:root{--bg:#f6fafc;--surface:#fff;--pale:#eaf6fa;--pale2:#edf4f8;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--navy:#174b78;--title:#183a56;--body:#31485d;--muted:#687d8e;--line:#dce9f0;--footer:#123653;--radius:18px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:25px}body{margin:0;background:var(--bg);font-family:Arial,'PingFang SC','Microsoft YaHei',sans-serif;color:var(--body);font-size:16px;line-height:1.8;overflow-x:hidden}body.drawer-open{overflow:hidden}a{color:var(--navy);text-underline-offset:3px}a:hover{color:var(--blue)}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--sky);outline-offset:3px}button{font:inherit;cursor:pointer}.container{width:min(100% - 56px,1180px);margin-inline:auto}.skip-link{position:absolute;top:-100px;left:10px;background:#fff;padding:10px;z-index:101}.skip-link:focus{top:10px}.site-header{background:#fff;border-bottom:1px solid var(--line)}.topbar{height:72px;display:flex;align-items:center;gap:24px}.brand{display:inline-flex;align-items:center;min-width:0;text-decoration:none}.brand img{display:block;width:auto;height:auto;max-height:38px;max-width:210px;object-fit:contain}.brand-fallback{color:var(--navy);font-size:23px;font-weight:800;white-space:nowrap;line-height:1.15}.brand-fallback small,.footer-brand small{display:block;font-size:10px;letter-spacing:2.6px}.top-tagline{font-size:13px;letter-spacing:2px;color:var(--muted);margin:auto}.entry-btn{white-space:nowrap;display:inline-flex;align-items:center;gap:12px;text-decoration:none;background:var(--navy);color:white;border-radius:9px;padding:8px 20px;font-size:14px;font-weight:700;min-height:42px}.entry-btn:hover{color:#fff;background:#116ba2}.desktop-nav{background:var(--navy)}.nav-inner{height:48px;display:flex;align-items:stretch;justify-content:space-between;gap:10px}.nav-inner a{display:inline-flex;align-items:center;white-space:nowrap;color:#e6f6ff;font-size:14px;text-decoration:none;border-bottom:3px solid transparent;padding:2px 10px 0}.nav-inner a:hover,.nav-inner a[aria-current]{color:#fff;border-color:var(--cyan);background:rgba(255,255,255,.09)}.menu-toggle{display:none;width:40px;height:40px;border:1px solid var(--line);border-radius:9px;background:#fff;align-items:center;justify-content:center;flex-direction:column;gap:5px;flex-shrink:0}.menu-toggle span{width:18px;height:2px;background:var(--navy)}.quick-strip{background:#f0f8fb;border-bottom:1px solid var(--line)}.quick-inner{display:flex;justify-content:space-between;gap:24px;padding-block:10px;font-size:12px}.quick-inner>div{display:flex;flex-wrap:wrap;gap:12px;align-items:center}.quick-inner strong{color:var(--navy)}.quick-inner a{text-decoration:none;color:var(--muted)}.quick-inner a:hover{text-decoration:underline;color:var(--blue)}.main-content{padding-top:38px;padding-bottom:85px;min-height:65vh}h1,h2,h3{color:var(--title);line-height:1.38;margin-top:0}h1{font-size:clamp(32px,3.3vw,42px);letter-spacing:-.7px}h2{font-size:26px}h3{font-size:20px}p{margin:0 0 17px}section{margin-block:48px}section section{margin-block:25px}.eyebrow{display:inline-flex;align-items:center;gap:8px;color:var(--blue);font-weight:700;font-size:12px;letter-spacing:2px;text-transform:uppercase;margin-bottom:16px}.eyebrow:before{content:'';display:block;width:25px;height:2px;background:var(--cyan)}.lead{font-size:17px;color:#4b6477;max-width:790px}.hero{display:grid;grid-template-columns:minmax(0,56fr) minmax(0,44fr);align-items:center;gap:35px;background:linear-gradient(120deg,#fff 30%,#edf8fb);border:1px solid var(--line);border-radius:24px;padding:38px 42px;margin:0 0 56px}.hero h1{font-size:clamp(36px,3.4vw,42px)}.hero p{max-width:620px}.hero .hero-sub{font-size:14px;color:var(--muted)}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:24px}.btn-primary,.btn-secondary{display:inline-flex;min-height:44px;align-items:center;justify-content:center;border-radius:9px;padding:9px 19px;text-decoration:none;font-size:14px;font-weight:700}.btn-primary{background:linear-gradient(110deg,#188dc6,#174b78);color:white}.btn-primary:hover{color:white;filter:brightness(1.09)}.btn-secondary{border:1px solid #b3d6e8;background:white;color:var(--navy)}.media{display:flex;align-items:center;justify-content:center;margin:0;background:#eaf6fa;overflow:hidden;border-radius:15px;min-width:0;width:100%}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media--hero{height:clamp(250px,26vw,330px)}.media--feature{height:250px}.media--card{height:170px}.media--banner{height:220px}.media--mobile{height:350px;max-width:320px}.media--portrait{max-width:420px;margin-inline:auto}.media--wide{height:180px}.media--missing{border:1px solid #d9ebf2;background:linear-gradient(145deg,#eaf6fa,#dceff5)}.placeholder-shape{width:42%;height:42%;border:1px solid #b8d7e4;border-radius:13px;transform:rotate(-6deg);opacity:.55}.section-top{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:24px}.section-top p{margin:0;max-width:630px}.text-link{font-size:14px;font-weight:700;white-space:nowrap}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}.topic-card{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:22px;min-width:0;text-decoration:none;transition:border-color .15s,transform .15s}.topic-card:hover{transform:translateY(-3px);border-color:#86cddd}.topic-card .number{color:var(--blue);font-size:12px;font-weight:700;display:block;margin-bottom:10px}.topic-card h3{font-size:18px;margin-bottom:9px}.topic-card p{font-size:14px;color:var(--muted);margin:0;line-height:1.75}.editor-grid{display:grid;grid-template-columns:2fr 1fr;gap:17px}.editor-main{background:var(--navy);border-radius:18px;padding:32px;color:#ecf7fd}.editor-main h3{font-size:25px;color:white}.editor-main p{color:#daedfb}.editor-main a{color:white;font-weight:700}.editor-side{display:grid;gap:16px}.editor-side article{background:#fff;border:1px solid var(--line);border-radius:16px;padding:20px}.editor-side h3{font-size:18px;margin:0 0 8px}.editor-side p{font-size:14px;color:var(--muted);margin-bottom:10px}.split-section{display:grid;grid-template-columns:1fr 1fr;gap:35px;align-items:center}.split-section.reverse .media{order:0}.split-section ul{padding-left:21px}.feature-band{background:#edf6fa;border:1px solid var(--line);border-radius:18px;padding:28px}.feature-columns{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.feature-columns article{padding:20px 0;border-top:3px solid var(--cyan)}.feature-columns h3{font-size:18px}.feature-columns p{font-size:15px;color:var(--muted)}.steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;counter-reset:step}.steps article{border-left:2px solid #9adce2;padding-left:18px;position:relative}.steps article:before{counter-increment:step;content:counter(step,decimal-leading-zero);color:var(--blue);font-size:13px;font-weight:800}.steps h3{font-size:18px;margin:5px 0 8px}.steps p{font-size:14px;color:var(--muted)}.article-head{max-width:850px;margin:12px 0 35px}.article-head h1{font-size:35px}.article-head .lead{max-width:790px}.reading-layout{display:grid;grid-template-columns:minmax(0,760px) minmax(0,240px);gap:32px;align-items:start}.prose h2{margin-top:34px}.prose h3{margin-top:20px}.prose p,.prose li{line-height:1.85}.prose ul,.prose ol{padding-left:24px}.prose>section:first-child{margin-top:0}.note{padding:19px 22px;border-left:4px solid var(--cyan);background:var(--pale);border-radius:0 10px 10px 0;font-size:15px}.aside-box{background:#fff;border:1px solid var(--line);border-radius:15px;padding:22px;position:sticky;top:20px}.aside-box h2{font-size:20px}.aside-box dl{margin:0}.aside-box dt{font-weight:bold;color:var(--title);margin-top:13px}.aside-box dd{margin:2px 0 10px;font-size:14px;color:var(--muted)}.