/* ─── Variables ─────────────────────────────────────────── */
:root {
  --deep-space:  #183446;
  --cerulean:    #1D729B;
  --soft-linen:  #ECEBE4;
  --bright-snow: #F8F9FA;
  --we3-blue:    #21AFEF;
  --we3-green:   #36B74A;
  --gray-100:    #f0f2f5;
  --gray-200:    #e2e6ea;
  --gray-500:    #8c96a3;
  --gray-700:    #495057;
  --gray-900:    #212529;
  --white:       #ffffff;
  --black:       #2B2B2C;
  --shadow-sm:   0 1px 4px rgba(0,0,0,.08);
  --shadow-md:   0 4px 16px rgba(0,0,0,.12);
  --radius:      8px;
  --radius-lg:   14px;
  --max-w:       1080px;
  --nav-h:       68px;
  --header-h:    108px; /* identity bar (~40px) + nav (68px) */
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

/* ─── Reset & Base ──────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font);
  color: var(--gray-900);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: var(--cerulean); text-decoration: none; }
a:hover { color: var(--deep-space); }

/* ─── Typography ────────────────────────────────────────── */
h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 700; line-height: 1.2; }
h2 { font-size: clamp(1.4rem, 3vw, 2rem);   font-weight: 700; line-height: 1.3; }
h3 { font-size: 1.25rem; font-weight: 600; }
h4 { font-size: 1rem;    font-weight: 600; }
p  { color: var(--gray-700); margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

/* ─── Layout helpers ────────────────────────────────────── */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 1.5rem; }
.section    { padding: 5rem 0; }
.section-sm { padding: 3rem 0; }
.section-title {
  text-align: center;
  margin-bottom: 3rem;
}
.section-title h2 { color: var(--deep-space); margin-bottom: .5rem; }
.section-title p  { max-width: 600px; margin: 0 auto; color: var(--gray-500); }
.divider {
  width: 56px; height: 4px;
  background: var(--cerulean);
  border-radius: 2px;
  margin: .75rem auto 1.25rem;
}

/* ─── Site Header (Sticky Wrapper) ─────────────────────── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  box-shadow: 0 2px 8px rgba(0,0,0,.3);
}

/* ─── Stanford Identity Bar ─────────────────────────────── */
.identity-bar {
  background: var(--deep-space);
  padding: .55rem 0;
  font-size: .82rem;
  border-bottom: 1px solid rgba(255,255,255,.1);
}
.identity-bar a {
  color: var(--white);
  font-weight: 600;
  letter-spacing: .02em;
  text-decoration: none;
  font-family: var(--font);
}
.identity-bar a:hover { text-decoration: underline; color: var(--white); }

/* ─── Navigation ────────────────────────────────────────── */
.nav {
  background: var(--deep-space);
  height: var(--nav-h);
  display: flex; align-items: center;
}
/* White logo in dark nav */
.nav .nav-logo img {
  filter: invert(1) brightness(2);
}
/* Dropdown menu styles */
.nav-links .dropdown {
  position: relative;
  display: inline-block;
}
.nav-links .dropdown-content {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  min-width: 200px;
  background-color: var(--deep-space);
  border-radius: var(--radius);
  box-shadow: 0 6px 20px rgba(0,0,0,.25);
  z-index: 1200;
  list-style: none;
  padding: 0.5rem 0;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,.1);
}
.nav-links .dropdown:hover .dropdown-content {
  display: block;
}
.nav-links .dropdown-content li a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--white);
  text-decoration: none;
}
.nav-links .dropdown-content li a:hover {
  background-color: rgba(255,255,255,.12);
  color: var(--white);
}
.nav .container { display: flex; align-items: center; justify-content: space-between; width: 100%; }
.nav-logo {
  display: flex; align-items: center; gap: .6rem;
  color: var(--white); font-size: 1.25rem; font-weight: 700;
  letter-spacing: -.02em;
}
.nav-logo span { color: var(--we3-blue); }
.nav-logo svg  { flex-shrink: 0; }
.nav-links {
  display: flex; align-items: center; gap: .25rem;
  list-style: none;
}
.nav-links a {
  color: rgba(255,255,255,.85);
  padding: .5rem .85rem;
  border-radius: 6px;
  font-size: .9rem; font-weight: 500;
  transition: color .2s, background .2s;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--white);
  background: rgba(255,255,255,.12);
}
.nav-hamburger {
  display: none; flex-direction: column; gap: 5px;
  cursor: pointer; padding: .5rem;
}
.nav-hamburger span {
  display: block; width: 24px; height: 2px;
  background: var(--white); border-radius: 2px;
  transition: all .25s;
}
#nav-toggle { display: none; }

