@font-face{font-family:"Source Serif 4";font-style:normal;font-weight:300 700;font-display:swap;src:url("fonts/source-serif-4-normal-latin.woff2") format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:"Source Serif 4";font-style:normal;font-weight:300 700;font-display:swap;src:url("fonts/source-serif-4-normal-latin-ext.woff2") format("woff2");unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}
@font-face{font-family:"Source Serif 4";font-style:italic;font-weight:300 700;font-display:swap;src:url("fonts/source-serif-4-italic-latin.woff2") format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:"Source Serif 4";font-style:italic;font-weight:300 700;font-display:swap;src:url("fonts/source-serif-4-italic-latin-ext.woff2") format("woff2");unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}
@font-face{font-family:"IBM Plex Sans";font-style:normal;font-weight:300 700;font-display:swap;src:url("fonts/IBMPlexSans-latin.woff2") format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+2000-206F,U+2074,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:"IBM Plex Sans";font-style:normal;font-weight:300 700;font-display:swap;src:url("fonts/IBMPlexSans-latin-ext.woff2") format("woff2");unicode-range:U+0100-02AF,U+0304,U+0308,U+0329,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}

/* Water and ground measured from space: deep lake blue at night, survey paper by day; heights on a teal-to-ochre ramp. */
:root{
  color-scheme:light;
  --bg:#f3f1ea;--bg-2:#e9e6dc;--surface:#fbfaf6;--surface-2:#ebe8de;
  --ink:#121611;--ink-2:#2a2f28;--muted:#4b5148;--line:#c3c3b4;--line-soft:#dcdccf;
  --accent:#155e83;--accent-2:#7b3e0b;
  --stage-bg:#f1efe6;--stage-axis:#4e544b;--stage-text:#1b201a;--stage-faint:rgba(30,40,30,.28);--stage-label:#1b201a;
  --ph-ground:#9a5f14;
  --nodata:#d9d6cb;--water:#1c6c97;--water-hi:#0b4a6e;--land:rgba(120,100,60,.13);--drop:#8a4b12;--pin:#c2410c;
--ph-low:#8d9578;--ph-crown:#1f7a3a;--ph-building:#39465c;--ph-water:#1b67b8;--ph-head:#1aa31a;
  --serif:"Source Serif 4","Iowan Old Style",Georgia,serif;--sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",sans-serif;
  --topbar:48px;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  color-scheme:dark;
  --bg:#07090d;--bg-2:#0c0f15;--surface:#10141b;--surface-2:#181d26;
  --ink:#eef2ec;--ink-2:#d3d9d0;--muted:#a7b0a4;--line:#2b323d;--line-soft:#1d232c;
  --accent:#7dd3f2;--accent-2:#ffc174;
  --stage-bg:#06111a;--stage-axis:#97a19a;--stage-text:#e9efe8;--stage-faint:rgba(200,230,210,.22);--stage-label:#e3ece4;
  --ph-ground:#e0a957;
  --nodata:#1f2a31;--water:#5ec4ee;--water-hi:#bfeaff;--land:rgba(214,190,140,.10);--drop:#f0b36a;--pin:#ff8a4c;
--ph-low:#7e8b74;--ph-crown:#6fe08c;--ph-building:#dfe6f2;--ph-water:#62b8ff;--ph-head:#5cff4f;
}}
:root[data-theme="dark"]{
  color-scheme:dark;
  --bg:#07090d;--bg-2:#0c0f15;--surface:#10141b;--surface-2:#181d26;
  --ink:#eef2ec;--ink-2:#d3d9d0;--muted:#a7b0a4;--line:#2b323d;--line-soft:#1d232c;
  --accent:#7dd3f2;--accent-2:#ffc174;
  --stage-bg:#06111a;--stage-axis:#97a19a;--stage-text:#e9efe8;--stage-faint:rgba(200,230,210,.22);--stage-label:#e3ece4;
  --ph-ground:#e0a957;
  --nodata:#1f2a31;--water:#5ec4ee;--water-hi:#bfeaff;--land:rgba(214,190,140,.10);--drop:#f0b36a;--pin:#ff8a4c;
--ph-low:#7e8b74;--ph-crown:#6fe08c;--ph-building:#dfe6f2;--ph-water:#62b8ff;--ph-head:#5cff4f;
}
*{box-sizing:border-box}
[hidden]{display:none!important}
svg[hidden]{display:none}
html{-webkit-text-size-adjust:100%;scroll-padding-top:calc(var(--topbar) + 14px)}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:17px;line-height:1.58;-webkit-font-smoothing:antialiased;overflow-x:clip}
