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

:root {
  --primary: #1a3a5c;
  --primary-light: #2c5f8a;
  --accent: #3387a2;
  --accent-light: #e8f4f8;
  --text: #2a2a2a;
  --text-light: #5a5a5a;
  --bg: #ffffff;
  --bg-subtle: #f7f8fa;
  --border: #e2e5e9;
  --radius: 8px;
  --max-width: 1080px;
  --nav-height: 64px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--primary-light);
}

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

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
}

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

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--primary);
  text-decoration: none;
}

.nav-logo img {
  height: 36px;
  width: auto;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 4px;
  align-items: center;
}

.nav-links li {
  position: relative;
}

.nav-links > li > a {
  display: block;
  padding: 8px 16px;
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: var(--radius);
  transition: background 0.2s, color 0.2s;
  text-decoration: none;
}

.nav-links > li > a:hover,
.nav-links > li > a.active {
  background: var(--accent-light);
  color: var(--primary);
}

/* Dropdown */
.dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 180px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  padding: 6px;
  z-index: 200;
}

.nav-links li:hover .dropdown-menu {
  display: block;
}

.dropdown-menu a {
  display: block;
  padding: 8px 14px;
  color: var(--text);
  font-size: 0.85rem;
  border-radius: 6px;
  text-decoration: none;
}

.dropdown-menu a:hover {
  background: var(--accent-light);
  color: var(--primary);
}

/* Language toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 7px;
  margin-left: 14px;
  padding-left: 14px;
  border-left: 1px solid var(--border);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}
.lang-toggle .lang-link {
  color: var(--text-light);
  text-decoration: none;
  padding: 4px 6px;
  border-radius: 4px;
  transition: color 0.2s, background 0.2s;
}
.lang-toggle .lang-link:hover {
  color: var(--primary);
  background: var(--accent-light);
}
.lang-toggle .lang-active {
  color: var(--primary);
  padding: 4px 6px;
}
.lang-toggle .lang-sep {
  color: var(--border);
}

/* Mobile menu */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  margin: 5px 0;
  border-radius: 2px;
  transition: 0.3s;
}

/* ===== Layout ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.page-body {
  padding-top: var(--nav-height);
}

/* ===== Hero (Home) ===== */
.hero {
  position: relative;
  height: 520px;
  overflow: hidden;
  background: var(--primary);
}

.hero-slideshow {
  position: absolute;
  inset: 0;
}

.hero-slideshow img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity 1.2s ease;
}

.hero-slideshow img.active {
  opacity: 1;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(26,58,92,0.3) 0%, rgba(26,58,92,0.65) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.hero-content {
  color: #fff;
  padding: 24px;
}

.hero-content h1 {
  font-size: 2.4rem;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
  text-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

.hero-content p {
  font-size: 1.1rem;
  opacity: 0.9;
  margin-bottom: 28px;
}

/* ===== Page Header ===== */
.page-header {
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border);
  padding: 48px 0 40px;
}

.page-header h1 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.02em;
}

.page-header p {
  margin-top: 8px;
  color: var(--text-light);
  font-size: 1rem;
}

/* ===== Affiliation Banner ===== */
.affiliation-banner {
  background: var(--accent-light);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
}

.affiliation-banner p {
  text-align: center;
  font-size: 0.95rem;
  color: var(--primary);
  line-height: 1.6;
}

.affiliation-banner a {
  color: var(--primary);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.affiliation-banner a:hover {
  color: var(--accent);
}

/* ===== Sections ===== */
.section {
  padding: 64px 0;
}

.section + .section {
  border-top: 1px solid var(--border);
}

.section-alt {
  background: var(--bg-subtle);
}

.section h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 20px;
  letter-spacing: -0.01em;
}

.section h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 12px;
}

.section p {
  color: var(--text-light);
  line-height: 1.8;
}

.section p + p {
  margin-top: 12px;
}

/* ===== Button ===== */
.btn {
  display: inline-block;
  padding: 12px 32px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s;
  text-decoration: none;
}

.btn:hover {
  background: var(--primary-light);
  color: #fff;
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #fff;
}

.btn-white {
  background: #fff;
  color: var(--primary);
}

.btn-white:hover {
  background: #f0f0f0;
  color: var(--primary);
}

/* ===== Cards ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin-top: 24px;
}

.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: box-shadow 0.2s, transform 0.15s;
}

.card:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,0.06);
  transform: translateY(-2px);
}

.card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 8px;
}

.card p {
  font-size: 0.9rem;
  color: var(--text-light);
}

/* ===== Table ===== */
.table-wrap {
  overflow-x: auto;
  margin-top: 20px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

thead {
  background: var(--primary);
  color: #fff;
}

th {
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  white-space: nowrap;
}

td {
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

tbody tr:last-child td {
  border-bottom: none;
}

tbody tr:nth-child(even) {
  background: var(--bg-subtle);
}

tbody tr:hover {
  background: var(--accent-light);
}

/* ===== Activity item ===== */
.activity-item {
  margin-bottom: 48px;
}

.activity-item h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--accent);
  display: inline-block;
}

