:root {
  --paper: #f1ece5;
  --logo: #401212;
  --icon-shadow: 0 1px 2px rgb(60 40 20 / 0.08), 0 10px 28px rgb(60 40 20 / 0.16);
  --warm: rgb(255 196 150 / 0.22);
  --cool: rgb(160 185 255 / 0.16);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    --paper: #161412;
    --logo: #ffffff;
    --icon-shadow: 0 1px 2px rgb(0 0 0 / 0.3), 0 24px 60px rgb(0 0 0 / 0.5);
    --warm: rgb(255 160 100 / 0.08);
    --cool: rgb(120 150 255 / 0.08);
    color-scheme: dark;
  }
}
:root[data-theme='dark'] {
  --paper: #161412; --logo: #ffffff;
  --icon-shadow: 0 1px 2px rgb(0 0 0 / 0.3), 0 24px 60px rgb(0 0 0 / 0.5);
  --warm: rgb(255 160 100 / 0.08); --cool: rgb(120 150 255 / 0.08);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: var(--paper);
  background-image:
    url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='180' height='180'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='3' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.3  0 0 0 0 0.22  0 0 0 0 0.15  0 0 0 0.09 0'/></filter><rect width='100%25' height='100%25' filter='url(%23n)'/></svg>"),
    radial-gradient(900px 520px at 0% 0%, var(--warm), transparent 70%),
    radial-gradient(900px 600px at 100% 100%, var(--cool), transparent 70%);
  background-attachment: fixed;
}
main {
  min-height: 100%;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 48px; padding: 48px 16px;
}
.app-icon {
  display: block; width: clamp(56px, 14vw, 72px); height: auto;
  border-radius: 22.5%;
  box-shadow: var(--icon-shadow);
}
.logo { display: block; width: clamp(240px, 64vw, 400px); height: auto; color: var(--logo); }