a{color:inherit;text-decoration-color:var(--accent);text-underline-offset:.18em;text-decoration-thickness:1.5px}
a:hover{color:var(--accent)}
:focus-visible{outline:2.5px solid var(--accent);outline-offset:3px;border-radius:4px}
.skip-link{position:absolute;left:12px;top:-60px;z-index:100;background:var(--ink);color:var(--bg);padding:10px 14px;border-radius:8px;font-weight:600}
.skip-link:focus{top:10px}
.num{font-variant-numeric:tabular-nums lining-nums}
h1,h2,h3{font-family:var(--serif);font-weight:600;text-wrap:balance}
.anchor{opacity:0;margin-left:.3em;text-decoration:none;color:var(--muted);font-family:var(--sans);font-size:.6em;vertical-align:middle}
h2:hover .anchor,h3:hover .anchor,.anchor:focus-visible{opacity:1}

/* ---------- top bar: slim, quiet, in the stage's colours */
.topbar{position:fixed;inset:0 0 auto 0;height:var(--topbar);z-index:40;display:flex;align-items:center;gap:6px;padding:0 max(12px,env(safe-area-inset-right)) 0 max(12px,env(safe-area-inset-left));background:color-mix(in srgb,var(--bg) 94%,transparent);border-bottom:1px solid var(--line-soft);font-size:14px}
.brand{display:flex;align-items:center;gap:9px;font-weight:600;text-decoration:none;white-space:nowrap;min-width:0}
.brand span:last-child{overflow:hidden;text-overflow:ellipsis}
/* the home glyph: a beam falling on a roofline */
.brand-mark{width:20px;height:20px;flex:none;border-radius:5px;background:var(--stage-bg);border:1px solid var(--line);position:relative;overflow:hidden}
.brand-mark::before{content:"";position:absolute;inset:auto 0 0 0;height:12px;background:var(--water);clip-path:polygon(0 0,30% 0,30% 30%,60% 30%,60% 60%,100% 60%,100% 100%,0 100%)}

.topnav{display:none;gap:1px;margin-left:12px;overflow:hidden}
.topnav a{padding:6px 9px;border-radius:999px;text-decoration:none;color:var(--ink-2);white-space:nowrap}
.topnav a:hover,.topnav a[aria-current="true"]{color:var(--ink);background:var(--surface-2)}
@media (min-width:1180px){.topnav{display:flex}}
.spacer{flex:1}
.chip{padding:5px 10px;border-radius:999px;text-decoration:none;font-weight:600;font-size:13px;border:1px solid var(--line);color:var(--ink-2)}
.chip[aria-current="page"]{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.icon-btn{width:36px;height:36px;flex:none;display:grid;place-items:center;border-radius:50%;border:1px solid var(--line);background:transparent;color:var(--ink);cursor:pointer}
.icon-btn:hover{background:var(--surface-2)}
.i-moon{display:none}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .i-sun{display:none}:root:not([data-theme="light"]) .i-moon{display:block}}
:root[data-theme="dark"] .i-sun{display:none}:root[data-theme="dark"] .i-moon{display:block}
/* progress: a hairline the laser front rides along */
.progress{position:fixed;left:0;right:0;top:var(--topbar);height:2px;z-index:41;pointer-events:none}
.progress i{display:block;height:100%;width:100%;background:var(--water);transform-origin:0 50%;transform:scaleX(0)}

/* ---------- reading rail: a hairline of dots at the far edge */
.rail{display:none}
@media (min-width:1180px){
.rail{display:flex;flex-direction:column;position:fixed;right:4px;top:50%;transform:translateY(-50%);z-index:30;padding:4px 2px}
.rail-dot{position:relative;display:flex;align-items:center;justify-content:center;width:22px;height:20px;text-decoration:none}
.rail-dot .dot{width:5px;height:5px;border-radius:50%;background:var(--muted);opacity:.7;transition:transform .2s,background .2s}
.rail-dot:hover .dot,.rail-dot:focus-visible .dot{background:var(--accent);transform:scale(1.4);opacity:1}
.rail-dot[aria-current="true"] .dot{background:var(--accent);transform:scale(1.6);opacity:1}
