/* ==========================================================================
   main.css — 核心样式系统
   Reset · Base · 导航 · Hero · 组件 · 页面 · Footer · 响应式
   ========================================================================== */

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

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

body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-normal);
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg, video { max-width: 100%; height: auto; display: block; }
p, li { overflow-wrap: break-word; }

a { color: var(--c-primary); text-decoration: none; transition: color .2s ease; }
a:hover { color: var(--c-primary-600); }

ul, ol { padding-left: 1.25rem; }

h1, h2, h3, h4, h5, h6 { line-height: var(--lh-tight); font-weight: var(--fw-bold); color: var(--c-text); }

hr { border: 0; border-top: 1px solid var(--c-border); margin: var(--s-12) 0; }

::selection { background: rgba(99,102,241,.2); }

/* ---------- Layout primitives ---------- */
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 var(--container-pad); }

.section { padding: var(--s-20) 0; }
.section--alt { background: var(--c-bg-alt); }
.section--tint { background: var(--c-bg-tint); }

.section-head { max-width: 720px; margin-bottom: var(--s-12); }
.section-head--center { margin-left: auto; margin-right: auto; text-align: center; }
.eyebrow {
  display: inline-flex; align-items: center; gap: var(--s-2);
  font-size: var(--fs-xs); font-weight: var(--fw-semi);
  letter-spacing: .08em; text-transform: uppercase;
  color: var(--c-primary); background: var(--c-bg-tint);
  padding: var(--s-2) var(--s-4); border-radius: var(--r-full);
  margin-bottom: var(--s-4);
}
.section-head h2 { font-size: var(--fs-h2); margin-bottom: var(--s-3); }
.section-head p { color: var(--c-text-2); font-size: var(--fs-lg); }
.gradient-text {
  background: var(--c-gradient);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}

/* ---------- Navigation ---------- */
.site-nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--c-border);
}
.site-nav__inner { display: flex; align-items: center; justify-content: space-between; height: var(--nav-height); }
.site-nav__brand { display: flex; align-items: center; gap: var(--s-3); font-weight: var(--fw-extra); font-size: var(--fs-lg); color: var(--c-text); }
.site-nav__brand .brand-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--c-gradient); box-shadow: var(--shadow-glow); }
.site-nav__menu { display: flex; align-items: center; gap: var(--s-1); }
.site-nav__menu a {
  display: block; padding: var(--s-2) var(--s-4);
  color: var(--c-text-2); font-weight: var(--fw-med); font-size: var(--fs-sm);
  border-radius: var(--r-md); transition: all .2s ease;
}
.site-nav__menu a:hover { color: var(--c-primary); background: var(--c-bg-tint); }
.site-nav__menu a.active { color: var(--c-primary); background: var(--c-bg-tint); }
.nav-toggle {
  display: none; border: 0; background: none; cursor: pointer;
  width: 40px; height: 40px; border-radius: var(--r-sm);
  flex-direction: column; align-items: center; justify-content: center; gap: 5px;
}
.nav-toggle span { display: block; width: 20px; height: 2px; background: var(--c-text); border-radius: 2px; transition: all .25s ease; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative; overflow: hidden;
  background: var(--c-gradient-deep);
  color: #fff;
  padding: clamp(4rem, 9vw, 7rem) 0 clamp(3rem, 6vw, 5rem);
}

/* ---------- Hero：左矩形照片 + 右信息 ---------- */
.hero__profile { display: flex; gap: var(--s-10); align-items: flex-start; }
.hero__photo {
  position: relative;
  width: min(100%, 256px); flex-shrink: 0;
  padding: 9px;
  border-radius: 24px;
  background: linear-gradient(160deg, rgba(255,255,255,.96), rgba(255,255,255,.38) 42%, rgba(255,255,255,.88));
  box-shadow:
    0 38px 72px -20px rgba(37,99,235,.62),
    0 18px 38px -14px rgba(124,58,237,.55),
    0 6px 14px -4px rgba(15,23,42,.42),
    inset 0 1px 1px rgba(255,255,255,.85),
    inset 0 -1px 2px rgba(255,255,255,.35);
  transition: box-shadow .3s var(--ease-out);
  animation: float 6s ease-in-out infinite alternate;
}
.hero__photo::before {
  content: ""; position: absolute; inset: -20px; z-index: -1;
  border-radius: 32px;
  background: radial-gradient(ellipse at 30% 22%, rgba(96,165,250,.42), rgba(124,58,237,.26) 55%, transparent 74%);
  filter: blur(24px);
}
.hero__photo:hover { box-shadow:
    0 46px 84px -20px rgba(37,99,235,.72),
    0 22px 44px -14px rgba(124,58,237,.62),
    0 8px 16px -4px rgba(15,23,42,.46),
    inset 0 1px 1px rgba(255,255,255,.9);
}
.hero__photo img {
  width: 100%; aspect-ratio: 3/4; object-fit: cover; display: block;
  border-radius: 17px;
  box-shadow: inset 0 2px 12px rgba(15,23,42,.3);
}
.hero__info { flex: 1; min-width: 0; animation: fadeUp .55s var(--ease-out) both; }
.hero__info h1 { margin-bottom: var(--s-2); }
.hero__contact {
  display: grid; grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--s-2) var(--s-4); margin: var(--s-4) 0;
}
.hero__contact a {
  display: flex; align-items: center; gap: var(--s-2);
  font-size: var(--fs-sm); color: rgba(255,255,255,.88);
  transition: color .2s; overflow-wrap: anywhere;
}
.hero__contact a:hover { color: #fff; }
.hero__contact .icon { width: 15px; height: 15px; flex-shrink: 0; }

