:root{--brand:#5698c3;--deep:#33789f;--ink:#17252f;--muted:#667783;--line:#dfe9ef;--soft:#f5f9fb;--blue-soft:#eaf4fa;--white:#fff;--page:min(1120px,calc(100% - 48px));--shadow:0 22px 65px rgba(40,93,126,.13)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:#fff;font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif;-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}button{font:inherit}.container{width:var(--page);margin:auto}
.header{height:72px;border-bottom:1px solid var(--line);background:rgba(255,255,255,.94);position:sticky;top:0;z-index:30;backdrop-filter:blur(16px)}.nav{height:100%;display:flex;align-items:center;justify-content:space-between}.brand{display:flex;align-items:center;gap:11px;font-size:20px;font-weight:700}.brand img{width:36px;height:36px;border-radius:11px}.nav-links{display:flex;align-items:center;gap:30px;color:#4d616c;font-size:14px}.nav-links a:hover{color:var(--deep)}.nav-cta,.button{border:0;border-radius:11px;background:var(--brand);color:#fff;padding:12px 18px;cursor:pointer}.menu{display:none;border:0;background:transparent;font-size:25px;cursor:pointer}
.hub-hero{padding:94px 0 72px;background:linear-gradient(180deg,#fff,#f5f9fb)}.hub-hero h1{margin:0;max-width:850px;font-size:58px;line-height:1.16;letter-spacing:-.045em;font-weight:650}.hub-hero p{max-width:710px;margin:24px 0 0;color:var(--muted);font-size:17px;line-height:1.9}.topic-nav{display:flex;gap:10px;margin-top:32px;flex-wrap:wrap}.topic-nav a{padding:9px 13px;border:1px solid var(--line);border-radius:9px;background:#fff;color:#526974;font-size:12px}
.question-section{padding:80px 0}.section-head{display:flex;justify-content:space-between;gap:40px;align-items:end;margin-bottom:35px}.section-head h2{margin:0;font-size:38px;letter-spacing:-.035em}.section-head p{max-width:480px;margin:0;color:var(--muted);line-height:1.7;font-size:14px}.question-list{border-top:1px solid var(--line)}.question-card{display:grid;grid-template-columns:70px 1fr 130px;gap:24px;align-items:center;padding:28px 0;border-bottom:1px solid var(--line);transition:padding .2s ease}.question-card:hover{padding-left:12px}.question-index{color:var(--brand);font-size:13px;font-weight:700}.question-card h3{margin:0;font-size:21px}.question-card p{margin:9px 0 0;color:var(--muted);font-size:13px;line-height:1.7}.read{color:var(--deep);font-size:13px;text-align:right}.read::after{content:" →"}
.hub-principle{padding:76px 0;background:#183242;color:#fff}.principle-grid{display:grid;grid-template-columns:.8fr 1.2fr;gap:80px}.principle-grid h2{margin:0;font-size:40px;line-height:1.25}.principle-grid p{margin:0;color:#c7d8e1;line-height:2}.principle-grid strong{color:#fff}
.breadcrumb{padding:28px 0;color:#748690;font-size:12px}.breadcrumb a{color:var(--deep)}.article-hero{padding:48px 0 72px;border-bottom:1px solid var(--line)}.article-hero h1{max-width:940px;margin:0;font-size:54px;line-height:1.2;letter-spacing:-.045em;font-weight:650}.direct-answer{max-width:900px;margin-top:30px;padding-left:20px;border-left:4px solid var(--brand);color:#425964;font-size:19px;line-height:1.9}.article-meta{display:flex;gap:22px;margin-top:28px;color:#86959d;font-size:12px}
