:root { color-scheme: light; }
* { box-sizing: border-box; }
html { font-size: 18px; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.55;
  color: #111;
  background: #fafafa;
}
header, main, footer { max-width: 42rem; margin: 0 auto; padding: 1.25rem 1.1rem; }
header { padding-bottom: 0; }
h1 { font-size: 1.45rem; margin: 0 0 0.35rem; }
h2 { font-size: 1.05rem; margin: 1.4rem 0 0.45rem; }
p, li { font-size: 1rem; }
.sub { color: #444; font-size: 0.95rem; margin: 0 0 1rem; }
nav a, a { color: #0b57d0; }
ul, ol { padding-left: 1.2rem; }
.card { background: #fff; border: 1px solid #e6e6e6; border-radius: 10px; padding: 1rem 1.1rem 1.2rem; }
footer { color: #555; font-size: 0.88rem; }