/* How Hot Is the Sun — shared styles */
:root{
  --space:#1C1530;      /* deep indigo night */
  --space-2:#2A2048;
  --paper:#F6F4FB;      /* the Sun's true white, faintly violet */
  --ink:#1C1530;
  --muted:#5B5570;
  --line:#DCD7EA;
  --core:#C8281B;       /* 15 million degrees */
  --flame:#E8591A;
  --gold:#F4AE22;
  --corona:#4057D6;     /* hottest = blue */
  --display:"Big Shoulders Display","Arial Narrow","Roboto Condensed",Impact,sans-serif;
  --serif:"Source Serif 4",Georgia,"Times New Roman",serif;
  --col:44rem;
  --wide:66rem;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font:1.125rem/1.7 var(--serif);font-optical-sizing:auto}
img,svg{max-width:100%;height:auto}
a{color:var(--corona);text-underline-offset:.18em;text-decoration-thickness:1px}
a:hover{text-decoration-thickness:2px}
:focus-visible{outline:3px solid var(--gold);outline-offset:3px;border-radius:2px}
.skip{position:absolute;left:-999px;top:0;background:var(--gold);color:var(--ink);padding:.5rem 1rem;z-index:10}
.skip:focus{left:1rem}

/* ---------- header / nav ---------- */
.site-head{background:var(--space);color:var(--paper)}
.site-head .bar{max-width:var(--wide);margin:0 auto;padding:1rem 1.25rem;display:flex;gap:1.5rem;align-items:center;justify-content:space-between;flex-wrap:wrap}
.brand{font:800 1.35rem/1 var(--display);color:var(--paper);text-decoration:none;letter-spacing:.01em;display:flex;align-items:center;gap:.5rem}
.brand svg{width:26px;height:26px}
.site-head nav a{color:#CFC8E6;text-decoration:none;font:600 1.05rem var(--display);letter-spacing:.02em;margin-left:1.25rem}
.site-head nav a[aria-current="page"],.site-head nav a:hover{color:var(--gold)}

/* ---------- hero ---------- */
.hero{background:
  radial-gradient(1px 1px at 12% 22%,#fff8 50%,transparent 51%),
  radial-gradient(1px 1px at 72% 12%,#fff6 50%,transparent 51%),
  radial-gradient(1.5px 1.5px at 88% 68%,#fff7 50%,transparent 51%),
  radial-gradient(1px 1px at 32% 82%,#fff5 50%,transparent 51%),
  radial-gradient(1px 1px at 55% 40%,#fff4 50%,transparent 51%),
  var(--space);color:var(--paper);overflow:hidden}
.hero .in{max-width:var(--wide);margin:0 auto;padding:2.5rem 1.25rem 3.5rem;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.05fr);gap:2.5rem;align-items:center}
.hero h1{font:800 clamp(3.2rem,9vw,6.5rem)/.9 var(--display);margin:0 0 1.25rem;letter-spacing:-.005em;text-wrap:balance}
.answer{font-size:1.2rem;line-height:1.6;color:#E9E5F5;max-width:34rem}
.answer strong{color:#fff}
.hero .facts{display:grid;grid-template-columns:repeat(3,auto);gap:.25rem 1.25rem;margin:1.75rem 0 0;padding:0;justify-content:start}
.hero .facts dt{font-size:.9rem;color:#B8B0D4}
.hero .facts dd{margin:0;font:800 clamp(1.35rem,2.6vw,2rem)/1.05 var(--display);color:var(--gold);white-space:nowrap}
.hero .facts dd.hot{color:#FF8A5B}
.hero .facts dd.hotter{color:#9DB0FF}
.updated{font-size:.9rem;color:#9E96BC;margin-top:1.5rem}

