/* X-Sleep Lab — Main Stylesheet */
/* Morandi Deep Blue Palette · Space Grotesk · DM Sans */

/* ==================== CUSTOM PROPERTIES ==================== */
:root {
  /* Morandi Deep Blue Palette */
  --color-primary:      #4A6580;
  --color-primary-dark: #2E4A63;
  --color-primary-mid:  #6B8BA4;
  --color-accent:       #8AACBF;
  --color-accent-light: #B5CFD8;
  --color-bg:           #F0F4F7;
  --color-bg-alt:       #E8EFF4;
  --color-white:        #FFFFFF;
  --color-text:         #2C3E4A;
  --color-text-light:   #5A7080;
  --color-border:       #C8D8E4;
  --color-nav:          #1E3347;
  --color-footer:       #1A2E3D;

  /* Typography */
  --font-brand:   'Syne', 'Space Grotesk', sans-serif;
  --font-display: 'Space Grotesk', 'DM Sans', sans-serif;
  --font-body:    'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif:      'Noto Serif SC', Georgia, serif;
  --font-zh-display: 'Noto Serif SC', serif;
  --font-zh-title:   'Ma Shan Zheng', 'Noto Serif SC', serif;

  /* UI */
  --radius:      12px;
  --radius-sm:   8px;
  --shadow:      0 1px 2px rgba(46,74,99,0.06), 0 4px 14px rgba(46,74,99,0.09), inset 0 1px 0 rgba(255,255,255,0.85);
  --shadow-md:   0 2px 4px rgba(46,74,99,0.07), 0 8px 24px rgba(46,74,99,0.13), inset 0 1px 0 rgba(255,255,255,0.75);
  --shadow-hover:0 6px 14px rgba(46,74,99,0.13), 0 28px 56px rgba(46,74,99,0.26), inset 0 1px 0 rgba(255,255,255,0.60);
  --transition:  all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width:   1200px;
}

/* ==================== RESET ==================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background-color: var(--color-bg);
  background-image:
    radial-gradient(ellipse at 18% 52%, rgba(74, 101, 128, 0.045) 0%, transparent 58%),
    radial-gradient(ellipse at 82% 18%, rgba(138, 172, 191, 0.04) 0%, transparent 55%),
    radial-gradient(ellipse at 60% 88%, rgba(46, 74, 99, 0.03) 0%, transparent 50%);
  background-attachment: fixed;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ==================== NAVIGATION ==================== */
.site-header {
  background: var(--color-nav);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 20px rgba(30, 51, 71, 0.3);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 68px;
}

.site-title {
  font-family: var(--font-brand);
  font-size: 1.52rem;
  font-weight: 700;
  color: var(--color-white);
  text-decoration: none;
  letter-spacing: 0.02em;
  display: flex;
  align-items: baseline;
  gap: 0;
  flex-shrink: 0;
}

.site-title .x-letter {
  color: var(--color-accent);
  font-size: 1.82rem;
  font-weight: 800;
}

.site-title:hover { opacity: 0.88; }

.main-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.main-nav a {
  font-family: var(--font-display);
  font-size: 1.13rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.80);
  text-decoration: none;
  letter-spacing: 0.01em;
  transition: var(--transition);
  position: relative;
  white-space: nowrap;
}

.main-nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width 0.25s ease;
}

.main-nav a:hover { color: var(--color-white); }
.main-nav a:hover::after,
.main-nav a.active::after { width: 100%; }
.main-nav a.active { color: var(--color-white); }

/* Language switch */
.lang-switch {
  display: flex;
  gap: 4px;
  margin-left: 16px;
  padding-left: 20px;
  border-left: 1px solid rgba(255, 255, 255, 0.18);
}

.lang-switch button {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.32);
  color: rgba(255, 255, 255, 0.72);
  padding: 4px 12px;
  font-size: 0.82rem;
  font-family: var(--font-display);
  font-weight: 600;
  border-radius: 4px;
  cursor: pointer;
  transition: var(--transition);
  letter-spacing: 0.04em;
}

.lang-switch button:hover {
  border-color: var(--color-accent);
  color: var(--color-white);
}

.lang-switch button.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-white);
}

/* ==================== HERO SWIPER ==================== */
.hero-swiper {
  width: 100%;
  height: 520px;
}

.swiper-slide {
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.slide-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  transform: scale(1.14);
  transition: transform 8s ease;
}

.slide-bg--dream {
  transform: scale(1.2);
}

.swiper-slide-active .slide-bg {
  transform: scale(1);
}

.slide-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    135deg,
    rgba(30, 51, 71, 0.85) 0%,
    rgba(46, 74, 99, 0.70) 55%,
    rgba(74, 101, 128, 0.58) 100%
  );
}

