/* bupt.ai Portal v2. Editorial, responsive, and independent of application CSS. */
:root{color-scheme:light;--paper:#f5f4ef;--surface:#fff;--ink:#172b3a;--muted:#536874;--line:#d8dfdf;--accent:#1c6561;--warm:#995337;--radius:16px;font-family:Inter,"PingFang SC","Microsoft YaHei",system-ui,sans-serif}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:90px}body{margin:0;background:var(--paper);color:var(--ink);font-size:16px;line-height:1.7}a{color:inherit;text-underline-offset:4px}button,input{font:inherit}button,a,input{touch-action:manipulation}a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible{outline:3px solid #216aab;outline-offset:4px}[hidden]{display:none!important}.skip-link{position:fixed;left:12px;top:-90px;padding:10px 18px;z-index:9;background:var(--ink);color:#fff}.skip-link:focus{top:12px}.wrap{width:min(1240px,calc(100% - 64px));margin:auto}.site-header{border-bottom:1px solid var(--line);background:var(--paper)}.header-inner{min-height:84px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none}.brand-mark{display:grid;place-items:center;width:42px;height:42px;border:1px solid var(--ink);border-radius:11px;font-size:15px;font-weight:800;letter-spacing:-1px}.brand strong{display:block;font-size:24px;line-height:1.1;letter-spacing:-1px}.brand small{font-size:10px;letter-spacing:.16em;color:var(--muted)}.main-nav{display:flex;gap:24px;align-items:center}.main-nav a{font-size:14px;text-decoration:none;padding:8px 0}.main-nav a:hover{color:var(--accent)}.main-nav .lang{border-left:1px solid var(--line);padding-left:24px}.hero{padding:50px 0 34px;display:grid;grid-template-columns:1.3fr .8fr;gap:48px;align-items:end}.eyebrow{display:block;color:var(--accent);font-size:11px;letter-spacing:.16em;font-weight:750;text-transform:uppercase;margin:0 0 14px}.hero h1{font-size:clamp(32px,3.8vw,50px);letter-spacing:-.035em;line-height:1.3;margin:0;font-weight:700}.hero h1 span{color:var(--accent)}.hero .intro{margin:18px 0 0;max-width:660px;color:var(--muted);font-size:15px;line-height:1.85}.hero-note{padding:5px 0 5px 24px;border-left:2px solid var(--line);font-size:14px;color:var(--muted)}.hero-note strong{display:block;color:var(--ink);font-size:15px;margin-bottom:8px}.hero-note a{color:var(--accent);font-size:13px}.section{padding:24px 0 36px}.section-heading{display:flex;justify-content:space-between;align-items:flex-end;gap:22px;margin-bottom:20px}.section-heading h2{font-size:22px;line-height:1.35;margin:0;letter-spacing:-.025em}.section-heading .eyebrow{margin-bottom:5px;font-size:10px}.section-heading p{color:var(--muted);font-size:13px;margin:0}.section-heading>a{font-size:13px;color:var(--accent)}.entry-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.entry-card{display:flex;flex-direction:column;position:relative;min-height:234px;padding:25px 26px 21px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);text-decoration:none;transition:border-color .18s ease,transform .18s ease,box-shadow .18s ease}.entry-card:hover{border-color:#548680;transform:translateY(-3px);box-shadow:0 9px 20px #162b3710}.entry-card .card-meta{display:flex;justify-content:space-between;align-items:center;margin-bottom:22px}.card-category{color:var(--muted);font-size:10px;letter-spacing:.14em;font-weight:650}.card-icon{display:grid;place-items:center;width:34px;height:34px;background:#f1f5f4;color:var(--accent);border-radius:8px}.card-icon svg{width:21px;height:21px;stroke:currentColor;fill:none;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round}.entry-card h3{font-size:24px;line-height:1.25;letter-spacing:-.025em;margin:0 0 8px}.entry-card .subtitle{font-size:12px;font-weight:500;color:var(--muted);margin:0 0 10px}.entry-card .description{font-size:13px;color:var(--muted);line-height:1.7;margin:0 0 20px;max-width:34em}.card-bottom{display:flex;gap:12px;justify-content:space-between;align-items:center;margin-top:auto;border-top:1px