/* sun explorer */
.explorer{position:relative}
.explorer svg{display:block;width:100%;max-width:560px;margin:0 auto}
.layer-hit{cursor:pointer;transition:filter .2s}
.layer-hit:hover,.layer-hit:focus{filter:brightness(1.18)}
.layer-hit.on{filter:brightness(1.25) drop-shadow(0 0 6px #fff9)}
.readout{margin:.5rem auto 0;max-width:560px;background:var(--space-2);border:1px solid #3F3563;border-radius:14px;padding:1rem 1.2rem;min-height:9.5rem}
.readout .nm{font:700 1.4rem/1.1 var(--display);color:var(--paper);margin:0}
.readout .tp{font:800 2.2rem/1.1 var(--display);color:var(--gold);margin:.3rem 0 .1rem}
.readout .alt{font-size:.95rem;color:#CFC8E6;margin:0}
.readout .ds{font-size:1rem;color:#E4DFF2;margin:.5rem 0 0;line-height:1.5}
.chips{display:flex;flex-wrap:wrap;gap:.4rem;justify-content:center;margin:.9rem auto 0;max-width:560px;padding:0;list-style:none}
.chips button{font:600 .95rem var(--display);letter-spacing:.02em;background:transparent;color:#DCD6F0;border:1px solid #4A4072;border-radius:99px;padding:.35rem .8rem;cursor:pointer}
.chips button[aria-pressed="true"]{background:var(--gold);border-color:var(--gold);color:var(--ink)}
@media (max-width:860px){.hero .in{grid-template-columns:1fr;gap:1.5rem;padding-top:1.75rem}}
@media (max-width:480px){.hero .facts{grid-template-columns:1fr 1fr}}

/* ---------- article ---------- */
main{padding:1rem 1.25rem 4rem}
.col{max-width:var(--col);margin:0 auto}
.wide{max-width:var(--wide);margin:2.5rem auto}
.crumbs{max-width:var(--col);margin:1.25rem auto 0;font-size:.9rem;color:var(--muted)}
.crumbs ol{list-style:none;padding:0;margin:0;display:flex;flex-wrap:wrap;gap:.4rem}
.crumbs li+li::before{content:"›";margin-right:.4rem}
h2{font:800 clamp(2rem,4.6vw,2.9rem)/1 var(--display);margin:4rem 0 1rem;letter-spacing:-.003em;text-wrap:balance}
h3{font:700 1.55rem/1.15 var(--display);margin:2.25rem 0 .5rem;letter-spacing:.005em}
h2 .t,h3 .t{display:block;font:600 1rem/1.3 var(--serif);color:var(--muted);letter-spacing:0;margin-top:.4rem}
p,ul,ol{margin:0 0 1.1rem}
li{margin-bottom:.4rem}
.lead{font-size:1.25rem}
.num{font-family:var(--display);font-weight:800;font-size:1.12em;letter-spacing:.01em;white-space:nowrap}
.toc{border-left:4px solid var(--gold);padding:.25rem 0 .25rem 1.25rem;margin:2rem 0}
.toc p{font:700 1.2rem var(--display);margin:0 0 .4rem}
.toc ol{margin:0;padding-left:1.2rem;columns:2 18rem;column-gap:2rem}
.toc a{color:var(--ink)}
.callout{background:#fff;border:1px solid var(--line);border-left:6px solid var(--flame);padding:1.1rem 1.3rem;border-radius:4px 12px 12px 4px;margin:1.75rem 0}
.callout p:last-child{margin:0}
.callout.blue{border-left-color:var(--corona)}

/* tables */
.tbl{overflow-x:auto;margin:1.5rem 0;border:1px solid var(--line);border-radius:12px;background:#fff}
table{border-collapse:collapse;width:100%;min-width:34rem;font-size:1rem;line-height:1.45}
caption{text-align:left;font:700 1.15rem var(--display);padding:.9rem 1rem .2rem;letter-spacing:.01em}
th,td{text-align:left;padding:.65rem 1rem;border-bottom:1px solid var(--line);vertical-align:top}
thead th{font:700 1rem var(--display);letter-spacing:.02em;color:var(--muted);background:#FAF9FD}
tbody tr:last-child td,tbody tr:last-child th{border-bottom:0}
td.n{font-family:var(--display);font-weight:700;font-size:1.08rem;white-space:nowrap}
tbody th{font-weight:600}

/* figures */
figure{margin:2rem 0}
figure svg{display:block;width:100%}
figcaption{font-size:.95rem;color:var(--muted);margin-top:.6rem;line-height:1.5}
.panel{background:#fff;border:1px solid var(--line);border-radius:16px;padding:1.25rem}
.panel.dark{background:var(--space);border-color:var(--space);color:var(--paper)}
.panel.dark figcaption{color:#B8B0D4}