.slide-content {
  position: relative;
  z-index: 2;
  text-align: center;
  color: white;
  padding: 60px 32px;
  max-width: 860px;
}

.slide-tag {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent-light);
  background: rgba(138, 172, 191, 0.15);
  border: 1px solid rgba(181, 207, 216, 0.40);
  padding: 5px 16px;
  border-radius: 20px;
  margin-bottom: 22px;
}

.slide-title {
  font-family: var(--font-brand);
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.12;
  margin-bottom: 18px;
  text-shadow: 0 2px 16px rgba(0, 0, 0, 0.20);
}

.slide-title .x-mark { color: var(--color-accent); }

.slide-subtitle {
  font-size: 1.7rem;
  line-height: 1.78;
  opacity: 0.88;
  max-width: 620px;
  margin: 0 auto 30px;
}

.slide-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-white);
  text-decoration: none;
  border: 1.5px solid rgba(255, 255, 255, 0.55);
  padding: 11px 26px;
  border-radius: 6px;
  transition: var(--transition);
  letter-spacing: 0.04em;
}

.slide-cta:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--color-accent-light);
}

/* Swiper controls */
.swiper-button-next,
.swiper-button-prev {
  color: rgba(255, 255, 255, 0.65) !important;
  transition: var(--transition);
}

.swiper-button-next:hover,
.swiper-button-prev:hover {
  color: var(--color-white) !important;
}

.swiper-button-next::after,
.swiper-button-prev::after {
  font-size: 20px !important;
  font-weight: 700 !important;
}

.swiper-pagination-bullet {
  background: rgba(255, 255, 255, 0.45) !important;
  opacity: 1 !important;
  width: 8px !important;
  height: 8px !important;
  transition: var(--transition) !important;
}

.swiper-pagination-bullet-active {
  background: var(--color-accent-light) !important;
  width: 28px !important;
  border-radius: 4px !important;
}

/* ==================== ABOUT / MAIN CONTENT ==================== */
.about-section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 80px 32px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.about-text .section-label {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-primary-mid);
  margin-bottom: 12px;
}

.about-text h2 {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 24px;
  letter-spacing: -0.02em;
  line-height: 1.18;
}

.about-text p {
  font-size: 1.2rem;
  color: var(--color-text);
  margin-bottom: 18px;
  line-height: 1.82;
}

.about-text p:last-of-type { margin-bottom: 28px; }

.about-visual {
  position: relative;
}

.about-stat-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.stat-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 24px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.stat-card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--color-accent);
  transform: translateY(-2px);
}

.stat-number {
  font-family: var(--font-display);
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--color-primary);
  letter-spacing: -0.03em;
  line-height: 1;
  margin-bottom: 6px;
}

.stat-label {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-text-light);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ==================== RESEARCH HIGHLIGHTS (homepage) ==================== */
.research-highlights {
  background: var(--color-bg-alt);
  padding: 80px 32px;
}

.section-header {
  max-width: var(--max-width);
  margin: 0 auto 40px;
}

.section-header .section-label {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-primary-mid);
  margin-bottom: 10px;
}

.section-header h2 {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 10px;
}

.section-header p {
  font-size: 1.4rem;
  color: var(--color-text-light);
  max-width: 560px;
}

.highlights-grid {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
}

.highlight-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0 0 26px;
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1),
              border-color 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  will-change: transform;
}

.highlight-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: linear-gradient(180deg, var(--color-accent) 0%, var(--color-primary) 100%);
}

.highlight-card:hover {
  transform: translateY(-8px);
  border-color: var(--color-accent);
}

.highlight-icon {
  font-size: 2.2rem;
  margin-bottom: 18px;
  display: block;
}

.highlight-card picture,
.highlight-card > .highlight-media {
  display: block;
  width: 100%;
  aspect-ratio: 3 / 2;
  margin-bottom: 20px;
  overflow: hidden;
  background-color: #e9f0f5;
}

.highlight-media {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  object-position: center;
}

.highlight-card > .highlight-media {
  height: auto;
}

.highlight-card h3 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin: 0 28px 12px;
  line-height: 1.35;
}

.highlight-card p {
  font-size: 1.1rem;
  color: var(--color-text-light);
  line-height: 1.72;
  margin: 0 28px 20px;
}

.highlight-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: var(--transition);
  margin: 0 28px;
}

.highlight-link:hover {
  color: var(--color-primary-dark);
  gap: 10px;
}

/* ==================== NEWS STRIP (homepage) ==================== */
.news-strip {
  padding: 72px 32px;
}

