/* APL - Aerospace Propulsion Laboratory  |  dark tech theme */
:root {
  --bg: #070b14;
  --bg-2: #0c1220;
  --surface: #111a2b;
  --surface-2: #17223a;
  --line: rgba(148, 170, 205, .16);
  --text: #e8eef8;
  --text-2: #a9b6cc;
  --muted: #7a889f;
  --accent: #4fa3ff;
  --accent-2: #7cc4ff;
  --accent-glow: rgba(79, 163, 255, .35);
  --amber: #ffb547;
  --max: 1200px;
  --radius: 14px;
  --font: "Inter", "Pretendard", "Noto Sans KR", "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif;
  --mono: "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, monospace;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text); font-family: var(--font); font-size: 16px; line-height: 1.7; -webkit-font-smoothing: antialiased; }
body::before { content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background:
    radial-gradient(900px 500px at 15% -10%, rgba(79,163,255,.14), transparent 60%),
    radial-gradient(700px 400px at 100% 10%, rgba(124,196,255,.08), transparent 60%),
    linear-gradient(rgba(255,255,255,.025) 1px, transparent 1px) 0 0 / 100% 56px,
    linear-gradient(90deg, rgba(255,255,255,.025) 1px, transparent 1px) 0 0 / 56px 100%; }
img { max-width: 100%; height: auto; }
a { color: var(--accent-2); text-decoration: none; }
a:hover { color: #fff; }
h1, h2, h3, h4 { color: #fff; line-height: 1.25; margin: 0 0 .5em; letter-spacing: -.01em; }
h2 { font-size: 1.7rem; margin-top: 2.2rem; }
h3 { font-size: 1.25rem; margin-top: 1.6rem; }
h4 { font-size: 1.05rem; }
p { margin: 0 0 1em; }
hr { border: 0; border-top: 1px solid var(--line); margin: 1.8rem 0; }
strong { color: #fff; }
blockquote { margin: 1.5rem 0; padding: 14px 20px; border-left: 3px solid var(--amber); background: var(--surface); color: var(--text-2); border-radius: 0 8px 8px 0; }
.container { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 10px; top: 10px; background: #fff; color: #000; padding: 8px; z-index: 999; }
.eyebrow { display: inline-block; font-family: var(--mono); font-size: .75rem; letter-spacing: .18em; text-transform: uppercase; color: var(--accent); margin-bottom: 10px; }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; margin-bottom: 24px; flex-wrap: wrap; }
.section-head h2 { margin: 0; font-size: 1.9rem; }
.section-head a { font-size: .95rem; color: var(--text-2); }
.section-head a:hover { color: #fff; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 100; background: rgba(7,11,20,.72); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); border-bottom: 1px solid var(--line); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-logo { height: 40px; width: auto; display: block; filter: invert(1) brightness(1.4); }
.nav-list, .sub-list { list-style: none; margin: 0; padding: 0; }
.nav-list { display: flex; gap: 4px; }
.nav-item { position: relative; }
.nav-item > a { display: block; padding: 24px 16px; font-weight: 600; font-size: .95rem; color: var(--text-2); letter-spacing: .01em; }
.nav-item > a:hover, .nav-item.active > a { color: #fff; }
.nav-item.active > a::after { content: ""; position: absolute; left: 16px; right: 16px; bottom: 18px; height: 2px; background: var(--accent); border-radius: 2px; box-shadow: 0 0 10px var(--accent-glow); }
.sub-toggle { display: none; }
.sub-list { position: absolute; left: 8px; top: calc(100% - 10px); min-width: 230px; padding: 8px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; box-shadow: 0 20px 40px rgba(0,0,0,.45); opacity: 0; visibility: hidden; transform: translateY(8px); transition: .18s; }
.nav-item:hover .sub-list, .nav-item:focus-within .sub-list { opacity: 1; visibility: visible; transform: none; }
.sub-list li a { display: block; padding: 9px 14px; border-radius: 8px; color: var(--text-2); font-size: .93rem; }
.sub-list li a:hover, .sub-list li.current a { background: rgba(79,163,255,.12); color: #fff; }
.nav-toggle { display: none; background: none; border: 0; width: 44px; height: 44px; padding: 8px; cursor: pointer; }
.nav-toggle span { display: block; height: 2px; background: #fff; margin: 7px 0; border-radius: 2px; }
@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .site-nav { display: none; position: absolute; left: 0; right: 0; top: 72px; background: rgba(7,11,20,.97); border-bottom: 1px solid var(--line); max-height: calc(100vh - 72px); overflow: auto; }
  .site-nav.open { display: block; }
  .nav-list { flex-direction: column; gap: 0; padding: 8px 0; }
  .nav-item > a { padding: 14px 24px; }
  .nav-item.active > a::after { display: none; }
  .sub-toggle { display: block; position: absolute; right: 12px; top: 8px; width: 40px; height: 40px; border: 0; background: none; cursor: pointer; }
  .sub-toggle::after { content: ""; display: block; width: 9px; height: 9px; border-right: 2px solid var(--text-2); border-bottom: 2px solid var(--text-2); transform: rotate(45deg); margin: 10px auto; transition: .15s; }
  .nav-item.sub-open .sub-toggle::after { transform: rotate(-135deg); margin-top: 16px; }
  .sub-list { position: static; display: none; opacity: 1; visibility: visible; transform: none; border: 0; box-shadow: none; background: transparent; padding: 0 0 8px; }
  .nav-item.sub-open .sub-list { display: block; }
  .sub-list li a { padding-left: 40px; }
}

