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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: #1a1a1a;
  background: #fff;
  line-height: 1.7;
}

a {
  color: #2563eb;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* ===== Layout ===== */
.wrapper {
  display: flex;
  min-height: 100vh;
}

/* ===== Sidebar ===== */
.sidebar {
  width: 280px;
  background: #fafafa;
  border-right: 1px solid #e5e5e5;
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2.5rem 1.5rem;
}

.profile-photo {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid #e5e5e5;
  margin-bottom: 1.2rem;
  background: #e5e5e5;
}

.profile-name {
  font-size: 1.4rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.2rem;
}

.profile-name-kr {
  font-size: 1rem;
  color: #666;
  text-align: center;
  margin-bottom: 0.3rem;
}

.profile-title {
  font-size: 0.9rem;
  color: #555;
  text-align: center;
  margin-bottom: 0.1rem;
}

.profile-affiliation {
  font-size: 0.85rem;
  color: #777;
  text-align: center;
  margin-bottom: 1.5rem;
}

/* Nav */
.sidebar nav {
  width: 100%;
}

.sidebar nav ul {
  list-style: none;
}

.sidebar nav ul li {
  margin-bottom: 0.2rem;
}

.sidebar nav ul li a {
  display: block;
  padding: 0.5rem 1rem;
  color: #333;
  font-size: 0.95rem;
  border-radius: 6px;
  transition: background 0.15s;
}

.sidebar nav ul li a:hover,
.sidebar nav ul li a.active {
  background: #e8efff;
  color: #2563eb;
  text-decoration: none;
}

/* Social links */
.social-links {
  margin-top: auto;
  padding-top: 1.5rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

.social-links a {
  color: #555;
  font-size: 0.8rem;
  transition: color 0.15s;
}

.social-links a:hover {
  color: #2563eb;
}

/* ===== Main Content ===== */
.main {
  margin-left: 280px;
  padding: 3rem 3.5rem;
  max-width: 900px;
  flex: 1;
}

/* ===== Sections ===== */
section {
  margin-bottom: 3rem;
}

section h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: #111;
  border-bottom: 2px solid #2563eb;
  padding-bottom: 0.4rem;
  margin-bottom: 1.2rem;
}

section h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: #333;
  margin-top: 1.2rem;
  margin-bottom: 0.6rem;
}

/* About */
.about p {
  margin-bottom: 0.8rem;
}

.interests {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.8rem;
}

.interest-tag {
  background: #eef2ff;
  color: #3b5bdb;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.4rem 1.2rem;
  font-size: 0.95rem;
}

.contact-grid dt {
  font-weight: 600;
  color: #555;
}

.contact-grid dd {
  color: #333;
}

/* Timeline items (Education, Positions) */
.timeline-item {
  padding-left: 1.2rem;
  border-left: 2px solid #e5e5e5;
  margin-bottom: 1.2rem;
  position: relative;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -5px;
  top: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #2563eb;
}

.timeline-item .org {
  font-weight: 600;
  font-size: 1rem;
}

.timeline-item .role {
  color: #555;
  font-size: 0.95rem;
}

.timeline-item .period {
  color: #888;
  font-size: 0.85rem;
}

/* Publications */
.pub-category {
  margin-bottom: 2rem;
}

.pub-item {
  margin-bottom: 1.2rem;
  padding-left: 0.5rem;
}

.pub-id {
  font-weight: 700;
  color: #2563eb;
  margin-right: 0.3rem;
  font-size: 0.9rem;
}

.pub-title {
  font-weight: 600;
  color: #111;
}

.pub-authors {
  font-size: 0.9rem;
  color: #555;
  margin-top: 0.15rem;
}

.pub-authors .me {
  font-weight: 700;
  color: #1a1a1a;
}

.pub-venue {
  font-size: 0.9rem;
  color: #666;
  font-style: italic;
}

.pub-links {
  margin-top: 0.3rem;
}

.pub-links a {
  font-size: 0.8rem;
  margin-right: 0.8rem;
  color: #2563eb;
}

.pub-year {
  font-size: 0.85rem;
  color: #888;
}

/* Patents */
.patent-item {
  margin-bottom: 1rem;
  padding-left: 0.5rem;
}

.patent-id {
  font-family: monospace;
  font-size: 0.85rem;
  color: #888;
}

.patent-title {
  font-weight: 600;
}

.patent-inventors {
  font-size: 0.9rem;
  color: #555;
}

/* Awards */
.award-item {
  margin-bottom: 0.8rem;
  padding-left: 0.5rem;
}

.award-name {
  font-weight: 600;
}

.award-detail {
  font-size: 0.9rem;
  color: #555;
}

/* Software */
.software-item {
  margin-bottom: 1.2rem;
  padding-left: 0.5rem;
}

.software-name {
  font-weight: 600;
  font-size: 1.05rem;
}

.software-desc {
  font-size: 0.9rem;
  color: #555;
  margin-top: 0.2rem;
}

.software-links {
  margin-top: 0.3rem;
}

.software-links a {
  font-size: 0.85rem;
  margin-right: 1rem;
}

/* ===== Mobile Nav Toggle ===== */
.nav-toggle {
  display: none;
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 1000;
  background: #fff;
  border: 1px solid #ddd;
  border-radius: 6px;
  padding: 0.5rem 0.8rem;
  cursor: pointer;
  font-size: 1.2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    z-index: 999;
    width: 260px;
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .main {
    margin-left: 0;
    padding: 4rem 1.5rem 2rem;
  }
}

@media (max-width: 480px) {
  .main {
    padding: 4rem 1rem 2rem;
  }

  section h2 {
    font-size: 1.3rem;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }
}

/* ===== Footer ===== */
footer {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid #e5e5e5;
  font-size: 0.8rem;
  color: #999;
  text-align: center;
}