:root{color-scheme:light;--paper:#f4f6f9;--ink:#17232d;--muted:#687982;--line:#d5dfe5;--ice:#7fb5ff;--ice-soft:#dbeaff;--ember:#e26d5c;--panel:#fff;--night:#0d131a;--shadow:0 18px 55px #182c3a16}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:82px}body{margin:0;background:linear-gradient(180deg,#f4f6f9 0%,color-mix(in srgb,#eaf1f7 calc(100% - var(--scroll-warm, 35%)),#f5ece6 var(--scroll-warm, 35%)) 52%,#eaf1f7 100%);color:var(--ink);font:16px/1.75 "Segoe UI","Microsoft YaHei",sans-serif;transition:background .45s,color .3s}body.night{--paper:#0d131a;--ink:#e7edf2;--muted:#9aa9b1;--line:#2b3b46;--panel:#141f28;--ice-soft:#20344a;background:linear-gradient(180deg,#101923,#0d131a 55%,#172536)}a{color:inherit;text-decoration:none}a:hover{color:#356da9}button{font:inherit}.skip{position:absolute;left:-9999px}.skip:focus{left:1rem;top:1rem;background:#fff;padding:.7rem;z-index:10}.site-header{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--paper) 90%,transparent);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}.nav-wrap{max-width:1180px;margin:auto;padding:12px 24px;display:flex;gap:24px;align-items:center}.brand{font:700 17px Georgia,serif;white-space:nowrap}.brand span{color:var(--ember)}.nav{display:flex;align-items:center;gap:20px;margin-left:auto;font-size:14px;color:var(--muted)}.nav a:hover,.nav a[aria-current=page]{color:var(--ink)}.icon-button{width:40px;height:40px;border:1px solid var(--line);border-radius:50%;background:var(--panel);color:var(--ink);cursor:pointer}.menu-toggle{display:none}.wrap{max-width:1120px;margin:auto;padding:0 24px}.hero{min-height:640px;display:grid;grid-template-columns:1.03fr .97fr;align-items:center;gap:54px;padding-top:54px;padding-bottom:72px}.eyebrow{font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}h1,h2,h3,p{margin-top:0}h1{font:500 clamp(38px,5vw,64px)/1.12 Georgia,"Noto Serif SC",serif;max-width:650px;margin:18px 0}.hero p{max-width:620px;color:var(--muted);font-size:17px}.hero-media{position:relative}.hero-media img{display:block;width:100%;height:auto;aspect-ratio:16/10;object-fit:cover;border:1px solid #b7cad8;box-shadow:var(--shadow)}.caption{font-size:12px;color:var(--muted);margin-top:10px}.actions{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin-top:28px}.button{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:0 22px;border:1px solid var(--ink);background:var(--ink);color:#fff;font-weight:650;cursor:pointer}.button:hover{background:#284b65;color:white}.button.secondary{background:transparent;color:var(--ink);border-color:var(--line)}.button.secondary:hover{border-color:var(--ice);background:var(--ice-soft)}.text-link{border-bottom:1px solid var(--ember);padding-bottom:2px}.meta-line{font-size:13px;color:var(--muted);margin-top:17px}.section{padding:76px 0;border-top:1px solid var(--line)}.section-head{display:flex;justify-content:space-between;align-items:end;gap:30px;margin-bottom:30px}.section h2{font:500 34px/1.2 Georgia,"Noto Serif SC",serif;margin-bottom:8px}.section-intro{max-width:630px;color:var(--muted);margin:0}.split{display:grid;grid-template-columns:1fr 1fr;gap:44px;align-items:start}.prose{max-width:780px}.prose h2{font:500 29px Georgia,"Noto Serif SC",serif;margin:40px 0 12px}.prose h3{font-size:19px;margin:26px 0 8px}.prose p,.prose li{color:color-mix(in srgb,var(--ink) 85%,var(--muted))}.prose ul,.prose ol{padding-left:1.25rem}.entity{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--line);border-left:1px solid var(--line)}.entity div{padding:16px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.entity dt{font-size:12px;color:var(--muted)}.entity dd{margin:3px 0 0;font-weight:600}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.card{border:1px solid var(--line);background:var(--panel);padding:22px;min-height:170px;box-shadow:0 5px 22px #162a3810}.card h3{font-size:18px;margin:0 0 8px}.card p{font-size:14px;color:var(--muted);margin:0 0 15px}.card-link{font-size:14px;border-bottom:1px solid var(--ember)}.feature-band{background:linear-gradient(115deg,#eaf1f7,#f4f6f9 50%,#f9ece8);padding:38px;display:grid;grid-template-columns:1fr 1fr;gap:30px;border-left:3px solid var(--ember)}body.night .feature-band{background:linear-gradient(115deg,#172536,#141f28 55%,#30211f)}.index-list{display:grid;grid-template-columns:repeat(5,1fr);gap:0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.index-list a{padding:19px 16px;border-right:1px solid var(--line);font-size:14px}.index-list a:last-child{border:0}.index-list small{display:block;color:var(--muted);margin-top:4px}.faq-list details{border-top:1px solid var(--line);padding:17px 0}.faq-list summary{font-weight:650;cursor:pointer}.faq-list details p{margin:10px 0 0;color:var(--muted)}.timeline{border-left:1px solid var(--ice);padding-left:24px}.timeline article{position:relative;padding:0 0 25px}.timeline article:before{content:"";position:absolute;left:-29px;top:9px;width:9px;height:9px;border-radius:50%;background:var(--ember);box-shadow:0 0 0 4px var(--paper)}.timeline time{font-size:13px;color:var(--muted)}.site-footer{border-top:1px solid var(--line);padding:34px 0 50px;color:var(--muted);font-size:13px}.footer-grid{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap}.footer-links{display:flex;gap:14px;flex-wrap:wrap}.friend-links{display:flex;gap:12px;flex-wrap:wrap}.friend-links a{border-bottom:1px solid var(--line)}.page-hero{padding:78px 0 46px;border-bottom:1px solid var(--line)}.page-hero h1{font-size:46px}.page-hero p{color:var(--muted);max-width:720px}.download-note{font-size:12px;color:var(--muted)}@media(max-width:850px){.nav{gap:12px;font-size:13px}.hero{gap:30px;min-height:560px}.cards{grid-template-columns:repeat(2,1fr)}.index-list{grid-template-columns:repeat(3,1fr)}}@media(max-width:650px){.nav-wrap{padding:10px 16px;gap:12px}.menu-toggle{display:inline-grid;place-items:center;margin-left:auto}.nav{display:none;position:absolute;top:61px;left:0;right:0;background:var(--paper);border-bottom:1px solid var(--line);padding:14px 20px 20px;grid-template-columns:1fr 1fr}.nav.open{display:grid}.theme-toggle{flex:none}.wrap{padding:0 18px}.hero{grid-template-columns:1fr;gap:24px;padding-top:40px;padding-bottom:48px;min-height:0}.hero-media{order:-1}.hero h1{font-size:42px}.hero p{font-size:16px}.section{padding:52px 0}.section h2{font-size:29px}.section-head{display:block}.split{grid-template-columns:1fr;gap:22px}.cards{grid-template-columns:1fr}.card{min-height:0}.feature-band{grid-template-columns:1fr;padding:24px}.index-list{grid-template-columns:1fr 1fr}.index-list a:nth-child(2n){border-right:0}.entity{grid-template-columns:1fr 1fr}.page-hero{padding:50px 0 32px}.page-hero h1{font-size:38px}.footer-grid{display:block}.footer-links{margin-top:14px}}

/* Backend-managed download confirmation. Static href remains in source for no-JS access. */
.download-guard-overlay{position:fixed;z-index:9999;inset:0;display:grid;place-items:center;padding:20px;background:rgba(2,6,11,.82);backdrop-filter:blur(5px)}
.download-guard-overlay[hidden]{display:none!important}.download-guard-dialog{width:min(440px,100%);padding:28px;border:1px solid #8edfff;background:#101b27;color:#f4f8fc;box-shadow:0 24px 70px rgba(0,0,0,.58)}
.download-guard-dialog h2{margin:0 0 10px;color:#fff;font-size:1.55rem}.download-guard-dialog p{margin:0;color:#d2deea}.download-guard-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:24px}.download-guard-actions button{min-height:42px;padding:0 16px;border:1px solid #86a2ba;background:#182a3a;color:#fff;cursor:pointer;font-weight:700}.download-guard-actions .download-guard-confirm{background:#72dff5;border-color:#72dff5;color:#061018}