/* ==========================================================================
   SPEL — Soft Photonics & Electro-optics Lab, Hanyang University ERICA
   Shared stylesheet — light, minimal (ref: flexlab.korea.ac.kr feel)
   ========================================================================== */

:root {
  --ink: #191d26;
  --ink-soft: #454c5e;
  --muted: #7a8194;
  --bg: #ffffff;
  --bg-soft: #f6f7fa;
  --line: #e7e9f0;
  --navy: #101527;
  --accent: #3452e0;
  --spectrum: linear-gradient(90deg, #7b2ff7, #2f80ed, #00c48c, #f5a623, #f0304a);
  --radius: 16px;
  --shadow: 0 8px 32px rgba(20, 24, 40, 0.08);
  --maxw: 1280px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", "Pretendard", -apple-system, "Segoe UI", "Malgun Gothic", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  word-break: keep-all;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* --------------------------------------------------------------------------
   Header — white, minimal, dropdown nav
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.brand { display: flex; align-items: center; gap: 12px; }
.brand img { height: 36px; width: auto; }
.brand .brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand .brand-text strong { color: var(--ink); font-size: 1.05rem; letter-spacing: 0.2em; font-weight: 800; }
.brand .brand-text span { color: var(--muted); font-size: 0.6rem; letter-spacing: 0.05em; }

.nav { display: flex; align-items: center; gap: 2px; }

.nav > .nav-item { position: relative; }

.nav a.top-link,
.nav .nav-item > button {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: var(--ink-soft);
  font-size: 0.93rem;
  font-weight: 600;
  padding: 9px 14px;
  border-radius: 9px;
  border: 0;
  background: none;
  cursor: pointer;
  font-family: inherit;
  transition: color 0.15s, background 0.15s;
}
.nav a.top-link:hover,
.nav .nav-item > button:hover { color: var(--ink); background: var(--bg-soft); }
.nav a.top-link.active { color: var(--accent); }

.nav .nav-item > a .caret {
  font-size: 0.6rem;
  transform: translateY(1px);
}

.dropdown {
  position: absolute;
  top: 100%;
  left: 8px;
  min-width: 185px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: var(--shadow);
  padding: 8px;
  display: none;
  z-index: 50;
}
.nav-item:hover .dropdown,
.nav-item:focus-within .dropdown { display: block; }
.dropdown a {
  display: block;
  padding: 9px 12px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--ink-soft);
}
.dropdown a:hover { background: var(--bg-soft); color: var(--ink); }

.nav-toggle {
  display: none;
  background: none; border: 0;
  width: 42px; height: 42px;
  cursor: pointer;
  position: relative;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  content: "";
  position: absolute;
  left: 9px;
  width: 24px; height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}
.nav-toggle span { top: 20px; }
.nav-toggle span::before { left: 0; top: -7px; }
.nav-toggle span::after { left: 0; top: 7px; }

/* --------------------------------------------------------------------------
   Hero (home) — light, centered, spectral accent
   -------------------------------------------------------------------------- */
.hero {
  position: relative;
  text-align: center;
  padding: 110px 0 84px;
  background:
    radial-gradient(720px 340px at 50% -140px, rgba(47, 128, 237, 0.09), transparent 65%),
    linear-gradient(180deg, #fbfbfd 0%, #ffffff 100%);
  overflow: hidden;
}

.hero .logo-wave { height: 72px; margin: 0 auto 26px; width: auto; }

.hero h1 {
  font-size: clamp(2.1rem, 4.8vw, 3.4rem);
  font-weight: 800;
  letter-spacing: 0.28em;
  text-indent: 0.28em;
  line-height: 1.15;
}

.hero .sub {
  margin-top: 10px;
  font-size: clamp(1rem, 2vw, 1.3rem);
  font-weight: 600;
  color: var(--ink-soft);
  letter-spacing: 0.01em;
}

.hero .lede {
  margin: 22px auto 0;
  max-width: 660px;
  font-size: 1rem;
  color: var(--muted);
}

.hero .lede-kr {
  margin-top: 8px;
  font-size: 0.92rem;
  color: var(--muted);
}

