:root{--green:#20483a;--ink:#263a30;--muted:#596e61;--paper:#f6f7f0;--line:#d4ddcf;--gold:#8b7648}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:15px/1.8 system-ui,"Microsoft YaHei",sans-serif}button,input,select{font:inherit}button,select{cursor:pointer}a{color:var(--green)}header.site{padding:18px max(22px,calc((100vw - 1660px)/2));display:flex;gap:18px;align-items:baseline;background:#173b2f;color:#f3f5e9}header.site strong{font:500 22px Georgia,"Songti SC",serif;letter-spacing:.08em}header.site small{color:#c7d6c2;font-size:10px;letter-spacing:.16em}main{max-width:1708px;margin:auto;padding:34px 24px 48px}.intro{max-width:940px;margin-bottom:24px}.kicker{color:var(--gold);font-size:11px;letter-spacing:.16em;margin:0 0 6px}h1{font:500 clamp(28px,3vw,40px)/1.4 Georgia,"Songti SC",serif;margin:0 0 12px}.intro p:last-child{font-size:14px;color:var(--muted);margin:0}.toolbar{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:15px;margin-bottom:17px;border-block:1px solid var(--line);padding:15px 0}.region-label{display:flex;align-items:center;gap:12px;flex-wrap:wrap;font-size:13px}.region-label select{min-height:44px;min-width:235px;max-width:100%;padding:9px 36px 9px 12px;border:1px solid #b8c8b4;border-radius:8px;background:#fff;color:var(--ink);font-size:15px}.toggles{display:flex;align-items:center;flex-wrap:wrap;gap:12px 22px}.toggles label{display:flex;align-items:center;gap:8px;min-height:44px;font-size:13px;cursor:pointer}.toggles input{width:18px;height:18px;accent-color:var(--green)}.map-stage{position:relative;overflow:hidden;isolation:isolate;border:1px solid var(--line);border-radius:12px;background:white}.map-stage svg{display:block;width:100%;height:auto;overflow:hidden;touch-action:pan-y}.map-image{pointer-events:none}.sea-lines use{fill:none;stroke:#3f615b;stroke-opacity:.24;stroke-width:.85;vector-effect:non-scaling-stroke;pointer-events:none}.sea-lines .selected{stroke:#245e4c;stroke-opacity:.85;stroke-width:1.5}.land-tints use{stroke:none;fill-opacity:.045;pointer-events:none}.land-tints .selected{fill:#245e4c!important;fill-opacity:.12;stroke:#245e4c;stroke-opacity:.85;stroke-width:1;vector-effect:non-scaling-stroke}.coast-check use{fill:none;stroke:#b24c39;stroke-width:1;stroke-opacity:.88;vector-effect:non-scaling-stroke;pointer-events:none}.hit-layer use{fill:transparent;stroke:none;pointer-events:fill;cursor:pointer}.hit-layer use:focus{outline:none;stroke:#69521c;stroke-width:1.5;vector-effect:non-scaling-stroke}.selected-note{display:flex;align-items:baseline;flex-wrap:wrap;gap:8px 18px;padding:18px 1px;border-bottom:1px solid var(--line)}.selected-note strong{font:500 24px/1.5 Georgia,"Songti SC",serif;color:var(--green)}.selected-note span{color:var(--muted);font-size:13px}.caption{color:var(--muted);font-size:12px;margin:11px 0 0}.details{display:grid;grid-template-columns:1fr 1fr;gap:34px;margin-top:28px}.details h2{font:500 22px/1.5 Georgia,"Songti SC",serif;margin:0 0 10px}.details p{font-size:13px;color:var(--muted);margin:0 0 10px}.details ol{font-size:13px;color:var(--muted);padding-left:1.6em;margin:0}.details code{font-size:12px;overflow-wrap:anywhere}footer{margin-top:32px;border-top:1px solid var(--line);padding-top:13px;font-size:12px;color:var(--muted)}[hidden]{display:none!important}:focus-visible{outline:3px solid #a28645;outline-offset:3px}
