:root {
  --bg: #f8f8f6;
  --surface: #ffffff;
  --text: #222222;
  --muted: #666666;
  --accent: #7a1f2b;
  --accent-dark: #54151d;
  --border: #deded8;

  --content-width: 920px;
  --text-width: 760px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);

  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    Roboto,
    Helvetica,
    Arial,
    sans-serif;

  font-size: 17px;
  line-height: 1.65;
}


/* --------------------------------------------------
   Header
-------------------------------------------------- */

header {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 5rem 2rem 3rem;
  text-align: center;
}

header h1 {
  max-width: 850px;
  margin: 0 auto;

  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2.2rem, 5vw, 4rem);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: -0.025em;
}

.conference-details {
  margin-top: 1.6rem;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.6;
}


/* --------------------------------------------------
   Navigation
-------------------------------------------------- */

nav {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;

  padding: 1rem 2rem;

  background: var(--surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);

  position: sticky;
  top: 0;
  z-index: 10;
}

nav a {
  color: var(--text);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.02em;

  transition:
    color 0.15s ease,
    border-color 0.15s ease;
}

nav a:hover {
  color: var(--accent);
}

nav a[aria-current="page"] {
  color: var(--accent);
}


/* --------------------------------------------------
   Main content
-------------------------------------------------- */

main {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 3.5rem 2rem 5rem;
}

section {
  max-width: var(--text-width);
  margin: 0 auto 4.5rem;
}

section:last-child {
  margin-bottom: 0;
}

h2 {
  margin: 0 0 1.5rem;

  font-family: Georgia, "Times New Roman", serif;
  font-size: 2rem;
  font-weight: 400;
  line-height: 1.25;

  padding-bottom: 0.55rem;
  border-bottom: 1px solid var(--border);
}

h3 {
  margin-top: 2.3rem;
  margin-bottom: 0.8rem;

  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.35rem;
  font-weight: 400;
}

p {
  margin: 0 0 1.3rem;
}

a {
  color: var(--accent);
  text-underline-offset: 0.16em;
}

a:hover {
  color: var(--accent-dark);
}


/* --------------------------------------------------
   Lists
-------------------------------------------------- */

ul {
  padding-left: 1.3rem;
}

li {
  margin-bottom: 0.6rem;
}


/* Practical information lists */

ul.data {
  list-style: none;
  padding: 0;
  margin: 1.4rem 0;
}

ul.data li {
  padding: 1rem 0;
  margin: 0;
  border-bottom: 1px solid var(--border);
}

ul.data li:first-child {
  border-top: 1px solid var(--border);
}

ul.data strong {
  display: inline;
  font-weight: 600;
}


/* --------------------------------------------------
   Speaker / participant lists
-------------------------------------------------- */

.speaker-list,
.participant-list {
  list-style: none;
  padding: 0;
}

.speaker-list li,
.participant-list li {
  padding: 0.65rem 0;
  margin: 0;
  border-bottom: 1px solid var(--border);
}


/* --------------------------------------------------
   Footer
-------------------------------------------------- */

footer {
  padding: 2.5rem 2rem;
  text-align: center;

  border-top: 1px solid var(--border);
  color: var(--muted);

  font-size: 0.85rem;
}

footer p {
  margin: 0;
}


/* --------------------------------------------------
   Responsive layout
-------------------------------------------------- */

@media (max-width: 700px) {

  header {
    padding: 3.5rem 1.3rem 2.5rem;
  }

  nav {
    gap: 1.1rem;
    padding: 0.9rem 1rem;
  }

  nav a {
    font-size: 0.9rem;
  }

  main {
    padding: 2.5rem 1.3rem 4rem;
  }

  h2 {
    font-size: 1.7rem;
  }

  body {
    font-size: 16px;
  }
}