@keyframes float { from { transform: translateY(0); } to { transform: translateY(-7px); } }
@keyframes fadeUp { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
.hero__bg { position: absolute; inset: 0; pointer-events: none; }
.hero__bg .glow { position: absolute; border-radius: 50%; filter: blur(50px); }
.hero__bg .glow--1 { width: 420px; height: 420px; top: -140px; left: -80px; background: rgba(96,165,250,.45); }
.hero__bg .glow--2 { width: 360px; height: 360px; bottom: -120px; right: -60px; background: rgba(249,115,22,.42); }
.hero__bg .dots {
  position: absolute; inset: 0; opacity: .5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='26' height='26'%3E%3Ccircle cx='2' cy='2' r='1.6' fill='%23ffffff' fill-opacity='.16'/%3E%3C/svg%3E");
}
.hero__inner { position: relative; display: grid; grid-template-columns: minmax(0,1.1fr) minmax(0,.9fr); gap: var(--s-16); align-items: center; }
.hero h1 { font-size: var(--fs-h1); color: #fff; margin-bottom: var(--s-2); }
.hero .hero__role { font-size: var(--fs-xl); font-weight: var(--fw-semi); color: rgba(255,255,255,.9); margin-bottom: var(--s-3); }
.hero .hero__tagline { font-size: var(--fs-lg); color: rgba(255,255,255,.82); max-width: 560px; margin-bottom: var(--s-5); }
.hero__ctas { display: flex; flex-wrap: wrap; gap: var(--s-4); }
/* Compact hero (inner pages) */
.hero--compact { padding: var(--s-16) 0; }
.hero--compact .hero__inner { display: block; }
.hero--compact h1 { font-size: var(--fs-h2); }
.hero--compact p.hero__sub { color: rgba(255,255,255,.85); max-width: 640px; margin-top: var(--s-3); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: var(--s-2);
  padding: var(--s-2) var(--s-5); border-radius: 10px;
  font-size: var(--fs-sm); font-weight: var(--fw-semi);
  background: var(--c-gradient); color: #fff; border: 0; cursor: pointer;
  box-shadow: var(--shadow-lg); transition: all .2s ease; white-space: nowrap;
}
.btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-glow); color: #fff; filter: brightness(1.05); }
.btn--ghost { background: transparent; color: #fff; border: 1.5px solid rgba(255,255,255,.5); box-shadow: none; }
.btn--ghost:hover { border-color: #fff; background: rgba(255,255,255,.12); }
.btn--light { background: #fff; color: var(--c-primary); }
.btn--light:hover { background: var(--c-bg-alt); color: var(--c-primary-600); }
.btn--lg { padding: var(--s-3) var(--s-6); font-size: var(--fs-base); }
.btn--sm { padding: var(--s-2) var(--s-3); font-size: var(--fs-xs); border-radius: 8px; }
.btn .icon { width: 16px; height: 16px; }

/* ---------- Icons ---------- */
.icon { width: 22px; height: 22px; stroke: currentColor; stroke-width: 1.7; fill: none; stroke-linecap: round; stroke-linejoin: round; flex-shrink: 0; }
.icon-tile {
  width: 52px; height: 52px; border-radius: var(--r-md);
  display: flex; align-items: center; justify-content: center;
  background: var(--c-gradient-soft); color: var(--c-primary);
}
.icon-tile .icon { width: 26px; height: 26px; }

/* ---------- Cards ---------- */
.card {
  position: relative; background: var(--c-bg);
  border: 1px solid var(--c-border); border-radius: var(--r-lg);
  padding: var(--s-8); box-shadow: var(--shadow-sm);
  transition: all .25s ease; overflow: hidden;
}
.card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: var(--c-gradient); opacity: .35; transition: opacity .25s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-glow); border-color: transparent; }
.card:hover::before { opacity: 1; }
.card h3 { font-size: var(--fs-h3); margin-bottom: var(--s-2); }
.card p { color: var(--c-text-2); font-size: var(--fs-sm); }
.card .icon-tile { margin-bottom: var(--s-4); }