@media(max-width:760px){header.site{padding:15px 18px}header.site small{display:none}main{padding:24px 14px 32px}.intro{margin-bottom:18px}.toolbar{display:block;padding:11px 0}.region-label{display:grid;grid-template-columns:auto minmax(0,1fr);gap:10px}.region-label select{min-width:0;width:100%;font-size:16px}.toggles{gap:0 20px;margin-top:8px}.map-stage{border-radius:8px}.details{grid-template-columns:1fr;gap:20px}.selected-note strong{font-size:22px}.selected-note{gap:5px 12px}.caption{font-size:12px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}

html{scroll-behavior:smooth}body{font-size:16px;line-height:1.9}h2{font:500 clamp(27px,3vw,36px)/1.4 Georgia,"Songti SC",serif;margin:0}h3{font:500 25px/1.5 Georgia,"Songti SC",serif;margin:0 0 16px}button{border:1px solid #c1cec1;color:var(--green);background:transparent;min-height:44px;border-radius:6px;padding:8px 15px}button:hover{background:#e8eee2}button[aria-pressed=true]{background:var(--green);border-color:var(--green);color:#fff}button,input,select{touch-action:manipulation}main{max-width:1708px;padding:0 28px 60px}.overview-hero{padding:65px 0 25px;max-width:1080px}.overview-hero h1{font-size:clamp(44px,5vw,72px);letter-spacing:.08em;margin:10px 0}.deck{font-size:19px;color:var(--muted)}.prose{overflow-wrap:anywhere}.prose p{margin:0 0 1.15em}.overview-hero .prose{margin:28px 0}.chapter-nav{display:flex;gap:16px 35px;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:20px;margin-top:30px;font-size:14px}.chapter-nav a{text-decoration:none}.chapter{padding:50px 0 10px;border-top:1px solid var(--line);margin-top:30px;scroll-margin-top:20px}.chapter-heading{margin-bottom:28px}.system-layout,.sky-layout{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);gap:40px;align-items:start}.visual-column{min-width:0}.system-copy{max-width:760px}.orrery{width:100%;aspect-ratio:1000/660;position:relative;isolation:isolate;background:#163c36;border-radius:10px;overflow:hidden;margin:16px 0}.orrery svg{position:absolute;inset:0;width:100%;height:100%}.orbit-line{fill:none;stroke:#b6cbb9;stroke-opacity:.33;stroke-width:1.2}.star-body{position:absolute;transform:translate(-50%,-50%);background:none!important;border:0!important;border-radius:50%;padding:0;width:44px;height:44px;display:grid;place-items:center;color:#fff;z-index:2}.star-body i{display:block;width:var(--body-size);height:var(--body-size);background:var(--body-color);border-radius:50%;border:1px solid #dbe4d4;box-shadow:inset -8px -4px 0 #0002}.star-body.devia i{background:repeating-linear-gradient(12deg,#bbd6d9 0px,#bbd6d9 6px,#6c9da9 7px,#a5c3bb 11px)}.star-body.symalg i{box-shadow:0 0 28px #dc8a5666,inset -8px -4px 0 #0002}.star-body span{position:absolute;top:calc(100% + 6px);font-size:12px;white-space:nowrap;line-height:1.3;pointer-events:none}.star-body[aria-pressed=true] i{outline:2px solid #dfcb91;outline-offset:5px}.switches,.body-list,.model-controls{display:flex;flex-wrap:wrap;gap:8px}.switches button{font-size:14px}.body-list button{font-size:13px;min-height:40px;padding:4px 12px}.model-controls{align-items:center;justify-content:space-between}.model-controls label{display:flex;align-items:center;gap:9px;font-size:13px}.model-controls input{width:110px;accent-color:var(--green);min-height:44px}.model-note{font-size:12px;line-height:1.8;color:var(--muted);margin:12px 0 15px}.object-readout{border-left:3px solid #9bb29b;padding:10px 0 10px 20px;margin:28px 0}.object-readout h3{margin:0 0 8px}.object-readout .prose{font-size:15px}.reference{margin:16px 0;color:var(--muted);font-size:13px}.reference summary{cursor:pointer;min-height:44px;padding:10px 0}.reference figure{margin:10px 0}.reference img,figure