/* ==================== ROOT VARIABLES ==================== */
:root {
  --primary: #102e52;        /* 学术深蓝（北洋蓝） */
  --primary-dark: #0a1f3a;
  --primary-light: #1d5a96;
  --accent: #b08d3e;         /* 哑光金（浅底） */
  --accent-bright: #d9bc6f;  /* 亮金（深蓝底） */
  --bg: #f7f8fa;
  --bg-card: #ffffff;
  --text: #2f3b48;
  --text-muted: #68737f;
  --border: #e3e8ef;
  --shadow: 0 1px 3px rgba(16,46,82,0.06), 0 1px 2px rgba(16,46,82,0.04);
  --shadow-hover: 0 12px 32px rgba(16,46,82,0.13);
  --radius: 4px;
  --transition: 0.25s ease;
  --serif: Georgia, 'Times New Roman', 'Noto Serif SC', 'Songti SC', serif;
}

/* ==================== RESET & BASE ==================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary-light); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent); }
img { max-width: 100%; display: block; }
ul { list-style: none; }
::selection { background: var(--primary); color: #fff; }

/* ==================== LAYOUT ==================== */
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.section { padding: 72px 0; }
.section-title {
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 0.01em;
  margin-bottom: 12px;
}
.section-subtitle {
  color: var(--text-muted);
  font-size: 0.98rem;
  margin-bottom: 44px;
}
.section-title::after {
  content: '';
  display: block;
  width: 72px;
  height: 2px;
  background: linear-gradient(90deg, var(--accent) 0, var(--accent) 36px, var(--border) 36px);
  margin-top: 12px;
}

/* ==================== NAVBAR ==================== */
.navbar {
  background: var(--primary-dark);
  border-top: 3px solid var(--accent);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 12px rgba(4,15,30,0.35);
}
.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 66px;
}
.navbar-brand {
  color: #fff;
  font-family: var(--serif);
  font-size: 1.12rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  white-space: nowrap;
}
.navbar-brand span { color: var(--accent-bright); }
.navbar-menu { display: flex; gap: 2px; align-items: center; }
.navbar-menu a {
  color: rgba(255,255,255,0.78);
  padding: 8px 13px;
  border-radius: 2px;
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: color var(--transition), box-shadow var(--transition), background var(--transition);
}
.navbar-menu a:hover,
.navbar-menu a.active {
  color: #fff;
  background: rgba(255,255,255,0.05);
  box-shadow: inset 0 -2px 0 var(--accent);
}
.navbar-search-btn {
  background: none;
  border: 1px solid rgba(255,255,255,0.3);
  color: rgba(255,255,255,0.85);
  padding: 6px 14px;
  border-radius: 2px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: background var(--transition), border-color var(--transition);
  margin-left: 10px;
}
.navbar-search-btn:hover { background: rgba(255,255,255,0.1); border-color: rgba(255,255,255,0.55); }
.lang-toggle {
  background: transparent;
  border: 1px solid rgba(217,188,111,0.55);
  color: var(--accent-bright);
  padding: 4px 11px;
  border-radius: 2px;
  cursor: pointer;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.8px;
  transition: all var(--transition);
  flex-shrink: 0;
  margin-left: 8px;
}
.lang-toggle:hover { background: rgba(217,188,111,0.12); color: #fff; border-color: var(--accent-bright); }
/* 双语显示控制 */
html.lang-en .zh-only { display: none !important; }
html:not(.lang-en) .en-only { display: none !important; }
.burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}
.burger span { display: block; width: 24px; height: 2px; background: #fff; border-radius: 2px; transition: transform 0.3s; }

