/* ========================================
   BLAST Lab – Main Stylesheet
   ======================================== */

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

:root {
  --primary:      #0d1b2a;
  --accent:       #2563eb;
  --accent-light: #dbeafe;
  --accent-dark:  #1d4ed8;
  --text:         #1e293b;
  --text-muted:   #64748b;
  --bg:           #ffffff;
  --bg-alt:       #f8fafc;
  --border:       #e2e8f0;
  --max-w:        1080px;
  --nav-h:        64px;
  --radius:       8px;
  --shadow:       0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
  --shadow-md:    0 4px 6px -1px rgba(0,0,0,.10), 0 2px 4px -1px rgba(0,0,0,.06);
  --shadow-lg:    0 10px 15px -3px rgba(0,0,0,.10), 0 4px 6px -2px rgba(0,0,0,.05);
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }
button { cursor: pointer; font-family: inherit; }

/* ── Typography ── */
h1 { font-size: clamp(2rem, 5vw, 3rem); font-weight: 800; line-height: 1.15; letter-spacing: -0.03em; }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 700; line-height: 1.25; letter-spacing: -0.02em; }
h3 { font-size: 1.2rem; font-weight: 700; line-height: 1.35; }
h4 { font-size: 1rem; font-weight: 600; }
p  { line-height: 1.75; }

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

/* ── Section ── */
.section { padding: 88px 0; }
.section-alt { background: var(--bg-alt); }

.section-title {
  text-align: center;
  margin-bottom: 56px;
}
.section-title h2 { color: var(--primary); }
.section-title p {
  color: var(--text-muted);
  margin-top: 10px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
  font-size: 1.05rem;
}
.section-title .divider {
  width: 40px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
  margin: 14px auto 0;
}

/* ── Navigation ── */
.nav {
  position: fixed;
  top: 0;
  width: 100%;
  height: var(--nav-h);
  background: rgba(255,255,255);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 900;
}

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

.nav__logo {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav__logo .blast { color: var(--accent); }

.nav__links {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav__links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 6px 14px;
  border-radius: 6px;
  transition: color .15s, background .15s;
}
.nav__links a:hover,
.nav__links a.active {
  color: var(--accent);
  background: var(--accent-light);
}

.nav__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  border: none;
  background: none;
  padding: 6px;
  border-radius: 6px;
}
.nav__hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: .2s;
}
.nav__hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__hamburger.open span:nth-child(2) { opacity: 0; }
.nav__hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Mobile Nav ── */
.nav-mobile {
  display: none;
  position: fixed;
  top: var(--nav-h);
  left: 0;
  right: 0;
  background: white;
  border-bottom: 1px solid var(--border);
  z-index: 899;
  padding: 8px 16px 16px;
  box-shadow: var(--shadow-md);
}
.nav-mobile.open { display: block; }
.nav-mobile a {
  display: block;
  padding: 11px 12px;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  border-radius: 6px;
  transition: background .15s;
}
.nav-mobile a:hover,
.nav-mobile a.active { background: var(--accent-light); color: var(--accent); }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  transition: .15s;
  border: none;
  white-space: nowrap;
}
.btn-primary { background: var(--accent); color: white; }
.btn-primary:hover { background: var(--accent-dark); }
.btn-ghost {
  background: transparent;
  color: white;
  border: 1.5px solid rgba(255,255,255,.35);
}
.btn-ghost:hover { background: rgba(255,255,255,.1); border-color: white; }
.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1.5px solid var(--accent);
}
.btn-outline:hover { background: var(--accent-light); }

/* ── Hero ── */
.hero {
  padding-top: calc(var(--nav-h) + 96px);
  padding-bottom: 96px;
  background: linear-gradient(145deg, #0a1628 0%, #0d1b2a 40%, #11264b 70%, #152e5c 100%);
  color: white;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(37,99,235,.18) 0%, transparent 70%);
  top: -100px;
  right: -100px;
  pointer-events: none;
}
.hero::after {
  content: '';
  position: absolute;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(37,99,235,.12) 0%, transparent 70%);
  bottom: -80px;
  left: 50px;
  pointer-events: none;
}
.hero__inner { position: relative; z-index: 1; }

