/* Keep SWAP and PEPSSI On
   Palette comes from the physics on the page: indigo space, amber for the region the
   Sun's wind fills, pale cyan for interstellar space past the heliopause.
   Every text/background pair meets WCAG 2.1 AA (checked in tests/check.py). */
:root{
  --space:#101433;
  --space-2:#161b40;
  --line:#2c3266;
  --text:#eef0f7;      /* 15.6:1 on space */
  --muted:#aab0cc;     /* 8.4:1 on space */
  --sun:#f2b33d;       /* 9.6:1 on space */
  --on-sun:#1b1402;
  --ism:#8cc8e8;       /* 9.7:1 on space, used for links and interstellar */
  --serif:"Instrument Serif",Georgia,"Times New Roman",serif;
  --sans:"Instrument Sans",system-ui,-apple-system,"Segoe UI",sans-serif;
  --wrap:1120px;
  color-scheme:dark;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:72px}
body{margin:0;background:var(--space);color:var(--text);font-family:var(--sans);font-size:18px;line-height:1.6;
  -webkit-font-smoothing:antialiased;overflow-x:hidden}
a{color:var(--ism);text-underline-offset:3px;text-decoration-thickness:1px}
a:hover{text-decoration-thickness:2px}
:focus-visible{outline:3px solid var(--sun);outline-offset:3px;border-radius:3px}
p{margin:0 0 1em}
h1,h2,h3{margin:0;font-weight:400}
h1,h2{font-family:var(--serif);letter-spacing:-.01em;text-wrap:balance}
h2{font-size:clamp(36px,5.2vw,60px);line-height:1.02;margin-bottom:.5em;max-width:20ch}
h3{font-family:var(--sans);font-weight:600;font-size:20px;line-height:1.3}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 32px}
.measure{max-width:62ch;color:var(--muted)}
.fine{font-size:15px;color:var(--muted);max-width:70ch}
.tnum{font-variant-numeric:tabular-nums}

.skip{position:absolute;left:16px;top:-60px;z-index:100;background:var(--text);color:var(--space);padding:10px 16px;border-radius:6px;font-weight:600}
.skip:focus{top:12px}

/* Header */
.top{position:sticky;top:0;z-index:40;background:rgba(16,20,51,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.top-row{display:flex;align-items:center;gap:8px;min-height:60px}
.brand{font-family:var(--serif);font-size:22px;color:var(--text);text-decoration:none;margin-right:auto;white-space:nowrap}
.top nav{display:flex;gap:2px}
.top nav a{color:var(--muted);text-decoration:none;font-size:15px;font-weight:500;padding:10px 12px;border-radius:6px;min-height:44px;display:inline-flex;align-items:center}
.top nav a:hover{color:var(--text)}
.top nav .nav-act{color:var(--on-sun);background:var(--sun);font-weight:600;margin-left:6px}
.top nav .nav-act:hover{color:var(--on-sun);filter:brightness(1.08)}

/* Hero */
.hero{padding:72px 0 0}
h1{font-family:var(--serif);font-size:clamp(46px,8.4vw,112px);line-height:.95;letter-spacing:-.02em;max-width:13ch;margin-bottom:28px}
.lede{font-size:clamp(19px,2vw,23px);line-height:1.5;max-width:44ch;color:var(--text)}
.hero-act{display:flex;flex-wrap:wrap;align-items:center;gap:14px 24px;margin:32px 0 8px}
.countdown{margin:0;color:var(--muted);font-variant-numeric:tabular-nums;max-width:40ch}
.countdown strong{color:var(--sun);font-weight:600}

.btn{display:inline-flex;align-items:center;justify-content:center;min-height:52px;padding:0 26px;border-radius:999px;
  background:var(--sun);color:var(--on-sun);font-weight:700;font-size:17px;text-decoration:none;border:0;cursor:pointer}
.btn:hover{filter:brightness(1.08);text-decoration:none}
.btn-quiet{display:inline-flex;align-items:center;min-height:44px;padding:0 16px;border-radius:999px;border:1px solid var(--line);
  background:transparent;color:var(--text);font:600 15px var(--sans);text-decoration:none;cursor:pointer}
.btn-quiet:hover{border-color:var(--muted)}
.btn-quiet[data-done]{border-color:var(--sun);color:var(--sun)}