.news-strip-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.news-strip-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 36px;
}

.news-strip-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  transition: var(--transition);
  text-decoration: none;
  display: block;
}

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

.news-strip-tag {
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
  display: block;
}

.news-strip-card h4 {
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  line-height: 1.38;
  margin-bottom: 8px;
}

.news-strip-card p {
  font-size: 1rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

.news-strip-date {
  font-size: 1.08rem;
  color: var(--color-text-light);
  margin-top: 14px;
  display: block;
  font-family: var(--font-display);
}

/* ==================== PAGE HERO ==================== */
.page-hero {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  padding: 64px 32px 56px;
  position: relative;
  overflow: hidden;
}

.page-hero::after {
  content: '';
  position: absolute;
  right: -100px;
  top: -100px;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: rgba(138, 172, 191, 0.08);
  pointer-events: none;
}

.page-hero::before {
  content: '';
  position: absolute;
  left: -60px;
  bottom: -80px;
  width: 280px;
  height: 280px;
  border-radius: 50%;
  background: rgba(46, 74, 99, 0.20);
  pointer-events: none;
}

.page-hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.page-hero-label {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-accent-light);
  margin-bottom: 12px;
}

.page-hero h1 {
  font-family: var(--font-brand);
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--color-white);
  letter-spacing: -0.025em;
  line-height: 1.1;
  margin-bottom: 16px;
}

.page-hero p {
  font-size: 1.2rem;
  color: rgba(255, 255, 255, 0.80);
  max-width: 720px;
  line-height: 1.72;
}

.page-hero a { color: var(--color-accent-light); text-decoration: none; }
.page-hero a:hover { text-decoration: underline; }

/* Breadcrumb */
.breadcrumb {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 32px;
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--color-text-light);
  font-family: var(--font-display);
}

.breadcrumb a {
  color: var(--color-primary-mid);
  text-decoration: none;
  transition: var(--transition);
}

.breadcrumb a:hover { color: var(--color-primary); }

.breadcrumb .sep {
  margin: 0 8px;
  opacity: 0.5;
}

/* ==================== TEAM PAGE ==================== */
.team-section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 56px 32px 80px;
}

.team-section-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary-mid);
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-border);
}

/* PI Card */
.pi-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 44px;
  margin-bottom: 52px;
  box-shadow: var(--shadow-md);
  display: flex;
  gap: 40px;
  align-items: flex-start;
  transition: var(--transition);
}

.pi-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
  border-color: var(--color-accent);
}

.pi-avatar {
  width: 204px;
  height: 235px;
  border-radius: 12px;
  object-fit: cover;
  object-position: center top;
  flex-shrink: 0;
  border: 3px solid var(--color-border);
  box-shadow: var(--shadow);
}

.pi-info h2 {
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--color-primary-dark);
  margin-bottom: 4px;
  letter-spacing: -0.02em;
}

.pi-role {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-accent);
  margin-bottom: 6px;
}

.pi-affiliation {
  font-size: 1.15rem;
  color: var(--color-text-light);
  margin-bottom: 18px;
  line-height: 1.55;
}

.pi-bio {
  font-size: 1.08rem;
  color: var(--color-text);
  line-height: 1.80;
  margin-bottom: 20px;
}

.pi-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.pi-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  border: 1.5px solid var(--color-border);
  padding: 7px 16px;
  border-radius: 6px;
  transition: var(--transition);
  letter-spacing: 0.02em;
}

.pi-link-btn:hover {
  background: var(--color-bg-alt);
  border-color: var(--color-primary-mid);
  color: var(--color-primary-dark);
}

/* Team grid */
.team-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.member-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

.member-card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--color-accent);
  transform: translateY(-8px);
}

.member-avatar {
  width: 110px;
  height: 150px;
  border-radius: 12px;
  object-fit: cover;
  margin: 0 auto 14px;
  display: block;
  border: 2px solid var(--color-border);
}

.member-card h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 4px;
}

.member-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--color-primary-mid);
  margin-bottom: 8px;
}

.member-education {
  font-size: 1.08rem;
  color: var(--color-text-light);
  margin-bottom: 8px;
}

.member-contact { margin-bottom: 8px; }

.member-contact a {
  font-size: 1.08rem;
  color: var(--color-primary-mid);
  text-decoration: none;
  transition: var(--transition);
}

.member-contact a:hover { color: var(--color-primary-dark); }

.member-research {
  font-size: 1.08rem;
  color: var(--color-text-light);
  line-height: 1.5;
  margin-top: 8px;
}