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(37,99,235,.2);
  border: 1px solid rgba(37,99,235,.4);
  color: #93c5fd;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
  padding: 5px 14px;
  border-radius: 100px;
  margin-bottom: 28px;
}
.hero h1 {
  color: white;
  max-width: 840px;
  margin: 0 auto 8px;
}
.hero__abbr {
  color: #60a5fa;
  font-style: italic;
}
.hero__affil {
  font-size: 1rem;
  color: rgba(255,255,255,.55);
  margin-bottom: 20px;
  font-weight: 400;
}
.hero__desc {
  font-size: 1.1rem;
  color: rgba(255,255,255,.75);
  max-width: 600px;
  margin: 0 auto 36px;
  line-height: 1.7;
}
.hero__btns {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero__stats {
  display: flex;
  gap: 48px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 72px;
  padding-top: 40px;
  border-top: 1px solid rgba(255,255,255,.1);
}
.hero__stat { text-align: center; }
.hero__stat-num {
  font-size: 2.25rem;
  font-weight: 800;
  color: white;
  line-height: 1;
}
.hero__stat-num span { color: #60a5fa; }
.hero__stat-label {
  font-size: 0.8rem;
  color: rgba(255,255,255,.5);
  margin-top: 5px;
  text-transform: uppercase;
  letter-spacing: .06em;
}

/* ── Cards ── */
.card {
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: box-shadow .2s, transform .2s;
}
.card:hover { box-shadow: var(--shadow-md); transform: translateY(-3px); }

/* ── Grid ── */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }

/* ── Research Card ── */
.research-card { padding: 28px 24px; }
.research-icon {
  width: 52px; height: 52px;
  border-radius: 12px;
  background: var(--accent-light);
  color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 18px;
}
.research-card h3 { margin-bottom: 8px; color: var(--primary); }
.research-card p { font-size: 0.9rem; color: var(--text-muted); }
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; }
.tag {
  font-size: 0.72rem;
  padding: 3px 10px;
  border-radius: 100px;
  background: var(--bg-alt);
  color: var(--text-muted);
  border: 1px solid var(--border);
  font-weight: 500;
}

/* ── News ── */
.news-list { display: flex; flex-direction: column; gap: 12px; }
.news-item {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  padding: 20px 24px;
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: box-shadow .15s;
}
.news-item:hover { box-shadow: var(--shadow); }
.news-item__date {
  flex-shrink: 0;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  background: var(--bg-alt);
  padding: 5px 12px;
  border-radius: 6px;
  white-space: nowrap;
  border: 1px solid var(--border);
}
.news-item__badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: .05em;
  margin-bottom: 5px;
}
.badge-paper  { background: #dbeafe; color: #1d4ed8; }
.badge-award  { background: #fef9c3; color: #854d0e; }
.badge-grant  { background: #dcfce7; color: #15803d; }
.badge-conf   { background: #f3e8ff; color: #6d28d9; }
.badge-news   { background: #f1f5f9; color: #475569; }
.news-item__title { font-weight: 600; font-size: 0.95rem; margin-bottom: 3px; }
.news-item__body p { font-size: 0.88rem; color: var(--text-muted); margin: 0; }

/* ── Page Header ── */
.page-header {
  padding-top: calc(var(--nav-h) + 30px);
  padding-bottom: 30px;
  background: linear-gradient(145deg, #0a1628 0%, #0d1b2a 50%, #11264b 100%);
  color: white;
  text-align: center;
}
.page-header h1 { color: white; font-size: clamp(1.75rem, 4vw, 2.5rem); }
.page-header p {
  color: rgba(255,255,255,.65);
  margin-top: 10px;
  font-size: 1rem;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* ── Breadcrumb ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  color: rgba(255,255,255,.45);
  justify-content: center;
  margin-bottom: 16px;
}
.breadcrumb a { color: rgba(255,255,255,.6); }
.breadcrumb a:hover { color: white; }
.breadcrumb i { font-size: 0.65rem; }