.rail-label{position:absolute;right:calc(100% + 6px);top:50%;transform:translate(6px,-50%);padding:3px 10px;border:1px solid var(--line);border-radius:8px;background:var(--surface);color:var(--ink);font-size:13px;font-weight:600;white-space:nowrap;opacity:0;pointer-events:none;transition:opacity .15s,transform .15s}
.rail-dot:hover .rail-label,.rail-dot:focus-visible .rail-label{opacity:1;transform:translate(0,-50%)}
}

/* ---------- the story: text on the left, the laser line on the right */
.story{position:relative;padding-top:var(--topbar);display:grid;grid-template-columns:minmax(330px,33%) 1fr}
.stage{grid-column:2;grid-row:1;position:sticky;top:var(--topbar);align-self:start;height:calc(100vh - var(--topbar));height:calc(var(--vh,1vh) * 100 - var(--topbar));overflow:hidden;background:var(--stage-bg)}
.stage canvas{position:absolute;inset:0;width:100%;height:100%;display:block}
.stage .still{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.stage-ready .stage .still{display:none}
.loading{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);font-size:13.5px;color:var(--stage-text);margin:0}
.stage-ready .loading,.no-stage .loading{display:none}
.hud{position:absolute;left:58px;bottom:44px;z-index:2;pointer-events:none;color:var(--stage-text);display:flex;flex-wrap:wrap;gap:2px 12px;align-items:baseline;max-width:46%;opacity:0;transition:opacity .4s}
.stage-ready .hud{opacity:1}
.hud-clock{font:600 30px/1 var(--sans);letter-spacing:-.01em;font-variant-numeric:tabular-nums;color:var(--ph-head)}
.hud-lab{flex-basis:100%;font:500 12.5px/1.2 var(--sans);color:var(--stage-text);opacity:.8}
.hud-place{font:500 14px/1.2 var(--sans);color:var(--stage-text);opacity:.85}
.legend{position:absolute;right:16px;bottom:44px;z-index:2;display:flex;flex-wrap:wrap;justify-content:flex-end;gap:4px 12px;max-width:62%;font-size:12.5px;color:var(--stage-text);pointer-events:none}
.legend span{display:inline-flex;align-items:center;gap:6px}
.legend i{width:9px;height:9px;border-radius:50%;display:inline-block}
.k-g{background:var(--ph-ground)}.k-c{background:var(--ph-crown)}.k-b{background:var(--ph-building)}.k-w{background:var(--ph-water)}.k-l{background:var(--ph-low)}
.steps{grid-column:1;grid-row:1;margin:0;padding:0 0 26vh;list-style:none}
.step{min-height:96vh;display:flex;align-items:center;padding:0 clamp(20px,3vw,44px)}
.step.hero{min-height:calc(100vh - var(--topbar))}
.step-card,.hero-card{width:100%;max-width:500px}
.step-card h2{font-size:clamp(24px,2.2vw,32px);line-height:1.13;margin:0 0 12px}
.step-card p{margin:0 0 12px;color:var(--ink-2)}
strong{color:var(--ink);font-weight:600}
.when,.kicker{font:600 12.5px var(--sans);letter-spacing:.09em;text-transform:uppercase;color:var(--accent);margin:0 0 9px}
h1{font-size:clamp(34px,3.5vw,52px);line-height:1.05;letter-spacing:-.012em;margin:0 0 16px}
.deck{font-family:var(--serif);font-size:clamp(19px,1.45vw,22px);line-height:1.42;margin:0 0 18px;color:var(--ink-2)}
.hero-actions{display:flex;flex-wrap:wrap;align-items:center;gap:10px 16px}
.scroll-cue{font-size:14px;color:var(--muted)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:44px;padding:9px 18px;border-radius:999px;border:1px solid var(--line);background:var(--surface);color:var(--ink);font:600 15px var(--sans);cursor:pointer;text-decoration:none}
.btn:hover{background:var(--surface-2);color:var(--ink)}
.btn.primary{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.btn.primary:hover{background:var(--ink-2);color:var(--bg)}
.btn.small{min-height:40px;padding:6px 14px;font-size:14px}
.shared{margin:0 0 14px;padding:10px 14px;border-left:3px solid var(--accent);background:var(--surface);font-size:15.5px}

@media (max-width:859px){
