 600; }
tr:nth-child(even) td { background: var(--bg-alt); }
td.date { font-weight: 700; color: var(--blue-dark); white-space: nowrap; }

/* Topics list (CFP) */
.topics { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1rem; margin: 1rem 0 1.5rem; }
.topic { border: 1px solid var(--border); border-left: 4px solid var(--blue); border-radius: 4px; padding: 1rem 1.2rem; }
.topic h4 { color: var(--heading-color); font-size: 1.05rem; margin-bottom: 0.3rem; }
.topic p { font-size: 0.92rem; color: var(--muted); }

/* News */
.news-item { padding: 1.4rem 0; border-bottom: 1px solid var(--border); }
.news-item:first-child { padding-top: 0; }
.news-item time { font-size: 0.88rem; font-weight: 600; color: #b37d00; }
.news-item h3 { margin: 0.2rem 0 0.4rem; }
.tag { display: inline-block; font-size: 0.75rem; font-weight: 700; background: var(--blue-light); color: var(--blue); padding: 0.1rem 0.5rem; border-radius: 3px; margin-left: 0.4rem; vertical-align: middle; }

/* Callout */
.callout { background: var(--blue-light); border-left: 4px solid var(--blue); padding: 1rem 1.25rem; border-radius: 4px; margin: 1.25rem 0; }

/* Committee */
.committee { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1rem; margin: 1rem 0 1.5rem; }
.member { border: 1px solid var(--border); border-top: 4px solid var(--blue); border-radius: 4px; padding: 1rem 1.25rem; }
.member h4 { font-family: inherit; font-size: 0.85rem; font-weight: 600; color: var(--blue); margin-bottom: 0.3rem; }
.member p { font-family: var(--heading-font); font-size: 1.1rem; }
.member p { font-weight: 600; }
.member span { font-weight: 400; color: var(--muted); font-size: 0.9rem; }
.tpc { columns: 2 260px; padding-left: 1.2rem; }

/* Keynote speakers */
.speaker { display: grid; grid-template-columns: 170px 1fr; gap: 2rem; padding: 2rem 0; border-bottom: 1px solid var(--border); }
.speaker:first-child { padding-top: 0; }
.speaker h2 { margin: 0; }
.speaker h3 { margin-top: 0.75rem; font-style: italic; font-weight: 500; }
.speaker-role { color: var(--muted); }
.speaker-photo {
  width: 170px; height: 170px; border-radius: 50%; object-fit: cover;
  background: var(--blue-light); color: var(--blue); border: 3px solid var(--blue);
  display: grid; place-items: center; font-family: var(--heading-font); font-size: 2.4rem;
}
@media (max-width: 640px) { .speaker { grid-template-columns: 1fr; } .speaker-photo { width: 130px; height: 130px; } }

/* Home: highlights */
.highlights { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.25rem; }
.highlight { background: #fff; border: 1px solid var(--border); border-radius: 4px; padding: 1.5rem; }
.highlight h3 { margin-top: 0; }
.highlight a { font-weight: 600; text-decoration: none; }

/* ---------- Footer ---------- */
.site-footer { background: var(--blue-dark); color: #b9cbdb; font-size: 0.9rem; padding: 2rem 0; }
.site-footer .container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 1rem; }
.site-footer a { color: #fff; text-decoration: none; }
.site-footer a:hover { text-decoration: underline; color: #fff; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .highlights { grid-template-columns: 1fr; }
}
@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .nav { display: none; flex-direction: column; padding: 0.25rem 0; }
  .nav.open { display: flex; }
  .nav a.active { border-bottom-color: transparent; border-left: 3px solid var(--accent); }
}