/* ladder */
.bar-fill{transform-box:fill-box;transform-origin:left center;transform:scaleX(1);transition:transform 1.4s cubic-bezier(.2,.8,.2,1)}
.pending .bar-fill{transform:scaleX(0)}
.draw{transition:stroke-dashoffset 2.2s ease}

/* FAQ */
.faq details{border-bottom:1px solid var(--line);padding:.9rem 0}
.faq summary{cursor:pointer;font:700 1.3rem/1.25 var(--display);letter-spacing:.005em;list-style:none;display:flex;justify-content:space-between;gap:1rem}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:1.6rem;line-height:1;color:var(--flame);transition:transform .2s}
.faq details[open] summary::after{transform:rotate(45deg)}
.faq details p{margin:.6rem 0 0}

/* next-page link */
.next{display:grid;grid-template-columns:auto 1fr;gap:1.25rem;align-items:center;background:var(--space);color:var(--paper);border-radius:18px;padding:1.4rem 1.5rem;text-decoration:none;margin:3rem 0}
.next svg{width:92px}
.next b{display:block;font:800 1.7rem/1.05 var(--display);color:#fff;margin-bottom:.3rem}
.next span{color:#D6D0EA;font-size:1rem}
.next:hover b{color:var(--gold)}

/* calculator */
.calc{background:var(--space);color:var(--paper);border-radius:18px;padding:1.25rem 1.25rem 1.5rem}
.calc label{font:700 1.15rem var(--display);letter-spacing:.02em;display:block}
.calc input[type=range]{width:100%;accent-color:var(--gold);margin:.75rem 0 .25rem;height:2rem}
.calc .dist{font:800 clamp(1.8rem,5vw,2.6rem)/1 var(--display);color:#fff;margin:.2rem 0 0}
.calc .out{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:1rem;margin:1.25rem 0 .5rem}
.calc .out div{border-top:1px solid #4A4072;padding-top:.5rem}
.calc .out span{display:block;font-size:.9rem;color:#B8B0D4}
.calc .out b{font:800 clamp(1.4rem,4vw,2rem)/1.1 var(--display);color:var(--gold)}
.calc .presets{display:flex;flex-wrap:wrap;gap:.4rem;margin-top:1rem}
.calc .presets button{font:600 .95rem var(--display);background:transparent;color:#DCD6F0;border:1px solid #4A4072;border-radius:99px;padding:.35rem .75rem;cursor:pointer}
.calc .presets button:hover{border-color:var(--gold);color:#fff}
.calc .note{font-size:.95rem;color:#CFC8E6;margin:.75rem 0 0}
@media (max-width:520px){.calc .out{grid-template-columns:1fr 1fr}}

/* footer */
footer{background:var(--space);color:#B8B0D4;font-size:.95rem}
footer .in{max-width:var(--wide);margin:0 auto;padding:2rem 1.25rem;display:flex;flex-wrap:wrap;gap:1rem 2rem;justify-content:space-between}
footer a{color:#DCD6F0}

/* motion */
.pulse{animation:pulse 5s ease-in-out infinite;transform-box:fill-box;transform-origin:center}
@keyframes pulse{50%{opacity:.7;transform:scale(1.03)}}
.spin{animation:spin 160s linear infinite;transform-box:view-box;transform-origin:center}
@keyframes spin{to{transform:rotate(360deg)}}
.flow{stroke-dasharray:6 8;animation:flow 2.4s linear infinite}
@keyframes flow{to{stroke-dashoffset:-28}}
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}
  .pending .bar-fill{transform:none}
}
.site-head nav a:first-child{margin-left:0}
.crumbs{padding:0 1.25rem}
@media (max-width:600px){
  .site-head .bar{gap:.5rem}
  .site-head nav{display:flex;gap:1rem}
  .site-head nav a{margin-left:0;font-size:.98rem}
  body{font-size:1.0625rem}
}
@media (max-width:600px){
  .panel{overflow-x:auto;padding:1rem}
  .panel > svg{min-width:560px}
  .panel{scrollbar-width:thin}
}