  /* phones: the line keeps the top of the screen, the text passes below it */
  .story{display:block}
  .stage{height:40vh;height:calc(var(--vh,1vh) * 40);z-index:5}
  .steps{padding-bottom:10vh}
  .step{min-height:70vh;align-items:flex-start;padding:22px 18px 0}
  .step.hero{min-height:0;padding:18px 18px 40px}
  .steps h2{scroll-margin-top:calc(var(--topbar) + 40vh + 14px)}
  .hud{left:46px;bottom:34px;max-width:60%}.hud-clock{font-size:20px}.hud-place{font-size:12px}.hud-lab{font-size:11px}
  .legend{top:6px;bottom:auto;right:8px;max-width:none;gap:2px 8px;font-size:11px}
  .stage canvas{top:16px;height:calc(100% - 16px)}
  .hero-card{display:flex;flex-direction:column}.hero-card .kicker{order:1}.hero-card h1{order:2}.hero-card .hero-actions{order:3;margin:0 0 14px}.hero-card .deck{order:4}
}

/* ---------- after the story */
.after{position:relative;z-index:6;background:var(--bg);border-top:1px solid var(--line)}
.prose{max-width:760px;margin:0 auto;padding:26px max(18px,4vw) 30px}
.block{padding:30px 0 6px}
.prose h2,.explorer h2{font-size:clamp(28px,3vw,40px);line-height:1.08;margin:0 0 14px}
.prose p{color:var(--ink-2);margin:0 0 14px}
.fig{margin:22px 0;padding:16px 16px 12px;border:1px solid var(--line);border-radius:14px;background:var(--surface)}
.fig-h{font:600 15px var(--sans);color:var(--ink);margin:0 0 10px}
.fig-note{font-size:13.5px;color:var(--muted);margin:8px 0 0!important}
.bars{display:grid;gap:10px}
.bar-row{display:grid;grid-template-columns:minmax(96px,150px) 1fr;gap:10px;align-items:center;font-size:14.5px}
.bar-row .lab{color:var(--ink);font-weight:600}
.bar-track{position:relative;height:30px;border-radius:6px;background:var(--surface-2)}
.bar-fill{position:absolute;inset:0 auto 0 0;border-radius:6px;background:var(--ph-crown);opacity:.85}
.bar-ci{position:absolute;top:50%;height:2px;background:var(--ink);transform:translateY(-50%)}
.bar-val{position:absolute;left:8px;top:50%;transform:translateY(-50%);font-weight:600;color:var(--ink);font-variant-numeric:tabular-nums;text-shadow:0 0 4px var(--surface)}
.bar-row.home .lab{color:var(--accent)}
.bar-sub{font-size:13px;color:var(--muted);font-weight:500}
table.pub{width:100%;border-collapse:collapse;font-size:15px;margin:6px 0}
table.pub th,table.pub td{text-align:left;padding:8px 6px;border-bottom:1px solid var(--line-soft);vertical-align:top}
table.pub td.n{font-weight:600;white-space:nowrap;font-variant-numeric:tabular-nums}
/* explorer */
.explorer{padding:46px max(18px,4vw) 30px;max-width:1440px;margin:0 auto}
.ex-head{max-width:760px}
.ex-head p{color:var(--ink-2);margin:0 0 18px}
.ex-grid{display:grid;grid-template-columns:minmax(300px,420px) 1fr;gap:26px;align-items:start}
.pick{display:grid;grid-template-columns:1fr auto;gap:10px;align-items:end;margin-bottom:8px}
.field label{display:block;font-weight:600;font-size:14.5px;margin-bottom:5px}
.field input{width:100%;min-height:46px;padding:8px 12px;border-radius:12px;border:1.5px solid var(--muted);background:var(--surface);color:var(--ink);font:500 16px var(--sans)}
.sugg{display:flex;flex-wrap:wrap;gap:6px;margin:0 0 10px}
.sugg button,.examples button{min-height:38px;padding:5px 12px;border-radius:999px;border:1px solid var(--line);background:var(--surface-2);color:var(--ink);font:500 14px var(--sans);cursor:pointer}
.sugg .empty{margin:0;color:var(--muted);font-size:14.5px}
.examples{display:flex;flex-wrap:wrap;gap:6px;align-items:center;font-size:14px;color:var(--muted);margin:0 0 14px}
.result{border:1px solid var(--line);border-radius:14px;background:var(--surface);padding:16px 18px}
.res-empty{margin:0;color:var(--muted);font-size:15.5px}
.result h3{font-size:24px;line-height:1.15;margin:0 0 8px}
