* { box-sizing: border-box; }

:root {
  color-scheme: light;
  font-family: Arial, Helvetica, sans-serif;
  color: #222;
  background: #fff;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

html { min-width: 320px; scroll-behavior: smooth; scroll-padding-top: 80px; }
body { margin: 0; }
a { color: inherit; }

.topbar {
  display: flex;
  min-height: 64px;
  align-items: center;
  justify-content: space-between;
  width: min(920px, calc(100% - 48px));
  margin: 0 auto;
}
.brand { color: #222; font-size: 15px; font-weight: 600; text-decoration: none; }
nav { display: flex; gap: 22px; }
nav a { color: #555; font-size: 13px; text-decoration: none; }
nav a:hover { color: #1769d2; }

main { width: min(680px, calc(100% - 48px)); margin: 0 auto; }
.intro { padding: 100px 0 72px; }
.label { margin: 0 0 18px; color: #666; font-size: 11px; letter-spacing: .1em; }
h1 { margin: 0 0 22px; font-size: clamp(38px, 8vw, 58px); font-weight: 500; letter-spacing: -.055em; line-height: 1.1; }
.lead { max-width: 640px; margin: 0 0 15px; color: #444; font-size: 18px; line-height: 1.65; }
.description { max-width: 640px; margin: 0; color: #666; font-size: 15px; line-height: 1.8; }

.section { padding: 27px 0; }
h2 { margin: 0 0 13px; font-size: 20px; font-weight: 500; letter-spacing: -.02em; }
.section > p, details p { max-width: 660px; margin: 0; color: #666; font-size: 14px; line-height: 1.8; }
.section + .section { margin-top: 14px; }
details { padding: 0; }
summary { padding: 10px 20px 10px 0; font-size: 14px; line-height: 1.5; cursor: pointer; }
details p { padding: 0 20px 12px 0; }

footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 20px;
  width: min(920px, calc(100% - 48px));
  margin: 58px auto 0;
  padding: 18px 0 24px;
  color: #777;
  font-size: 12px;
}

@media (max-width: 560px) {
  .topbar, footer { width: calc(100% - 36px); }
  nav { gap: 14px; }
  nav a { font-size: 12px; }
  main { width: calc(100% - 36px); }
  .intro { padding: 78px 0 55px; }
  .lead { font-size: 16px; }
  .description { font-size: 14px; }
  footer span:nth-child(2) { width: 100%; order: 1; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}