/* ==========================================================================
   课题组网站模板 · 全站样式表
   --------------------------------------------------------------------------
   这个文件控制"网站长什么样"（颜色、字号、间距、排版）。
   你后续加内容时，一般【不需要】改这个文件。
   只有想换主题颜色时，才去改下面 :root 里的 --brand / --accent 两行。
   ========================================================================== */

/* ---------- 1. 主题色与全局变量（改这里就能换全站配色） ---------- */
:root {
  --brand:        #12406e;   /* 主色：深蓝，用于标题、导航、按钮 */
  --brand-dark:   #0b2b4a;
  --brand-light:  #1c6bb0;
  --accent:       #0f9b8e;   /* 点缀色：青绿，用于小标签、下划线、图标 */
  --accent-soft:  #e3f5f3;

  --text:         #1f2a37;   /* 正文颜色 */
  --text-soft:    #5a6b7d;   /* 次要文字 */
  --line:         #e2e8f0;   /* 分隔线 */
  --bg:           #ffffff;
  --bg-soft:      #f4f7fb;   /* 浅灰蓝底，用于交替区块 */

  --radius:       10px;
  --radius-lg:    16px;
  --shadow-sm:    0 1px 3px rgba(18, 64, 110, .07);
  --shadow:       0 6px 24px rgba(18, 64, 110, .10);
  --shadow-lg:    0 18px 46px rgba(18, 64, 110, .16);

  --container:    1180px;    /* 内容最大宽度 */
  --header-h:     72px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC",
          "Noto Sans CJK SC", sans-serif;
}

/* ---------- 2. 基础重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  word-break: break-word;
}

img { max-width: 100%; display: block; border: 0; }
a { color: var(--brand-light); text-decoration: none; transition: color .2s; }
a:hover { color: var(--accent); }

h1, h2, h3, h4 { margin: 0 0 .6em; line-height: 1.3; color: var(--brand-dark); font-weight: 700; }
h1 { font-size: 2.1rem; }
h2 { font-size: 1.6rem; }
h3 { font-size: 1.15rem; }
p  { margin: 0 0 1em; }
ul, ol { margin: 0 0 1em; padding-left: 1.3em; }
li { margin-bottom: .35em; }
hr { border: 0; border-top: 1px solid var(--line); margin: 2.5rem 0; }
strong { color: var(--brand-dark); }

/* ---------- 3. 通用布局工具类 ---------- */
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.section   { padding: 76px 0; }
.section--soft { background: var(--bg-soft); }
.section--tight { padding: 52px 0; }
.text-center { text-align: center; }

/* 区块标题：小标签 + 大标题 + 说明文字 */
.section-head { max-width: 760px; margin: 0 auto 46px; text-align: center; }
.section-head--left { margin-left: 0; text-align: left; }
.eyebrow {
  display: inline-block; margin-bottom: 10px;
  font-size: .8rem; font-weight: 700; letter-spacing: .16em;
  text-transform: uppercase; color: var(--accent);
}
.section-head h2 { margin-bottom: 12px; }
.section-head p  { color: var(--text-soft); margin: 0; }

/* ---------- 4. 顶部导航 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, .96);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
  transition: box-shadow .25s;
}
.site-header.is-scrolled { box-shadow: var(--shadow-sm); }

.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; height: var(--header-h);
}

/* 站点标识：左侧图标 + 两行文字（组名 / 单位） */
.brand { display: flex; align-items: center; gap: 12px; flex-shrink: 1; min-width: 0; }
.brand img { width: 40px; height: 40px; border-radius: 8px; object-fit: cover; flex-shrink: 0; }
.brand-text { min-width: 0; overflow: hidden; }
.brand-text strong {
  display: block; font-size: 1.02rem; line-height: 1.25;
  color: var(--brand-dark); letter-spacing: .01em;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.brand-text span {
  display: block; font-size: .74rem; color: var(--text-soft); letter-spacing: .04em;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

