:root { --fg: #10233b; --bg: #f3f6fb; --accent: #116a4e; --muted: #5a6b84; }
* { box-sizing: border-box; }
body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: var(--fg);
  background: var(--bg);
  margin: 0;
  padding: 2rem;
  line-height: 1.5;
}
header, main, footer { max-width: 60rem; margin: 0 auto; }
h1 { color: var(--accent); }
nav a { color: var(--accent); text-decoration: none; }
nav a:hover { text-decoration: underline; }
form { display: grid; gap: .75rem; max-width: 22rem; margin-top: 1rem; }
label { display: grid; gap: .25rem; font-weight: 600; }
input { padding: .5rem; border: 1px solid #c3cede; border-radius: 6px; }
button {
  padding: .55rem 1rem; border: 0; border-radius: 6px;
  background: var(--accent); color: #fff; font-weight: 600; cursor: pointer;
}
code { background: #e7edf6; padding: .1rem .3rem; border-radius: 4px; }
ul { padding-left: 1.2rem; }
.preview { border: 1px solid #c3cede; border-radius: 6px; padding: .75rem; background: #fff; }
footer { margin-top: 2rem; color: var(--muted); font-size: .9rem; }