/* EinsteinPy site styles: dark by default, light via prefers-color-scheme or the toggle */
  :root{
    --bg:#070b17; --bg-2:#0c1224; --surface:#111a31; --surface-2:#16213f;
    --line:rgba(148,163,200,.16); --text:#e8ecf8; --muted:#97a3c4;
    --accent:#7c8cff; --accent-2:#5bc3c2; --warm:#ffb86b;
    --glow:rgba(124,140,255,.35);
    --code-bg:#0a1020;
    --radius:16px;
  }
  :root[data-theme="light"]{
    --bg:#f7f8fc; --bg-2:#eef0f8; --surface:#ffffff; --surface-2:#f1f3fb;
    --line:rgba(30,41,90,.12); --text:#0f1733; --muted:#56628a;
    --accent:#4c5bd4; --accent-2:#2f8f8f; --warm:#c2600a;
    --glow:rgba(76,91,212,.22); --code-bg:#0f1733;
  }
  *{box-sizing:border-box}
  html{scroll-behavior:smooth}
  body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 Inter,system-ui,sans-serif;-webkit-font-smoothing:antialiased}
  a{color:inherit;text-decoration:none}
  .wrap{max-width:1160px;margin:0 auto;padding:0 24px}
  code,pre,.mono{font-family:"JetBrains Mono",ui-monospace,monospace}

  /* nav */
  nav{position:sticky;top:0;z-index:20;backdrop-filter:blur(14px);background:color-mix(in srgb,var(--bg) 78%,transparent);border-bottom:1px solid var(--line)}
  .nav{display:flex;align-items:center;gap:28px;height:64px}
  .brand{display:flex;align-items:center;gap:8px;font-weight:700;letter-spacing:-.01em;font-size:18px}
  .brand img{width:36px;height:36px;object-fit:contain}
  .brand .py{color:#44aaaa}
  .links{display:flex;gap:22px;margin-left:12px;font-size:14.5px;color:var(--muted)}
  .links a:hover{color:var(--text)}
  .spacer{flex:1}
  .btn{display:inline-flex;align-items:center;gap:8px;padding:10px 18px;border-radius:999px;font-weight:600;font-size:14.5px;border:1px solid var(--line);background:var(--surface);color:var(--text);cursor:pointer;transition:.18s}
  .btn:hover{transform:translateY(-1px);border-color:var(--accent)}
  .btn.primary{background:linear-gradient(135deg,var(--accent),#5b6cf0);border-color:transparent;color:#fff;box-shadow:0 8px 28px -8px var(--glow)}
  .btn.primary:hover{box-shadow:0 12px 34px -8px var(--glow)}
  .icon-btn{width:38px;height:38px;padding:0;justify-content:center}

  /* hero */
  .hero{position:relative;overflow:hidden;padding:84px 0 56px}
  .hero::before{content:"";position:absolute;inset:-20% -10% auto auto;width:720px;height:720px;background:radial-gradient(closest-side,var(--glow),transparent 70%);filter:blur(10px);pointer-events:none}
  .hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center;position:relative}
  .pill{display:inline-flex;align-items:center;gap:8px;padding:6px 14px 6px 8px;border-radius:999px;border:1px solid var(--line);background:var(--surface);font-size:13px;color:var(--muted)}
  .pill b{background:var(--accent);color:#fff;border-radius:999px;padding:2px 9px;font-size:12px;font-weight:600}
  h1{font-size:clamp(38px,5.2vw,64px);line-height:1.04;letter-spacing:-.035em;margin:20px 0 18px;font-weight:800}
  h1 span{background:linear-gradient(120deg,var(--accent) 10%,var(--accent-2) 60%,var(--warm));-webkit-background-clip:text;background-clip:text;color:transparent}
  .lead{font-size:19px;color:var(--muted);max-width:560px;margin:0 0 28px}
  .cta{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:26px}
  .install{display:inline-flex;align-items:center;gap:14px;padding:12px 14px 12px 18px;border-radius:12px;background:var(--code-bg);color:#dfe6ff;border:1px solid var(--line);font-size:14.5px}
  .install .prompt{color:var(--accent-2)}
  .copy{all:unset;cursor:pointer;display:inline-flex;padding:6px 10px;border-radius:8px;background:rgba(255,255,255,.08);font:500 12px "JetBrains Mono",monospace;color:#cdd6f7}
  .copy:hover{background:rgba(255,255,255,.16)}
  .meta{display:flex;flex-wrap:wrap;gap:18px;margin-top:22px;font-size:13.5px;color:var(--muted)}
  .meta span::before{content:"";display:inline-block;width:6px;height:6px;border-radius:50%;background:var(--accent-2);margin-right:8px;vertical-align:middle}