/* 导航区（导航 + 语言切换 + 手机汉堡按钮） */
.header-right { display: flex; align-items: center; gap: 10px; }

/* 中英文切换开关 */
.lang-switch {
  display: inline-flex; align-items: center; flex-shrink: 0;
  padding: 2px; border: 1px solid var(--line);
  border-radius: 999px; background: #fff;
}
.lang-switch button {
  padding: 5px 11px; border: 0; border-radius: 999px;
  background: transparent; cursor: pointer;
  font-family: inherit; font-size: .8rem; font-weight: 600; line-height: 1.1;
  color: var(--text-soft); transition: .2s;
}
.lang-switch button:hover { color: var(--brand); }
.lang-switch button.is-active { background: var(--brand); color: #fff; }

/* 一级导航 */
.nav { display: flex; align-items: center; gap: 4px; }
.nav a {
  position: relative; padding: 8px 11px; border-radius: 6px;
  font-size: .93rem; color: var(--text); white-space: nowrap;
}
.nav a:hover { color: var(--brand); background: var(--bg-soft); }
.nav a.is-active { color: var(--brand); font-weight: 700; }
.nav a.is-active::after {
  content: ""; position: absolute; left: 11px; right: 11px; bottom: 2px;
  height: 2px; background: var(--accent); border-radius: 2px;
}

/* 手机端汉堡按钮 */
.nav-toggle {
  display: none; width: 42px; height: 42px; padding: 0;
  border: 1px solid var(--line); border-radius: 8px;
  background: #fff; cursor: pointer;
}
.nav-toggle span {
  display: block; width: 18px; height: 2px; margin: 3px auto;
  background: var(--brand-dark); border-radius: 2px; transition: .25s;
}
.nav-toggle.is-open span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-toggle.is-open span:nth-child(2) { opacity: 0; }
.nav-toggle.is-open span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* ---------- 4.5 英文模式下的微调（英文比中文长，适当收紧一点） ---------- */
html[data-lang="en"] .brand-text strong { font-size: .96rem; }
html[data-lang="en"] .nav a { font-size: .86rem; padding: 8px 9px; }
html[data-lang="en"] .nav a.is-active::after { left: 9px; right: 9px; }
html[data-lang="en"] .hero h1 { font-size: 2.5rem; }

/* ---------- 5. 首页大图（Hero，可轮播） ---------- */
.hero {
  position: relative; min-height: 620px;
  display: flex; align-items: center;
  background: var(--brand-dark); overflow: hidden;
}
.hero-slides { position: absolute; inset: 0; }
.hero-slide {
  position: absolute; inset: 0;
  background-size: cover; background-position: center;
  opacity: 0; transition: opacity 1.2s ease;
}
.hero-slide.is-active { opacity: 1; }
/* 深色遮罩，保证白色文字看得清 */
.hero::after {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(100deg, rgba(9, 32, 55, .90) 0%, rgba(9, 32, 55, .74) 55%, rgba(9, 32, 55, .58) 100%);
}
.hero-inner { position: relative; z-index: 2; padding: 100px 0 90px; max-width: 760px; }
.hero h1 { color: #fff; font-size: 2.7rem; margin-bottom: 14px; }
.hero .hero-sub { color: #dfeaf5; font-size: 1.05rem; margin-bottom: 6px; }
.hero .hero-affil {
  color: #a8c6e0; font-size: .92rem; letter-spacing: .04em;
  margin-bottom: 26px; padding-bottom: 22px; border-bottom: 1px solid rgba(255,255,255,.18);
  display: inline-block;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }

/* 轮播圆点 */
.hero-dots { position: absolute; z-index: 3; bottom: 26px; left: 0; right: 0; }
.hero-dots .container { display: flex; gap: 9px; }
.hero-dots button {
  width: 30px; height: 4px; padding: 0; border: 0; border-radius: 2px;
  background: rgba(255,255,255,.35); cursor: pointer; transition: background .25s;
}
.hero-dots button.is-active { background: #fff; }