/* ==================== HERO ==================== */
.hero {
  background:
    linear-gradient(160deg, rgba(11,31,58,0.28) 0%, rgba(16,46,82,0.24) 55%, rgba(22,64,110,0.28) 100%),
    url('../images/hero-research.jpg') center / cover no-repeat;
  color: #fff;
  padding: 96px 0 80px;
  position: relative;
  overflow: hidden;
  /* 轻微提升对比/饱和，让放大的背景图看起来更利落（非真正锐化） */
  filter: contrast(1.07) saturate(1.08);
}
/* 工程网格底纹 */
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 56px 56px;
  pointer-events: none;
}
.hero .container { max-width: 1240px; }
.hero-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 44px;
  align-items: stretch;
  position: relative;
  z-index: 1;
}
.hero-photo { display: none; }
.hero-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  border-radius: 6px;
  border: 1px solid rgba(255,255,255,0.18);
  box-shadow: 0 18px 44px rgba(4,15,30,0.45);
  display: block;
}
.hero-content { max-width: 720px; position: relative; z-index: 1; }
.hero-tag {
  display: inline-block;
  background: transparent;
  border: 1px solid rgba(217,188,111,0.55);
  color: var(--accent-bright);
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  padding: 5px 16px;
  border-radius: 2px;
  margin-bottom: 24px;
}
.hero h1 { font-size: 2.6rem; font-weight: 700; line-height: 1.25; letter-spacing: 0.01em; margin-bottom: 18px; }
.hero h1 span { color: var(--accent-bright); }
.hero p { font-size: 1.02rem; color: rgba(255,255,255,0.82); max-width: 600px; margin-bottom: 34px; }
.hero-btns { display: flex; gap: 14px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  padding: 11px 30px;
  border-radius: 2px;
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition), border-color var(--transition);
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 8px 22px rgba(4,15,30,0.25); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #9a7a33; }
.btn-outline { background: transparent; color: #fff; border: 1px solid rgba(255,255,255,0.5); }
.btn-outline:hover { background: rgba(255,255,255,0.08); color: #fff; border-color: rgba(255,255,255,0.85); }

.hero-stats {
  display: flex;
  gap: 48px;
  margin-top: 52px;
  padding-top: 34px;
  border-top: 1px solid rgba(255,255,255,0.16);
  flex-wrap: wrap;
}
.stat-item { text-align: center; }
.stat-num { font-family: 'Times New Roman', Georgia, serif; font-size: 2.1rem; font-weight: 700; color: var(--accent-bright); line-height: 1.2; }
.stat-label { font-size: 0.8rem; color: rgba(255,255,255,0.65); letter-spacing: 0.06em; margin-top: 4px; }

/* ==================== CARDS ==================== */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  overflow: hidden;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); border-color: #d3dbe6; }

/* GRID LAYOUTS */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }

/* ==================== PEOPLE ==================== */
.people-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 24px; }
.person-card { text-align: center; padding: 28px 20px 24px; }
.person-avatar {
  width: 100px; height: 100px;
  border-radius: 50%;
  margin: 0 auto 16px;
  object-fit: cover;
  border: 2px solid var(--border);
  background: #f1f4f8;
  display: flex; align-items: center; justify-content: center;
  font-size: 2.2rem;
  color: var(--primary);
  font-weight: 700;
  overflow: hidden;
}
.person-avatar img { width: 100%; height: 100%; object-fit: cover; }
.person-name { font-size: 1rem; font-weight: 700; color: var(--primary); margin-bottom: 4px; }
.person-role { font-size: 0.8rem; color: var(--accent); font-weight: 600; letter-spacing: 0.04em; margin-bottom: 6px; }
.person-info { font-size: 0.82rem; color: var(--text-muted); }
.person-links { display: flex; justify-content: center; gap: 10px; margin-top: 12px; }
.person-links a {
  font-size: 0.78rem;
  color: var(--primary-light);
  border: 1px solid var(--border);
  padding: 3px 12px;
  border-radius: 2px;
}
.person-links a:hover { background: var(--primary); color: #fff; border-color: var(--primary); }

.role-section { margin-bottom: 48px; }
.role-label {
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  padding-bottom: 10px;
  margin-bottom: 22px;
}