.hero .spectral-bar {
  width: 120px; height: 5px;
  border-radius: 4px;
  background: var(--spectrum);
  margin: 30px auto 0;
}

.hero .cta-row { margin-top: 34px; display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: 11px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.18s, box-shadow 0.18s, background 0.18s, color 0.18s;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: var(--ink);
  color: #fff;
  box-shadow: 0 6px 22px rgba(20, 24, 40, 0.18);
}
.btn-primary:hover { background: #000; }
.btn-ghost {
  border: 1px solid var(--line);
  color: var(--ink-soft);
  background: #fff;
}
.btn-ghost:hover { border-color: var(--ink-soft); color: var(--ink); }

/* --------------------------------------------------------------------------
   Sections
   -------------------------------------------------------------------------- */
.section { padding: 84px 0; }
.section.alt { background: var(--bg-soft); }

.section-head { margin-bottom: 44px; }
.section-head.center { text-align: center; }
.section-head .kicker {
  display: inline-block;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin-bottom: 12px;
  background: var(--spectrum);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.section-head h2 {
  font-size: clamp(1.6rem, 3.2vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.015em;
  line-height: 1.2;
}
.section-head p { margin-top: 12px; color: var(--muted); font-size: 1rem; max-width: 680px; }
.section-head.center p { margin-left: auto; margin-right: auto; }

.more-link {
  display: inline-block;
  margin-top: 26px;
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--accent);
}
.more-link:hover { text-decoration: underline; }

/* --------------------------------------------------------------------------
   Research category / cards
   -------------------------------------------------------------------------- */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.cat-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.22s ease, box-shadow 0.22s ease;
  display: flex;
  flex-direction: column;
}
.card:hover { transform: translateY(-5px); box-shadow: var(--shadow); }

.card .thumb {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--bg-soft);
}
.card .thumb img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.35s ease;
}
.card:hover .thumb img { transform: scale(1.04); }

.card .body { padding: 20px 22px 24px; flex: 1; }
.card .cat {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  padding: 4px 12px;
  border-radius: 999px;
  color: var(--ink-soft);
  background: var(--bg-soft);
  border: 1px solid var(--line);
}
.card h3 { margin-top: 6px; font-size: 1.05rem; font-weight: 700; line-height: 1.35; }
.card h3 .kr { display: block; font-size: 0.8rem; font-weight: 500; color: var(--muted); margin-top: 3px; }
.card p { margin-top: 9px; font-size: 0.9rem; color: var(--muted); }

/* --------------------------------------------------------------------------
   Research page — grouped feature rows
   -------------------------------------------------------------------------- */
.group-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin: 84px 0 8px;
  padding-bottom: 16px;
  border-bottom: 3px solid var(--ink);
}
.group-head:first-of-type { margin-top: 0; }
.group-head h2 {
  font-size: clamp(1.7rem, 3.4vw, 2.1rem);
  font-weight: 800;
  letter-spacing: 0.12em;
  color: var(--ink);
  line-height: 1.15;
}
.group-head span { color: var(--muted); font-size: 0.95rem; font-weight: 600; }

.feature {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 52px;
  align-items: center;
  padding: 56px 0;
  border-bottom: 1px solid var(--line);
}
.feature:last-child { border-bottom: 0; }
.feature.flip .media { order: 2; }

.feature .media {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  width: fit-content;
  justify-self: center;
  align-self: center;
}
/* cap height so wide and near-square figures render at similar sizes,
   without cropping or letterboxing (frame hugs the image) */
.feature .media img {
  display: block;
  max-width: 100%;
  max-height: 400px;
  width: auto;
  height: auto;
}

.feature .num {
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  background: var(--spectrum);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.feature h3 { margin-top: 8px; font-size: 1.42rem; font-weight: 800; letter-spacing: -0.01em; line-height: 1.28; }
.feature .kr-sub { margin-top: 4px; color: var(--muted); font-size: 0.94rem; font-weight: 500; }
.feature p { margin-top: 14px; color: var(--ink-soft); font-size: 0.96rem; }
.feature .tags { margin-top: 16px; display: flex; flex-wrap: wrap; gap: 8px; }
.feature .tags li {
  font-size: 0.77rem;
  font-weight: 600;
  color: var(--ink-soft);
  background: var(--bg-soft);
  border: 1px solid var(--line);
  padding: 4px 12px;
  border-radius: 999px;
}