/* Page head */
.page-head { position: relative; padding: 64px 0 48px; margin-bottom: 44px; border-bottom: 1px solid var(--line); background: linear-gradient(180deg, rgba(79,163,255,.08), transparent); }
.page-head h1 { margin: 0; font-size: 2.6rem; font-weight: 800; }
.page-head .subtitle { margin: 8px 0 0; color: var(--text-2); font-size: 1.05rem; }
.page-head .crumb { font-family: var(--mono); font-size: .72rem; letter-spacing: .16em; text-transform: uppercase; color: var(--accent); margin-bottom: 12px; }
.site-main { min-height: 60vh; padding-bottom: 80px; }

/* ---------- HOME ---------- */
.hero { position: relative; min-height: 100vh; display: grid; align-items: end; overflow: hidden; border-bottom: 1px solid var(--line); }
.hero-media { position: absolute; inset: 0; }
.hero-media .slide { position: absolute; inset: 0; opacity: 0; transition: opacity 1.2s ease; }
.hero-media .slide.on { opacity: 1; }
.hero-media img, .hero-media video { width: 100%; height: 100%; object-fit: cover; display: block; }
.hero-media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, rgba(7,11,20,.72) 0%, rgba(7,11,20,.35) 45%, rgba(7,11,20,0) 75%), linear-gradient(180deg, rgba(7,11,20,.35) 0%, rgba(7,11,20,0) 30%, rgba(7,11,20,.25) 65%, rgba(7,11,20,.95) 100%); }
.hero-media .slide.on img, .hero-media .slide.on video { animation: kenburns 9s ease-out forwards; }
@keyframes kenburns { from { transform: scale(1.06); } to { transform: scale(1); } }
.hero-content { position: relative; z-index: 2; padding: 120px 24px 110px; max-width: var(--max); margin: 0 auto; width: 100%; }
.hero-content .eyebrow { color: var(--accent-2); }
.hero-content h1 { text-shadow: 0 4px 30px rgba(0,0,0,.6); font-size: clamp(2.4rem, 6vw, 4.6rem); font-weight: 800; line-height: 1.05; letter-spacing: -.02em; margin: 0 0 18px; max-width: 14ch; }
.hero-content h1 span { color: var(--accent-2); }
.hero-content p.lead { text-shadow: 0 2px 16px rgba(0,0,0,.7); font-size: 1.15rem; color: #dfe7f3; max-width: 58ch; margin: 0 0 30px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 22px; border-radius: 999px; font-weight: 600; font-size: .95rem; border: 1px solid transparent; transition: .15s; }
.btn-primary { background: var(--accent); color: #051022 !important; box-shadow: 0 0 0 0 var(--accent-glow); }
.btn-primary:hover { background: var(--accent-2); box-shadow: 0 0 24px var(--accent-glow); }
.btn-ghost { border-color: rgba(255,255,255,.28); color: #fff !important; background: rgba(255,255,255,.04); }
.btn-ghost:hover { border-color: #fff; background: rgba(255,255,255,.1); }
.hero-controls { position: absolute; right: 24px; bottom: 28px; z-index: 3; display: flex; align-items: center; gap: 10px; }
.hero-controls .dot { width: 8px; height: 8px; border-radius: 50%; border: 0; padding: 0; background: rgba(255,255,255,.35); cursor: pointer; transition: .2s; }
.hero-controls .dot.on { background: var(--accent-2); width: 22px; border-radius: 4px; }
.hero-controls .prev, .hero-controls .next { width: 36px; height: 36px; border-radius: 50%; border: 1px solid rgba(255,255,255,.3); background: rgba(7,11,20,.4); color: #fff; cursor: pointer; font-size: 1.1rem; }
.hero-caption { position: absolute; left: 24px; bottom: 34px; z-index: 3; font-family: var(--mono); font-size: .72rem; letter-spacing: .12em; color: var(--text-2); text-transform: uppercase; }
@media (max-width: 800px) { .hero { min-height: 78vh; } .hero-caption { display: none; } .hero-content { padding: 90px 20px 80px; } }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; margin: -36px auto 0; position: relative; z-index: 4; max-width: var(--max); width: calc(100% - 48px); }
.stats div { background: var(--surface); padding: 22px 24px; }
.stats b { display: block; font-size: 2rem; font-weight: 800; color: #fff; font-family: var(--mono); letter-spacing: -.02em; }
.stats span { color: var(--muted); font-size: .85rem; }
@media (max-width: 800px) { .stats { grid-template-columns: repeat(2, 1fr); width: calc(100% - 40px); } }