/* ==================== NEWS ==================== */
.news-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.news-card { }
.news-img {
  width: 100%; height: 180px;
  object-fit: cover;
  background:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(150deg, #0a1f3a, #16406e);
  background-size: 28px 28px, 28px 28px, 100% 100%;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 14px;
}
.news-img::before {
  content: 'Wang Research Group';
  font-family: var(--serif);
  font-style: italic;
  font-size: 0.98rem;
  letter-spacing: 0.14em;
  color: rgba(217,188,111,0.9);
}
.news-img::after {
  content: '';
  width: 40px; height: 1px;
  background: rgba(217,188,111,0.45);
}
.news-body { padding: 22px; }
.news-date {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 600;
  letter-spacing: 0.04em;
  margin-bottom: 8px;
  display: flex; align-items: center; gap: 6px;
}
.news-tag {
  display: inline-block;
  background: #edf2f8;
  color: var(--primary-light);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 9px;
  border-radius: 2px;
  margin-left: 6px;
  letter-spacing: 0.06em;
}
.news-tag.award { background: #f7f1e2; color: #97793a; }
.news-tag.paper { background: #eaf2ec; color: #2e6b46; }
.news-tag.event { background: #efecf5; color: #5e5286; }
.news-title { font-size: 0.96rem; font-weight: 700; color: var(--primary); margin-bottom: 8px; line-height: 1.45; }
.news-excerpt { font-size: 0.85rem; color: var(--text-muted); line-height: 1.65; }
.news-read-more { display: inline-block; margin-top: 12px; font-size: 0.82rem; font-weight: 600; color: var(--accent); }
.news-read-more:hover { color: var(--primary); }

/* ==================== PUBLICATIONS ==================== */
.pub-filters { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 24px; }
.filter-btn {
  padding: 6px 18px;
  border: 1px solid var(--border);
  border-radius: 2px;
  background: #fff;
  color: var(--text-muted);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: all var(--transition);
}
.filter-btn:hover, .filter-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.pub-search-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 28px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 2px;
  padding: 9px 16px;
  box-shadow: var(--shadow);
}
.pub-search-bar input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 0.92rem;
  color: var(--text);
  background: transparent;
}
.pub-search-bar svg { color: var(--text-muted); flex-shrink: 0; }
.pub-list { display: flex; flex-direction: column; gap: 14px; }
.pub-item {
  background: #fff;
  border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
  border-radius: var(--radius);
  padding: 20px 24px;
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition), border-color var(--transition);
}
.pub-item:hover { box-shadow: var(--shadow-hover); border-left-color: var(--accent); }
.pub-item.hidden { display: none; }
.pub-title { font-size: 0.96rem; font-weight: 700; color: var(--primary); margin-bottom: 6px; line-height: 1.45; }
.pub-authors { font-size: 0.84rem; color: var(--text-muted); margin-bottom: 4px; }
.pub-authors strong { color: var(--text); }
.pub-journal { font-size: 0.84rem; color: var(--primary-light); font-style: italic; font-family: 'Times New Roman', Georgia, serif; }
.pub-meta { display: flex; align-items: center; gap: 12px; margin-top: 10px; flex-wrap: wrap; }
.pub-year {
  background: var(--primary);
  color: #fff;
  font-size: 0.73rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 2px 10px;
  border-radius: 2px;
}
.pub-badge {
  font-size: 0.73rem;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 2px;
  border: 1px solid;
}
.pub-badge.nature { border-color: #b3403a; color: #b3403a; }
.pub-badge.science { border-color: #1d5a96; color: #1d5a96; }
.pub-badge.acs { border-color: #2e6b46; color: #2e6b46; }
.pub-doi { font-size: 0.78rem; color: var(--primary-light); }