solid #e5eaea;padding-top:13px;font-size:12px}.card-bottom .path{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;color:var(--muted);font-size:11px;overflow-wrap:anywhere}.card-bottom .go{color:var(--accent);white-space:nowrap}.entry-card.featured{background:var(--ink);color:#f7faf8;border-color:var(--ink)}.entry-card.featured .card-icon{background:#29424e;color:#b5d7c9}.entry-card.featured .card-category,.entry-card.featured .subtitle,.entry-card.featured .description,.entry-card.featured .path{color:#c6d5dc}.entry-card.featured .card-bottom{border-color:#45606b}.entry-card.featured .go{color:#c3e4d5}.search-tools{display:flex;align-items:center;gap:9px}.search-tools label{font-size:12px;color:var(--muted)}.search-tools input{max-width:230px;width:100%;border:1px solid var(--line);border-radius:8px;background:#fff;padding:9px 12px;font-size:13px}.search-tools button{border:0;background:none;color:var(--accent);font-size:12px;min-height:40px;cursor:pointer}.empty{padding:24px;background:#fff;border:1px solid var(--line);border-radius:12px}.search-status{font-size:12px;color:var(--muted);margin:8px 0 0;min-height:21px}.divider{border:0;border-top:1px solid var(--line);margin:0}.reading-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:28px}.reading-card{display:block;text-decoration:none;border-top:2px solid var(--ink);padding-top:18px}.reading-card .number{font:12px ui-monospace,monospace;color:var(--warm)}.reading-card h3{font-size:18px;margin:9px 0;line-height:1.5}.reading-card p{font-size:13px;color:var(--muted);margin:0 0 13px}.reading-card .read-more{font-size:12px;color:var(--accent)}.reading-card:hover h3{text-decoration:underline;text-underline-offset:5px}.research-band{padding:28px;border:1px solid var(--line);background:#eaf0ed;border-radius:var(--radius);display:grid;grid-template-columns:1fr 1fr;gap:36px;margin:8px 0 34px}.research-band h2{font-size:21px;margin:0 0 10px}.research-band p{font-size:14px;color:var(--muted);margin:0 0 10px}.research-band a{color:var(--accent);font-size:13px}.method-list{display:grid;gap:13px}.method-list div{border-bottom:1px solid #cbd7d1;padding-bottom:13px;font-size:13px;color:var(--muted)}.method-list div:last-child{border:0;padding-bottom:0}.method-list strong{color:var(--ink);display:inline-block;margin-right:14px}.faq details{border-top:1px solid var(--line);padding:15px 0}.faq summary{cursor:pointer;font-size:14px;font-weight:650}.faq details p{font-size:14px;color:var(--muted);max-width:900px;margin:10px 0 0}.site-footer{border-top:1px solid var(--line);padding:30px 0 20px}.footer-top{display:flex;justify-content:space-between;gap:28px}.footer-top p{font-size:12px;color:var(--muted);margin:7px 0;max-width:500px}.footer-nav{display:flex;flex-wrap:wrap;align-content:flex-start;gap:8px 20px;max-width:500px}.footer-nav a{font-size:12px;min-height:32px}.footer-bottom{display:flex;gap:22px;justify-content:space-between;margin-top:20px;border-top:1px solid var(--line);padding-top:14px;font-size:11px;color:var(--muted)}.visit-value{font-variant-numeric:tabular-nums}.article{max-width:840px;padding:40px 0 54px}.breadcrumb{font-size:12px;color:var(--muted);margin:0 0 24px}.article h1{font-size:clamp(29px,3vw,40px);line-height:1.4;letter-spacing:-.03em;margin:0 0 12px}.article .article-meta{color:var(--muted);font-size:12px;border-bottom:1px solid var(--line);padding:0 0 20px;margin-bottom:27px}.article h2{font-size:23px;line-height:1.5;margin:32px 0 12px}.article h3{font-size:18px;margin:23px 0 8px}.article p,.article li{font-size:16px;line-height:1.9}.article a{color:var(--accent)}.article pre{white-space:pre;overflow:auto;padding:20px;background:#182d3a;color:#eaf2ef;border-radius:10px;font:13px/1.8 ui-monospace,SFMono-Regular,Consolas,monospace}.article code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;overflow-wrap:anywhere}.callout{border-left:3px solid var(--accent);background:#edf2ee;padding:14px 20px;margin:20px 0}.callout p{margin:0}.table-scroll{overflow:auto}.article table{border-collapse:collapse;width:100%;font-size:14px}.article th,.article td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line)}.article th{background:#eaf0ed}.article .source-note{font-size:13px;color:var(--muted)}.article ul,.article ol{padding-left:23px}.noscript{padding:10px;border:1px solid var(--line);font-size:13px}.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