img{width:100%;height:auto;display:block;border-radius:8px}figure{margin:0}figcaption{font-size:12px;color:var(--muted);margin-top:6px}.sky-preface{max-width:1100px}.sky-layout{margin-top:26px}.sky-layout canvas{display:block;width:100%;height:auto;border-radius:10px;margin-top:16px}.sky-layout .visual-column{position:sticky;top:20px}.phenomenon-layout{display:grid;grid-template-columns:minmax(0,.85fr) minmax(0,1fr);gap:45px;border-top:1px solid var(--line);margin-top:35px;padding-top:30px}.phenomenon-layout img{max-height:280px;object-fit:cover;margin-top:20px}.surface-copy{max-width:1100px}.map-instruction{color:var(--muted);font-size:15px;margin:24px 0 20px}.region-prose{max-width:1080px;margin-top:20px}.geography-notes{display:grid;grid-template-columns:1fr 1fr;gap:45px;margin-top:35px;padding-top:30px;border-top:1px solid var(--line)}.geography-notes h3{font-size:24px}.selected-note{padding-top:20px}.text-link{display:inline-block;font-size:14px;margin:12px 0}footer{display:flex;justify-content:space-between;gap:20px}footer a{text-decoration:none}
@media(min-width:1900px){.system-layout,.sky-layout{gap:65px}.overview-hero{max-width:1150px}.prose{font-size:17px}}@media(max-width:1050px){.system-layout,.sky-layout{gap:26px}.model-controls{justify-content:start;gap:10px}.star-body span{display:none}.star-body[aria-pressed=true] span{display:block}.system-copy{font-size:15px}}
@media(max-width:760px){main{padding:0 16px 35px}.overview-hero{padding-top:35px}.overview-hero .prose{margin-top:20px}.chapter{padding-top:30px}.chapter-nav{gap:10px 20px}.system-layout,.sky-layout,.phenomenon-layout,.geography-notes{grid-template-columns:1fr;gap:22px}.sky-layout .visual-column{position:static}.system-copy{max-width:none;font-size:16px}.chapter-heading{margin-bottom:20px}.model-controls button{padding:7px 11px}.model-controls label{flex:1;justify-content:center}.model-controls input{width:85px}.orrery{aspect-ratio:1000/750}.star-body i{max-width:42px;max-height:42px}.star-body.symalg i,.star-body.devia i{max-width:52px;max-height:52px}.star-body span{top:38px;font-size:10px}.body-list button{min-height:44px}.switches button{flex:1;padding:8px 10px;white-space:nowrap}.map-instruction{font-size:14px}.geography-notes{gap:14px}.sky-layout canvas{min-height:180px}.phenomenon-layout{padding-top:25px}.phenomenon-layout img{max-height:240px}footer{flex-wrap:wrap}.object-readout{margin-top:24px}}
@media(max-width:760px){.orrery{aspect-ratio:1000/660}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}


.site .site-brand{color:inherit;text-decoration:none;display:flex;flex-direction:row;flex-wrap:nowrap;align-items:center;min-width:0}
header.site{align-items:center;justify-content:space-between;flex-wrap:wrap;gap:14px}
header.site .site-brand strong{color:inherit}
header.site .site-brand small{display:block}
header.site a{color:inherit}
.world-overview-accessible{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}

/* Phone symbols track the orbit stage, rather than retaining desktop pixels. */
@media(max-width:760px){
 .orrery .star-body i{
  width:var(--mobile-body-size,calc(var(--body-size)*.35));
  height:var(--mobile-body-size,calc(var(--body-size)*.35));
  max-width:none;max-height:none;
  box-shadow:inset -3px -2px 0 #0002;
 }
 .orrery .star-body.symalg i{box-shadow:0 0 14px #dc8a5644,inset -3px -2px 0 #0002}
 .orrery .star-body.devia i{background:repeating-linear-gradient(12deg,#bbd6d9 0px,#bbd6d9 3px,#6c9da9 4px,#a5c3bb 6px)}
 .orrery .star-body[aria-pressed=true] i{outline-width:1.5px;outline-offset:3px}
 .orrery .star-body span{top:calc(50% + var(--mobile-body-size,20px)/2 + 5px);font-size:11px}
}