@font-face{font-family:Inter;font-style:normal;font-weight:400 800;font-display:swap;src:url(fonts/inter-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:Inter;font-style:normal;font-weight:400 800;font-display:swap;src:url(fonts/inter-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}

:root{
  --bg:#f5f5f7;--surface:#fff;--surface-2:#f0f0f3;--text:#0b0b0c;--muted:#5f6068;--line:#e3e3e8;
  --ink:#0b0b0c;--on-ink:#fff;--accent:#0b0b0c;--warn:#b54708;--warn-bg:#fff4e5;
  --radius:18px;--radius-sm:12px;--shadow:0 1px 2px rgba(0,0,0,.04),0 8px 24px rgba(0,0,0,.06);
  --max:1120px;color-scheme:light dark
}
@media (prefers-color-scheme:dark){
  :root{--bg:#000;--surface:#141416;--surface-2:#1c1c1f;--text:#f5f5f7;--muted:#a1a1aa;--line:#2a2a2e;
    --ink:#f5f5f7;--on-ink:#0b0b0c;--accent:#f5f5f7;--warn:#fdb022;--warn-bg:#2b1d05;--shadow:0 1px 2px rgba(0,0,0,.5)}
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 Inter,system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:6px}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-999px;top:8px;background:var(--ink);color:var(--on-ink);padding:8px 12px;border-radius:8px;z-index:10}
.skip:focus{left:8px}

.top{position:sticky;top:0;z-index:5;background:color-mix(in srgb,var(--bg) 82%,transparent);backdrop-filter:saturate(1.6) blur(14px);-webkit-backdrop-filter:saturate(1.6) blur(14px);border-bottom:1px solid var(--line)}
.top .wrap{display:flex;align-items:center;gap:20px;height:60px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;text-decoration:none;letter-spacing:-.01em}
.brand img{width:28px;height:28px}
.nav{display:flex;gap:4px;margin-left:auto;overflow-x:auto;scrollbar-width:none}
.nav::-webkit-scrollbar{display:none}
.nav a{white-space:nowrap;text-decoration:none;font-size:14px;font-weight:500;color:var(--muted);padding:7px 12px;border-radius:999px}
.nav a:hover{color:var(--text);background:var(--surface-2)}
.nav a[aria-current=page]{color:var(--text);background:var(--surface)}

.hero{padding:56px 0 24px}
.hero-grid{display:grid;gap:40px;align-items:center;grid-template-columns:1fr}
@media (min-width:900px){.hero-grid{grid-template-columns:1.05fr 1fr}}
.app-id{display:flex;align-items:center;gap:14px;margin-bottom:22px}
.app-id img,.app-icon{width:64px;height:64px;border-radius:15px;box-shadow:var(--shadow);background:var(--surface)}
.app-icon.svg{display:grid;place-items:center;background:var(--ink);color:var(--on-ink)}
.app-id b{display:block;font-size:15px}
.app-id span{font-size:13px;color:var(--muted)}
.eyebrow{font-size:13px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
h1{font-size:clamp(34px,6vw,58px);line-height:1.04;letter-spacing:-.035em;margin:0 0 18px;font-weight:800}
h2{font-size:clamp(26px,3.6vw,38px);line-height:1.1;letter-spacing:-.03em;margin:0 0 14px;font-weight:800}
h3{font-size:18px;letter-spacing:-.01em;margin:0 0 6px}
.lead{font-size:clamp(17px,2vw,20px);color:var(--muted);margin:0 0 26px;max-width:560px}
.cta{display:flex;flex-wrap:wrap;gap:12px;align-items:center}
.btn{display:inline-flex;align-items:center;gap:10px;text-decoration:none;font-weight:600;font-size:15px;border-radius:999px;padding:12px 20px;border:1px solid var(--line);background:var(--surface)}
.btn:hover{border-color:var(--muted)}
.btn.primary{background:var(--ink);color:var(--on-ink);border-color:var(--ink)}
.btn svg{width:18px;height:18px}
.meta{font-size:13px;color:var(--muted);margin-top:14px}
.hero-art{border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);border:1px solid var(--line)}

section{padding:56px 0}
.section-head{max-width:720px;margin-bottom:28px}
.section-head p{color:var(--muted);margin:0}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}

