/* 公共导航：教学栏目与账号操作分组，全站保持一致的当前页与触控反馈。 */
.site-header.site-shell{height:84px;gap:24px;position:relative;z-index:30;flex-wrap:nowrap}
.site-shell .logo{flex-shrink:0;min-height:44px}
.site-shell .site-navigation{width:auto;display:flex;flex-wrap:nowrap;gap:24px;font-size:15px;font-weight:600}
.site-sections{display:flex;align-items:center;gap:4px;padding:6px;background:transparent}
.site-shell .site-link{position:relative;display:flex;align-items:center;justify-content:center;gap:8px;min-height:44px;padding:0 15px;border:1px solid transparent;border-radius:0;color:#355466;white-space:nowrap;transition:color .16s}
.site-shell .site-link:hover{color:#116e64;background:transparent}
.site-shell .site-link[aria-current=page]{color:#126d62;background:transparent}
/* 用细线标记当前栏目，不再叠加底色与卡片阴影。 */
.site-link[aria-current=page]::after,.science-mobile-navigation a[aria-current=page]::after{content:"";position:absolute;bottom:0;left:15px;right:15px;height:2px;border-radius:2px;background:#188777}
.site-account-area{display:flex;align-items:center;gap:16px;border-left:1px solid #dbe5e9;padding-left:24px}
.site-shell .site-login{display:flex;align-items:center;justify-content:center;min-height:44px;padding:0 4px;color:#405e70;white-space:nowrap}
.site-shell .site-register{display:flex;align-items:center;justify-content:center;gap:12px;min-height:44px;padding:0 17px;border:1px solid #176e62;border-radius:10px;background:#176e62;color:white;white-space:nowrap;box-shadow:0 3px 7px #176e6214}
.site-shell .site-register:hover{background:#10594f;color:#fff}
.site-account-menu{position:relative}
.site-account-menu summary{display:flex;align-items:center;gap:9px;min-height:44px;padding:4px 8px 4px 4px;border:1px solid transparent;border-radius:12px;cursor:pointer;list-style:none;color:#355464;white-space:nowrap}
.site-account-menu summary::-webkit-details-marker{display:none}
.site-account-menu summary:hover,.site-account-menu[open] summary{background:transparent;color:#126d62}
.site-avatar{display:grid;place-items:center;width:34px;height:34px;border-radius:10px;background:transparent;color:#176e62}
.site-chevron{transition:transform .16s}
.site-account-menu[open] .site-chevron{transform:rotate(180deg)}
.site-account-panel{position:absolute;right:0;top:calc(100% + 12px);width:272px;max-width:calc(100vw - 28px);padding:8px;background:#fff;border:1px solid #dce6e9;border-radius:16px;box-shadow:0 16px 48px #173f5926,0 3px 8px #173f590a}
.site-account-identity{display:grid;gap:5px;padding:12px 12px 16px;margin-bottom:6px;border-bottom:1px solid #e8eef0}
.site-account-identity small{font-size:12px;font-weight:500;color:#687f8a}
.site-account-identity b{font-size:15px;font-weight:600;overflow-wrap:anywhere;line-height:1.5;color:#234b5d}
.site-shell .site-account-panel a,.site-shell .site-account-panel button{display:flex;align-items:center;gap:11px;width:100%;min-height:46px;padding:10px 12px;border:0;border-radius:9px;background:transparent;color:#405e6f;font-size:14px;font-weight:500;text-align:left}
.site-shell .site-account-panel a:hover{background:#edf5f2;color:#14685f}
.site-menu-arrow{margin-left:auto;color:#8a9ba4;font-size:21px}
.site-account-panel form{padding-top:6px;margin-top:6px!important;border-top:1px solid #e8eef0}
.site-shell .site-account-panel button:hover{background:#fff1ee;color:#a23c2f}
.site-shell :is(a,summary,button):focus-visible,.science-mobile-navigation a:focus-visible{outline:3px solid #299c8a;outline-offset:3px}
.science-mobile-navigation{display:none}
@media(max-width:1180px){.site-shell .site-navigation{gap:14px}.site-shell .site-link{padding:0 10px;gap:6px}.site-account-area{padding-left:14px;gap:12px}}
@media(max-width:1000px){
 .site-header.site-shell{height:72px;min-height:72px;padding:0;gap:12px}
 .site-shell .site-sections{display:none}
 .site-shell .site-navigation{width:auto;gap:0}
 .site-account-area{border:0;padding:0;gap:14px}
 .science-mobile-navigation{display:flex;justify-content:center;gap:8px;width:calc(100% - 28px);margin:0 auto;padding:4px 0 12px;border-bottom:1px solid #dbe6ed}
 .science-mobile-navigation a{position:relative;display:flex;align-items:center;justify-content:center;gap:7px;min-height:44px;padding:8px 18px;color:#355466;font-size:14px;font-weight:600;white-space:nowrap}
 .science-mobile-navigation a[aria-current=page]{background:transparent;color:#126d62}
 .science-mobile-navigation a:hover{background:transparent;color:#116e64}
}
@media(max-width:600px){
 .site-shell .site-register{display:none}
 .site-shell .site-login{padding:0 14px;border:1px solid #c3d8d1;border-radius:9px;color:#176e62;background:transparent}
 .site-account-label{display:none}
 .site-account-menu summary{gap:5px;padding-right:5px}
 .science-mobile-navigation{gap:4px}
 .science-mobile-navigation a{flex:1;gap:5px;padding:8px 3px;font-size:13px}
 .science-mobile-navigation svg{width:17px;height:17px;flex-shrink:0}
}
@media(max-width:360px){.science-mobile-navigation a{flex-direction:column;gap:4px;font-size:14px;min-height:60px}}
@media(prefers-reduced-motion:reduce){.site-shell .site-link,.site-chevron{transition:none}}