.home-section { padding: 88px 0 0; }
.area-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
@media (max-width: 1000px) { .area-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .area-grid { grid-template-columns: 1fr; } }
.area-card { position: relative; display: block; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); background: var(--surface); min-height: 340px; color: #fff; }
.area-card img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; opacity: .55; transition: transform .6s ease, opacity .3s; }
.area-card:hover img { transform: scale(1.06); opacity: .7; }
.area-card::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, rgba(7,11,20,.1), rgba(7,11,20,.92) 70%); }
.area-card .body { position: absolute; left: 0; right: 0; bottom: 0; z-index: 2; padding: 22px; }
.area-card .idx { font-family: var(--mono); font-size: .72rem; color: var(--accent-2); letter-spacing: .14em; }
.area-card h3 { margin: 6px 0 8px; font-size: 1.25rem; color: #fff; }
.area-card p { margin: 0; color: var(--text-2); font-size: .9rem; line-height: 1.55; }

.home-cols { display: grid; grid-template-columns: 1.5fr 1fr; gap: 40px; align-items: start; }
@media (max-width: 900px) { .home-cols { grid-template-columns: 1fr; } }
.news-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 12px; }
.news-list li a { display: grid; grid-template-columns: 96px 1fr auto; gap: 16px; align-items: center; padding: 10px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); color: var(--text); transition: .15s; }
.news-list li a:hover { border-color: rgba(79,163,255,.5); background: var(--surface-2); }
.news-list .thumb { width: 96px; height: 64px; border-radius: 8px; object-fit: cover; background: var(--bg-2); }
.news-list .t { font-weight: 600; }
.news-list time { color: var(--muted); font-family: var(--mono); font-size: .78rem; white-space: nowrap; }
@media (max-width: 560px) { .news-list li a { grid-template-columns: 1fr auto; } .news-list .thumb { display: none; } }
.notice-card { border: 1px solid rgba(255,181,71,.35); background: linear-gradient(180deg, rgba(255,181,71,.08), rgba(255,181,71,.02)); border-radius: var(--radius); padding: 24px; }
.notice-card .eyebrow { color: var(--amber); }
.notice-card p { color: var(--text-2); }
.pub-mini { display: grid; gap: 12px; }
.pub-mini a { display: grid; grid-template-columns: 1fr 120px; gap: 14px; padding: 14px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); color: var(--text); transition: .15s; }
.pub-mini a:hover { border-color: rgba(79,163,255,.5); }
.pub-mini .t { font-weight: 600; font-size: .95rem; line-height: 1.45; }
.pub-mini .c { color: var(--muted); font-size: .82rem; margin-top: 4px; }
.pub-mini img { width: 120px; height: 80px; object-fit: cover; border-radius: 8px; background: #fff; }
.cta { margin: 96px 0 0; padding: 56px; border-radius: var(--radius); border: 1px solid var(--line); background: radial-gradient(600px 300px at 0% 0%, rgba(79,163,255,.22), transparent 60%), var(--surface); display: flex; justify-content: space-between; align-items: center; gap: 28px; flex-wrap: wrap; }
.cta h2 { margin: 0 0 8px; font-size: 1.8rem; }
.cta p { margin: 0; color: var(--text-2); max-width: 60ch; }