/* --------------------------------------------------------------------------
   Page hero (subpages) — light
   -------------------------------------------------------------------------- */
.page-hero {
  padding: 74px 0 56px;
  background: linear-gradient(180deg, #fbfbfd, #ffffff);
  border-bottom: 1px solid var(--line);
}
.page-hero .kicker {
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  background: var(--spectrum);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.page-hero h1 { margin-top: 10px; font-size: clamp(1.9rem, 4vw, 2.7rem); font-weight: 800; letter-spacing: -0.02em; }
.page-hero p { margin-top: 12px; max-width: 860px; color: var(--muted); }

/* --------------------------------------------------------------------------
   Cover gallery / carousel
   -------------------------------------------------------------------------- */
.cover-strip {
  display: flex;
  gap: 22px;
  overflow-x: auto;
  padding: 8px 4px 22px;
  scroll-snap-type: x mandatory;
}
.cover-strip::-webkit-scrollbar { height: 8px; }
.cover-strip::-webkit-scrollbar-thumb { background: var(--line); border-radius: 4px; }

.cover-item {
  flex: 0 0 210px;
  scroll-snap-align: start;
}
.cover-item .frame {
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  aspect-ratio: 3 / 4;
  background: var(--bg-soft);
  transition: transform 0.22s ease;
}
.cover-item:hover .frame { transform: translateY(-5px); }
.cover-item .frame img { width: 100%; height: 100%; object-fit: cover; }
.cover-item figcaption { margin-top: 10px; font-size: 0.82rem; color: var(--ink-soft); line-height: 1.4; }
.cover-item figcaption strong { display: block; color: var(--ink); font-size: 0.86rem; }

.cover-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 26px;
}
.cover-grid .cover-item { flex: none; }

/* --------------------------------------------------------------------------
   Publications
   -------------------------------------------------------------------------- */
.pub-year { margin: 46px 0 16px; display: flex; align-items: center; gap: 18px; }
.pub-year:first-of-type { margin-top: 0; }
.pub-year h2 { font-size: 1.4rem; font-weight: 800; }
.pub-year::after { content: ""; flex: 1; height: 1px; background: var(--line); }

.pub-list { display: flex; flex-direction: column; gap: 14px; }

.pub {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 13px;
  padding: 18px 22px;
  display: flex;
  gap: 16px;
  transition: box-shadow 0.18s, transform 0.18s;
}
.pub:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.pub .no {
  flex: 0 0 auto;
  font-weight: 800;
  font-size: 0.85rem;
  color: var(--muted);
  padding-top: 2px;
  min-width: 26px;
}
.pub .title { display: block; font-weight: 700; font-size: 0.98rem; line-height: 1.45; }
.pub a.title:hover { color: var(--accent); text-decoration: underline; }
a.badge:hover { text-decoration: underline; }
.pub .authors { margin-top: 5px; font-size: 0.86rem; color: var(--muted); }
.pub .authors .me { color: var(--ink); font-weight: 700; text-decoration: underline; text-underline-offset: 3px; }
.page-hero .me { font-weight: 700; text-decoration: underline; text-underline-offset: 3px; }
.pub .meta { margin-top: 7px; display: flex; flex-wrap: wrap; gap: 7px; align-items: center; }
.pub .journal { font-size: 0.86rem; font-style: italic; font-weight: 600; color: var(--accent); }
.pub .vol { font-size: 0.84rem; color: var(--muted); }
.badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 999px;
  letter-spacing: 0.02em;
}
.badge.cover { background: #fef3e2; color: #b45309; }
.badge.if { background: #eef2ff; color: #4338ca; }
.badge.jcr { background: #f0f9ff; color: #0369a1; }
.badge.award { background: #ecfdf5; color: #047857; }
.badge.invited { background: #fdf2f8; color: #be185d; }