.grid { display: grid; gap: var(--s-6); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--5 { grid-template-columns: repeat(5, 1fr); }

/* ---------- Tags ---------- */
.tag {
  display: inline-flex; align-items: center; gap: var(--s-1);
  font-size: var(--fs-xs); font-weight: var(--fw-semi);
  padding: 2px var(--s-3); border-radius: var(--r-full);
  color: var(--c-primary); background: var(--c-bg-tint);
}
.tag--esi { color: #92400E; background: #FEF3C7; }
.tag--q1 { color: #065F46; background: #D1FAE5; }
.tag--q2 { color: #1E40AF; background: #DBEAFE; }
.tag--q3 { color: #6B7280; background: #F3F4F6; }
.tag--conf { color: #6D28D9; background: #EDE9FE; }
.tag--gold { color: #92400E; background: linear-gradient(135deg,#FEF3C7,#FDE68A); }

/* ---------- Stats band ---------- */
.stats { display: grid; grid-template-columns: repeat(5, 1fr); gap: var(--s-4); }
.stat {
  text-align: center; background: var(--c-bg);
  border: 1px solid var(--c-border); border-radius: var(--r-lg);
  padding: var(--s-6) var(--s-4); box-shadow: var(--shadow-sm);
  transition: all .25s ease;
}
.stat:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.stat .stat__num { font-size: 2.2rem; font-weight: var(--fw-extra); background: var(--c-gradient); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; line-height: 1.1; }
.stat .stat__label { font-size: var(--fs-sm); color: var(--c-text-2); margin-top: var(--s-2); }

/* ---------- News timeline ---------- */
.timeline { position: relative; padding-left: var(--s-8); }
.timeline::before { content: ""; position: absolute; left: 6px; top: 6px; bottom: 6px; width: 2px; background: var(--c-border-2); }
.timeline__item { position: relative; padding-bottom: var(--s-6); }
.timeline__item:last-child { padding-bottom: 0; }
.timeline__item::before {
  content: ""; position: absolute; left: calc(-1 * var(--s-8) + 2px); top: 6px;
  width: 10px; height: 10px; border-radius: 50%; background: var(--c-gradient); box-shadow: var(--shadow-glow);
}
.timeline__year { font-size: var(--fs-xs); font-weight: var(--fw-bold); color: var(--c-primary); text-transform: uppercase; letter-spacing: .06em; }
.timeline__item p { color: var(--c-text-2); margin-top: var(--s-1); }

/* ---------- Publication cards ---------- */
.pub {
  display: flex; gap: var(--s-5); align-items: flex-start;
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); padding: var(--s-6) var(--s-8);
  box-shadow: var(--shadow-sm); transition: all .2s ease;
}
.pub:hover { box-shadow: var(--shadow-glow); transform: translateY(-2px); border-color: transparent; }
.pub__num {
  flex-shrink: 0; width: 44px; height: 44px; border-radius: var(--r-md);
  display: flex; align-items: center; justify-content: center;
  font-weight: var(--fw-extra); font-size: var(--fs-lg); color: #fff;
  background: var(--c-gradient); box-shadow: var(--shadow-md);
}
.pub__body { flex: 1; min-width: 0; }
.pub__title { font-weight: var(--fw-semi); font-size: var(--fs-base); margin-bottom: var(--s-2); }
.pub__title a { color: var(--c-text); }
.pub__title a:hover { color: var(--c-primary); }
.pub__venue { font-size: var(--fs-sm); color: var(--c-text-2); margin-bottom: var(--s-3); }
.pub__venue em { font-style: italic; }
.pub__tags { display: flex; flex-wrap: wrap; gap: var(--s-2); }

/* ---------- Teaching cards ---------- */
.teaching-card {
  display: flex; gap: var(--s-6); align-items: center;
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); padding: var(--s-8);
  box-shadow: var(--shadow-sm); transition: all .2s ease;
}
.teaching-card:hover { box-shadow: var(--shadow-glow); transform: translateY(-3px); }
.teaching-card .type-badge {
  font-size: var(--fs-xs); font-weight: var(--fw-semi); color: var(--c-primary);
  background: var(--c-bg-tint); padding: 2px var(--s-3); border-radius: var(--r-full);
}
.teaching-card h3 { margin: var(--s-2) 0; font-size: var(--fs-h3); }
.teaching-card p { color: var(--c-text-2); font-size: var(--fs-sm); }

/* ---------- Contact cards ---------- */
.contact-card {
  display: flex; align-items: center; gap: var(--s-5);
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); padding: var(--s-6);
  box-shadow: var(--shadow-sm); transition: all .2s ease;
}
.contact-card:hover { box-shadow: var(--shadow-glow); transform: translateY(-3px); }
.contact-card .contact-card__label { font-size: var(--fs-xs); color: var(--c-text-3); text-transform: uppercase; letter-spacing: .05em; margin-bottom: 2px; }
.contact-card .contact-card__value { font-weight: var(--fw-semi); color: var(--c-text); overflow-wrap: anywhere; }