.article-layout{display:grid;grid-template-columns:1fr 260px;gap:80px;padding:72px 0 90px}.article-body{max-width:760px}.article-body h2{margin:58px 0 18px;font-size:30px;letter-spacing:-.025em}.article-body h2:first-child{margin-top:0}.article-body h3{margin:32px 0 12px;font-size:20px}.article-body p,.article-body li{color:#536872;font-size:16px;line-height:2}.article-body ul{padding-left:22px}.answer-box{margin:34px 0;padding:28px;border-radius:16px;background:var(--blue-soft)}.answer-box strong{display:block;margin-bottom:10px;color:var(--deep)}.answer-box p{margin:0}.comparison{width:100%;border-collapse:collapse;margin:28px 0;font-size:14px}.comparison th,.comparison td{padding:16px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top;line-height:1.7}.comparison th{background:var(--soft)}.side{position:sticky;top:105px;align-self:start}.side-box{padding:22px;border:1px solid var(--line);border-radius:15px}.side-box b{font-size:14px}.side-box a{display:block;padding:11px 0;border-bottom:1px solid var(--line);color:#60737e;font-size:12px;line-height:1.55}.side-box a:last-child{border:0}.side-cta{margin-top:16px;padding:22px;border-radius:15px;background:var(--brand);color:#fff}.side-cta b{display:block;font-size:17px}.side-cta p{font-size:12px;line-height:1.7;color:#e8f4fa}.side-cta button{width:100%;padding:10px;border:0;border-radius:9px;background:#fff;color:var(--deep);cursor:pointer}
.related{padding:72px 0;background:var(--soft)}.related h2{margin:0 0 30px;font-size:32px}.related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.related-card{min-height:170px;padding:24px;border:1px solid var(--line);border-radius:15px;background:#fff}.related-card span{color:var(--brand);font-size:11px}.related-card h3{margin:15px 0 0;font-size:18px;line-height:1.5}.related-card p{color:var(--muted);font-size:12px;line-height:1.7}.footer{padding:50px 0 30px}.footer-main{display:flex;justify-content:space-between;gap:40px;padding-bottom:32px;border-bottom:1px solid var(--line)}.footer p{max-width:450px;color:var(--muted);font-size:12px;line-height:1.8}.footer-links{display:flex;gap:28px;color:#5e717c;font-size:12px}.copy{display:flex;flex-wrap:wrap;gap:8px 16px;padding-top:20px;color:#8d9aa2;font-size:11px}.copy a:hover{color:var(--brand-deep)}
.modal-wrap{position:fixed;inset:0;z-index:100;display:none;place-items:center;padding:20px;background:rgba(19,37,48,.48);backdrop-filter:blur(7px)}.modal-wrap.open{display:grid}.modal{width:min(480px,100%);padding:28px;border-radius:22px;background:#fff;text-align:center;box-shadow:var(--shadow)}.modal-head{display:flex;justify-content:space-between;align-items:center}.modal h3{margin:0;font-size:23px}.close{width:36px;height:36px;border:0;border-radius:9px;background:var(--soft);color:var(--muted);font-size:21px;cursor:pointer}.modal p{color:var(--muted);font-size:13px;line-height:1.7}.modal img{display:block;width:230px;height:230px;margin:20px auto 0;padding:8px;border:1px solid var(--line);border-radius:16px}
@media(max-width:900px){.principle-grid,.article-layout{grid-template-columns:1fr}.side{position:static}.related-grid{grid-template-columns:1fr 1fr}.hub-hero h1,.article-hero h1{font-size:44px}.question-card{grid-template-columns:55px 1fr}.read{grid-column:2;text-align:left}}
@media(max-width:700px){:root{--page:min(100% - 32px,600px)}.header{height:64px}.menu{display:block}.nav-links{display:none;position:fixed;top:64px;left:0;right:0;padding:16px;flex-direction:column;align-items:stretch;background:#fff;border-bottom:1px solid var(--line)}.nav-links.open{display:flex}.hub-hero{padding:68px 0 55px}.hub-hero h1,.article-hero h1{font-size:38px}.section-head,.footer-main{align-items:start;flex-direction:column}.question-card{grid-template-columns:40px 1fr;gap:12px}.principle-grid{gap:25px}.article-layout{padding-top:52px}.direct-answer{font-size:17px}.article-meta{flex-direction:column;gap:8px}.related-grid{grid-template-columns:1fr}.footer-links{flex-direction:column}.comparison{font-size:12px}.comparison th,.comparison td{padding:10px}.article-body p,.article-body li{font-size:15px}}