/* Conference compact list */
.conf-list { display: flex; flex-direction: column; }
.conf {
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 12px;
  padding: 13px 4px;
  border-bottom: 1px solid var(--line);
  font-size: 0.9rem;
}
.conf .no { font-weight: 700; color: var(--muted); font-size: 0.82rem; padding-top: 2px; }
.conf .t { color: var(--ink-soft); }
.conf .t strong { color: var(--ink); font-weight: 600; }
.conf .t .me { color: var(--ink); font-weight: 700; text-decoration: underline; text-underline-offset: 3px; }
.conf .venue { color: var(--muted); font-size: 0.84rem; }

/* --------------------------------------------------------------------------
   People
   -------------------------------------------------------------------------- */
.pi-card {
  display: grid;
  grid-template-columns: 255px 1fr;
  gap: 44px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 38px;
  box-shadow: var(--shadow);
}
.pi-photo {
  border-radius: 14px;
  background: linear-gradient(165deg, #eef0f6, #dfe3ee);
  aspect-ratio: 3 / 4;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: 0.85rem;
  overflow: hidden;
}
.pi-photo img { width: 100%; height: 100%; object-fit: cover; }
.pi-info h3 { font-size: 1.55rem; font-weight: 800; }
.pi-info h3 .kr { font-weight: 500; color: var(--muted); font-size: 1.25rem; }
.pi-info .role { margin-top: 3px; color: var(--accent); font-weight: 600; font-size: 0.94rem; }
.pi-info .contact-line { margin-top: 10px; font-size: 0.9rem; color: var(--ink-soft); }
.pi-info .pi-links { margin-top: 13px; display: flex; flex-wrap: wrap; gap: 8px; }
.pi-info .pi-links a {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--accent);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 5px 14px;
  transition: border-color 0.2s ease, background 0.2s ease;
}
.pi-info .pi-links a:hover { border-color: var(--accent); background: var(--bg-soft); }
.pi-info .bio { margin-top: 14px; color: var(--ink-soft); font-size: 0.95rem; }

.cv-block { margin-top: 24px; }
.cv-block h4 {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 9px;
}
.cv-block li {
  position: relative;
  padding-left: 17px;
  margin-bottom: 7px;
  font-size: 0.92rem;
  color: var(--ink-soft);
}
.cv-block li::before {
  content: "";
  position: absolute;
  left: 0; top: 9px;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--spectrum);
}
.cv-block li strong { color: var(--ink); }

.member-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}
.member {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 34px;
  display: flex;
  gap: 30px;
  align-items: center;
  transition: transform 0.2s, box-shadow 0.2s;
}
.member:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.member .photo {
  flex: 0 0 175px;
  width: 175px;
  aspect-ratio: 3 / 4;
  border-radius: 12px;
  overflow: hidden;
  background: #ffffff;
  border: 1px solid var(--line);
}
.member .photo img {
  width: 100%; height: 100%;
  object-fit: cover;
  object-position: center 30%;
}
.member .info { flex: 1; min-width: 0; }
.member h3 { font-size: 1.4rem; font-weight: 700; }
.member h3 .kr { font-weight: 500; color: var(--muted); font-size: 1.15rem; }
.member .role { margin-top: 5px; font-size: 1.02rem; font-weight: 600; color: var(--accent); }
.member .m-mail { margin-top: 4px; font-size: 0.92rem; }
.member .m-mail a { color: var(--muted); }
.member .m-mail a:hover { color: var(--accent); }
.member .ri-block { margin-top: 14px; }
.member .ri { display: block; font-weight: 700; color: var(--ink); font-size: 1rem; }
.member .ri-list { margin-top: 8px; display: flex; flex-direction: column; gap: 5px; }
.member .ri-list li {
  position: relative;
  padding-left: 15px;
  font-size: 0.96rem;
  color: var(--muted);
  line-height: 1.5;
}
.member .ri-list li::before {
  content: "";
  position: absolute;
  left: 1px; top: 0.55em;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--spectrum);
}