/* ---------- CV ---------- */
.cv-block { margin-bottom: var(--s-12); }
.cv-block__head { display: flex; align-items: center; gap: var(--s-3); margin-bottom: var(--s-5); }
.cv-block__head .icon-tile { width: 42px; height: 42px; }
.cv-block__head h2 { font-size: var(--fs-h3); }
.cv-block__body { padding-left: var(--s-8); border-left: 2px solid var(--c-border); }
.cv-item { position: relative; padding-bottom: var(--s-6); }
.cv-item::before { content: ""; position: absolute; left: calc(-1 * var(--s-8) - 5px); top: 6px; width: 8px; height: 8px; border-radius: 50%; background: var(--c-primary); }
.cv-item h3 { font-size: var(--fs-base); font-weight: var(--fw-semi); }
.cv-item .cv-item__meta { font-size: var(--fs-sm); color: var(--c-text-3); margin-top: 2px; }
.cv-item p, .cv-item li { color: var(--c-text-2); font-size: var(--fs-sm); margin-top: var(--s-2); }

/* ---------- CTA banner ---------- */
.cta-banner {
  position: relative; overflow: hidden;
  background: var(--c-gradient); border-radius: var(--r-2xl);
  color: #fff; text-align: center; padding: var(--s-16) var(--s-8);
  box-shadow: var(--shadow-lg);
}
.cta-banner h2 { color: #fff; font-size: var(--fs-h2); margin-bottom: var(--s-4); }
.cta-banner p { color: rgba(255,255,255,.85); max-width: 560px; margin: 0 auto var(--s-8); }
.cta-banner .dots {
  position: absolute; inset: 0; opacity: .5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='26' height='26'%3E%3Ccircle cx='2' cy='2' r='1.6' fill='%23ffffff' fill-opacity='.18'/%3E%3C/svg%3E");
}

/* ---------- Footer ---------- */
.site-footer { background: #0B1220; color: #94A3B8; padding: var(--s-16) 0 var(--s-8); margin-top: var(--s-20); }
.site-footer__grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1.3fr; gap: var(--s-10); }
.site-footer h4 { color: #fff; font-size: var(--fs-sm); margin-bottom: var(--s-4); text-transform: uppercase; letter-spacing: .05em; }
.site-footer a { color: #94A3B8; }
.site-footer a:hover { color: #fff; }
.site-footer ul { list-style: none; padding: 0; }
.site-footer ul li { margin-bottom: var(--s-2); font-size: var(--fs-sm); }
.site-footer .footer-brand { font-size: var(--fs-lg); font-weight: var(--fw-extra); color: #fff; margin-bottom: var(--s-3); display: flex; align-items: center; gap: var(--s-3); }
.site-footer .footer-brand .brand-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--c-gradient); }
.site-footer__bottom { margin-top: var(--s-12); padding-top: var(--s-6); border-top: 1px solid rgba(148,163,184,.15); display: flex; flex-wrap: wrap; justify-content: space-between; gap: var(--s-4); font-size: var(--fs-xs); }

/* ---------- Social icons ---------- */
.socials { display: flex; gap: var(--s-3); }
.socials a {
  width: 40px; height: 40px; border-radius: var(--r-md);
  display: flex; align-items: center; justify-content: center;
  background: rgba(255,255,255,.06); color: #94A3B8;
  transition: all .2s ease;
}
.socials a:hover { background: var(--c-gradient); color: #fff; transform: translateY(-2px); }

/* ---------- Misc ---------- */
.page-title { padding: var(--s-16) 0; }
.prose { max-width: 760px; }
.prose p { margin-bottom: var(--s-4); color: var(--c-text-2); }
.prose ul, .prose ol { margin-bottom: var(--s-4); color: var(--c-text-2); }
.prose h2 { margin: var(--s-12) 0 var(--s-4); }
.prose h3 { margin: var(--s-8) 0 var(--s-3); }
.prose a { font-weight: var(--fw-med); }
.prose blockquote { border-left: 4px solid var(--c-primary); padding: var(--s-4) var(--s-6); background: var(--c-bg-tint); border-radius: 0 var(--r-md) var(--r-md) 0; margin: var(--s-6) 0; font-style: italic; color: var(--c-text-2); }

.redirect-note { font-size: var(--fs-xs); color: var(--c-text-3); }

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--5 { grid-template-columns: repeat(3, 1fr); }
  .hero__inner { grid-template-columns: 1fr; gap: var(--s-10); }
  .site-footer__grid { grid-template-columns: 1fr 1fr; }
  .contact-layout { grid-template-columns: 1fr; gap: var(--s-8); }
  .pub-detail-grid { grid-template-columns: 1fr !important; }
  .hero__profile { gap: var(--s-8); }
}

