/* Chinese-first navigation and bilingual content. */
body{font-family:Inter,ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei","Noto Sans CJK SC",Helvetica,Arial,sans-serif}
.section-head{display:block}
.section-actions{margin-top:16px}
.nav-in{gap:18px}
.brand{margin-right:auto;flex-shrink:0}
.nav-links{gap:18px}
.nav-tools{display:flex;align-items:center;gap:8px;flex-shrink:0}
.lang-btn{font-weight:600;line-height:1.2;font-family:inherit;font-size:12px;min-width:44px;min-height:34px;padding:7px 10px;border:1px solid var(--line);border-radius:999px;color:var(--navy);background:var(--paper);cursor:pointer}
.lang-btn:hover{border-color:var(--navy)}
.lang-btn:focus-visible,.menu-btn:focus-visible{outline:2px solid var(--blue);outline-offset:3px}
.nav-cta.active{font-weight:700}
html[lang="zh-CN"] .hero h1,html[lang="zh-CN"] .page-hero h1,html[lang="zh-CN"] .section-title,html[lang="zh-CN"] .article h2,html[lang="zh-CN"] .article h3,html[lang="zh-CN"] .callout h2,html[lang="zh-CN"] .research-card h3{font-family:"PingFang SC","Microsoft YaHei","Noto Sans CJK SC",sans-serif;letter-spacing:0;font-weight:650}
html[lang="zh-CN"] .hero h1{font-size:42px}
html[lang="zh-CN"] .hero .lede,html[lang="zh-CN"] .article p,html[lang="zh-CN"] .article li{line-height:1.8}
html[lang="zh-CN"] .section-title{font-size:28px}
html[lang="zh-CN"] .research-card h3{font-size:20px;line-height:1.4}
html[lang="zh-CN"] .project-card .type{letter-spacing:.03em}
@media(max-width:980px){.nav-links{gap:13px;font-size:12px}.nav-in{gap:14px}}
@media(max-width:900px){
  .nav-in{position:relative}
  .nav-links{position:absolute;left:0;right:0;top:100%;padding:16px 20px;display:none;flex-direction:column;align-items:flex-start;gap:8px;background:var(--paper);border-bottom:1px solid var(--line);font-size:14px}
  .nav-links.open{display:flex}
  .nav-links a{padding:7px 0}
  .nav-links .nav-cta{padding:7px 13px}
  .menu-btn{display:block;min-width:40px;min-height:40px;padding:4px}
}
@media(max-width:720px){
  html[lang="zh-CN"] .hero h1{font-size:34px}
  html[lang="zh-CN"] .page-hero h1{font-size:30px}
  html[lang="zh-CN"] .section-title{font-size:25px}
  html[lang="zh-CN"] .callout h2{font-size:25px}
  .nav-tools{gap:5px}
}