@media (max-width: 720px) {
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    background: var(--deep-space);
    padding: 1.25rem 1.5rem; gap: .25rem;
    box-shadow: var(--shadow-md);
    z-index: 199;
  }
}

/* ─── Hero (Home page specific) ─────────────────────────── */
.hero {
  background: linear-gradient(rgba(255,255,255,0.62), rgba(255,255,255,0.62)),
              url('../logos/sb_landscape.jpeg') center/cover no-repeat;
  color: var(--deep-space);
  padding: 7rem 0 5rem;
  position: relative; overflow: hidden;
}
.hero::after { display: none; }
.hero-content { position: relative; max-width: 700px; }
.hero-badge {
  display: inline-block;
  background: rgba(29,114,155,.15);
  color: var(--cerulean);
  font-size: .8rem; font-weight: 600;
  letter-spacing: .08em; text-transform: uppercase;
  padding: .35rem .85rem; border-radius: 100px;
  border: 1px solid rgba(29,114,155,.4);
  margin-bottom: 1.25rem;
}
.hero h1 { margin-bottom: 1.25rem; }
.hero h1 em { color: var(--cerulean); font-style: normal; }
.hero p { color: rgba(20,40,70,.75); font-size: 1.1rem; max-width: 560px; }
.hero-actions { display: flex; gap: 1rem; flex-wrap: wrap; margin-top: 2rem; }

/* ─── Page Banner (all inner pages) ────────────────────── */
.page-banner {
  position: relative;
  background: url('../logos/sb_landscape.jpeg') center/cover no-repeat;
  padding: 5rem 0 4rem;
  overflow: hidden;
}
.page-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(24, 52, 70, 0.72);
}
.page-banner .container { position: relative; z-index: 1; }
.page-banner .breadcrumb {
  font-size: .85rem;
  color: rgba(255,255,255,.65);
  margin-bottom: .75rem;
}
.page-banner .breadcrumb a { color: rgba(255,255,255,.65); }
.page-banner .breadcrumb a:hover { color: var(--white); }
.page-banner h1 {
  color: var(--white);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  margin-bottom: .75rem;
}
.page-banner p {
  color: rgba(255,255,255,.85);
  font-size: 1.05rem;
  max-width: 640px;
  margin-bottom: 0;
}

/* ─── Buttons ───────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  padding: .7rem 1.4rem; border-radius: var(--radius);
  font-size: .9rem; font-weight: 600;
  transition: all .2s; cursor: pointer; border: none;
}
.btn-primary   { background: var(--deep-space); color: var(--white); }
.btn-primary:hover  { background: #0f2333; color: var(--white); }
.btn-outline   { background: transparent; color: var(--deep-space); border: 1.5px solid rgba(24,52,70,.35); }
.btn-outline:hover  { background: rgba(24,52,70,.07); color: var(--deep-space); border-color: rgba(24,52,70,.6); }
.btn-cerulean  { background: var(--cerulean); color: var(--white); }
.btn-cerulean:hover { background: #1a5e82; color: var(--white); }
.btn-navy      { background: var(--deep-space); color: var(--white); }
.btn-navy:hover     { background: #0f2333; color: var(--white); }
.btn-black     { background: var(--deep-space); color: #fff; }
.btn-black:hover    { background: #0f2333; color: #fff; }

/* ─── Cards ─────────────────────────────────────────────── */
.card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: transform .2s, box-shadow .2s;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.card-body { padding: 1.5rem; }