.activity-item p {
  max-width: 780px;
}

.activity-item img {
  margin-top: 20px;
  border-radius: var(--radius);
  max-height: 400px;
  object-fit: cover;
}

/* ===== Gallery grid ===== */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 20px;
}

.gallery-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: box-shadow 0.2s, transform 0.15s;
  text-decoration: none;
  color: var(--text);
}

.gallery-item:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
  transform: translateY(-1px);
  color: var(--primary);
}

.gallery-item .icon {
  font-size: 1.4rem;
  flex-shrink: 0;
}

.gallery-item .label {
  font-weight: 500;
  font-size: 0.9rem;
}

/* ===== Webzine list ===== */
.webzine-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.webzine-list li a {
  display: block;
  padding: 14px 20px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 0.92rem;
  transition: all 0.2s;
}

.webzine-list li a:hover {
  border-color: var(--accent);
  background: var(--accent-light);
}

/* ===== Timeline ===== */
.timeline {
  position: relative;
  padding-left: 36px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border);
}

.timeline-year {
  position: relative;
  margin-bottom: 40px;
}

.timeline-year:last-child {
  margin-bottom: 0;
}

.timeline-year-label {
  position: relative;
  display: inline-block;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 16px;
  padding: 4px 16px;
  background: var(--accent-light);
  border-radius: 20px;
}

.timeline-year-label::before {
  content: '';
  position: absolute;
  left: -32px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  background: var(--accent);
  border: 3px solid var(--bg);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--accent);
}

.timeline-events {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.timeline-event {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  transition: box-shadow 0.2s;
}

.timeline-event:hover {
  box-shadow: 0 2px 12px rgba(0,0,0,0.05);
}

.timeline-event-title {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text);
  margin-bottom: 4px;
}

.timeline-event-desc {
  font-size: 0.85rem;
  color: var(--text-light);
  line-height: 1.6;
}

@media (max-width: 768px) {
  .timeline {
    padding-left: 28px;
  }
  .timeline-year-label::before {
    left: -24px;
    width: 10px;
    height: 10px;
  }
}

/* ===== Colloquium ===== */
.colloquium-list {
  margin-top: 20px;
}

.colloquium-item {
  display: flex;
  gap: 20px;
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}

.colloquium-item:last-child {
  border-bottom: none;
}

.colloquium-num {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
}

.colloquium-body {
  flex: 1;
}

.colloquium-body .date {
  font-size: 0.82rem;
  color: var(--text-light);
  margin-bottom: 4px;
}

.colloquium-body .speaker {
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 4px;
}

.colloquium-body .title {
  font-size: 0.9rem;
  color: var(--text-light);
  font-style: italic;
}

/* ===== Join page ===== */
.join-reasons {
  list-style: none;
  margin: 20px 0 32px;
}

.join-reasons li {
  padding: 8px 0;
  padding-left: 24px;
  position: relative;
  color: var(--text-light);
}

.join-reasons li::before {
  content: ">";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

/* ===== Contact form ===== */
.contact-form {
  max-width: 560px;
  margin-top: 24px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 6px;
  color: var(--text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.95rem;
  font-family: inherit;
  transition: border-color 0.2s;
  background: var(--bg);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(51,135,162,0.1);
}

.form-group textarea {
  min-height: 140px;
  resize: vertical;
}

/* ===== Image with caption ===== */
.img-frame {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 24px 0;
}

.img-frame img {
  width: 100%;
}

/* ===== Photo grid ===== */
.photo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
  margin-top: 20px;
}

.photo-grid img {
  border-radius: var(--radius);
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
}

/* ===== Footer ===== */
.footer {
  background: var(--primary);
  color: rgba(255,255,255,0.7);
  padding: 40px 0;
  margin-top: 0;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer a {
  color: rgba(255,255,255,0.85);
}

.footer a:hover {
  color: #fff;
}

.footer-logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: #fff;
}

.footer-links {
  display: flex;
  list-style: none;
  gap: 20px;
  font-size: 0.85rem;
}

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

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 12px 24px;
    gap: 0;
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links > li > a {
    padding: 12px 0;
  }

  .dropdown-menu {
    position: static;
    box-shadow: none;
    border: none;
    padding: 0 0 0 16px;
    display: none;
  }

  .nav-links li:hover .dropdown-menu,
  .nav-links li.open .dropdown-menu {
    display: block;
  }

  .lang-toggle {
    margin-left: 0;
    padding: 12px 0;
    border-left: none;
    border-top: 1px solid var(--border);
    margin-top: 8px;
    justify-content: flex-start;
  }

  .hero {
    height: 380px;
  }

  .hero-content h1 {
    font-size: 1.6rem;
  }

  .page-header {
    padding: 32px 0 28px;
  }

  .page-header h1 {
    font-size: 1.5rem;
  }

  .section {
    padding: 40px 0;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }

  .colloquium-item {
    flex-direction: column;
    gap: 8px;
  }
}