/* Member cards */
.member-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px; }
.member-card { border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--surface); display: flex; flex-direction: column; transition: .15s; }
.member-card:hover { border-color: rgba(79,163,255,.5); transform: translateY(-2px); }
.member-card .photo { aspect-ratio: 4 / 4.6; background: var(--bg-2); overflow: hidden; }
.member-card .photo img { width: 100%; height: 100%; object-fit: cover; object-position: top; display: block; }
.member-card .body { padding: 16px 18px 18px; }
.member-card .role { font-family: var(--mono); font-size: .7rem; color: var(--accent); letter-spacing: .14em; text-transform: uppercase; margin: 0 0 6px; }
.member-card .name { font-size: 1.15rem; margin: 0; }
.member-card .name-en { margin: 0 0 8px; color: var(--text-2); font-size: .9rem; }
.member-card ul { margin: 6px 0 0; padding-left: 16px; font-size: .88rem; color: var(--text-2); }
.member-card ul li { margin: 2px 0; }
.member-card .email { font-size: .82rem; color: var(--muted); margin: 0; word-break: break-all; font-family: var(--mono); }

/* PI */
.pi-grid { display: grid; grid-template-columns: 320px 1fr; gap: 48px; align-items: start; }
@media (max-width: 800px) { .pi-grid { grid-template-columns: 1fr; } .pi-grid .pi-photo { max-width: 320px; } }
.pi-photo img { border-radius: var(--radius); width: 100%; border: 1px solid var(--line); }
.pi-head .role { font-family: var(--mono); font-size: .75rem; letter-spacing: .16em; color: var(--accent); margin: 0; }
.pi-head h2 { margin: 4px 0 6px; font-size: 2rem; }
.pi-contact { color: var(--muted); margin: 0 0 20px; font-family: var(--mono); font-size: .85rem; }
.pi-body ul { padding-left: 20px; color: var(--text-2); }
.pi-body ul ul { padding-left: 20px; }
.pi-body li { margin: 3px 0; }
.pi-body p strong { color: #fff; }
.pi-body hr + p strong { display: inline-block; font-size: 1.05rem; padding-bottom: 6px; border-bottom: 2px solid var(--accent); }

/* Publications */
.pub-list { list-style: none; margin: 0; padding: 0; }
.pub-item { display: grid; grid-template-columns: 1fr 190px; gap: 24px; padding: 20px 0; border-bottom: 1px solid var(--line); align-items: center; }
@media (max-width: 700px) { .pub-item { grid-template-columns: 1fr; } .pub-item .thumb { order: -1; max-width: 240px; } }
.pub-item .title { font-size: 1.05rem; font-weight: 600; margin: 0 0 6px; line-height: 1.45; }
.pub-item .title a { color: #fff; }
.pub-item .title a:hover { color: var(--accent-2); }
.pub-item .cite { margin: 0; color: var(--text-2); font-size: .92rem; }
.pub-item .thumb img { width: 100%; border-radius: 10px; background: #fff; border: 1px solid var(--line); }
.year-head { position: sticky; top: 72px; z-index: 5; margin: 40px 0 0; padding: 10px 0; background: var(--bg); font-family: var(--mono); font-size: 1.1rem; color: var(--accent-2); border-bottom: 1px solid var(--line); }

