/* ==========================================================================
   CSP Lab website — base styles
   ========================================================================== */

:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f6f7fa;
  --color-bg-raised: #ffffff;
  --color-text: #191c24;
  --color-text-muted: #656b78;
  --color-text-faint: #8990a0;
  --color-border: #e6e8ee;
  --color-primary: #14318c;
  --color-primary-dark: #0b2266;
  --color-primary-light: #eaf0fd;
  --color-accent: #b8862e;
  --max-width: 1140px;
  --radius-sm: 8px;
  --radius: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 2px rgba(20, 30, 60, 0.05), 0 1px 1px rgba(20, 30, 60, 0.04);
  --shadow-md: 0 8px 24px rgba(20, 30, 60, 0.08), 0 2px 6px rgba(20, 30, 60, 0.05);
  --shadow-lg: 0 20px 50px rgba(20, 30, 60, 0.14), 0 6px 16px rgba(20, 30, 60, 0.07);
  --font-sans: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo",
    "Pretendard Variable", Pretendard, "Segoe UI", "Noto Sans KR",
    "Malgun Gothic", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0e1116;
    --color-bg-alt: #161a21;
    --color-bg-raised: #181c24;
    --color-text: #eceef2;
    --color-text-muted: #a4abba;
    --color-text-faint: #6f7688;
    --color-border: #262b35;
    --color-primary: #7da2ff;
    --color-primary-dark: #a9c2ff;
    --color-primary-light: #17203a;
    --color-accent: #e0b566;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.55);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  text-decoration: underline;
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

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

/* Header / nav ------------------------------------------------------------ */

.site-header {
  border-bottom: 1px solid var(--color-border);
  background: color-mix(in srgb, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.12rem;
  letter-spacing: -0.01em;
  color: var(--color-text);
}

.brand:hover {
  text-decoration: none;
  color: var(--color-primary);
}

.brand img {
  height: 30px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--color-text-muted);
  font-weight: 600;
  font-size: 0.94rem;
  padding: 8px 14px;
  border-radius: 999px;
  transition: color 0.15s ease, background 0.15s ease;
}

.nav-links a:hover {
  color: var(--color-text);
  background: var(--color-bg-alt);
  text-decoration: none;
}

.nav-links a.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  cursor: pointer;
  color: var(--color-text);
}

@media (max-width: 720px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px;
    display: none;
  }

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

  .nav-links a {
    padding: 12px 16px;
    border-radius: var(--radius-sm);
  }
}

/* Hero ---------------------------------------------------------------- */

.hero {
  position: relative;
  background:
    radial-gradient(720px 360px at 85% -10%, color-mix(in srgb, var(--color-primary) 14%, transparent), transparent),
    linear-gradient(180deg, var(--color-primary-light), var(--color-bg) 85%);
  padding: 88px 0 68px;
  overflow: hidden;
}

.hero h1 {
  font-size: clamp(1.9rem, 3.4vw, 2.6rem);
  line-height: 1.25;
  letter-spacing: -0.01em;
  margin: 0 0 16px;
  max-width: 720px;
}

.hero p {
  max-width: 640px;
  color: var(--color-text-muted);
  font-size: 1.08rem;
}

.hero .tag {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: var(--color-primary-light);
  padding: 6px 12px;
  border-radius: 999px;
  margin-bottom: 18px;
}

/* Page header (for non-home pages) ------------------------------------ */

.page-header {
  padding: 52px 0 32px;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-alt);
}

.page-header h1 {
  margin: 0 0 8px;
  font-size: clamp(1.6rem, 2.6vw, 2rem);
  letter-spacing: -0.01em;
}

.page-header p {
  color: var(--color-text-muted);
  margin: 0;
  font-size: 1.02rem;
}

/* Sections -------------------------------------------------------------- */

section {
  padding: 56px 0;
}

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

.section-title {
  font-size: 1.4rem;
  letter-spacing: -0.01em;
  margin: 0 0 24px;
  padding-left: 14px;
  border-left: 4px solid var(--color-primary);
}

.section-lede {
  color: var(--color-text-muted);
  max-width: 720px;
  margin: -10px 0 24px;
}

/* Card grid -------------------------------------------------------------- */

.grid {
  display: grid;
  gap: 20px;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 22px;
  background: var(--color-bg-raised);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease, transform 0.2s ease, border-color 0.2s ease;
}

.grid .card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--color-primary) 25%, var(--color-border));
}

.card h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
  letter-spacing: -0.005em;
}

.card p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* People / member cards --------------------------------------------------- */

.member-card {
  text-align: center;
}

.member-photo {
  width: 132px;
  height: 132px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 14px;
  background: var(--color-bg-alt);
  border: 3px solid var(--color-bg-alt);
  box-shadow: 0 0 0 1px var(--color-border);
}

.member-card h3 {
  margin: 0 0 2px;
  font-size: 1.08rem;
}

.member-role {
  display: inline-block;
  color: var(--color-primary);
  background: var(--color-primary-light);
  font-weight: 700;
  font-size: 0.78rem;
  padding: 3px 10px;
  border-radius: 999px;
  margin: 0 0 14px;
}