/* ---------- 6. 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: 999px;
  font-size: .95rem; font-weight: 600; line-height: 1;
  border: 1px solid transparent; cursor: pointer; transition: .22s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #0b827a; color: #fff; transform: translateY(-1px); }
.btn-ghost { background: transparent; color: #fff; border-color: rgba(255,255,255,.55); }
.btn-ghost:hover { background: rgba(255,255,255,.14); color: #fff; }
.btn-outline { background: #fff; color: var(--brand); border-color: var(--line); }
.btn-outline:hover { border-color: var(--brand-light); color: var(--brand-light); }
.btn-sm { padding: 9px 18px; font-size: .87rem; }

/* ---------- 7. 首屏数据条（论文数 / 成员数 等） ---------- */
.stats { background: var(--brand); color: #fff; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; padding: 34px 24px; }
.stat { text-align: center; padding: 6px 12px; border-right: 1px solid rgba(255,255,255,.16); }
.stat:last-child { border-right: 0; }
.stat b { display: block; font-size: 2rem; line-height: 1.2; font-weight: 700; }
.stat span { font-size: .86rem; color: #b9d3e8; }

/* ---------- 8. 卡片网格（研究方向 / 招生类别 等） ---------- */
.grid { display: grid; gap: 26px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg);
  padding: 30px 26px; transition: .25s;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: #cfe0f0; }
.card-icon {
  width: 46px; height: 46px; margin-bottom: 16px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft); color: var(--accent);
}
.card h3 { margin-bottom: 8px; }
.card p { color: var(--text-soft); font-size: .94rem; margin: 0; }
.card .card-more { display: inline-block; margin-top: 14px; font-size: .87rem; font-weight: 600; }

/* 图片在上、文字在下的卡片（研究领域 / 相册用） */
.card-media { padding: 0; overflow: hidden; }
.card-media img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.card-body { padding: 22px 24px 26px; }
.card-body h3 { font-size: 1.08rem; }
.card-body p { font-size: .93rem; color: var(--text-soft); margin: 0; }

/* ---------- 9. 图文两栏（简介 / 研究详情） ---------- */
.split { display: grid; grid-template-columns: 1.05fr 1fr; gap: 56px; align-items: center; }
.split--reverse .split-media { order: 2; }
.split-media img { width: 100%; border-radius: var(--radius-lg); box-shadow: var(--shadow); }
.split-body h2 { margin-bottom: 14px; }
.split-body p { color: var(--text-soft); }
.split-list { list-style: none; padding: 0; margin: 22px 0 0; }
.split-list li { position: relative; padding-left: 26px; margin-bottom: 10px; color: var(--text-soft); }
.split-list li::before {
  content: ""; position: absolute; left: 4px; top: .62em;
  width: 8px; height: 8px; border-radius: 50%; background: var(--accent);
}

/* ---------- 10. 新闻 / 动态列表 ---------- */
.news-list { list-style: none; padding: 0; margin: 0; border-top: 1px solid var(--line); }
.news-list li {
  display: flex; gap: 26px; align-items: flex-start;
  padding: 20px 4px; margin: 0; border-bottom: 1px solid var(--line);
  transition: background .2s;
}
.news-list li:hover { background: var(--bg-soft); }
.news-date { flex: 0 0 106px; font-size: .88rem; color: var(--text-soft); font-variant-numeric: tabular-nums; padding-top: 2px; }
.news-body { flex: 1; }
.news-body h3 { font-size: 1.02rem; margin: 0 0 4px; }
.news-body p { margin: 0; font-size: .92rem; color: var(--text-soft); }
/* 新闻标签（如"论文""获奖"） */
.tag {
  display: inline-block; margin-left: 8px; padding: 1px 9px; border-radius: 999px;
  font-size: .74rem; font-weight: 600; vertical-align: 2px;
  background: var(--accent-soft); color: #0b7a71;
}

/* 带图片的新闻/相册卡片 */
.news-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; transition: .25s; }
.news-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.news-card img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; }
.news-card .card-body { padding: 20px 22px 24px; }
.news-card time { font-size: .82rem; color: var(--accent); font-weight: 600; letter-spacing: .03em; }
.news-card h3 { font-size: 1.02rem; margin: 6px 0 8px; }