@media (max-width: 900px) {
  .nav-toggle { display: flex; }
  .site-nav__menu {
    position: absolute; top: var(--nav-height); left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: #fff; border-bottom: 1px solid var(--c-border);
    box-shadow: var(--shadow-lg); padding: var(--s-3);
    display: none;
  }
  .site-nav__menu.open { display: flex; }
  .site-nav__menu a { padding: var(--s-3) var(--s-4); border-radius: var(--r-md); }
  .stats { grid-template-columns: repeat(2, 1fr); gap: var(--s-3); }
}

@media (max-width: 640px) {
  .section { padding: var(--s-12) 0; }
  .grid--2, .grid--3 { grid-template-columns: 1fr; }
  .grid--4, .grid--5 { grid-template-columns: repeat(2, 1fr); }
  .hero { padding-top: var(--s-16); }
  .hero__profile { flex-direction: column; gap: var(--s-8); text-align: center; }
  .hero__photo { width: min(100%, 220px); }
  .hero__contact { grid-template-columns: 1fr; gap: var(--s-2); justify-items: center; }
  .hero__ctas { justify-content: center; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .site-footer__grid { grid-template-columns: 1fr; gap: var(--s-8); }
  .pub { flex-direction: column; }
}

/* ---------- 详情页小节标题 ---------- */
.pub-section-title {
  font-size: var(--fs-h3); font-weight: var(--fw-bold); margin-bottom: var(--s-4);
  display: flex; align-items: center; gap: var(--s-3);
}
.pub-section-title::before { content: ""; width: 4px; height: 1.05em; border-radius: 2px; background: var(--c-gradient); }

/* ---------- 课程资料站 ---------- */
.course-meta { display: flex; flex-wrap: wrap; gap: var(--s-4); margin-bottom: var(--s-8); }
.course-meta .cm-item {
  display: inline-flex; align-items: center; gap: var(--s-2);
  font-size: var(--fs-sm); color: var(--c-text-2);
  background: var(--c-bg-alt); border: 1px solid var(--c-border); border-radius: var(--r-full);
  padding: var(--s-2) var(--s-4);
}
.course-meta .cm-item .icon { width: 15px; height: 15px; color: var(--c-primary); }
.course-resource-list { list-style: none; padding: 0; }
.course-resource-list li {
  display: flex; align-items: center; justify-content: space-between; gap: var(--s-4);
  padding: var(--s-3) 0; border-bottom: 1px solid var(--c-border);
}
.course-resource-list li:last-child { border-bottom: 0; }
.course-resource-list .rl-title { display: flex; align-items: center; gap: var(--s-3); color: var(--c-text-2); font-size: var(--fs-sm); }
.course-resource-list .rl-title .icon { width: 16px; height: 16px; color: var(--c-primary); }

/* ---------- 招生流程流线 ---------- */
.flow-steps { display: flex; gap: var(--s-4); margin: var(--s-10) 0 var(--s-12); align-items: stretch; }
.flow-step {
  flex: 1; text-align: center; padding: var(--s-8) var(--s-4);
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); position: relative; box-shadow: var(--shadow-sm);
  transition: all .25s var(--ease-out);
}
.flow-step:hover { box-shadow: var(--shadow-glow); transform: translateY(-4px); }
.flow-step__num {
  width: 44px; height: 44px; margin: 0 auto var(--s-4); border-radius: 50%;
  background: var(--c-gradient); color: #fff; font-weight: var(--fw-extra);
  display: flex; align-items: center; justify-content: center; box-shadow: var(--shadow-md);
}
.flow-step h4 { font-size: var(--fs-base); margin-bottom: var(--s-2); }
.flow-step p { font-size: var(--fs-sm); color: var(--c-text-2); }
.flow-step .icon-tile { margin: 0 auto var(--s-3); }
.flow-arrow { display: flex; align-items: center; color: var(--c-primary-400); font-size: var(--fs-xl); flex-shrink: 0; }
.flow-arrow .icon { width: 22px; height: 22px; }

/* 曲线分隔装饰 */
.section-wave { position: relative; }
.recruit-grid-bg {
  position: relative;
  background-image:
    linear-gradient(rgba(37,99,235,.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(37,99,235,.04) 1px, transparent 1px);
  background-size: 34px 34px;
}
.recruit-grid-bg::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 60%;
  background: radial-gradient(ellipse at 20% 0%, rgba(96,165,250,.12), transparent 60%),
              radial-gradient(ellipse at 80% 0%, rgba(124,58,237,.12), transparent 60%);
  pointer-events: none;
}