  .hero-grid>*,.code-split>*{min-width:0}
  .stage{position:relative;border-radius:22px;border:1px solid var(--line);background:#01020a;box-shadow:0 30px 80px -30px rgba(0,0,0,.6);overflow:hidden}
  .stage canvas{display:block;width:100%;aspect-ratio:1/0.82}
  .stage .tag{position:absolute;left:16px;bottom:14px;font:500 12px "JetBrains Mono",monospace;color:#9aa6c8;background:rgba(1,2,10,.62);padding:5px 10px;border-radius:8px;border:1px solid var(--line)}

  /* sections */
  section{padding:76px 0}
  .eyebrow{font:600 12.5px Inter;letter-spacing:.14em;text-transform:uppercase;color:var(--accent-2)}
  h2{font-size:clamp(28px,3.4vw,40px);letter-spacing:-.025em;line-height:1.12;margin:10px 0 14px;font-weight:700}
  .sub{color:var(--muted);max-width:620px;font-size:17px;margin:0 0 40px}

  .code-split{display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:stretch}
  .codecard{background:var(--code-bg);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;display:flex;flex-direction:column}
  .codebar{display:flex;align-items:center;gap:7px;padding:12px 16px;border-bottom:1px solid rgba(255,255,255,.08);color:#8b97bd;font:500 12.5px "JetBrains Mono",monospace}
  .dot{width:11px;height:11px;border-radius:50%}
  pre{margin:0;padding:20px 22px;overflow:auto;font-size:13.5px;line-height:1.75;color:#d6defa;flex:1}
  .k{color:#c792ea}.s{color:#a5e8c1}.n{color:#ffb86b}.c{color:#6c7a9f}.f{color:#82aaff}
  .points{display:flex;flex-direction:column;gap:16px;justify-content:center}
  .point{display:flex;gap:16px;padding:18px 20px;border-radius:var(--radius);border:1px solid var(--line);background:var(--surface)}
  .point i{flex:none;width:38px;height:38px;border-radius:10px;display:grid;place-items:center;background:var(--surface-2);color:var(--accent);font-style:normal;font-weight:700}
  .point h4{margin:0 0 2px;font-size:16px}
  .point p{margin:0;color:var(--muted);font-size:14.5px}


  /* symbolic section */
  .sym-grid{display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:stretch}
  .sym-grid>*{min-width:0}
  .result{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;display:flex;flex-direction:column}
  .result .bar{display:flex;align-items:center;justify-content:space-between;padding:12px 18px;border-bottom:1px solid var(--line);color:var(--muted);font:500 12.5px "JetBrains Mono",monospace}
  .result .bar em{font-style:normal;color:var(--accent-2)}
  .rows{padding:6px 22px 18px;display:flex;flex-direction:column}
  .row{padding:16px 0;border-bottom:1px dashed var(--line)}
  .row:last-child{border-bottom:0}
  .row small{display:block;margin-bottom:8px;color:var(--muted);font-size:12.5px;letter-spacing:.06em;text-transform:uppercase;font-weight:600}
  .tex{overflow-x:auto;overflow-y:hidden;color:var(--text);font-size:17px}
  .tex .katex-display{margin:.2em 0}
  .check{display:flex;flex-wrap:wrap;gap:10px}
  .check>span{display:inline-flex;align-items:center;gap:8px;padding:7px 13px;border-radius:10px;background:color-mix(in srgb,var(--accent-2) 12%,transparent);border:1px solid color-mix(in srgb,var(--accent-2) 35%,var(--line));font-size:15px}
  .check>span::before{content:"✓";color:var(--accent-2);font-weight:700}
  .sym-chips{margin-top:26px;display:grid;grid-template-columns:auto 1fr;gap:12px 18px;align-items:center}
  .sym-chips h6{margin:0;font:600 12.5px Inter;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
  .sym-chips .metrics{margin:0}
  .features{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
  .card{padding:26px;border-radius:var(--radius);border:1px solid var(--line);background:var(--surface);transition:.2s;position:relative;overflow:hidden}
  .card:hover{transform:translateY(-3px);border-color:color-mix(in srgb,var(--accent) 55%,var(--line));box-shadow:0 18px 40px -22px var(--glow)}
  .card .ic{width:44px;height:44px;border-radius:12px;display:grid;place-items:center;margin-bottom:16px;background:linear-gradient(135deg,color-mix(in srgb,var(--accent) 22%,transparent),color-mix(in srgb,var(--accent-2) 18%,transparent));color:var(--accent)}
  .card .ic svg{width:22px;height:22px}
  .card h3{margin:0 0 8px;font-size:18px;letter-spacing:-.01em}
  .card p{margin:0;color:var(--muted);font-size:15px}