@media(max-width:1000px){.entry-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero{gap:24px;grid-template-columns:1.4fr 1fr}.main-nav{gap:16px}.reading-grid{gap:18px}}
@media(max-width:700px){.wrap{width:calc(100% - 32px)}.header-inner{flex-wrap:wrap;gap:12px;padding:18px 0}.main-nav{width:100%;justify-content:space-between;gap:10px}.main-nav a{font-size:12px}.main-nav .lang{padding-left:10px}.hero{grid-template-columns:1fr;gap:23px;padding:30px 0 20px}.hero h1{font-size:34px}.hero-note{font-size:13px}.entry-grid,.reading-grid,.research-band{grid-template-columns:1fr}.entry-card{min-height:212px;padding:21px}.entry-card .card-meta{margin-bottom:15px}.section-heading{align-items:flex-start;flex-direction:column;gap:12px}.section-heading p{font-size:12px}.search-tools{width:100%;flex-wrap:wrap;gap:8px}.search-tools input{max-width:none;flex:1;min-width:140px}.research-band{gap:22px;padding:22px}.footer-top,.footer-bottom{flex-direction:column;gap:12px}.article{padding-top:24px}.article p,.article li{font-size:15px}.article h2{font-size:21px}.reading-card{padding-top:14px;margin-bottom:10px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.entry-card{transition:none}.entry-card:hover{transform:none}}
@media print{body{background:#fff}.main-nav,.search-tools,.site-footer,.skip-link{display:none}.wrap{width:100%}.article{max-width:none}.entry-grid{grid-template-columns:repeat(2,1fr)}.entry-card{break-inside:avoid;box-shadow:none}.article pre{white-space:pre-wrap;color:#000;background:#f4f4f4}}
.access-label{display:inline-flex;align-self:flex-start;color:var(--muted);font-size:11px;line-height:1.6;border:1px solid var(--line);border-radius:5px;padding:3px 7px;margin:0 0 13px}.entry-card.featured .access-label{border-color:#55707a;color:#d4e6e7}.hero-note span{display:inline-block;margin-bottom:9px}
.search-tools label,.search-tools button{white-space:nowrap;flex-shrink:0}.search-tools input{width:220px}@media(max-width:700px){.search-tools input{width:auto}}

/* Public site identity: email-only contact, no operator profile. */
.contact-card{padding:24px;border:1px solid var(--line);border-radius:12px;background:#fff;margin:22px 0}
.contact-email{overflow-wrap:anywhere;word-break:break-word}
.contact-card>.contact-email{font-size:clamp(17px,2.4vw,25px);font-weight:650;color:var(--accent)}
.contact-card p{font-size:13px;color:var(--muted);margin:10px 0 0}

/* Portal navigation completion: retain existing reading routes outside tool filtering. */
.research-navigation{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:10px;margin:0 0 30px;padding:14px;background:#eaf0ed;border:1px solid var(--line);border-radius:12px}
.research-navigation a{display:flex;flex-direction:column;justify-content:center;gap:4px;min-height:70px;padding:10px 12px;border:1px solid transparent;border-radius:8px;text-decoration:none}
.research-navigation a:hover{background:#fff;border-color:var(--line)}
.research-navigation strong{color:var(--ink);font-size:14px;font-weight:650}
.research-navigation span{color:var(--muted);font-size:11px;line-height:1.6}
@media(max-width:1000px){.research-navigation{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:700px){.research-navigation{grid-template-columns:repeat(2,minmax(0,1fr));padding:10px;gap:4px}.research-navigation a{padding:8px}}
@media print{.research-navigation{break-inside:avoid}}