:root {
  --pku-red: #94070a;
  --pku-red-dark: #6f1016;
  --paper: #f7f4ef;
  --white: #ffffff;
  --accent: #c98288;
  --pku-tint: #f8ecec;
  --ink: #30292a;
  --muted: #716668;
  --line: #eadedf;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 6rem;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Arial, "Helvetica Neue", sans-serif;
  font-size: 16px;
  line-height: 1.65;
}

a {
  color: #85141d;
}

a:hover,
a:focus {
  color: #5f0b12;
}

h1,
h2,
h3,
h4 {
  color: #3c2f31;
  font-family: Georgia, "Times New Roman", serif;
}

.site-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  background: rgba(255, 255, 255, 0.97);
  border-top: 4px solid var(--pku-red);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 3px 14px rgba(75, 35, 39, 0.08);
}

.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0.8rem 1.25rem;
}

.site-nav__home,
.site-nav__link {
  color: #563b3e;
  text-decoration: none;
}

.site-nav__home {
  flex: 0 0 auto;
  color: var(--pku-red);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.site-nav__links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.25rem;
}

.site-nav__link {
  display: inline-block;
  padding: 0.55rem 0.75rem;
  border-radius: 999px;
  font-size: 0.95rem;
  line-height: 1.25;
  transition: background-color 0.15s ease, color 0.15s ease;
}

.site-nav__link:hover,
.site-nav__link:focus {
  color: var(--pku-red);
  background: var(--pku-tint);
  text-decoration: none;
  outline: none;
}

.site-nav__link[aria-current="page"] {
  color: var(--white);
  background: var(--pku-red);
}

.page-heading {
  margin: 2.4rem 1rem 0.7rem;
  color: #382b2d;
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 500;
  text-align: center;
}

.profile-meta {
  max-width: 780px;
  margin: 0 auto 1.6rem;
  padding: 0 1.25rem;
  color: var(--muted);
  text-align: center;
}

.section-heading {
  margin-top: 1.75rem;
  scroll-margin-top: 6rem;
}

.content-page {
  max-width: 1050px;
  margin: 0 auto;
  padding: 1.25rem 1.5rem 3.5rem;
}

.content-page__intro {
  max-width: 760px;
  margin: 0 auto 2rem;
  color: var(--muted);
  text-align: center;
}

.publication-list,
.talk-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.publication,
.talk-item {
  margin-bottom: 0.85rem;
  padding: 1rem 1.1rem;
  background: var(--white);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  border-radius: 0.6rem;
  box-shadow: 0 3px 12px rgba(71, 48, 51, 0.05);
}

.publication p,
.talk-item p {
  margin: 0.2rem 0;
}

.publication__number,
.talk-item__number {
  display: inline-block;
  min-width: 2.2rem;
  color: #65748b;
  font-weight: 700;
}

.talk-item__date {
  display: inline-block;
  min-width: 9.5rem;
  color: var(--pku-red-dark);
  font-weight: 700;
}

.content-section {
  margin-top: 2.5rem;
}

.talks-page {
  max-width: 1120px;
}

.talks-page .content-page__intro {
  margin-bottom: 1.25rem;
}

.talks-page .content-section {
  margin-top: 1.5rem;
}

.talks-page h2 {
  margin: 0 0 0.35rem;
  padding-bottom: 0.25rem;
  border-bottom: 1px solid var(--line);
  font-size: 1.5rem;
}

.talks-page .talk-item {
  display: grid;
  grid-template-columns: 2.4rem 12.5rem minmax(0, 1fr);
  column-gap: 0.75rem;
  align-items: baseline;
  margin: 0;
  padding: 0.55rem 0.25rem;
  background: transparent;
  border: 0;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  box-shadow: none;
  line-height: 1.45;
}

.talks-page .talk-item__number,
.talks-page .talk-item__date {
  min-width: 0;
}

.talks-page .talk-item__date {
  white-space: nowrap;
}

.talks-page .talk-item__details {
  padding-left: 0.75rem;
}

.conference-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1rem 0 2.25rem;
}

.conference-card {
  padding: 1.1rem 1.2rem;
  background: var(--white);
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  border-radius: 0.7rem;
  box-shadow: 0 4px 15px rgba(71, 48, 51, 0.06);
}

.conference-card h3 {
  margin-top: 0;
  font-size: 1.2rem;
  line-height: 1.35;
}

.conference-card p {
  margin-bottom: 0;
  color: #5e4a4c;
}

.seminar-gallery {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 0.65rem;
  margin: 1.75rem 0 1rem;
}

.seminar-gallery img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: 0.55rem;
  box-shadow: 0 4px 14px rgba(45, 35, 37, 0.12);
}

.container-fluid.border {
  max-width: 1120px;
  margin: 1.5rem auto 3rem;
  overflow: hidden;
  background: var(--white);
  border: 1px solid var(--line) !important;
  border-radius: 0.85rem;
  box-shadow: 0 6px 22px rgba(71, 48, 51, 0.06);
}

.container-fluid.border > .row > [class*="col"] {
  padding: 2.5rem 3rem;
  background: var(--white) !important;
}

.container-fluid.border h2:first-child {
  margin-top: 0;
}

center img {
  margin: 0.75rem 0 1.25rem;
  border-radius: 0.65rem;
  box-shadow: 0 5px 18px rgba(45, 35, 37, 0.12);
}

img {
  max-width: 100%;
  height: auto;
}

@media (max-width: 860px) {
  .site-nav {
    position: static;
  }

  .site-nav__inner {
    display: block;
    padding: 0.75rem 1rem;
  }

  .site-nav__home {
    display: block;
    margin-bottom: 0.5rem;
    text-align: center;
  }

  .site-nav__links {
    justify-content: center;
  }

  .site-nav__link {
    text-align: center;
  }

  .talk-item__date {
    display: block;
    min-width: 0;
    margin-bottom: 0.3rem;
  }

  .talks-page .talk-item {
    grid-template-columns: 2.2rem minmax(0, 1fr);
  }

  .talks-page .talk-item__date {
    margin-bottom: 0;
    white-space: normal;
  }

  .talks-page .talk-item__details {
    grid-column: 2;
    padding-left: 0;
  }

  [class*="col"] {
    width: 100% !important;
  }

  .container-fluid.border {
    margin: 1rem;
  }

  .container-fluid.border > .row > [class*="col"] {
    padding: 1.6rem;
  }

  .seminar-gallery {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

}

@media (max-width: 560px) {
  .site-nav__links {
    display: grid;
    grid-template-columns: 1fr 1fr;
    width: 100%;
  }

  .site-nav__link {
    padding: 0.65rem 0.4rem;
  }

  .seminar-gallery {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}