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:14px;background:white}.data-table{width:100%;border-collapse:collapse;min-width:560px;text-align:left;font-size:15px}.data-table th{background:#eaf6fa;color:var(--title);font-weight:700}.data-table th,.data-table td{padding:13px 16px;border-bottom:1px solid var(--line);vertical-align:top}.data-table tr:last-child td{border-bottom:0}.matrix{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.matrix article{background:white;padding:23px;border:1px solid var(--line);border-radius:15px}.matrix h3{margin-bottom:8px}.matrix p{font-size:15px}.matrix strong{color:var(--navy)}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}.gallery article{background:white;border:1px solid var(--line);padding:18px;border-radius:16px}.gallery h3{margin:16px 0 8px}.gallery p{font-size:15px;color:var(--muted)}.inpage{display:flex;flex-wrap:wrap;gap:10px;margin:16px 0 30px}.inpage a{border-radius:7px;border:1px solid #bcdae7;padding:6px 12px;text-decoration:none;font-size:14px;background:white}.number-list{counter-reset:num;display:grid;gap:13px}.number-list article{background:#fff;border:1px solid var(--line);padding:17px 20px;border-radius:12px}.number-list h3:before{counter-increment:num;content:counter(num,decimal-leading-zero) '  ';color:var(--blue)}.number-list h3{font-size:18px;margin:0 0 6px}.number-list p{font-size:15px;margin:0}.faq-list{display:grid;gap:10px}.faq-list details{background:white;border:1px solid var(--line);border-radius:12px;padding:0 18px}.faq-list summary{cursor:pointer;font-weight:700;color:var(--title);padding:15px 0}.faq-list details p{margin:0 0 17px;font-size:15px}.related{border-top:1px solid var(--line);margin-top:50px;padding-top:30px}.related h2{font-size:24px}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.related-item{position:relative;background:white;border:1px solid var(--line);border-radius:12px;padding:19px 39px 19px 19px;text-decoration:none;display:flex;flex-direction:column;gap:7px}.related-item strong{color:var(--title)}.related-item span:not(.arrow){font-size:13px;color:var(--muted)}.related-item .arrow{position:absolute;top:16px;right:16px;color:var(--blue)}.site-footer{background:var(--footer);color:#eaf7ff}.footer-grid{display:grid;grid-template-columns:1.25fr 1fr;gap:80px;padding:42px 0}.footer-brand{font-size:22px;font-weight:800;line-height:1.3}.footer-grid p{font-size:14px;color:#cbdfeb;margin-top:12px}.footer-grid .fine{font-size:12px;max-width:580px}.footer-grid h2{color:#fff;font-size:18px}.footer-links{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:9px}.footer-links a,.footer-bottom a{font-size:13px;color:#d2e7f4;text-decoration:none}.footer-bottom{border-top:1px solid #32617c;padding:18px 0;display:flex;justify-content:space-between;font-size:12px;color:#c5dbe7}.drawer,.drawer-overlay{visibility:hidden;pointer-events:none}.drawer-overlay{position:fixed;inset:0;background:rgba(11,36,54,.5);z-index:99;opacity:0;transition:opacity .2s,visibility .2s}.drawer-overlay.is-open{visibility:visible;pointer-events:auto;opacity:1}.drawer{position:fixed;top:0;left:0;bottom:0;width:min(86vw,344px);background:white;z-index:100;overflow-y:auto;transform:translateX(-105%);transition:transform .2s,visibility .2s;padding:19px 22px}.drawer.is-open{visibility:visible;pointer-events:auto;transform:translateX(0)}.drawer-head{display:flex;align-items:center;justify-content:space-between;color:var(--navy);font-weight:800;font-size:20px;padding-bottom:18px;border-bottom:1px