/* ---------- 语言切换按钮 ---------- */
.lang-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  padding: var(--s-2) var(--s-4); margin-left: var(--s-2);
  font-size: var(--fs-sm); font-weight: var(--fw-semi);
  color: var(--c-primary); background: var(--c-bg-tint);
  border: 1px solid var(--c-border); border-radius: var(--r-full);
  cursor: pointer; transition: all .2s var(--ease-out); white-space: nowrap;
}
.lang-toggle:hover { background: var(--c-gradient); color: #fff; border-color: transparent; }

/* ---------- 导航链接下划线动画 ---------- */
.site-nav__menu a { position: relative; }
.site-nav__menu a::after {
  content: ""; position: absolute; left: var(--s-4); right: var(--s-4); bottom: 4px;
  height: 2px; border-radius: 2px; background: var(--c-primary);
  transform: scaleX(0); transform-origin: left; transition: transform var(--dur-med) var(--ease-out);
}
.site-nav__menu a:hover::after, .site-nav__menu a.active::after { transform: scaleX(1); }

/* ---------- 按钮变体 ---------- */
.btn--outline {
  background: var(--c-bg); color: var(--c-primary);
  border: 1.5px solid var(--c-border-2); box-shadow: none; padding: var(--s-2) var(--s-4);
}
.btn--outline:hover { border-color: var(--c-primary); color: var(--c-primary-600); background: var(--c-bg-tint); box-shadow: var(--shadow-sm); }
.btn--outline .icon { width: 16px; height: 16px; }

/* ---------- Hero 身份卡 ---------- */
.hero__panel { display: flex; justify-content: center; align-items: center; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
.hero__inner > div:first-child { animation: fadeUp .55s var(--ease-out) both; }

/* ---------- 图文论文卡（首页精选）---------- */
.pub-card {
  display: flex; gap: var(--s-6); align-items: stretch;
  background: var(--c-bg); border: 1px solid var(--c-border);
  border-radius: var(--r-lg); overflow: hidden;
  box-shadow: var(--shadow-sm); transition: all .25s var(--ease-out);
}
.pub-card:hover { box-shadow: var(--shadow-glow); transform: translateY(-4px); }
.pub-card__media { width: 200px; flex-shrink: 0; display: block; }
.pub-card__media img { width: 100%; height: 100%; object-fit: cover; }
.pub-card__body { padding: var(--s-6) var(--s-6) var(--s-6) 0; display: flex; flex-direction: column; min-width: 0; }
.pub-card__title { font-size: var(--fs-base); margin: var(--s-3) 0 var(--s-2); }
.pub-card__title a { color: var(--c-text); }
.pub-card__title a:hover { color: var(--c-primary); }
.pub-card__excerpt { color: var(--c-text-2); font-size: var(--fs-sm); margin-top: var(--s-2); }
.pub-card__actions { display: flex; flex-wrap: wrap; gap: var(--s-3); margin-top: auto; padding-top: var(--s-4); }

/* ---------- 论文动作按钮行 ---------- */
.pub-actions { display: flex; flex-wrap: wrap; gap: var(--s-3); }

/* ---------- Publications 排序工具栏 ---------- */
.pub-toolbar { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: var(--s-4); margin-bottom: var(--s-8); }
.seg { display: inline-flex; background: var(--c-bg-alt); border: 1px solid var(--c-border); border-radius: var(--r-full); padding: 3px; }
.seg button {
  border: 0; background: transparent; cursor: pointer;
  padding: var(--s-2) var(--s-5); border-radius: var(--r-full);
  font-size: var(--fs-sm); font-weight: var(--fw-semi); color: var(--c-text-2);
  transition: all .2s var(--ease-out);
}
.seg button.active { background: var(--c-gradient); color: #fff; box-shadow: var(--shadow-md); }
.pub-group-head {
  font-size: var(--fs-h3); font-weight: var(--fw-bold); margin: var(--s-12) 0 var(--s-6);
  display: flex; align-items: center; gap: var(--s-3);
}
.pub-group-head::after { content: ""; flex: 1; height: 1px; background: var(--c-border); }

/* ---------- 弹窗（BibTeX / 学生详情）---------- */
.modal-overlay {
  position: fixed; inset: 0; z-index: 200; background: rgba(15,23,42,.55);
  backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px);
  opacity: 0; visibility: hidden; transition: opacity .25s var(--ease-out), visibility .25s;
}
.modal-overlay.visible { opacity: 1; visibility: visible; }
.modal, .student-dialog {
  position: fixed; top: 50%; left: 50%; z-index: 210;
  transform: translate(-50%, -46%); width: min(92vw, 640px); max-height: 80vh; overflow-y: auto;
  background: var(--c-bg); border-radius: var(--r-xl); box-shadow: var(--shadow-glow);
  padding: var(--s-8); opacity: 0; visibility: hidden;
  transition: opacity .25s var(--ease-out), transform .25s var(--ease-out), visibility .25s;
}
.modal.open, .student-dialog.open { opacity: 1; visibility: visible; transform: translate(-50%, -50%); }
.modal pre {
  background: var(--c-bg-alt); border: 1px solid var(--c-border); border-radius: var(--r-md);
  padding: var(--s-4); font-family: var(--font-mono); font-size: var(--fs-xs);
  white-space: pre-wrap; overflow-wrap: break-word; color: var(--c-text-2);
  max-height: 300px; overflow-y: auto; margin-bottom: var(--s-4);
}
.modal-close {
  position: absolute; top: var(--s-4); right: var(--s-4); width: 32px; height: 32px;
  border: 0; background: var(--c-bg-alt); border-radius: 50%; cursor: pointer;
  color: var(--c-text-2); font-size: 18px; line-height: 1; transition: all .2s;
}
.modal-close:hover { background: var(--c-danger); color: #fff; }
body.modal-open { overflow: hidden; }