/* ==================== RESEARCH ==================== */
.research-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 28px; }
.research-card { padding: 32px 30px 30px; }
.research-num {
  font-family: 'Times New Roman', Georgia, serif;
  font-size: 1.7rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 16px;
}
.research-num::after {
  content: '';
  display: block;
  width: 28px;
  height: 1px;
  background: var(--border);
  margin-top: 12px;
  transition: width 0.35s ease, background 0.35s ease;
}
.research-card:hover .research-num::after { width: 56px; background: var(--accent); }
.research-card h3 { font-size: 1.05rem; font-weight: 700; color: var(--primary); margin-bottom: 10px; }
.research-card p { font-size: 0.88rem; color: var(--text-muted); line-height: 1.75; }
.research-card ul { margin-top: 12px; }
.research-card ul li {
  font-size: 0.84rem;
  color: var(--text-muted);
  padding: 3px 0 3px 16px;
  position: relative;
}
.research-card ul li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* ==================== SEARCH PAGE ==================== */
.search-hero {
  background: var(--primary-dark);
  padding: 44px 0;
  color: #fff;
}
.search-hero h1 { font-size: 1.8rem; font-weight: 700; margin-bottom: 20px; }
.search-bar-big {
  display: flex;
  align-items: center;
  background: #fff;
  border-radius: 3px;
  padding: 10px 20px;
  gap: 12px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.25);
}
.search-bar-big input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1rem;
  color: var(--text);
}
.search-bar-big button {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 8px 24px;
  border-radius: 2px;
  font-weight: 600;
  cursor: pointer;
  font-size: 0.92rem;
}
.search-bar-big button:hover { background: #9a7a33; }
.search-result-item {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  box-shadow: var(--shadow);
  margin-bottom: 16px;
  transition: box-shadow var(--transition);
}
.search-result-item:hover { box-shadow: var(--shadow-hover); }
.search-result-item.hidden { display: none; }
.result-category {
  font-size: 0.73rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 6px;
}
.result-title { font-size: 1rem; font-weight: 700; color: var(--primary); margin-bottom: 6px; }
.result-title mark { background: #f6edd6; color: var(--text); border-radius: 2px; padding: 0 2px; }
.result-excerpt { font-size: 0.85rem; color: var(--text-muted); line-height: 1.6; }
.result-excerpt mark { background: #f6edd6; }
.result-link { margin-top: 8px; font-size: 0.82rem; font-weight: 600; color: var(--primary-light); }
.search-stats { font-size: 0.9rem; color: var(--text-muted); margin-bottom: 20px; }
.no-results { text-align: center; padding: 60px 0; color: var(--text-muted); }
.no-results svg { font-size: 3rem; margin-bottom: 12px; display: block; margin: 0 auto 16px; }

/* ==================== CONTACT ==================== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.contact-info h3 { font-size: 1.1rem; font-weight: 700; color: var(--primary); margin-bottom: 20px; }
.contact-item { display: flex; gap: 14px; margin-bottom: 20px; align-items: flex-start; }
.contact-icon {
  width: 40px; height: 40px;
  background: #f1f4f8;
  border: 1px solid var(--border);
  border-radius: 6px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.05rem;
  flex-shrink: 0;
}
.contact-detail label { font-size: 0.74rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: 0.1em; }
.contact-detail p { font-size: 0.92rem; color: var(--text); margin-top: 2px; }
.map-placeholder {
  background: #f7f9fb;
  border: 1px dashed #c8d2de;
  border-radius: var(--radius);
  height: 300px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  color: var(--primary);
  font-weight: 600;
  text-align: center;
}

/* ==================== LIGHTBOX ==================== */
.lightbox-trigger { cursor: zoom-in; display: block; position: relative; }
.lightbox-trigger::after {
  content: '🔍 点击查看大图';
  position: absolute; bottom: 8px; right: 10px;
  background: rgba(0,0,0,0.55); color: #fff;
  font-size: 0.75rem; padding: 3px 10px; border-radius: 2px;
  opacity: 0; transition: opacity 0.2s;
  pointer-events: none;
}
.lightbox-trigger:hover::after { opacity: 1; }
#lightbox-overlay {
  display: none; position: fixed; inset: 0; z-index: 9999;
  background: rgba(4,12,24,0.9);
  align-items: center; justify-content: center;
  cursor: zoom-out;
}
#lightbox-overlay.active { display: flex; }
#lightbox-overlay img {
  max-width: 92vw; max-height: 92vh;
  object-fit: contain; border-radius: 4px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.6);
  cursor: default;
}
#lightbox-close {
  position: fixed; top: 18px; right: 24px;
  color: #fff; font-size: 2rem; line-height: 1;
  cursor: pointer; user-select: none; opacity: 0.8;
}
#lightbox-close:hover { opacity: 1; }