/* ==================== RESEARCH PAGE ==================== */
.research-section {
  max-width: 940px;
  margin: 0 auto;
  padding: 56px 32px 80px;
}

.research-item {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 40px 44px;
  margin-bottom: 28px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  transition: var(--transition);
}

.research-item:hover { box-shadow: var(--shadow-hover); transform: translateY(-5px); }

.research-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 4px;
  height: 100%;
  background: linear-gradient(180deg, var(--color-accent) 0%, var(--color-primary) 100%);
}

.research-num {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 10px;
}

.research-item h3 {
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 16px;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.research-item p {
  color: var(--color-text);
  font-size: 1.1rem;
  margin-bottom: 18px;
  line-height: 1.82;
}

.research-item a {
  color: var(--color-primary-mid);
  text-decoration: none;
  transition: var(--transition);
}

.research-item a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

.pub-list {
  list-style: none;
  padding: 0;
  margin: 4px 0 0;
}

.pub-list li {
  font-size: 1rem;
  color: var(--color-text);
  padding: 10px 0;
  border-bottom: 1px solid var(--color-bg-alt);
  line-height: 1.62;
}

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

.pub-list li a {
  color: var(--color-primary-mid);
  text-decoration: none;
  font-weight: 600;
}

.pub-list li a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* ==================== PUBLICATIONS PAGE ==================== */
.pub-section {
  max-width: 940px;
  margin: 0 auto;
  padding: 56px 32px 80px;
}

.pub-year-block { margin-bottom: 44px; }

.pub-year {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--color-primary-dark);
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.pub-entry {
  padding: 18px 0;
  border-bottom: 1px solid var(--color-bg-alt);
  font-size: 1.2rem;
  line-height: 1.78;
  color: var(--color-text);
}

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

.pub-entry a {
  color: var(--color-primary-mid);
  text-decoration: none;
  font-weight: 600;
  transition: var(--transition);
}

.pub-entry a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

em { color: var(--color-text-light); }

/* ==================== NEWS PAGE ==================== */
.news-section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 56px 32px 80px;
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.news-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.news-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-8px);
  border-color: var(--color-accent);
}

.news-card-img {
  width: 100%;
  aspect-ratio: 2 / 1;
  display: block;
  object-fit: cover;
  object-position: center;
  background-color: #f5f8fa;
}

.news-card-placeholder {
  width: 100%;
  aspect-ratio: 2 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
}

.news-card-body {
  padding: 26px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.news-tag {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
  display: block;
}

.news-card h3 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 10px;
  line-height: 1.36;
}

.news-card p {
  font-size: 1rem;
  color: var(--color-text-light);
  line-height: 1.66;
  flex: 1;
}

.news-date {
  display: block;
  font-family: var(--font-display);
  font-size: 1.1rem;
  color: var(--color-text-light);
  margin-top: 16px;
  font-weight: 500;
}

.news-read-more {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 14px;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition);
}

.news-read-more:hover {
  color: var(--color-primary-dark);
  gap: 8px;
}

/* ==================== JOIN PAGE ==================== */
.join-section {
  max-width: 920px;
  margin: 0 auto;
  padding: 56px 32px 80px;
}

.join-block {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 40px 44px;
  margin-bottom: 28px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
  transition: var(--transition);
}

.join-block:hover { box-shadow: var(--shadow-hover); transform: translateY(-5px); }

.join-block::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 4px;
  height: 100%;
  background: linear-gradient(180deg, var(--color-accent) 0%, var(--color-primary) 100%);
}

.join-block-label {
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 10px;
}

.join-block h2 {
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.join-block p {
  font-size: 1rem;
  color: var(--color-text);
  line-height: 1.82;
  margin-bottom: 14px;
}

.join-block a {
  color: var(--color-primary-mid);
  text-decoration: none;
  font-weight: 600;
  transition: var(--transition);
}

.join-block a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

.join-block ul {
  padding-left: 22px;
  margin: 12px 0 16px;
}

.join-block ul li {
  font-size: 1rem;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.65;
}

.contact-info-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-top: 18px;
}

.contact-item .label {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.10em;
  color: var(--color-primary-mid);
  margin-bottom: 4px;
  display: block;
}

.contact-item .value {
  font-size: 1rem;
  color: var(--color-text);
  line-height: 1.55;
}

/* ==================== FOOTER ==================== */
.site-footer {
  background: var(--color-footer);
  color: rgba(255, 255, 255, 0.82);
  padding: 60px 32px 32px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 56px;
  padding-bottom: 44px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.10);
}

.footer-brand-name {
  font-family: var(--font-brand);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: 0.02em;
  margin-bottom: 12px;
}