.calc{display:grid;gap:0;grid-template-columns:1fr;overflow:hidden}
@media (min-width:860px){.calc{grid-template-columns:1fr 1fr}}
.calc-in,.calc-out{padding:24px}
.calc-out{background:var(--surface-2);border-top:1px solid var(--line)}
@media (min-width:860px){.calc-out{border-top:0;border-left:1px solid var(--line)}}
.calc h3{margin-bottom:14px}
.seg{display:inline-flex;background:var(--surface-2);border-radius:999px;padding:3px;margin-bottom:16px;flex-wrap:wrap}
.seg button{font:inherit;font-size:14px;font-weight:600;border:0;background:none;color:var(--muted);padding:7px 14px;border-radius:999px;cursor:pointer}
.seg button[aria-pressed=true]{background:var(--surface);color:var(--text);box-shadow:0 1px 3px rgba(0,0,0,.12)}
.field{display:grid;grid-template-columns:40px 1fr auto;align-items:center;gap:12px;padding:10px 0;border-top:1px solid var(--line)}
.field:first-of-type{border-top:0}
.sym{width:34px;height:34px;border-radius:50%;display:grid;place-items:center;font-weight:700;font-size:15px;background:var(--surface-2);font-family:"Times New Roman",serif;font-style:italic}
.field.given .sym{background:var(--ink);color:var(--on-ink)}
.field label{display:block;font-size:13px;color:var(--muted);font-weight:500}
.field input{width:100%;font:inherit;font-size:20px;font-weight:600;font-variant-numeric:tabular-nums;border:0;background:none;color:var(--text);padding:2px 0;outline:none}
.field input::placeholder{color:var(--line)}
.unit{font-size:14px;color:var(--muted)}
.hint{font-size:13px;color:var(--muted);margin:12px 0 0}
.warn{display:none;margin-top:12px;font-size:14px;color:var(--warn);background:var(--warn-bg);padding:10px 12px;border-radius:var(--radius-sm)}
.warn.show{display:block}
.results{display:grid;gap:10px;margin:0 0 18px;padding:0;list-style:none}
.results li{display:flex;justify-content:space-between;gap:12px;align-items:baseline;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-sm);padding:12px 14px}
.results span{color:var(--muted);font-size:14px}
.results b{font-size:20px;font-variant-numeric:tabular-nums;letter-spacing:-.01em;text-align:right}
.steps{font:14px/1.7 ui-monospace,SFMono-Regular,Menlo,monospace;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-sm);padding:12px 14px;margin:0;white-space:pre-wrap;overflow-x:auto}
.empty{color:var(--muted);font-size:15px}
.actions{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap}
.chip{font:inherit;font-size:13px;font-weight:600;border:1px solid var(--line);background:var(--surface);color:var(--text);padding:7px 12px;border-radius:999px;cursor:pointer}
.chip:hover{border-color:var(--muted)}

.grid3{display:grid;gap:16px;grid-template-columns:1fr}
@media (min-width:720px){.grid3{grid-template-columns:repeat(3,1fr)}}
.grid2{display:grid;gap:16px;grid-template-columns:1fr}
@media (min-width:720px){.grid2{grid-template-columns:repeat(2,1fr)}}
.feature{padding:22px}
.feature p{margin:0;color:var(--muted);font-size:15px}
.feature .ico{width:36px;height:36px;border-radius:10px;background:var(--surface-2);display:grid;place-items:center;margin-bottom:14px;font-weight:700}

.formula{padding:20px}
.formula code{display:block;font:600 18px/1.4 ui-monospace,SFMono-Regular,Menlo,monospace;margin:4px 0 8px}
.formula p{margin:0;color:var(--muted);font-size:14px}