solid var(--line)}.drawer-close{width:40px;height:40px;border:0;border-radius:8px;background:#edf6fa;font-size:28px;line-height:1}.drawer-group{padding:17px 0;border-bottom:1px solid var(--line)}.drawer-group p{font-size:12px;font-weight:700;color:var(--muted);margin-bottom:6px}.drawer-group a{display:block;text-decoration:none;padding:8px 5px;font-size:16px;font-weight:600}.mobile-bottom{display:none}.back-top{position:fixed;right:25px;bottom:24px;width:42px;height:42px;border:0;background:var(--navy);color:white;border-radius:50%;opacity:0;pointer-events:none;transform:translateY(8px);transition:.15s}.back-top.visible{opacity:1;pointer-events:auto;transform:none}
@media(max-width:1180px){.container{width:min(100% - 44px,1180px)}.topic-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.reading-layout{grid-template-columns:minmax(0,1fr) 230px}}
@media(max-width:980px){.topbar{height:64px;justify-content:space-between;gap:12px}.menu-toggle{display:flex}.brand{margin:auto}.brand img{max-height:30px;max-width:175px}.brand-fallback{font-size:19px}.top-tagline,.desktop-nav{display:none}.entry-btn{min-height:40px;padding:6px 12px;font-size:13px}.quick-inner{flex-wrap:wrap;gap:5px 20px}.hero{padding:30px;gap:25px}.reading-layout{grid-template-columns:minmax(0,1fr) 220px}.footer-grid{gap:30px}}
@media(max-width:760px){.container{width:calc(100% - 32px)}.main-content{padding-top:23px;padding-bottom:105px}.hero{grid-template-columns:minmax(0,1fr);gap:19px;padding:22px}.hero .media{grid-row:1}.hero h1{font-size:30px}.hero p{font-size:15px}.hero .media--hero{height:210px}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.editor-grid,.split-section,.reading-layout{grid-template-columns:minmax(0,1fr)}.split-section .media{order:-1}.aside-box{position:static}.matrix,.feature-columns,.related-grid{grid-template-columns:1fr}.steps{grid-template-columns:repeat(2,minmax(0,1fr))}.gallery{grid-template-columns:1fr}.article-head h1{font-size:28px}.quick-inner{max-height:88px;overflow-x:auto;flex-wrap:nowrap;white-space:nowrap}.quick-inner>div{flex-wrap:nowrap}.footer-grid{grid-template-columns:1fr}.mobile-bottom{position:fixed;display:grid;grid-template-columns:repeat(4,1fr);left:0;right:0;bottom:0;z-index:50;background:#fff;box-shadow:0 -2px 16px rgba(13,61,90,.10);padding-bottom:env(safe-area-inset-bottom)}.mobile-bottom a{text-align:center;min-height:52px;display:grid;place-items:center;color:var(--navy);font-size:13px;text-decoration:none;font-weight:700}.mobile-bottom a[aria-current]{color:var(--blue);border-top:3px solid var(--cyan)}.back-top{bottom:calc(65px + env(safe-area-inset-bottom));right:16px}.site-footer{padding-bottom:calc(54px + env(safe-area-inset-bottom))}}
@media(max-width:640px){h1{font-size:29px}h2{font-size:22px}h3{font-size:18px}section{margin-block:32px}.lead{font-size:15px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.media--wide{height:145px}.section-top{display:block}.section-top .text-link{display:inline-block;margin-top:10px}.topic-card{padding:15px}.topic-card h3{font-size:16px}.topic-card p{font-size:13px}.editor-main{padding:23px}.feature-band{padding:18px}.steps{grid-template-columns:1fr}.footer-links{grid-template-columns:repeat(2,1fr)}.footer-bottom{flex-wrap:wrap;gap:8px}.entry-btn{padding:6px 9px;gap:4px}.brand-fallback{font-size:16px}.brand-fallback small{font-size:8px;letter-spacing:1px}}
@media(max-height:470px) and (max-width:760px){.mobile-bottom{position:static}.back-top{bottom:15px}.site-footer{padding-bottom:0}.main-content{padding-bottom:50px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}