/* ---------- 11. 内页页头（面包屑式标题条） ---------- */
.page-hero {
  background: linear-gradient(115deg, var(--brand-dark), var(--brand) 55%, #17547f);
  color: #fff; padding: 62px 0 56px; position: relative; overflow: hidden;
}
.page-hero::after {
  content: ""; position: absolute; right: -90px; top: -70px;
  width: 340px; height: 340px; border-radius: 50%;
  background: rgba(255,255,255,.05);
}
.page-hero h1 { color: #fff; margin-bottom: 8px; font-size: 2.15rem; }
.page-hero p { color: #b9d3e8; margin: 0; max-width: 720px; }
.page-hero .crumb { position: relative; z-index: 2; font-size: .84rem; color: #9dbfdd; margin-bottom: 12px; }
.page-hero .crumb a { color: #c8dcee; }

/* ---------- 12. 团队成员 ---------- */
/* PI（导师）介绍块 */
.pi-block { display: grid; grid-template-columns: 300px 1fr; gap: 44px; align-items: start; }
.pi-photo img { width: 100%; border-radius: var(--radius-lg); box-shadow: var(--shadow); aspect-ratio: 4 / 5; object-fit: cover; }
.pi-info h3 { font-size: 1.5rem; margin-bottom: 4px; }
.pi-role { color: var(--accent); font-weight: 600; margin-bottom: 4px; }
.pi-title { color: var(--text-soft); font-size: .92rem; margin-bottom: 18px; }
.pi-meta { list-style: none; padding: 0; margin: 0 0 18px; }
.pi-meta li { display: flex; gap: 10px; font-size: .93rem; color: var(--text-soft); margin-bottom: 6px; }
.pi-meta b { flex: 0 0 80px; color: var(--brand-dark); font-weight: 600; white-space: nowrap; }

/* 成员卡片 */
.member { display: flex; flex-direction: column; background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; transition: .25s; }
.member:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.member img { width: 100%; aspect-ratio: 4 / 5; object-fit: cover; background: var(--bg-soft); }
.member .card-body { flex: 1; display: flex; flex-direction: column; padding: 18px 20px 22px; }
.member h3 { font-size: 1.06rem; margin-bottom: 2px; }
.member .m-role { color: var(--accent); font-size: .87rem; font-weight: 600; margin-bottom: 6px; text-wrap: balance; }
.member .m-topic { font-size: .88rem; color: var(--text-soft); margin-bottom: 8px; }
/* 成员卡片的补充信息（教育经历 / 获奖 / 个人简介） */
.member .m-bio {
  margin: 10px 0 0; padding-top: 10px;
  border-top: 1px dashed var(--line);
  font-size: .82rem; line-height: 1.6; color: var(--text-soft);
}
.member .m-mail { font-size: .85rem; word-break: break-all; margin-top: auto; }

/* 小组成员小标题 */
.group-title {
  display: flex; align-items: center; gap: 14px; margin: 54px 0 26px;
}
.group-title h2 { margin: 0; font-size: 1.3rem; }
.group-title::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.group-title .count { font-size: .85rem; color: var(--text-soft); font-weight: 400; }

/* 毕业生列表（紧凑文字表） */
.alumni-list { list-style: none; padding: 0; margin: 0; }
.alumni-list li {
  display: flex; gap: 18px; padding: 13px 2px; margin: 0;
  border-bottom: 1px dashed var(--line); font-size: .93rem;
}
.alumni-list .a-name { flex: 0 0 130px; font-weight: 600; color: var(--brand-dark); }
.alumni-list .a-info { flex: 1; color: var(--text-soft); }

/* ---------- 13. 论文列表 ---------- */
.pub-year {
  display: flex; align-items: center; gap: 16px;
  margin: 46px 0 22px; font-size: 1.35rem; font-weight: 700; color: var(--brand);
}
.pub-year::after { content: ""; flex: 1; height: 2px; background: var(--line); }
.pub-year:first-of-type { margin-top: 8px; }