/* ─── Research page ─────────────────────────────────────── */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}
.research-card { text-decoration: none; color: inherit; display: block; }
.research-card-inner {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform .2s, box-shadow .2s;
}
.research-card:hover .research-card-inner { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.research-card-banner {
  height: 140px; display: flex; align-items: center; justify-content: center;
  font-size: 3rem;
}
.research-card-body { padding: 1.5rem; }
.research-card-body h3 { color: var(--deep-space); margin-bottom: .5rem; }
.research-card-body p  { font-size: .9rem; color: var(--gray-700); margin-bottom: 1rem; }
.research-card-link { color: var(--cerulean); font-size: .875rem; font-weight: 600; display: flex; align-items: center; gap: .3rem; }
.tag {
  display: inline-block;
  background: var(--gray-100);
  color: var(--cerulean);
  font-size: .75rem; font-weight: 600;
  padding: .25rem .65rem; border-radius: 100px;
  border: 1px solid var(--gray-200);
  margin: .2rem .2rem 0 0;
}
.tags { margin-bottom: .75rem; }

/* ─── Subgroup detail page ──────────────────────────────── */
.project-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }
.project-card { background: var(--bright-snow); border: 1px solid var(--gray-200); border-radius: var(--radius); padding: 1.5rem; }
.project-card h4 { color: var(--deep-space); margin-bottom: .5rem; }
.project-card p  { font-size: .875rem; }
.publication-list { list-style: none; }
.publication-list li {
  border-left: 3px solid var(--cerulean);
  padding: .75rem 1rem;
  background: var(--bright-snow);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin-bottom: .75rem;
  font-size: .9rem;
}
.publication-list li strong { color: var(--deep-space); display: block; margin-bottom: .25rem; }
.publication-list li span  { color: var(--gray-500); font-size: .8rem; }

/* ─── People page ───────────────────────────────────────── */
.people-section-title {
  display: flex; align-items: center; gap: 1rem;
  color: var(--deep-space); margin-bottom: 2rem;
}
.people-section-title::after {
  content: ''; flex: 1; height: 1px; background: var(--gray-200);
}
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3.5rem;
}
.person-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.5rem 1rem;
  text-align: center;
  transition: transform .2s, box-shadow .2s;
}
.person-card:hover { cursor: default; }
.pi-card, .pi-card:hover { transform: none; box-shadow: var(--shadow-sm); cursor: default; }
.person-avatar {
  width: 100px; height: 100px;
  border-radius: 20%; overflow: hidden;
  margin: 0 auto 1rem;
  background: var(--cerulean);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.6rem; font-weight: 700; color: var(--white);
  letter-spacing: -.02em;
  flex-shrink: 0;
}
.person-avatar img { width: 100%; height: 100%; object-fit: cover; }
.person-card h4 { color: var(--deep-space); font-size: .975rem; margin-bottom: .2rem; }
.person-card .role { font-size: .8rem; color: var(--cerulean); font-weight: 600; margin-bottom: .3rem; }
.person-card .research-area { font-size: .78rem; color: var(--gray-500); line-height: 1.4; }
.person-card .links { display: flex; justify-content: center; gap: .5rem; margin-top: .75rem; }
.person-card .links a { color: var(--gray-500); font-size: .8rem; }
.person-card .links a:hover { color: var(--cerulean); }
.group-tags { display: flex; flex-wrap: wrap; justify-content: center; gap: .35rem; margin-top: .4rem; }
.group-tag {
  display: inline-block;
  padding: .2rem .55rem;
  border-radius: 20px;
  font-size: .72rem; font-weight: 500;
  background: rgba(29,114,155,.1);
  color: var(--cerulean);
  border: 1px solid rgba(29,114,155,.25);
  cursor: pointer;
  transition: background .2s, border-color .2s;
}
.group-tag:hover { background: rgba(29,114,155,.2); border-color: var(--cerulean); color: var(--cerulean); }

/* Alumni grid is slightly more compact */
.alumni-grid { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
.alumni-card { padding: 1.25rem; text-align: left; display: flex; gap: .9rem; align-items: center; }
.alumni-card .person-avatar { width: 52px; height: 52px; font-size: 1rem; flex-shrink: 0; }
.alumni-card .info h4  { font-size: .9rem; }
.alumni-card .info .role { display: block; }
.alumni-card .info .placement { font-size: .78rem; color: var(--gray-500); }