/* Alumni */
.alumni-list { display: flex; flex-direction: column; }
.alumni-row {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 18px;
  align-items: baseline;
  padding: 16px 4px;
  border-bottom: 1px solid var(--line);
}
.alumni-row:first-child { border-top: 1px solid var(--line); }
.alumni-row .name { font-weight: 700; font-size: 0.98rem; }
.alumni-row .name .kr { font-weight: 500; color: var(--muted); font-size: 0.9rem; }
.alumni-row .arole { font-size: 0.86rem; font-weight: 600; color: var(--accent); }
.alumni-row .period { font-size: 0.86rem; color: var(--muted); }
@media (max-width: 720px) {
  .alumni-row { grid-template-columns: 1fr; gap: 2px; }
}

/* --------------------------------------------------------------------------
   Gallery
   -------------------------------------------------------------------------- */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.g-item {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  background: #fff;
  transition: transform 0.22s ease, box-shadow 0.22s ease;
}
.g-item:hover { transform: translateY(-5px); box-shadow: var(--shadow); }
.g-item .pic {
  aspect-ratio: 4 / 3;
  overflow: hidden;
  background: var(--navy);
}
.g-item .pic img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.35s ease;
}
.g-item:hover .pic img { transform: scale(1.04); }
.g-item figcaption {
  padding: 14px 18px 16px;
  font-size: 0.86rem;
  color: var(--ink-soft);
  line-height: 1.45;
}
.g-item figcaption strong { display: block; color: var(--ink); font-size: 0.92rem; }
.g-item.placeholder {
  border-style: dashed;
  border-width: 2px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  aspect-ratio: 4 / 3.55;
  color: var(--muted);
  gap: 8px;
  text-align: center;
  padding: 20px;
}
.g-item.placeholder .big { font-size: 2rem; }
.g-item.placeholder:hover { transform: none; box-shadow: none; }

@media (max-width: 960px) { .gallery-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 720px) { .gallery-grid { grid-template-columns: 1fr; } }

/* --------------------------------------------------------------------------
   News
   -------------------------------------------------------------------------- */
.news-list { display: flex; flex-direction: column; }
.news-item {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 22px;
  padding: 18px 4px;
  border-bottom: 1px solid var(--line);
}
.news-item:first-child { border-top: 1px solid var(--line); }
.news-item .date { font-size: 0.86rem; font-weight: 700; color: var(--muted); }
.news-item .txt { font-size: 0.94rem; color: var(--ink-soft); }
.news-item .txt .tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 9px;
  border-radius: 999px;
  margin-right: 8px;
  vertical-align: 1px;
}
.tag.grant { background: #eef2ff; color: #4338ca; }
.tag.award { background: #ecfdf5; color: #047857; }
.tag.people { background: #fef3e2; color: #b45309; }
.tag.lab { background: #fdf2f8; color: #be185d; }

/* --------------------------------------------------------------------------
   Join / banner
   -------------------------------------------------------------------------- */
.join-banner {
  border-radius: var(--radius);
  background: var(--navy);
  color: #fff;
  padding: 52px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.join-banner::before {
  content: "";
  position: absolute;
  left: 0; right: 0; top: 0;
  height: 5px;
  background: var(--spectrum);
}
.join-banner h3 { font-size: 1.6rem; font-weight: 800; }
.join-banner p { margin-top: 12px; color: rgba(255,255,255,0.72); max-width: 560px; margin-left: auto; margin-right: auto; font-size: 0.96rem; }
.join-banner .btn { margin-top: 26px; background: #fff; color: var(--navy); }

.perk-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
.perk {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
}
.perk .ico {
  width: 44px; height: 44px;
  border-radius: 11px;
  background: var(--bg-soft);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 14px;
}
.perk h3 { font-size: 1rem; font-weight: 700; }
.perk p { margin-top: 7px; color: var(--muted); font-size: 0.88rem; }

.apply-box {
  margin-top: 48px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 36px 40px;
}
.apply-box h3 { font-size: 1.15rem; font-weight: 800; }
.apply-box p { margin-top: 10px; color: var(--ink-soft); font-size: 0.94rem; }
.apply-box .mail { font-weight: 700; color: var(--accent); }