/* ---------- 学生卡 / 详情 ---------- */
.student-card {
  text-align: center; padding: var(--s-4) var(--s-3);
  background: linear-gradient(160deg, rgba(37,99,235,.07), rgba(124,58,237,.07));
  border: 1px solid var(--c-border);
  border-radius: var(--r-md); box-shadow: var(--shadow-sm); cursor: pointer;
  transition: all .25s var(--ease-out);
}
.student-card:hover {
  background: linear-gradient(160deg, rgba(37,99,235,.16), rgba(124,58,237,.16));
  box-shadow: var(--shadow-glow); transform: translateY(-3px);
}
.student-card__avatar {
  width: 64px; height: 64px; border-radius: 50%; margin: 0 auto var(--s-2);
  background: var(--c-gradient-soft); display: flex; align-items: center; justify-content: center;
  color: var(--c-primary); font-size: var(--fs-lg); font-weight: var(--fw-extra);
  overflow: hidden;
}
.student-card__avatar img { width: 100%; height: 100%; object-fit: cover; }
.student-card h3 { font-size: var(--fs-sm); }
.student-card__meta { font-size: var(--fs-xs); color: var(--c-text-3); margin-top: 2px; }
.student-card .student-card__meta { font-size: var(--fs-sm); color: var(--c-text-3); margin-top: var(--s-1); }
.student-card .badge-current {
  display: inline-block; font-size: var(--fs-xs); font-weight: var(--fw-semi);
  color: var(--c-primary); background: var(--c-bg-tint); padding: 2px var(--s-2); border-radius: var(--r-full);
  margin-bottom: var(--s-2);
}
.student-dialog h3 { font-size: var(--fs-h3); margin-bottom: var(--s-2); }
.student-dialog .sd-meta { color: var(--c-text-3); font-size: var(--fs-sm); margin-bottom: var(--s-5); }
.student-dialog h4 {
  font-size: var(--fs-sm); text-transform: uppercase; letter-spacing: .05em;
  color: var(--c-text-3); margin: var(--s-5) 0 var(--s-2);
}
.student-dialog ul { color: var(--c-text-2); font-size: var(--fs-sm); padding-left: 1.1rem; }
.student-dialog li { margin-bottom: 4px; }

/* ---------- 联系表单 ---------- */
.contact-layout { display: grid; grid-template-columns: 1.1fr .9fr; gap: var(--s-12); align-items: start; }
.contact-group .contact-card { height: 100%; }
.contact-form-wrap { position: sticky; top: calc(var(--nav-height) + 24px); }
.contact-groups { display: flex; flex-direction: column; gap: var(--s-8); }
.contact-group h3 { font-size: var(--fs-base); display: flex; align-items: center; gap: var(--s-2); margin-bottom: var(--s-4); }
.contact-group h3 .icon { width: 18px; height: 18px; color: var(--c-primary); }
.contact-group .grid { gap: var(--s-3); }
.contact-card { position: relative; }
.copy-btn {
  position: absolute; top: var(--s-3); right: var(--s-3);
  border: 1px solid var(--c-border); background: var(--c-bg); color: var(--c-text-3);
  border-radius: var(--r-sm); padding: 2px var(--s-2); font-size: var(--fs-xs); cursor: pointer;
  transition: all .2s;
}
.copy-btn:hover { color: var(--c-primary); border-color: var(--c-primary); }