/* The ruler: the one bold element on the page */
.ruler-fig{margin:56px 0 0;padding:0 0 40px}
.ruler{position:relative;height:280px;width:100%}
.ruler svg{display:block;width:100%;height:100%;overflow:visible}
.ruler text{font-family:var(--sans);fill:var(--muted);font-size:13px}
.ruler .lbl-strong{fill:var(--text);font-weight:600;font-size:14px}
.ruler .lbl-nh{fill:var(--sun);font-weight:700;font-size:15px}
.ruler .tick{stroke:var(--line)}
.ruler .axis{fill:var(--muted);font-size:12px;font-variant-numeric:tabular-nums}
.ruler-fig figcaption{color:var(--muted);font-size:16px;max-width:var(--wrap)}
.ruler-fig figcaption strong{color:var(--text);font-weight:600;font-variant-numeric:tabular-nums}
#nh-kms,#nh-lt{font-variant-numeric:tabular-nums}
.live-dot{display:inline-block;width:9px;height:9px;border-radius:50%;background:var(--sun);margin-right:6px;vertical-align:1px;
  box-shadow:0 0 0 0 rgba(242,179,61,.6);animation:pulse 2.4s ease-out infinite}
@keyframes pulse{0%{box-shadow:0 0 0 0 rgba(242,179,61,.55)}70%{box-shadow:0 0 0 10px rgba(242,179,61,0)}100%{box-shadow:0 0 0 0 rgba(242,179,61,0)}}
.nh-halo{animation:halo 2.4s ease-out infinite;transform-box:fill-box;transform-origin:center}
@keyframes halo{0%{opacity:.7;transform:scale(1)}100%{opacity:0;transform:scale(3.2)}}
.reach{stroke-dasharray:var(--len);stroke-dashoffset:var(--len);animation:reach 1.6s cubic-bezier(.2,.7,.2,1) .2s forwards}
@keyframes reach{to{stroke-dashoffset:0}}

/* Sections */
.band{padding:88px 0;border-top:1px solid var(--line)}
.band-data{background:var(--space-2)}
.h-small{font-size:clamp(28px,3.4vw,38px)}
.sub{margin:48px 0 16px;font-size:22px}
.aside-line{color:var(--muted);font-style:italic;margin-top:20px;max-width:62ch}

.pair{display:grid;grid-template-columns:1fr 1fr;gap:48px;margin-top:12px}
.inst h3{font-family:var(--serif);font-weight:400;font-size:clamp(44px,5vw,64px);line-height:1;color:var(--sun)}
.inst-name{color:var(--text);font-weight:600;margin:6px 0 14px;font-size:16px}
.inst p{max-width:52ch}
.spec{color:var(--muted);font-size:15px}
.found{list-style:none;padding:0;margin:0;max-width:74ch}
.found li{padding:14px 0 14px 22px;border-top:1px solid var(--line);position:relative}
.found li::before{content:"";position:absolute;left:0;top:25px;width:8px;height:8px;border-radius:50%;background:var(--ism)}
.found a{font-size:15px;white-space:nowrap}

/* Chart */
.chart-controls{display:flex;flex-wrap:wrap;gap:8px;margin:28px 0 12px}
.seg{min-height:44px;padding:0 18px;border-radius:999px;border:1px solid var(--line);background:transparent;color:var(--muted);
  font:600 15px var(--sans);cursor:pointer}
.seg:hover{color:var(--text)}
.seg[aria-pressed="true"]{background:var(--text);color:var(--space);border-color:var(--text)}
.chart-note{color:var(--muted);font-size:16px;max-width:70ch;min-height:1.6em;margin-bottom:8px}
.chart{position:relative;width:100%;height:440px;touch-action:pan-y}
.chart svg{display:block;width:100%;height:100%;overflow:visible}
.chart text{font-family:var(--sans);fill:var(--muted);font-size:12px;font-variant-numeric:tabular-nums}
.chart .zone-lbl{fill:var(--text);font-size:13px;font-weight:600}
.chart .zone-sub{fill:var(--muted);font-size:12px}
.chart .grid{stroke:var(--line);stroke-width:1}
.chart-tip{position:absolute;pointer-events:none;background:var(--space);border:1px solid var(--line);border-radius:8px;padding:8px 12px;
  font-size:14px;line-height:1.4;white-space:nowrap;transform:translate(-50%,-110%);opacity:0;transition:opacity .12s}
.chart-tip b{color:var(--sun);font-weight:700}
.chart-status{font-size:14px;color:var(--muted);margin-top:14px;max-width:80ch}