/* ==================== PAGE HERO ==================== */
.page-hero {
  background: linear-gradient(160deg, var(--primary-dark) 0%, var(--primary) 70%, #16406e 100%);
  color: #fff;
  padding: 80px 0;
  min-height: 220px;
  border-bottom: 3px solid var(--accent);
}
.page-hero h1 { font-size: 2rem; font-weight: 700; letter-spacing: 0.01em; margin-bottom: 8px; text-shadow: 0 2px 8px rgba(0,0,0,0.5); }
.page-hero p { color: rgba(255,255,255,0.88); font-size: 1rem; text-shadow: 0 1px 4px rgba(0,0,0,0.4); }

/* ==================== FOOTER ==================== */
.footer {
  background: var(--primary-dark);
  border-top: 3px solid var(--accent);
  color: rgba(255,255,255,0.68);
  padding: 52px 0 24px;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; margin-bottom: 32px; }
.footer h4 {
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 16px;
}
.footer p { font-size: 0.84rem; line-height: 1.8; }
.footer-links { display: flex; flex-direction: column; gap: 8px; }
.footer-links a { font-size: 0.84rem; color: rgba(255,255,255,0.58); }
.footer-links a:hover { color: var(--accent-bright); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  letter-spacing: 0.02em;
  flex-wrap: wrap;
  gap: 8px;
}

/* ==================== BACK TO TOP ==================== */
.back-to-top {
  position: fixed;
  bottom: 28px; right: 28px;
  width: 44px; height: 44px;
  background: var(--primary);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 4px;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-hover);
  opacity: 0;
  transform: translateY(10px);
  transition: opacity var(--transition), transform var(--transition), background var(--transition);
  z-index: 500;
}
.back-to-top.visible { opacity: 1; transform: translateY(0); }
.back-to-top:hover { background: var(--accent); }

/* ==================== BREADCRUMB ==================== */
.breadcrumb {
  display: flex;
  gap: 6px;
  align-items: center;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: rgba(255,255,255,0.6);
  margin-bottom: 12px;
}
.breadcrumb a { color: rgba(255,255,255,0.75); }
.breadcrumb a:hover { color: var(--accent-bright); }
.breadcrumb span.sep { opacity: 0.5; }

/* ==================== HIGHLIGHT BOX ==================== */
.highlight-box {
  background: #faf7f0;
  border: 1px solid #ece4d2;
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 16px 20px;
  font-size: 0.9rem;
  color: var(--text);
  margin: 16px 0;
}

/* ==================== SCROLL REVEAL ==================== */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.55s ease, transform 0.55s ease; }
.reveal.visible { opacity: 1; transform: none; }

/* ==================== 细节悬停 ==================== */
.person-card:hover .person-avatar { border-color: var(--accent); }
#alumni tbody tr:hover td { background: #eef2f7; }

/* ==================== RESPONSIVE ==================== */
@media (max-width: 900px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2rem; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-photo { display: none; }
  /* 手机端：把首页大图作为整个 hero 区的背景，铺在文字/数字后面 */
  .hero {
    background:
      linear-gradient(160deg, rgba(11,31,58,0.55) 0%, rgba(16,46,82,0.52) 55%, rgba(22,64,110,0.53) 100%),
      url('../images/hero-banner.jpg') center / cover no-repeat;
  }
}
@media (max-width: 700px) {
  .navbar-menu { display: none; flex-direction: column; position: absolute; top: 66px; left: 0; right: 0; background: var(--primary-dark); padding: 12px; gap: 0; }
  .navbar-menu.open { display: flex; }
  .navbar-menu a { padding: 12px 16px; border-radius: 0; border-bottom: 1px solid rgba(255,255,255,0.08); box-shadow: none; }
  .navbar-inner { position: relative; }
  .burger { display: flex; }
  .grid-3, .grid-4, .grid-2, .footer-grid { grid-template-columns: 1fr; }
  .hero { padding: 56px 0; }
  .hero h1 { font-size: 1.7rem; }
  .hero-stats { gap: 24px; }
  .section { padding: 44px 0; }
  .section-title { font-size: 1.55rem; }
}