:root {
  --tc-blue: #1557b0;
  --tc-ink: #0c1116;
  --tc-muted: #6b7785;
  --tc-bg: #fff;
  --tc-border: #e3e8ee;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font: 15px/1.5 -apple-system, "Segoe UI", Roboto, Inter, system-ui, sans-serif;
  color: var(--tc-ink);
  background: var(--tc-bg);
  padding: 24px;
}
header h1 { font-size: 22px; margin: 0 0 4px; color: var(--tc-blue); }
.muted { color: var(--tc-muted); }
.small { font-size: 12px; }
section#invoice-card {
  margin: 16px 0;
  padding: 16px;
  border: 1px solid var(--tc-border);
  border-radius: 10px;
  background: #f8fafc;
}
section#invoice-card h2 { margin: 0 0 8px; color: var(--tc-blue); font-size: 18px; }
section#invoice-card ul { margin: 8px 0; padding-left: 20px; }
section#invoice-card p.total { font-weight: 600; margin-top: 8px; }
nav.invoice-nav { display: flex; justify-content: space-between; margin: 12px 0; }
nav.invoice-nav a { color: var(--tc-blue); text-decoration: none; }
nav.invoice-nav a:hover { text-decoration: underline; }
footer { margin-top: 24px; }