  .metrics{display:flex;flex-wrap:wrap;gap:10px;margin-top:6px}
  .chip{padding:8px 16px;border-radius:999px;border:1px solid var(--line);background:var(--surface);font-size:14px;color:var(--muted)}
  .chip b{color:var(--text);font-weight:600}

  .band{background:linear-gradient(180deg,var(--bg-2),var(--bg));border-block:1px solid var(--line)}
  .connect{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
  .connect a{display:block;padding:22px;border-radius:var(--radius);border:1px solid var(--line);background:var(--surface);transition:.2s}
  .connect a:hover{border-color:var(--accent);transform:translateY(-2px)}
  .connect small{display:block;color:var(--muted);font-size:13px;margin-bottom:6px}
  .connect strong{font-size:17px}
  .connect span{display:block;margin-top:8px;color:var(--muted);font-size:14px}

  .support{display:flex;align-items:center;justify-content:space-between;gap:28px;padding:34px 38px;border-radius:22px;border:1px solid var(--line);background:radial-gradient(120% 160% at 0% 0%,var(--glow),transparent 60%),var(--surface)}
  .support h3{margin:0 0 6px;font-size:22px;letter-spacing:-.015em}
  .support p{margin:0;color:var(--muted);max-width:620px}

  footer{padding:46px 0 56px;border-top:1px solid var(--line);color:var(--muted);font-size:14px}
  .foot{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:30px}
  .foot h5{margin:0 0 12px;color:var(--text);font-size:13px;letter-spacing:.08em;text-transform:uppercase}
  .foot a{display:block;margin:7px 0}
  .foot a:hover{color:var(--text)}
  .foot a.brand{display:inline-flex;margin:0 0 12px;color:var(--text);font-size:18px}
  .foot a.brand img{width:32px;height:32px}
  .legal{margin-top:34px;padding-top:20px;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;font-size:13px}

  @media (max-width:920px){
    .hero-grid,.code-split,.sym-grid{grid-template-columns:minmax(0,1fr)}
    .features{grid-template-columns:1fr 1fr}
    .connect{grid-template-columns:1fr 1fr}
    .foot{grid-template-columns:1fr 1fr}
    .support{flex-direction:column;align-items:flex-start}
  }
  @media (max-width:640px){
    .features,.connect,.foot,.sym-chips{grid-template-columns:minmax(0,1fr)}
    .hero{padding-top:52px}
    .wrap{padding:0 16px}
    .nav .btn.gh,.nav .btn.primary{display:none}
  }
  @media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

  /* ---- shared page chrome / inner pages ---- */
  .menu{display:none}
  nav.open .links{display:flex}
  .prose{padding:56px 0 72px;max-width:820px}
  .prose h1,.prose h2{letter-spacing:-.025em;line-height:1.15}
  .prose h2{font-size:clamp(26px,3vw,34px);margin:0 0 18px}
  .prose p,.prose li{color:var(--muted);font-size:17px}
  .prose a{color:var(--accent);text-decoration:underline;text-underline-offset:3px}
  .prose ul{padding-left:1.2em}
  .prose pre{background:var(--code-bg);color:#d6defa;border:1px solid var(--line);border-radius:12px;margin:1.2em 0;padding:18px 20px;overflow:auto;font-size:13.5px;line-height:1.7}
  .prose :not(pre)>code{background:var(--surface-2);border:1px solid var(--line);border-radius:6px;padding:1px 6px;font-size:.9em}
  .skip{position:absolute;left:-999px}
  :focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:6px}
  @media (max-width:640px){
    .nav{flex-wrap:wrap;height:auto;min-height:64px;padding-block:10px}
    .links{display:none;order:5;flex-basis:100%;flex-direction:column;gap:2px;margin:0;padding:8px 0}
    .links a{padding:10px 4px;font-size:16px}
    .menu{display:inline-flex}
  }