/* Research */
.research-block { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; align-items: center; padding: 44px 0; border-bottom: 1px solid var(--line); }
.research-block:last-child { border-bottom: 0; }
@media (max-width: 800px) { .research-block { grid-template-columns: 1fr; } }
.research-block h2 { margin-top: 0; font-size: 1.7rem; }
.research-block ul { padding-left: 20px; color: var(--text-2); }
.research-block li { margin: 4px 0; }
.fig-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-items: start; }
.fig-grid.one { grid-template-columns: 1fr; }
.fig-grid img { width: 100%; max-height: 400px; object-fit: contain; border-radius: 10px; background: #fff; border: 1px solid var(--line); }
.gallery { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 14px; margin: 18px 0 36px; }
.gallery img { width: 100%; border-radius: 10px; border: 1px solid var(--line); }
.spec { margin: 0 0 16px; padding-left: 0; list-style: none; color: var(--text-2); }
.spec li { padding: 7px 0; border-bottom: 1px dashed var(--line); }
.project-list { padding-left: 0; list-style: none; margin: 0 0 32px; }
.project-list li { padding: 14px 0; border-bottom: 1px solid var(--line); display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.project-list .pname { font-weight: 600; color: #fff; }
.project-list .pmeta { color: var(--muted); font-family: var(--mono); font-size: .82rem; white-space: nowrap; }
.table { width: 100%; border-collapse: collapse; margin: 12px 0 28px; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.table th, .table td { border-bottom: 1px solid var(--line); padding: 12px 14px; text-align: left; vertical-align: top; color: var(--text-2); }
.table th { background: var(--surface); color: #fff; font-family: var(--mono); font-size: .8rem; letter-spacing: .1em; text-transform: uppercase; }
.table strong { color: #fff; }

/* Board */
.board-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(270px, 1fr)); gap: 20px; }
.board-card { border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; background: var(--surface); transition: .15s; }
.board-card:hover { border-color: rgba(79,163,255,.5); transform: translateY(-2px); }
.board-card .thumb { display: block; aspect-ratio: 780 / 550; background: var(--bg-2); overflow: hidden; }
.board-card .thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.board-card .body { padding: 14px 16px 16px; }
.board-card .body a { color: #fff; font-weight: 600; display: block; line-height: 1.45; }
.board-card time { color: var(--muted); font-family: var(--mono); font-size: .78rem; }
.post-meta { color: var(--muted); font-family: var(--mono); font-size: .85rem; margin: -20px 0 28px; }
.post-body { max-width: 900px; }
.post-body p { color: var(--text-2); }
.post-body img { display: block; margin: 18px auto; max-width: 100%; border-radius: 12px; border: 1px solid var(--line); }
.post-body .video { position: relative; padding-top: 56.25%; margin: 16px 0; border-radius: 12px; overflow: hidden; }
.post-body .video iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.post-nav { display: flex; justify-content: space-between; gap: 16px; margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--line); flex-wrap: wrap; align-items: center; }
.post-nav a { font-size: .92rem; color: var(--text-2); }
.post-nav a.btn { color: #fff !important; }

/* Directions / misc */
.contact-list { list-style: none; padding: 0; }
.contact-list li { padding: 10px 0; border-bottom: 1px dashed var(--line); color: var(--text-2); }
.contact-list strong { color: #fff; }
.apl-intro { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
@media (max-width: 800px) { .apl-intro { grid-template-columns: 1fr; } }
.apl-intro .logo-box { padding: 40px; background: #fff; border-radius: var(--radius); }
.apl-intro p, .apl-intro li { color: var(--text-2); }

/* Footer */
.site-footer { border-top: 1px solid var(--line); background: var(--bg-2); color: var(--text-2); padding: 48px 0 32px; margin-top: 80px; position: relative; font-size: .92rem; }
.footer-inner { display: grid; grid-template-columns: 1.2fr 1fr; gap: 32px; align-items: end; }
@media (max-width: 800px) { .footer-inner { grid-template-columns: 1fr; } }
.footer-brand img { height: 36px; filter: invert(1) brightness(1.4); margin-bottom: 14px; }
.footer-links { display: flex; gap: 20px; flex-wrap: wrap; margin-bottom: 8px; }
.footer-links a { color: #fff; font-weight: 600; }
.footer-addr { margin: 0 0 6px; }
.footer-copy { margin: 0; color: var(--muted); font-family: var(--mono); font-size: .72rem; letter-spacing: .06em; }
.to-top { position: fixed; right: 20px; bottom: 20px; width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center; background: var(--accent); color: #051022 !important; font-family: var(--mono); font-size: .7rem; font-weight: 700; opacity: 0; transition: .2s; pointer-events: none; box-shadow: 0 8px 24px rgba(0,0,0,.4); }
.to-top.show { opacity: 1; pointer-events: auto; }