.faq details{border-top:1px solid var(--line);padding:16px 0}
.faq details:last-child{border-bottom:1px solid var(--line)}
.faq summary{cursor:pointer;font-weight:600;font-size:17px;list-style:none;display:flex;justify-content:space-between;gap:16px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-weight:400;font-size:22px;line-height:1;color:var(--muted)}
.faq details[open] summary::after{content:"−"}
.faq details p{margin:10px 0 0;color:var(--muted)}

.pro{padding:28px;display:grid;gap:20px;grid-template-columns:1fr}
@media (min-width:860px){.pro{grid-template-columns:1.2fr 1fr;align-items:center}}
.pro ul{margin:0;padding:0;list-style:none;display:grid;gap:8px}
.pro li::before{content:"✓";font-weight:700;margin-right:10px}

.apps{display:grid;gap:16px;grid-template-columns:1fr}
@media (min-width:720px){.apps{grid-template-columns:repeat(3,1fr)}}
.app-card{padding:22px;display:flex;flex-direction:column;gap:12px;text-decoration:none}
.app-card:hover{border-color:var(--muted)}
.app-card p{margin:0;color:var(--muted);font-size:15px;flex:1}
.app-card .more{font-weight:600;font-size:14px}
.tag{display:inline-block;font-size:12px;font-weight:600;padding:3px 9px;border-radius:999px;background:var(--surface-2);color:var(--muted)}

.prose{max-width:760px;padding:48px 20px 64px;margin:0 auto}
.prose h1{font-size:clamp(30px,5vw,42px)}
.prose h2{font-size:22px;margin:34px 0 10px;letter-spacing:-.02em}
.prose h3{margin-top:18px}
.prose p,.prose li{color:var(--muted)}
.prose strong{color:var(--text)}
.prose .updated{font-size:14px;color:var(--muted)}

.foot{border-top:1px solid var(--line);padding:32px 0 48px;font-size:14px;color:var(--muted)}
.foot .wrap{display:flex;flex-wrap:wrap;gap:18px 28px;justify-content:space-between}
.foot nav{display:flex;flex-wrap:wrap;gap:6px 18px}
.foot a{text-decoration:none}
.foot a:hover{color:var(--text)}

.badge img{height:48px;width:auto}
.get-app{margin-top:16px;padding:14px 16px;border-radius:var(--radius-sm);background:var(--ink);color:var(--on-ink);display:flex;gap:12px;align-items:center;text-decoration:none}
.get-app picture{flex:none;display:flex}
.get-app img{width:40px;height:40px;border-radius:10px;flex:none}
.get-app b{display:block;font-size:15px}
.get-app span{font-size:13px;opacity:.8}
.get-app .go{margin-left:auto;font-weight:700;white-space:nowrap}
.sticky-cta{position:fixed;left:12px;right:12px;bottom:12px;z-index:6;display:flex;align-items:center;gap:12px;padding:10px 12px;border-radius:16px;background:var(--surface);border:1px solid var(--line);box-shadow:0 8px 30px rgba(0,0,0,.18);text-decoration:none}
.sticky-cta img{width:36px;height:36px;border-radius:9px}
.sticky-cta b{font-size:14px;display:block}
.sticky-cta span{font-size:12px;color:var(--muted)}
.sticky-cta .go{margin-left:auto;background:var(--ink);color:var(--on-ink);font-weight:700;font-size:14px;padding:8px 14px;border-radius:999px}
@media (min-width:860px){.sticky-cta{display:none}}
@media (max-width:859px){body.has-sticky{padding-bottom:84px}}
.store-btn{display:inline-flex;align-items:center;gap:10px;background:var(--ink);color:var(--on-ink);text-decoration:none;border-radius:12px;padding:8px 18px 8px 14px;min-height:50px}
.store-btn svg{width:26px;height:26px}
.store-btn span{display:flex;flex-direction:column;line-height:1.05;font-size:20px;font-weight:600;letter-spacing:-.01em}
.store-btn small{font-size:11px;font-weight:500;letter-spacing:0}
section[id]{scroll-margin-top:72px}
.foot .langs{width:100%;display:flex;flex-wrap:wrap;gap:6px 14px;font-size:13px}
.foot .langs a[aria-current]{color:var(--text);font-weight:600}