:root{--bg:#F6FAFC;--white:#fff;--pale:#EAF6FA;--pale2:#EDF4F8;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--ocean:#174B78;--title:#183A56;--body:#31485D;--muted:#687D8E;--line:#DCE9F0;--footer:#123653;--radius:18px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:145px}body{margin:0;background:var(--bg);color:var(--body);font:16px/1.8 Arial,'PingFang SC','Microsoft YaHei',sans-serif;overflow-x:hidden}img{max-width:100%;height:auto}a{color:var(--ocean);text-underline-offset:4px}a:hover{color:#0879b2}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--sky);outline-offset:3px}button{font:inherit;cursor:pointer}.wrap{width:min(1180px,calc(100% - 56px));margin-inline:auto}.section{margin-block:58px}.section-heading{margin-bottom:24px}.section-heading h2{margin:6px 0 0}.eyebrow{display:inline-block;color:#087d95;font-size:13px;font-weight:700;letter-spacing:.13em}.section-title{margin-bottom:12px}h1,h2,h3{line-height:1.38;color:var(--title);letter-spacing:-.018em}h1{font-size:clamp(32px,3.1vw,42px);margin:10px 0 21px}h2{font-size:26px;margin:0 0 18px}h3{font-size:20px;margin:0 0 11px}p{margin:0 0 17px}ul,ol{padding-left:1.45em}li+li{margin-top:8px}.muted{color:var(--muted)}.lead{font-size:17px;max-width:780px}.site-header{background:#fff;box-shadow:0 1px 0 var(--line);position:relative;z-index:10}.topbar{height:72px;display:flex;align-items:center;gap:22px}.brand{display:flex;align-items:center;text-decoration:none;min-width:0}.brand img{display:block;width:auto;height:auto;max-height:38px;max-width:220px;object-fit:contain}.brand-text{color:var(--ocean);font-size:21px;line-height:1.05;font-weight:800;white-space:nowrap}.brand-text small{display:block;font-size:10px;letter-spacing:.16em;margin-top:5px}.topbar-note{margin:0 auto;color:var(--muted);font-size:14px;white-space:nowrap}.entry-button{margin-left:auto;border-radius:9px;background:var(--ocean);color:#fff;text-decoration:none;font-weight:700;font-size:14px;padding:8px 19px;white-space:nowrap}.entry-button:hover{color:#fff;background:#0d6191}.desktop-nav{background:var(--ocean)}.nav-links{display:flex;justify-content:space-between;align-items:stretch;min-height:48px;gap:5px}.nav-links a{color:#e9f5ff;text-decoration:none;display:flex;align-items:center;padding:9px 13px;border-bottom:3px solid transparent;white-space:nowrap;font-size:14px}.nav-links a:hover,.nav-links a[aria-current]{color:#fff;border-bottom-color:#51e0e4;background:#ffffff12}.menu-trigger{display:none}.mobile-drawer,.drawer-overlay{display:none}.skip-link{position:absolute;top:-100px;left:12px;background:var(--ocean);color:#fff;padding:9px 16px;z-index:90}.skip-link:focus{top:8px}.hero{display:grid;grid-template-columns:56fr 44fr;gap:35px;align-items:center;padding-block:40px 14px}.hero-copy{padding-block:17px}.hero h1{font-size:clamp(32px,3.2vw,42px)}.hero p{max-width:600px}.hero-links{display:flex;gap:12px;flex-wrap:wrap;margin-top:23px}.button-primary,.button-secondary{padding:10px 19px;font-size:15px;text-decoration:none;border-radius:9px;font-weight:700;display:inline-block}.button-primary{background:linear-gradient(120deg,#1787DB,#1385b2);color:#fff}.button-primary:hover{color:#fff;background:#126999}.button-secondary{border:1px solid #bad5e2;background:#fff}.quickbar{border-top:1px solid var(--line);border-bottom:1px solid var(--line);background:#fff;padding:14px 0}.quickbar-inner{display:flex;gap:18px 26px;justify-content:space-between;flex-wrap:wrap}.quickbar span{font-weight:700;color:var(--title);margin-right:10px}.quickbar a{margin-right:12px;font-size:14px}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.topic-card{padding:22px;border:1px solid var(--line);background:#fff;border-radius:13px;text-decoration:none;display:block;transition:border-color .15s,transform .15s}.topic-card:hover{border-color:var(--sky);transform:translateY(-2px)}.topic-card strong{display:block;color:var(--title);font-size:18px;margin-bottom:8px}.topic-card p{font-size:14px;color:var(--muted);margin:0}.topic-card .arrow{display:block;text-align:right;color:#1787DB}.editorial-layout{display:grid;grid-template-columns:2fr 1fr;gap:17px}.editorial-main{border-radius:16px;background:var(--pale);padding:32px}.editorial-aside{display:grid;gap:17px}.editorial-aside article{padding:24px;border:1px solid var(--line);border-radius:16px;background:white}.text-link{font-weight:700;text-decoration:underline}.feature-row{display:grid;grid-template-columns:1fr 1fr;gap:32px;align-items:center}.feature-row.reverse .feature-copy{order:2}.feature-row.reverse .media{order:1}.feature-copy{min-width:0}.rule-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.rule-card{border-top:3px