.contact-form-wrap {
  background: var(--c-bg); border: 1px solid var(--c-border); border-radius: var(--r-xl);
  padding: var(--s-8); box-shadow: var(--shadow-md);
}
.contact-form-wrap h2 { font-size: var(--fs-h3); margin-bottom: var(--s-2); }
.contact-form-wrap > p { color: var(--c-text-3); font-size: var(--fs-sm); margin-bottom: var(--s-6); }
.form-field { margin-bottom: var(--s-5); }
.form-field label { display: block; font-size: var(--fs-sm); font-weight: var(--fw-semi); margin-bottom: var(--s-2); }
.form-field input, .form-field textarea {
  width: 100%; border: 1px solid var(--c-border); border-radius: var(--r-md);
  padding: var(--s-3) var(--s-4); font-size: var(--fs-base); font-family: inherit;
  background: var(--c-bg); color: var(--c-text); transition: border-color .2s;
}
.form-field input:focus, .form-field textarea:focus { outline: none; border-color: var(--c-primary); box-shadow: 0 0 0 3px rgba(37,99,235,.12); }
.form-field textarea { min-height: 120px; resize: vertical; }
.type-options { display: flex; flex-wrap: wrap; gap: var(--s-3); margin-bottom: var(--s-6); }
.type-option { flex: 1 1 140px; cursor: pointer; }
.type-option input { position: absolute; opacity: 0; pointer-events: none; }
.type-option .type-label {
  display: flex; align-items: center; gap: var(--s-2); justify-content: center;
  padding: var(--s-3) var(--s-2); border: 1.5px solid var(--c-border); border-radius: var(--r-md);
  font-size: var(--fs-sm); font-weight: var(--fw-med); color: var(--c-text-2);
  transition: all .2s var(--ease-out);
}
.type-option .type-label .icon { width: 16px; height: 16px; }
.type-option input:checked + .type-label { border-color: var(--c-primary); background: var(--c-bg-tint); color: var(--c-primary); }
.type-option.active .type-label { border-color: var(--c-primary); background: var(--c-bg-tint); color: var(--c-primary); }
.form-hint {
  display: flex; align-items: center; gap: var(--s-3); margin-top: var(--s-4);
  background: var(--c-bg-tint); border-radius: var(--r-md); padding: var(--s-3) var(--s-4);
  font-size: var(--fs-sm); color: var(--c-text-2);
}
.form-hint.hidden { display: none; }

/* ---------- 滚动显现 ---------- */
.section-head, .card, .pub-card, .teaching-card, .contact-card, .cv-block {
  opacity: 1; transform: none; transition: opacity .5s var(--ease-out), transform .5s var(--ease-out);
}
@media (prefers-reduced-motion: no-preference) {
  .section-head, .card, .pub-card, .teaching-card, .contact-card, .cv-block { opacity: 0; transform: translateY(16px); }
  .revealed { opacity: 1; transform: none; }
}

/* ---------- 主题切换按钮 ---------- */
.theme-toggle {
  display: inline-flex; align-items: center; justify-content: center;
  width: 38px; height: 38px; margin-left: var(--s-2);
  border: 1px solid var(--c-border); background: var(--c-bg-alt);
  border-radius: 50%; cursor: pointer; color: var(--c-text-2);
  transition: all .2s var(--ease-out);
}
.theme-toggle:hover { color: var(--c-primary); border-color: var(--c-primary); transform: translateY(-1px); }
.theme-toggle .icon { width: 18px; height: 18px; }

/* ---------- 黑暗模式适配 ---------- */
html[data-theme="dark"] .site-nav { background: rgba(11,18,32,.85); }
html[data-theme="dark"] .site-nav__menu { background: var(--c-bg); }
html[data-theme="dark"] .site-nav__menu a { color: var(--c-text-2); }
html[data-theme="dark"] .site-nav__menu a:hover,
html[data-theme="dark"] .site-nav__menu a.active { color: var(--c-primary); background: var(--c-bg-tint); }
html[data-theme="dark"] .nav-toggle span { background: var(--c-text); }
html[data-theme="dark"] .card, html[data-theme="dark"] .pub, html[data-theme="dark"] .teaching-card,
html[data-theme="dark"] .contact-card, html[data-theme="dark"] .stat, html[data-theme="dark"] .pub-card,
html[data-theme="dark"] .student-card { background: linear-gradient(160deg, rgba(37,99,235,.16), rgba(124,58,237,.16)); }
html[data-theme="dark"] .student-card:hover { background: linear-gradient(160deg, rgba(37,99,235,.3), rgba(124,58,237,.3)); }
html[data-theme="dark"] .modal, html[data-theme="dark"] .student-dialog, html[data-theme="dark"] .contact-form-wrap { background: var(--c-bg-alt); }
html[data-theme="dark"] .prose blockquote { background: var(--c-bg-tint); }
html[data-theme="dark"] .btn--light { color: var(--c-primary-600); }
html[data-theme="dark"] .cta-banner .btn--light { color: var(--c-primary); }

/* ---------- 动画降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important; animation-iteration-count: 1 !important;
    transition-duration: .01ms !important; scroll-behavior: auto !important;
  }
}

/* ---------- Print ---------- */
@media print {
  .site-nav, .site-footer, .hero__ctas, .pub-actions, .contact-form-wrap { display: none !important; }
  .hero { background: #fff; color: var(--c-text); padding: var(--s-8) 0; }
  .hero h1, .hero .hero__role, .hero .hero__tagline { color: var(--c-text); }
  body { font-size: 12px; }
}