/* ── Professor Card ── */
.professor-wrap {
  display: flex;
  gap: 36px;
  align-items: flex-start;
  padding: 36px;
}
.professor-photo {
  width: 200px;
  height: 250px;
  flex-shrink: 0;
  border-radius: 12px;
  background: var(--bg-alt);
  border: 2px solid var(--border);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  color: var(--text-muted);
  object-fit: cover;
}
.professor-photo img { width: 100%; height: 100%; object-fit: cover; }
.professor-name { font-size: 1.6rem; font-weight: 800; color: var(--primary); letter-spacing: -0.02em; }
.professor-title { font-size: 0.95rem; color: var(--accent); font-weight: 600; margin: 4px 0 14px; }
.professor-bio { font-size: 0.95rem; color: var(--text-muted); line-height: 1.7; max-width: 1000px; }
.professor-interests {
  margin-top: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.professor-links {
  display: flex;
  gap: 14px;
  margin-top: 18px;
  flex-wrap: wrap;
}
.prof-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 6px;
  border: 1px solid var(--accent-light);
  background: var(--accent-light);
  transition: .15s;
}
.prof-link:hover { background: var(--accent); color: white; }

/* ── Member Card ── */
.member-card {
  text-align: center;
  padding: 28px 10px;
}
.member-photo {
  width: 90px; height: 90px;
  border-radius: 50%;
  background: var(--bg-alt);
  border: 2px solid var(--border);
  margin: 0 auto 14px;
  overflow: hidden;
  display: flex; align-items: center; justify-content: center;
  font-size: 2rem;
  color: var(--text-muted);
}
.member-photo img { width: 100%; height: 100%; object-fit: cover; }
.member-name { font-size: 0.95rem; font-weight: 700; color: var(--primary); margin-bottom: 3px; }
.member-role { font-size: 0.8rem; color: var(--accent); font-weight: 600; margin-bottom: 8px; }
.member-info { font-size: 0.82rem; color: var(--text-muted); line-height: 1.5; }

/* ── Sub-section title ── */
.sub-heading {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--primary);
  padding-bottom: 12px;
  border-bottom: 2px solid var(--border);
  margin-bottom: 28px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.sub-heading::before {
  content: '';
  display: block;
  width: 4px;
  height: 18px;
  background: var(--accent);
  border-radius: 2px;
}

/* ── Publication Tabs ── */
.pub-tabs {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--border);
  margin-bottom: 36px;
}
.pub-tab {
  padding: 12px 28px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  border: none;
  background: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: .15s;
  white-space: nowrap;
}
.pub-tab:hover { color: var(--accent); }
.pub-tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.pub-panel { display: none; }
.pub-panel.active { display: block; }

.pub-list { display: flex; flex-direction: column; gap: 14px; }
.pub-item {
  padding: 20px 24px;
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  border-left: 3px solid var(--accent);
  transition: box-shadow .15s;
}
.pub-item:hover { box-shadow: var(--shadow); }
.pub-item__title { font-weight: 600; font-size: 0.97rem; margin-bottom: 5px; color: var(--primary); }
.pub-item__authors { font-size: 0.88rem; color: var(--text-muted); margin-bottom: 4px; }
.pub-item__venue { font-size: 0.85rem; color: var(--text); font-style: italic; }
.pub-item__links { display: flex; gap: 10px; margin-top: 10px; }
.pub-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--accent);
  padding: 3px 10px;
  border: 1px solid var(--accent-light);
  border-radius: 4px;
  background: var(--accent-light);
  transition: .15s;
}
.pub-link:hover { background: var(--accent); color: white; }

