/* ====== Top Navigation Bar ====== */
.top-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin: -2em 0 1.6em 0;
  padding: 0.5em 0;
  border-bottom: 1px solid #e5e5e5;
  position: sticky;
  top: 0;
  background: #fff;
  z-index: 50;
}

.top-nav a {
  font-size: 0.95rem;
  font-weight: 500;
  color: #043361;
  padding: 0.4em 0.9em;
  margin-right: 0.2em;
  border-radius: 4px;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease;
}

.top-nav a:hover {
  background: #043361;
  color: #fff;
}

@media (prefers-color-scheme: dark) {
  .top-nav {
    background: #20212b;
    border-bottom: 1px solid #2f3140;
  }
  .top-nav a {
    color: #3eb7f0;
  }
  .top-nav a:hover {
    background: #3eb7f0;
    color: #20212b;
  }
}

/* ====== Research Interest Cards ====== */
.interest-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 10px;
  margin: 0 0 20px 0;
}

.interest-card {
  border: 1px solid #e5e5e5;
  border-radius: 8px;
  padding: 14px 12px;
  text-align: center;
  font-size: 0.92rem;
  font-weight: 500;
  color: #043361;
  background: #fafbfc;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.interest-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(4, 51, 97, 0.12);
}

.interest-card .icon {
  display: block;
  font-size: 1.5rem;
  margin-bottom: 6px;
}

@media (prefers-color-scheme: dark) {
  .interest-card {
    background: #262834;
    border-color: #2f3140;
    color: #3eb7f0;
  }
  .interest-card:hover {
    box-shadow: 0 4px 10px rgba(62, 183, 240, 0.18);
  }
}

/* ====== Project Cards ====== */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
  margin: 0 0 24px 0;
}

.project-card {
  border: 1px solid #e5e5e5;
  border-left: 4px solid #043361;
  border-radius: 6px;
  padding: 14px 16px;
  background: #fafbfc;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.project-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(4, 51, 97, 0.12);
}

.project-card h4 {
  margin: 0 0 6px 0 !important;
  font-size: 1rem;
  color: #043361;
}

.project-card p {
  margin: 0 !important;
  font-size: 0.88rem;
  color: #555;
  line-height: 1.45;
}

.project-card .tag {
  display: inline-block;
  font-size: 0.7rem;
  background: #043361;
  color: #fff;
  padding: 2px 8px;
  border-radius: 10px;
  margin-bottom: 6px;
}

@media (prefers-color-scheme: dark) {
  .project-card {
    background: #262834;
    border-color: #2f3140;
    border-left-color: #3eb7f0;
  }
  .project-card h4 { color: #3eb7f0; }
  .project-card p { color: #b8bac4; }
  .project-card .tag { background: #3eb7f0; color: #20212b; }
}

/* ====== News Timeline ====== */
.timeline {
  position: relative;
  margin: 0 0 24px 0;
  padding-left: 22px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: #e5e5e5;
}

.timeline-item {
  position: relative;
  margin-bottom: 14px;
  font-size: 0.95rem;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -22px;
  top: 6px;
  width: 12px;
  height: 12px;
  background: #043361;
  border: 2px solid #fff;
  border-radius: 50%;
  box-shadow: 0 0 0 1px #043361;
}

.timeline-date {
  font-weight: 600;
  color: #043361;
  margin-right: 6px;
}

@media (prefers-color-scheme: dark) {
  .timeline::before { background: #2f3140; }
  .timeline-item::before {
    background: #3eb7f0;
    border-color: #20212b;
    box-shadow: 0 0 0 1px #3eb7f0;
  }
  .timeline-date { color: #3eb7f0; }
}

/* ====== Publication Filter Buttons ====== */
.pub-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 8px 0 16px 0;
}

.pub-filter button {
  font-size: 0.85rem;
  font-weight: 500;
  padding: 4px 12px;
  border: 1px solid #043361;
  background: transparent;
  color: #043361;
  border-radius: 14px;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
  font-family: inherit;
}

.pub-filter button:hover,
.pub-filter button.active {
  background: #043361;
  color: #fff;
}

@media (prefers-color-scheme: dark) {
  .pub-filter button {
    border-color: #3eb7f0;
    color: #3eb7f0;
  }
  .pub-filter button:hover,
  .pub-filter button.active {
    background: #3eb7f0;
    color: #20212b;
  }
}

.pub-item.hidden { display: none; }

/* ====== Blog list ====== */
.blog-list { list-style: none; padding: 0; margin: 0; }
.blog-list li {
  padding: 12px 0;
  border-bottom: 1px solid #eee;
}
.blog-list .post-date {
  font-size: 0.85rem;
  color: #888;
  margin-right: 10px;
}
.blog-list .post-title {
  font-size: 1.05rem;
  font-weight: 500;
}
@media (prefers-color-scheme: dark) {
  .blog-list li { border-bottom-color: #2f3140; }
  .blog-list .post-date { color: #b8bac4; }
}