.res-main{font-size:18px;line-height:1.42;margin:0 0 8px;color:var(--ink)}
.result p{margin:0 0 8px;color:var(--ink-2);font-size:15.5px}
.res-msg{font-size:14.5px;color:var(--accent-2);margin:8px 0 0}
.res-msg:empty{display:none}
.slice-wrap{position:relative;border-radius:12px;overflow:hidden;background:var(--stage-bg);aspect-ratio:16/8;margin:0 0 12px}
.slice-wrap canvas{position:absolute;inset:0;width:100%;height:100%}
.mapfig{margin:0}
.map{display:block;width:100%;height:auto;aspect-ratio:1/1;max-height:640px;border-radius:12px;background:var(--stage-bg);cursor:crosshair;touch-action:manipulation}
.map .city{fill:color-mix(in srgb,var(--ph-low) 10%,transparent);stroke:var(--stage-axis);stroke-width:40}
.map .sector{fill:none;stroke:var(--stage-faint);stroke-width:24}
.map .ln{fill:none;stroke:var(--ph-crown);stroke-width:34;opacity:.55;stroke-linecap:round}
.map .ln.night{stroke:var(--ph-head);opacity:.8}
.map .pin{fill:var(--accent-2);stroke:var(--stage-bg);stroke-width:60}
.map .pin-at{fill:var(--ph-head)}
.map .pin-link{stroke:var(--accent-2);stroke-width:40;stroke-dasharray:80 60}
.map-note{font-size:13.5px;color:var(--muted);margin:8px 0 0}
@media (max-width:859px){
  .explorer{padding:36px 16px 20px}
  .ex-grid{grid-template-columns:1fr;gap:16px}
}
.sources{padding-left:1.1em;margin:0 0 16px}
.sources li{margin-bottom:9px;color:var(--ink-2);font-size:15.5px}
.share{margin:14px 0}
.share-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.share-label{font-size:14px;color:var(--muted);margin-right:4px}
.ic{width:40px;height:40px;display:grid;place-items:center;border-radius:50%;border:1px solid var(--line-soft);background:transparent;color:var(--ink);cursor:pointer;text-decoration:none}
.ic:hover,.ic:focus-visible{color:var(--accent);border-color:var(--accent)}
@media (pointer:coarse){.ic{width:44px;height:44px}}
.share-msg{font-size:13.5px;color:var(--muted);margin:6px 0 0;min-height:1.2em}
.site-footer{display:flex;flex-wrap:wrap;gap:8px 22px;justify-content:center;padding:26px 18px calc(34px + env(safe-area-inset-bottom));border-top:1px solid var(--line);font-size:14px;color:var(--muted)}
.back-top{position:fixed;right:max(30px,env(safe-area-inset-right));bottom:calc(16px + env(safe-area-inset-bottom));z-index:45;width:44px;height:44px;border-radius:50%;border:1px solid var(--line);background:var(--surface);color:var(--ink);display:grid;place-items:center;cursor:pointer;opacity:.8}
.back-top span{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.place-page main{max-width:640px;margin:18vh auto;padding:0 20px}
.place-page h1{font-size:32px}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media print{.topbar,.rail,.stage,.back-top,.progress,.ex-grid{display:none}.story{display:block}.step{min-height:0;padding:8px 0}}

/* this page: the map and its ramp, the result */
.map-wrap{position:relative}
.map{display:block;width:100%;border-radius:12px;background:var(--stage-bg);cursor:crosshair;touch-action:manipulation;aspect-ratio:auto}
.ramp{display:flex;align-items:center;gap:10px;font-size:13px;color:var(--muted);margin:10px 0 0}
.ramp i{flex:1;height:10px;border-radius:5px;background:linear-gradient(90deg,rgb(31,95,122),rgb(74,151,140) 30%,rgb(171,196,131) 55%,rgb(232,205,128) 78%,rgb(196,127,59))}
.ramp b{font-weight:600;color:var(--ink)}
.res-main{font-size:21px}
.res-diff{font-size:18px;font-weight:600;color:var(--ink)}
.related{font-size:15.5px;color:var(--ink-2)}
.legend .k-w{background:var(--water);border-radius:2px;height:3px;width:14px}.legend .k-d{border-left:2px dashed var(--drop);height:12px;width:2px;border-radius:0;background:none}
.legend{top:12px;bottom:auto}