.pub-list { list-style: none; padding: 0; margin: 0; counter-reset: pub; }
.pub-list li {
  position: relative; padding: 0 0 22px 34px; margin: 0 0 22px;
  border-bottom: 1px solid var(--line);
}
.pub-list li::before {
  counter-increment: pub; content: counter(pub);
  position: absolute; left: 0; top: 2px;
  width: 24px; height: 24px; border-radius: 50%;
  background: var(--accent-soft); color: #0b7a71;
  font-size: .76rem; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.pub-title { font-weight: 600; color: var(--brand-dark); margin-bottom: 4px; }
.pub-authors { font-size: .92rem; color: var(--text-soft); margin-bottom: 4px; }
.pub-authors .me { color: var(--brand); font-weight: 700; text-decoration: underline; text-underline-offset: 3px; }
.pub-journal { font-size: .92rem; color: var(--text-soft); font-style: italic; }
.pub-links { margin-top: 10px; display: flex; flex-wrap: wrap; gap: 8px; }
.pub-links a {
  display: inline-block; padding: 3px 12px; border: 1px solid var(--line);
  border-radius: 999px; font-size: .8rem; font-weight: 600; color: var(--brand-light);
}
.pub-links a:hover { background: var(--brand-light); color: #fff; border-color: var(--brand-light); }
/* 高亮/亮点论文标记 */
.pub-flag {
  display: inline-block; margin-left: 8px; padding: 1px 8px; border-radius: 4px;
  font-size: .72rem; font-weight: 700; vertical-align: 2px;
  background: #fff3d6; color: #a06a00;
}

/* ---------- 14. 相册 ---------- */
.gallery { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.gallery a {
  display: block; position: relative; overflow: hidden;
  border-radius: var(--radius); background: var(--bg-soft);
}
.gallery img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; transition: transform .45s; }
.gallery a:hover img { transform: scale(1.06); }
.gallery .cap {
  position: absolute; inset: auto 0 0 0; padding: 26px 16px 12px;
  background: linear-gradient(transparent, rgba(9, 32, 55, .8));
  color: #fff; font-size: .88rem; opacity: 0; transition: opacity .3s;
}
.gallery a:hover .cap { opacity: 1; }

/* 点击放大用的灯箱 */
.lightbox {
  position: fixed; inset: 0; z-index: 200; display: none;
  align-items: center; justify-content: center; padding: 30px;
  background: rgba(6, 18, 32, .92);
}
.lightbox.is-open { display: flex; }
.lightbox img { max-width: 92vw; max-height: 84vh; border-radius: 8px; }
.lightbox figcaption { color: #cfe0f0; text-align: center; margin-top: 14px; font-size: .92rem; }
.lightbox-close {
  position: absolute; top: 18px; right: 22px; width: 40px; height: 40px;
  border: 1px solid rgba(255,255,255,.35); border-radius: 50%;
  background: transparent; color: #fff; font-size: 20px; cursor: pointer;
}

/* ---------- 15. 招募 / 加入我们 ---------- */
.cta-band {
  background: linear-gradient(115deg, var(--brand-dark), var(--brand) 60%, #1a5c8a);
  color: #fff; border-radius: var(--radius-lg); padding: 46px 48px;
  display: flex; align-items: center; justify-content: space-between; gap: 30px; flex-wrap: wrap;
}
.cta-band h2 { color: #fff; margin-bottom: 8px; }
.cta-band p { color: #c3d8ec; margin: 0; }

.check-list { list-style: none; padding: 0; margin: 0; }
.check-list li { position: relative; padding-left: 28px; margin-bottom: 10px; color: var(--text-soft); }
.check-list li::before {
  content: "✓"; position: absolute; left: 0; top: 0;
  color: var(--accent); font-weight: 700;
}