.limits{margin-top:28px;border:1px solid var(--line);border-radius:12px;background:var(--space)}
.limits summary{cursor:pointer;padding:18px 22px;font-weight:600;min-height:44px;list-style-position:inside}
.limits summary:hover{color:var(--sun)}
.limits-body{padding:0 22px 12px;max-width:74ch;font-size:16px;color:var(--muted)}
.limits-body strong{color:var(--text);font-weight:600}

/* Timeline: a real sequence, so it is an ordered list */
.timeline{list-style:none;padding:0;margin:36px 0 0;max-width:760px;position:relative}
.timeline::before{content:"";position:absolute;left:118px;top:8px;bottom:8px;width:1px;background:var(--line)}
.timeline li{display:grid;grid-template-columns:104px 1fr;gap:28px;padding:10px 0;position:relative}
.timeline li::after{content:"";position:absolute;left:114px;top:21px;width:9px;height:9px;border-radius:50%;background:var(--muted)}
.timeline time{color:var(--muted);text-align:right;font-variant-numeric:tabular-nums;font-size:16px;padding-top:1px}
.timeline .t-now time,.timeline .t-now span{color:var(--sun);font-weight:600}
.timeline .t-now::after{background:var(--sun);width:13px;height:13px;left:112px;top:19px}
.timeline .t-future span,.timeline .t-future time{color:var(--ism)}
.timeline .t-future::after{background:transparent;border:1px solid var(--ism)}

/* Money */
.money{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 48px;margin:36px 0 12px;max-width:900px}
.money div{border-top:1px solid var(--line);padding:18px 0 22px}
.money dt{font-family:var(--serif);font-size:clamp(40px,5vw,58px);line-height:1;color:var(--text)}
.money dd{margin:8px 0 0;color:var(--muted);max-width:34ch}
.quotes{display:grid;grid-template-columns:1fr 1fr;gap:48px;margin-top:56px}
blockquote{margin:0}
blockquote p{font-family:var(--serif);font-size:clamp(24px,2.6vw,30px);line-height:1.25;color:var(--text);margin-bottom:12px}
blockquote footer{color:var(--muted);font-size:15px}

/* Act */
.band-act{background:linear-gradient(180deg,var(--space-2),var(--space) 70%)}
.steps{list-style:none;counter-reset:s;padding:0;margin:40px 0 28px;display:grid;gap:20px}
.step{counter-increment:s;border:1px solid var(--line);border-radius:16px;padding:28px 28px 28px 88px;position:relative;background:var(--space)}
.step::before{content:counter(s);position:absolute;left:28px;top:20px;font-family:var(--serif);font-size:48px;line-height:1;color:var(--sun)}
.step h3{font-size:22px;margin-bottom:8px}
.step p{max-width:64ch;color:var(--muted)}
.script{border-left:2px solid var(--sun);padding:4px 0 4px 18px;margin-top:8px}
.script > p{color:var(--text);max-width:64ch}
.share-row{display:flex;flex-wrap:wrap;gap:8px}
.status{margin-top:28px;font-size:15px;color:var(--muted);border-top:1px solid var(--line);padding-top:18px}

.sources{padding-left:20px;max-width:80ch;color:var(--muted);font-size:16px}
.sources li{margin-bottom:6px}

.foot{border-top:1px solid var(--line);padding:40px 0 56px;color:var(--muted);font-size:15px}
.foot p{max-width:78ch}

/* How it works page */
.doc{padding:64px 0 88px}
.doc h1{font-size:clamp(44px,6vw,76px);max-width:16ch}
.doc h2{font-size:clamp(28px,3.4vw,38px);margin-top:56px}
.doc p,.doc li{max-width:68ch;color:var(--muted)}
.doc strong{color:var(--text)}
.doc code{font-size:15px;background:var(--space-2);padding:2px 6px;border-radius:4px;color:var(--text)}

@media (max-width:820px){
  .wrap{padding:0 16px}
  .top nav a:not(.nav-act){display:none}
  .hero{padding-top:44px}
  .pair,.quotes{grid-template-columns:1fr;gap:36px}
  .money{grid-template-columns:1fr}
  .band{padding:64px 0}
  .ruler{height:300px}
  .chart{height:380px}
  .step{padding:72px 20px 22px}
  .step::before{left:20px;top:18px}
  .timeline::before{left:84px}
  .timeline li{grid-template-columns:72px 1fr;gap:26px}
  .timeline li::after{left:80px}
  .timeline .t-now::after{left:78px}
  .timeline time{font-size:14px}
  .found a{white-space:normal}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .live-dot,.nh-halo{animation:none}
  .reach{animation:none;stroke-dashoffset:0}
}