/* Join — research topic quick links */
.topic-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px 20px;
}
.topic-list a {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 20px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 13px;
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.topic-list a:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.topic-list .no { font-weight: 800; font-size: 0.8rem; color: var(--accent); }
.topic-list .t strong { display: block; font-size: 0.94rem; font-weight: 700; }
.topic-list .t span { display: block; margin-top: 2px; color: var(--muted); font-size: 0.82rem; }

/* Join — detail bullets inside perk cards */
.perk ul { margin-top: 10px; display: flex; flex-direction: column; gap: 6px; }
.perk ul li {
  position: relative;
  padding-left: 15px;
  color: var(--muted);
  font-size: 0.88rem;
}
.perk ul li::before {
  content: "";
  position: absolute;
  left: 1px; top: 0.55em;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--accent);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background: var(--navy);
  color: rgba(255, 255, 255, 0.62);
  padding: 52px 0 38px;
}
.site-footer .top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 30px;
  flex-wrap: wrap;
  padding-bottom: 30px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}
.site-footer .f-brand img { height: 48px; }
.site-footer .f-logos { display: flex; align-items: center; gap: 16px; }
.site-footer .f-div { width: 1px; height: 34px; background: rgba(255, 255, 255, 0.22); }
.site-footer .f-brand img.f-seal { height: 52px; }
.site-footer .f-brand p { margin-top: 12px; font-size: 0.85rem; max-width: 300px; }
.site-footer .cols { display: flex; gap: 56px; flex-wrap: wrap; }
.site-footer .cols h4 { color: #fff; font-size: 0.83rem; margin-bottom: 11px; letter-spacing: 0.08em; }
.site-footer .cols a, .site-footer .cols span { display: block; font-size: 0.86rem; padding: 2px 0; }
.site-footer .cols a:hover { color: #fff; }
.site-footer .base {
  margin-top: 24px;
  font-size: 0.8rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}

/* --------------------------------------------------------------------------
   Reveal animation (JS-gated so content stays visible without JS)
   -------------------------------------------------------------------------- */
.js .reveal { opacity: 0; transform: translateY(22px); transition: opacity 0.65s ease, transform 0.65s ease; }
.js .reveal.in { opacity: 1; transform: none; }

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */
@media (max-width: 960px) {
  .cat-grid { grid-template-columns: repeat(2, 1fr); }
  .topic-list { grid-template-columns: 1fr; }
  .member-grid { grid-template-columns: 1fr; }
  .cover-grid { grid-template-columns: repeat(3, 1fr); }
  .perk-grid { grid-template-columns: 1fr; }
  .feature { grid-template-columns: 1fr; gap: 26px; }
  .feature.flip .media { order: 0; }
  .pi-card { grid-template-columns: 1fr; }
  .pi-photo { max-width: 255px; }
}

@media (max-width: 720px) {
  .nav {
    position: fixed;
    top: 70px; left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    background: #fff;
    padding: 12px 20px 20px;
    gap: 2px;
    display: none;
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
    max-height: calc(100vh - 70px);
    overflow-y: auto;
  }
  .nav.open { display: flex; }
  .nav-toggle { display: block; }
  .nav .nav-item > a.top-link { width: 100%; justify-content: space-between; }
  .dropdown {
    position: static;
    display: block;
    border: 0;
    box-shadow: none;
    padding: 0 0 4px 14px;
    min-width: 0;
  }
  .cat-grid { grid-template-columns: 1fr; }
  .member { flex-direction: row; gap: 18px; padding: 22px; }
  .member .photo { flex-basis: 110px; width: 110px; }
  .member h3 { font-size: 1.15rem; }
  .member p { font-size: 0.92rem; }
  .cover-grid { grid-template-columns: repeat(2, 1fr); }
  .hero { padding: 80px 0 64px; }
  .news-item { grid-template-columns: 1fr; gap: 4px; }
  .join-banner { padding: 38px 22px; }
  .apply-box { padding: 26px 22px; }
  .pub { flex-direction: column; gap: 6px; }
}