.pub-year-group { margin-bottom: 32px; }
.pub-year-label {
  font-size: 1rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.pub-year-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

/* ── Join Us ── */
.join-card {
  padding: 28px 32px;
  border-left: 4px solid var(--accent);
}
.join-card h3 { color: var(--primary); margin-bottom: 14px; font-size: 1.1rem; }
.join-card ul {
  padding-left: 18px;
  list-style: disc;
  color: var(--text-muted);
  line-height: 1.9;
  font-size: 0.9rem;
}

.contact-card { padding: 28px 32px; }
.contact-row {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}
.contact-row:last-child { border-bottom: none; }
.contact-icon {
  width: 36px; height: 36px;
  border-radius: 8px;
  background: var(--accent-light);
  color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.9rem;
  flex-shrink: 0;
}
.contact-label { font-size: 0.75rem; color: var(--text-muted); font-weight: 600; text-transform: uppercase; letter-spacing: .06em; margin-bottom: 3px; }
.contact-value { font-size: 0.95rem; font-weight: 500; }
.contact-value a { color: var(--accent); }
.contact-value a:hover { text-decoration: underline; }

/* ── Footer ── */
.footer {
  background: var(--primary);
  color: rgba(255,255,255,.65);
  padding: 52px 0 32px;
}
.footer__inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
}
.footer__brand { max-width: 320px; }
.footer__logo { font-size: 1.1rem; font-weight: 800; color: white; margin-bottom: 10px; }
.footer__logo .blast { color: #60a5fa; }
.footer__desc { font-size: 0.85rem; line-height: 1.65; }
.footer__nav h4 { font-size: 0.8rem; text-transform: uppercase; letter-spacing: .08em; color: rgba(255,255,255,.4); margin-bottom: 14px; font-weight: 600; }
.footer__nav ul { display: flex; flex-direction: column; gap: 8px; }
.footer__nav a { font-size: 0.88rem; transition: color .15s; }
.footer__nav a:hover { color: white; }
.footer__bottom {
  max-width: var(--max-w);
  margin: 32px auto 0;
  padding: 20px 24px 0;
  border-top: 1px solid rgba(255,255,255,.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 0.8rem;
  color: rgba(255,255,255,.35);
}

/* ── About strip on Home ── */
.about-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-top: 40px;
}
.about-strip__item {
  background: white;
  padding: 28px 24px;
  display: flex;
  align-items: flex-start;
  gap: 16px;
}
.about-strip__icon {
  width: 44px; height: 44px;
  border-radius: 10px;
  background: var(--accent-light);
  color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}
.about-strip__item h4 { font-size: 0.95rem; color: var(--primary); margin-bottom: 4px; }
.about-strip__item p { font-size: 0.84rem; color: var(--text-muted); line-height: 1.55; }

/* ── View All link ── */
.view-all {
  text-align: center;
  margin-top: 36px;
}
.view-all a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent);
  padding: 9px 20px;
  border: 1.5px solid var(--accent-light);
  border-radius: var(--radius);
  background: var(--accent-light);
  transition: .15s;
}
.view-all a:hover { background: var(--accent); color: white; border-color: var(--accent); }

/* ── Responsive ── */
@media (max-width: 900px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .about-strip { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .nav__links { display: none; }
  .nav__hamburger { display: flex; }
  .pub-tabs { overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .section { padding: 60px 0; }
  .professor-wrap { flex-direction: column; align-items: center; text-align: center; padding: 24px; }
  .professor-links { justify-content: center; }
  .professor-interests { justify-content: center; }
  .footer__inner { flex-direction: column; gap: 28px; }
  .footer__bottom { flex-direction: column; align-items: flex-start; }
  .hero { padding-top: calc(var(--nav-h) + 56px); padding-bottom: 56px; }
  .hero__stats { gap: 28px; margin-top: 48px; }
}

@media (max-width: 580px) {
  .grid-3 { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .news-item { flex-direction: column; gap: 8px; }
}