/* ---------- 16. 联系方式 ---------- */
.contact-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 26px; }
.contact-item { display: flex; gap: 16px; }
.contact-item .ci-icon {
  flex: 0 0 44px; height: 44px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft); color: var(--accent);
}
.contact-item h3 { font-size: 1rem; margin-bottom: 4px; }
.contact-item p { margin: 0; font-size: .94rem; color: var(--text-soft); }
.map-frame {
  margin-top: 34px; border: 1px solid var(--line); border-radius: var(--radius-lg);
  overflow: hidden; background: var(--bg-soft);
}
.map-frame img { width: 100%; }
.map-frame iframe { width: 100%; height: 380px; border: 0; display: block; }

/* ---------- 17. 页脚 ---------- */
.site-footer { background: var(--brand-dark); color: #a9c2d8; padding: 58px 0 0; font-size: .92rem; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.2fr; gap: 40px; padding-bottom: 40px; }
.site-footer h4 { color: #fff; font-size: .95rem; margin-bottom: 16px; letter-spacing: .04em; }
.site-footer a { color: #a9c2d8; }
.site-footer a:hover { color: #fff; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: 8px; }
.footer-brand { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; }
.footer-brand img { width: 40px; height: 40px; border-radius: 8px; }
.footer-brand strong { color: #fff; font-size: 1.02rem; display: block; line-height: 1.3; }
.footer-brand span { font-size: .78rem; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.12); padding: 18px 0 22px;
  display: flex; justify-content: space-between; gap: 14px; flex-wrap: wrap;
  font-size: .84rem; color: #7e9cba;
}

/* ---------- 18. 返回顶部按钮 ---------- */
.to-top {
  position: fixed; right: 24px; bottom: 24px; z-index: 90;
  width: 44px; height: 44px; border: 0; border-radius: 50%;
  background: var(--brand); color: #fff; cursor: pointer;
  box-shadow: var(--shadow); opacity: 0; visibility: hidden; transition: .3s;
}
.to-top.is-visible { opacity: 1; visibility: visible; }
.to-top:hover { background: var(--accent); }

/* ---------- 19. 滚动入场的淡入动画 ---------- */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ---------- 20. 响应式断点 ---------- */
@media (max-width: 1080px) {
  .nav a { padding: 8px 8px; font-size: .88rem; }
  .brand-text span { display: none; }
}

@media (max-width: 960px) {
  /* 手机/平板：导航收进抽屉 */
  .nav-toggle { display: block; }
  .nav {
    position: absolute; top: var(--header-h); left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: #fff; border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow); padding: 8px 16px 16px;
    display: none;
  }
  .nav.is-open { display: flex; }
  .nav a { padding: 12px 10px; border-bottom: 1px solid var(--line); border-radius: 0; font-size: .98rem; }
  .nav a.is-active::after { display: none; }
  .nav a.is-active { color: var(--brand); }

  .hero { min-height: 520px; }
  .hero h1 { font-size: 2rem; }
  .split { grid-template-columns: 1fr; gap: 32px; }
  .split--reverse .split-media { order: 0; }
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 22px; }
  .stat:nth-child(2) { border-right: 0; }
  .pi-block { grid-template-columns: 1fr; gap: 28px; }
  .pi-photo { max-width: 320px; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 30px; }
  .section { padding: 58px 0; }
}

@media (max-width: 640px) {
  body { font-size: 15.5px; }
  .container { padding: 0 18px; }
  .hero h1 { font-size: 1.6rem; }
  .section { padding: 46px 0; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .gallery { grid-template-columns: repeat(2, 1fr); }
  .news-list li { flex-direction: column; gap: 4px; }
  .news-date { flex: none; }
  .alumni-list li { flex-direction: column; gap: 2px; }
  .alumni-list .a-name { flex: none; }
  .cta-band { padding: 32px 24px; }
  .cta-band h2 { font-size: 1.25rem; }
  .contact-grid { grid-template-columns: 1fr; }
  .page-hero { padding: 44px 0 40px; }
  .footer-grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.35rem; }
}