solid var(--sky);padding:22px;background:#fff;border-radius:0 0 14px 14px}.path-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;counter-reset:steps;list-style:none;padding:0}.path-steps li{background:#fff;border:1px solid var(--line);border-radius:12px;padding:20px;margin:0}.path-steps li:before{counter-increment:steps;content:'0' counter(steps);display:block;color:#0b8497;font-weight:800;margin-bottom:8px}.notice{background:var(--pale);border-left:3px solid var(--cyan);padding:20px 25px;border-radius:0 12px 12px 0;font-size:14px}.page-intro{padding-block:39px 22px}.page-intro h1{font-size:clamp(28px,2.8vw,36px);max-width:960px}.page-intro .lead{margin:0}.article-body{max-width:780px}.article-body h2{margin-top:30px}.article-body p{margin-bottom:18px}.content-panel{padding:27px;background:#fff;border:1px solid var(--line);border-radius:16px}.content-panel+.content-panel{margin-top:16px}.panel-muted{background:var(--pale)}.split{display:grid;grid-template-columns:1fr 1fr;gap:25px;align-items:start}.split-wide{display:grid;grid-template-columns:minmax(0,760px) minmax(0,240px);gap:28px;align-items:start}.term-sidebar{background:var(--pale2);padding:20px;border-radius:14px}.term-sidebar dl{margin:0}.term-sidebar dt{font-weight:700;color:var(--title);margin-top:13px}.term-sidebar dd{margin:0;font-size:14px}.data-table{width:100%;border-collapse:collapse;font-size:15px}.data-table th,.data-table td{text-align:left;padding:13px 14px;border-bottom:1px solid var(--line);vertical-align:top}.data-table th{color:var(--title);background:var(--pale2);font-weight:700}.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:12px;background:#fff}.table-scroll .data-table{min-width:570px}.timeline{list-style:none;padding:0;border-left:2px solid #a9dce9;margin-left:12px}.timeline li{margin:0 0 20px 23px;position:relative}.timeline li:before{content:'';position:absolute;left:-31px;top:9px;width:12px;height:12px;background:var(--cyan);border:3px solid #fff;border-radius:50%}.step-list{list-style:none;padding:0;counter-reset:steps;display:grid;gap:13px}.step-list li{counter-increment:steps;padding:17px 19px 17px 66px;border:1px solid var(--line);border-radius:14px;background:#fff;position:relative;margin:0}.step-list li:before{content:counter(steps);position:absolute;left:18px;top:15px;display:grid;place-items:center;width:31px;height:31px;background:var(--pale);color:var(--ocean);border-radius:50%;font-weight:700}.matrix{display:grid;grid-template-columns:repeat(3,1fr);gap:15px}.matrix article{border-radius:14px;background:#fff;border:1px solid var(--line);padding:22px}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.gallery article{background:white;border:1px solid var(--line);border-radius:16px;overflow:hidden;padding:15px}.gallery article h3,.gallery article p{margin-left:5px;margin-right:5px}.gallery article p{font-size:14px}.toc{display:flex;gap:10px;flex-wrap:wrap}.toc a{padding:7px 13px;border:1px solid #b9dce8;background:#fff;border-radius:7px;font-size:14px;font-weight:700;text-decoration:none}.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;color:var(--title);font-weight:700;padding:16px 22px 16px 0}.faq-list summary::marker{color:var(--blue)}.faq-list details p{padding-bottom:14px;margin-bottom:0}.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:15px}.related-link{display:flex;align-items:center;justify-content:space-between;padding:22px;background:#fff;border:1px solid var(--line);border-radius:13px;font-weight:700;text-decoration:none}.related-link:hover{border-color:var(--sky)}.media{display:flex;align-items:center;justify-content:center;min-width:0;width:100%;max-width:100%;margin:0;border-radius:14px;background:var(--pale);overflow:hidden;padding:12px}.media img{display:block;max-width:100%;max-height:100%;width:auto;height:auto;object-fit:contain;object-position:center}.media-placeholder{width:100%;height:100%;border:1px solid #cfebf1;border-radius:9px;background:linear-gradient(135deg,#e9f5f9,#d9edf3)}.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;margin:auto}.media--wide{padding:7px}.media--portrait{max-width:320px;margin-inline:auto}.site-footer{background:var(--footer);color:#EAF7FF;margin-top:65px;padding:40px 0 16px}.footer-layout{display:grid;grid-template-columns:2fr 1fr;gap:70px}.footer-layout strong{font-size:20px;color:#fff}.footer-layout strong span{font-size:11px;letter-spacing:.12em;font-weight:400}.footer-layout p{color:#d6e7f2;font-size:14px;max-width:650px}.footer-layout nav{display:flex;flex-wrap:wrap;gap:5px 15px;align-content:start}.footer-layout nav h2{font-size:16px;color:#fff;width:100%;margin-bottom:7px}.footer-layout nav a,.footer-bottom a{color:#ecfaff;font-size:14px}.footer-bottom{display:flex;justify-content:space-between;border-top:1px solid #ffffff22;padding-top:15px;margin-top:32px;color:#c5d9e7;font-size:13px}.mobile-bottom-nav{display:none}.to-top{position:fixed;right:20px;bottom:24px;width:42px;height:42px;border:0;border-radius:50%;background:var(--ocean);color:#fff;opacity:0;pointer-events:none;transition:opacity .2s}.to-top.visible{opacity:1;pointer-events:auto}