.member-info {
  margin: 0 0 8px;
  font-size: 0.87rem;
  line-height: 1.55;
  color: var(--color-text-muted);
  text-align: left;
}

.member-quote {
  margin: 16px 0 0;
  padding: 12px 14px;
  border-left: 3px solid var(--color-primary-light);
  background: var(--color-bg-alt);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.86rem;
  font-style: italic;
  line-height: 1.6;
  color: var(--color-text-muted);
  text-align: left;
}

.member-contact {
  margin: 0 0 4px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  text-align: left;
}

.group-title {
  margin: 8px 0 18px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-text-muted);
}

.group-title:not(:first-of-type) {
  margin-top: 40px;
}

.grad-list summary {
  cursor: pointer;
  list-style: none;
}

.grad-list summary::-webkit-details-marker {
  display: none;
}

.grad-list summary h3 {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin: 0;
}

.grad-list summary h3::after {
  content: "\25B8";
  color: var(--color-text-faint);
  font-size: 0.8rem;
  transition: transform 0.2s ease;
}

.grad-list[open] summary h3::after {
  transform: rotate(90deg);
}

.grad-count {
  font-weight: 400;
  font-size: 0.8rem;
  color: var(--color-text-faint);
}

.grad-names {
  margin: 14px 0 0;
  columns: 2;
  column-gap: 24px;
  font-size: 0.88rem;
  line-height: 1.9;
  color: var(--color-text-muted);
}

@media (max-width: 560px) {
  .grad-names {
    columns: 1;
  }
}

/* Publications ------------------------------------------------------------ */

.pub-year {
  display: inline-block;
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  margin: 36px 0 16px;
  padding: 5px 14px;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: 999px;
}

.pub-year:first-of-type {
  margin-top: 0;
}

.pub-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.pub-item {
  padding: 16px 4px;
  border-bottom: 1px solid var(--color-border);
  transition: background 0.15s ease;
}

.pub-item:hover {
  background: var(--color-bg-alt);
}

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

.pub-title {
  font-weight: 600;
  line-height: 1.5;
  margin: 0 0 4px;
}

.pub-meta {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin: 0;
}

.pub-links a {
  font-size: 0.85rem;
  margin-right: 12px;
}

/* News list ---------------------------------------------------------------- */

.news-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.news-item {
  display: flex;
  gap: 20px;
  padding: 16px 0;
  border-bottom: 1px solid var(--color-border);
}

.news-date {
  flex: 0 0 100px;
  color: var(--color-text-faint);
  font-size: 0.88rem;
  white-space: nowrap;
}

.news-body {
  flex: 1 1 auto;
  min-width: 0;
}

.news-body h3 {
  margin: 0 0 4px;
  font-size: 1rem;
}

.news-body p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Unified news + photo grid (news.html) ------------------------------------ */

.news-grid {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
}

.news-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--color-bg-raised);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.news-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.news-photos {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  gap: 2px;
  background: var(--color-border);
}

.news-card img {
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  cursor: zoom-in;
  transition: transform 0.3s ease;
}

.news-card img:hover {
  transform: scale(1.04);
}

.news-card-body {
  padding: 14px 16px 16px;
}

.news-card .news-date {
  color: var(--color-text-faint);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-bottom: 4px;
}

.news-card h3 {
  margin: 0 0 4px;
  font-size: 1rem;
}

.news-card p {
  margin: 0;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Contact / footer -------------------------------------------------------- */

.contact-grid {
  display: grid;
  gap: 36px;
  grid-template-columns: 1fr 1fr;
}

@media (max-width: 720px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

.map-embed {
  width: 100%;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

/* Gallery ------------------------------------------------------------------ */

.gallery-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}

.gallery-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--color-bg-raised);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.gallery-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.gallery-item img {
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  cursor: zoom-in;
}

.gallery-caption {
  margin: 0;
  padding: 10px 12px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Lightbox ------------------------------------------------------------------ */

.lightbox-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: min(40px, 5vh) 20px;
  background: rgba(8, 10, 16, 0.9);
  cursor: zoom-out;
}

.lightbox-overlay[hidden] {
  display: none;
}

.lightbox-overlay img {
  max-width: 100%;
  max-height: 100%;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
}

.lightbox-close {
  position: fixed;
  top: max(16px, env(safe-area-inset-top, 0px));
  right: 16px;
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.15s ease;
}

.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.28);
}

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-alt);
  padding: 36px 0;
  color: var(--color-text-faint);
  font-size: 0.88rem;
}

.site-footer p {
  margin: 0 0 4px;
}

.site-footer a {
  color: var(--color-text-muted);
}

/* Buttons ------------------------------------------------------------------ */

.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: #fff;
  font-weight: 700;
  font-size: 0.96rem;
  box-shadow: var(--shadow-sm);
  transition: background 0.15s ease, box-shadow 0.2s ease, transform 0.15s ease;
}

.btn:hover {
  background: var(--color-primary-dark);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
  text-decoration: none;
}