/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Lato', Verdana, Helvetica, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: #333;
  background: #fff;
}

a { color: #1772d0; text-decoration: none; }
a:hover { color: #f09228; }

/* ===== LAYOUT ===== */
.container {
  max-width: 850px;
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 48px 0; }
section.alt-bg { background: #f9f9f9; }

h2 {
  font-size: 22px;
  font-weight: 700;
  color: #333;
  margin-bottom: 16px;
}

/* ===== NAV ===== */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 50px;
  background: #fff;
  border-bottom: 1px solid #e8e8e8;
  z-index: 100;
}

.nav-inner {
  max-width: 850px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-name {
  font-weight: 700;
  font-size: 15px;
  color: #333;
}

.nav-links a {
  margin-left: 24px;
  font-size: 14px;
  font-weight: 700;
  color: #555;
}

.nav-links a:hover { color: #1772d0; }

/* ===== ABOUT ===== */
#about { padding-top: 90px; } /* offset for fixed nav */

.about-grid {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 36px;
  align-items: start;
}

.about-photo img {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  display: block;
}

.about-text h1 {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 4px;
}

.about-title {
  color: #666;
  font-size: 14px;
  margin-bottom: 12px;
}

.about-text p { margin-bottom: 10px; }

.about-links { margin-top: 4px; }

/* ===== TOGGLE BAR ===== */
.toggle-bar {
  margin-bottom: 24px;
  display: flex;
  gap: 20px;
}

.toggle-btn {
  font-size: 14px;
  font-weight: 400;
  color: #888;
  padding-bottom: 3px;
  border-bottom: 2px solid transparent;
  transition: all 0.15s;
}

.toggle-btn.active {
  color: #1772d0;
  font-weight: 700;
  border-bottom: 2px solid #1772d0;
}

.toggle-btn:hover { color: #1772d0; }

/* ===== RESEARCH PAPERS ===== */
.paper-row {
  display: flex;
  gap: 20px;
  padding: 20px 0;
  border-bottom: 1px solid #eee;
}

.paper-row:last-child { border-bottom: none; }

.paper-img {
  flex-shrink: 0;
  width: 160px;
}

.paper-img img {
  width: 160px;
  height: 120px;
  object-fit: cover;
  border-radius: 4px;
  border: 1px solid #e8e8e8;
}

.paper-info { flex: 1; }

.paper-title {
  font-weight: 700;
  font-size: 14px;
  margin-bottom: 4px;
}

.paper-authors {
  font-size: 13px;
  color: #555;
  margin-bottom: 2px;
}

.paper-venue {
  font-size: 13px;
  color: #777;
  margin-bottom: 6px;
}

.paper-links {
  font-size: 13px;
  margin-bottom: 6px;
}

.paper-desc {
  font-size: 13px;
  color: #555;
}

/* ===== PROJECTS ===== */
.project-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.project-card {
  border: 1px solid #e8e8e8;
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
}

.project-card-img img {
  width: 100%;
  height: 140px;
  object-fit: cover;
  display: block;
}

.project-card-placeholder {
  width: 100%;
  height: 140px;
  background: #f0f0f0;
}

.project-card-body { padding: 14px; }

.project-card-body h3 {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 6px;
}

.project-card-body p {
  font-size: 13px;
  color: #555;
  margin-bottom: 4px;
}

.project-meta { color: #888 !important; font-size: 12px !important; }

/* ===== FOOTER ===== */
footer {
  background: #f9f9f9;
  border-top: 1px solid #e8e8e8;
  padding: 24px 0;
  text-align: center;
  font-size: 13px;
  color: #888;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 680px) {
  .about-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .about-photo { display: flex; justify-content: center; }
  .about-links { text-align: center; }
  .project-grid { grid-template-columns: 1fr; }
  .paper-row { flex-direction: column; }
  .paper-img { width: 100%; }
  .paper-img img { width: 100%; height: auto; }
}

@media (max-width: 900px) and (min-width: 681px) {
  .project-grid { grid-template-columns: repeat(2, 1fr); }
}