.footer-brand-name .x-letter { color: var(--color-accent); }

.footer-brand p {
  font-size: 1rem;
  line-height: 1.68;
  opacity: 0.68;
  max-width: 280px;
  margin-bottom: 6px;
}

.footer-col h4 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--color-accent-light);
  margin-bottom: 18px;
}

.footer-col ul { list-style: none; padding: 0; }

.footer-col ul li { margin-bottom: 10px; }

.footer-col ul li a {
  font-size: 1rem;
  color: rgba(255, 255, 255, 0.62);
  text-decoration: none;
  transition: var(--transition);
}

.footer-col ul li a:hover { color: var(--color-accent-light); }

.footer-bottom {
  max-width: var(--max-width);
  margin: 28px auto 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-bottom p {
  font-size: 1rem;
  opacity: 0.46;
}

/* ==================== UTILITIES ==================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-white);
  background: var(--color-primary);
  text-decoration: none;
  padding: 11px 24px;
  border-radius: 6px;
  transition: var(--transition);
  border: 1.5px solid transparent;
  cursor: pointer;
  letter-spacing: 0.03em;
}

.btn:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(46, 74, 99, 0.28);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: var(--color-white);
}

/* ==================== HAMBURGER TOGGLE ==================== */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: background 0.2s;
  flex-shrink: 0;
}

.menu-toggle:hover { background: rgba(255,255,255,0.08); }

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: rgba(255,255,255,0.85);
  border-radius: 2px;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.25s, background 0.2s;
  transform-origin: center;
}

.menu-toggle.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.is-open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.menu-toggle.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ==================== RESPONSIVE ==================== */
@media (max-width: 1024px) {
  .about-section {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .about-visual { order: -1; }

  .about-stat-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
  }

  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  .nav-container {
    padding: 0 20px;
    height: 60px;
    position: relative;
  }

  .menu-toggle { display: flex; }

  .main-nav {
    display: none;
    flex-direction: column;
    gap: 0;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--color-nav);
    box-shadow: 0 8px 24px rgba(30,51,71,0.35);
    padding: 8px 0 12px;
    z-index: 200;
  }

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

  .main-nav a {
    font-size: 1rem;
    padding: 13px 28px;
    white-space: normal;
    border-bottom: 1px solid rgba(255,255,255,0.06);
  }

  .main-nav a::after { display: none; }

  .main-nav a:last-of-type { border-bottom: none; }

  .lang-switch {
    border-left: none;
    border-top: 1px solid rgba(255,255,255,0.12);
    padding: 12px 28px 4px;
    margin-left: 0;
    justify-content: flex-start;
  }

  .hero-swiper { height: 420px; }

  .slide-title { font-size: 2rem; }

  .about-section { padding: 56px 20px; }

  .about-stat-grid { grid-template-columns: 1fr 1fr; }

  .highlights-grid { grid-template-columns: 1fr; }

  .news-strip-grid { grid-template-columns: 1fr; }

  .pi-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 32px 24px;
  }

  .pi-links { justify-content: center; }

  .team-grid { grid-template-columns: 1fr 1fr; }

  .research-item { padding: 28px 24px; }

  .join-block { padding: 28px 24px; }

  .contact-info-grid { grid-template-columns: 1fr; }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }

  .page-hero { padding: 48px 20px 42px; }
  .page-hero h1 { font-size: 2rem; }

  .breadcrumb {
    padding: 14px 20px;
    font-size: 1rem;
  }
}

@media (max-width: 480px) {
  .team-grid { grid-template-columns: 1fr; }
  .slide-title { font-size: 1.65rem; }
  .hero-swiper { height: 380px; }
  .about-stat-grid { grid-template-columns: 1fr 1fr; }
}

/* ==================== CHINESE FONT OVERRIDES ==================== */
/* Ma Shan Zheng (楷体) for hero/display titles · Noto Serif SC for section headings */

/* Hero & large display titles */
html[lang="zh-CN"] h1,
html[lang="zh-CN"] .slide-title {
  font-family: var(--font-zh-title);
  letter-spacing: 0.08em;
  font-weight: 400;
}

/* Section & card headings */
html[lang="zh-CN"] h2,
html[lang="zh-CN"] h3,
html[lang="zh-CN"] .about-text h2,
html[lang="zh-CN"] .section-header h2,
html[lang="zh-CN"] .highlight-card h3,
html[lang="zh-CN"] .news-card h3,
html[lang="zh-CN"] .news-strip-card h4,
html[lang="zh-CN"] .pub-year,
html[lang="zh-CN"] .pi-name {
  font-family: var(--font-zh-display);
  letter-spacing: 0.05em;
  font-weight: 600;
}