app/static/style.css

:root {
  --fg: #1a1a1a;
  --bg: #ffffff;
  --muted: #555;
  --accent: #0b4f9c;
  --rule: #d0d4da;
  --err-bg: #fde2e2;
  --err-fg: #7a0a0a;
}
@media (prefers-color-scheme: dark) {
  :root {
    --fg: #f1f1f1;
    --bg: #121417;
    --muted: #b0b6bd;
    --accent: #7eb6ff;
    --rule: #2a2f36;
    --err-bg: #4a1313;
    --err-fg: #ffd6d6;
  }
}
* { box-sizing: border-box; }
html { font-size: 18px; }
body {
  margin: 0;
  color: var(--fg);
  background: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  line-height: 1.6;
}
a.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 100;
}
a.skip-link:focus { left: 1rem; top: 1rem; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
header[role="banner"], main {
  max-width: 44rem;
  margin: 0 auto;
  padding: 1.5rem 1.25rem;
}
header[role="banner"] { border-bottom: 1px solid var(--rule); }
h1 { font-size: 1.875rem; margin: 0 0 0.25rem; }
h2 { font-size: 1.375rem; margin: 1.5rem 0 0.5rem; }
form { margin-top: 1rem; }
.field, fieldset { margin-bottom: 1.25rem; }
fieldset {
  border: 1px solid var(--rule);
  padding: 0.75rem 1rem;
  border-radius: 6px;
}
legend { font-weight: 600; padding: 0 0.4rem; }
label {
  display: block;
  margin: 0.5rem 0 0.25rem;
  font-weight: 500;
}
input[type="text"], input[type="number"], input[type="file"] {
  width: 100%;
  padding: 0.5rem 0.6rem;
  font-size: 1rem;
  border: 1px solid var(--rule);
  border-radius: 4px;
  background: var(--bg);
  color: var(--fg);
}
input[type="radio"] { margin-right: 0.4rem; }
button {
  background: var(--accent);
  color: #fff;
  border: 0;
  padding: 0.7rem 1.25rem;
  font-size: 1rem;
  border-radius: 4px;
  cursor: pointer;
}
button:hover { filter: brightness(1.08); }
.error {
  background: var(--err-bg);
  color: var(--err-fg);
  padding: 0.75rem 1rem;
  border-radius: 4px;
  margin-bottom: 1rem;
}