@media(max-width:980px){.wrap{width:calc(100% - 44px)}.topbar{height:64px;justify-content:space-between;gap:14px}.menu-trigger{display:flex;flex-direction:column;justify-content:center;align-items:center;gap:5px;width:40px;height:40px;border:1px solid var(--line);border-radius:9px;background:#fff;flex-shrink:0}.menu-trigger span{height:2px;width:19px;background:var(--ocean)}.brand{margin:auto}.brand img{max-height:30px;max-width:180px}.topbar-note,.desktop-nav{display:none}.entry-button{margin:0;padding:8px 12px;font-size:12px}.mobile-drawer{display:block;position:fixed;inset:0 auto 0 0;width:min(86vw,344px);max-height:100dvh;overflow:auto;background:#fff;z-index:31;transform:translateX(-105%);transition:transform .24s;visibility:hidden;padding:20px;box-shadow:9px 0 20px #10334a1c}.drawer-overlay{display:block;position:fixed;inset:0;background:#102b41a1;opacity:0;visibility:hidden;pointer-events:none;z-index:30;transition:opacity .24s}.drawer-open{overflow:hidden}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible}.drawer-open .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.drawer-head{display:flex;justify-content:space-between;align-items:center;padding-bottom:12px;border-bottom:1px solid var(--line);color:var(--title)}.drawer-close{border:0;background:var(--pale);border-radius:8px;width:40px;height:40px;font-size:29px;line-height:1}.drawer-group p{font-size:13px;color:var(--muted);font-weight:700;margin:22px 0 7px}.drawer-group a{display:block;text-decoration:none;padding:8px 9px;border-radius:7px}.drawer-group a[aria-current]{background:var(--pale);font-weight:700}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero{gap:22px}.editorial-layout{grid-template-columns:1.5fr 1fr}.split-wide{grid-template-columns:minmax(0,1fr) 220px}.mobile-bottom-nav{display:flex;position:fixed;bottom:0;left:0;right:0;z-index:20;background:#fff;border-top:1px solid var(--line);justify-content:space-around;padding:5px 8px calc(5px + env(safe-area-inset-bottom))}.mobile-bottom-nav a{color:var(--ocean);font-size:13px;text-decoration:none;padding:7px 17px;text-align:center}.mobile-bottom-nav a[aria-current]{font-weight:800;color:#007ea5}.site-footer{padding-bottom:80px}.to-top{bottom:75px}}
@media(max-width:760px){.wrap{width:calc(100% - 36px)}.hero,.feature-row,.editorial-layout,.split,.split-wide{grid-template-columns:1fr}.hero{padding-top:25px}.hero-copy{padding:0}.hero .media{max-width:680px}.feature-row.reverse .feature-copy,.feature-row.reverse .media{order:initial}.editorial-aside{grid-template-columns:repeat(2,1fr)}.rule-grid,.matrix{grid-template-columns:1fr}.gallery{grid-template-columns:1fr}.related-grid{grid-template-columns:1fr}.footer-layout{grid-template-columns:1fr;gap:22px}.term-sidebar{margin-top:4px}.section{margin-block:39px}.page-intro{padding-top:29px}.path-steps{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){body{font-size:15px;line-height:1.77}.wrap{width:calc(100% - 32px)}h1,.hero h1{font-size:29px}h2{font-size:22px}h3{font-size:18px}.lead{font-size:16px}.hero{gap:16px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.quickbar-inner{gap:7px}.quickbar-inner>div{width:100%}.quickbar span{display:inline-block;margin-right:5px}.topic-grid{grid-template-columns:1fr}.topic-card{padding:17px}.editorial-main,.editorial-aside article,.content-panel{padding:19px}.editorial-aside{grid-template-columns:1fr}.feature-row{gap:17px}.path-steps{gap:8px}.path-steps li{padding:13px}.brand img{max-height:28px;max-width:130px}.brand-text{font-size:15px}.brand-text small{font-size:8px}.entry-button{padding:7px 9px;font-size:12px}.entry-button span{display:none}.topbar{gap:7px}.hero-links{gap:9px}.button-primary,.button-secondary{font-size:14px;padding:10px 13px}.footer-bottom{gap:14px;flex-wrap:wrap}.mobile-bottom-nav a{padding:7px 12px}}
@media(max-height:480px) and (max-width:980px){.mobile-bottom-nav{position:static}.site-footer{padding-bottom:20px}.to-top{bottom:20px}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;animation-duration:.01ms!important;transition-duration:.01ms!important}}