/* ─── Stats strip ───────────────────────────────────────── */
.stats-strip {
  background: var(--deep-space);
  color: var(--white); padding: 2.5rem 0;
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 2rem;
  text-align: center;
}
.stat-number { font-size: 2.5rem; font-weight: 800; color: var(--we3-blue); line-height: 1; }
.stat-label  { font-size: .85rem; color: rgba(255,255,255,.65); margin-top: .35rem; }

/* ─── Contact page ──────────────────────────────────────── */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.6fr;
  gap: 3rem;
  align-items: start;
}
@media (max-width: 760px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-info h3 { color: var(--deep-space); margin-bottom: 1rem; }
.contact-item {
  display: flex; gap: .85rem; align-items: flex-start;
  margin-bottom: 1.25rem;
}
.contact-icon {
  width: 40px; height: 40px; border-radius: 8px;
  background: var(--gray-100); color: var(--cerulean);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0; font-size: 1.1rem;
}
.contact-item h4 { font-size: .875rem; font-weight: 600; color: var(--deep-space); margin-bottom: .15rem; }
.contact-item p  { font-size: .875rem; margin: 0; }
.form-group { margin-bottom: 1.25rem; }
.form-group label { display: block; font-size: .85rem; font-weight: 600; color: var(--gray-700); margin-bottom: .4rem; }
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%; padding: .7rem .9rem;
  border: 1.5px solid var(--gray-200); border-radius: var(--radius);
  font-family: var(--font); font-size: .9rem; color: var(--gray-900);
  background: var(--white);
  transition: border-color .2s, box-shadow .2s;
  outline: none;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--cerulean);
  box-shadow: 0 0 0 3px rgba(29,114,155,.15);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
@media (max-width: 480px) { .form-row { grid-template-columns: 1fr; } }

/* ─── WE3 Lab Footer ─────────────────────────────────────── */
.footer-we3 {
  background: var(--soft-linen);
  padding: 2rem 0;
  border-top: 1px solid #d8d7cf;
}
.footer-we3 .footer-inner {
  display: flex; justify-content: space-between; align-items: center;
  gap: 1rem; flex-wrap: wrap;
}
.footer-we3 .footer-dept {
  margin-top: .4rem; font-size: .8rem; color: var(--black);
}
.footer-social {
  display: flex; gap: 1rem; align-items: center;
}
.footer-social a {
  color: var(--black);
  font-size: 1.35rem;
  opacity: .65;
  transition: opacity .2s;
  display: inline-flex; align-items: center;
}
.footer-social a:hover { opacity: 1; color: var(--deep-space); }

/* ─── Stanford Global Footer ─────────────────────────────── */
.footer-stanford {
  background: var(--deep-space);
  color: rgba(255,255,255,.8);
  padding: 1.75rem 0;
  font-size: .82rem;
}
.footer-stanford a { color: rgba(255,255,255,.7); text-decoration: none; }
.footer-stanford a:hover { color: var(--white); text-decoration: underline; }
.footer-stanford-inner {
  display: flex; flex-wrap: wrap;
  gap: 1.25rem;
  align-items: center;
  justify-content: space-between;
}
.footer-stanford-logo a {
  color: var(--white); font-size: 1rem; font-weight: 700;
  letter-spacing: -.01em; text-decoration: none; line-height: 1.2;
}
.footer-stanford-logo a:hover { text-decoration: underline; color: var(--white); }
.footer-stanford-links {
  display: flex; flex-wrap: wrap;
  gap: .35rem 1.1rem;
  list-style: none;
  font-size: .78rem;
}
.footer-stanford-copy {
  font-size: .78rem;
  color: rgba(255,255,255,.55);
  white-space: nowrap;
}

/* ─── Utilities ──────────────────────────────────────────── */
.text-center { text-align: center; }
.text-cerulean   { color: var(--cerulean); }
.text-deep-space { color: var(--deep-space); }
.text-navy   { color: var(--deep-space); }
.mt-1 { margin-top: .5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-0 { margin-bottom: 0 !important; }
.gap-1 { gap: .5rem; }

/* Avatar color variants */
.av-1  { background: #1D729B; }
.av-2  { background: #1a5276; }
.av-3  { background: #117a65; }
.av-4  { background: #6c3483; }
.av-5  { background: #b7770d; }
.av-6  { background: #922b21; }
.av-7  { background: #1f618d; }
.av-8  { background: #27804b; }