:root {
  --bg: #f4f5f7; --surface: #fff; --text: #1c1f24; --muted: #646b75;
  --border: #dcdfe4; --accent: #2b59c3; --accent-text: #fff;
  --error-bg: #fdecec; --error: #a3221b; --ok-bg: #e9f5ec; --ok: #1d6b35;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171b; --surface: #1f2228; --text: #e8eaed; --muted: #9aa1ab;
    --border: #343941; --accent: #6b93f0; --accent-text: #0f1115;
    --error-bg: #3a1d1c; --error: #f2a29c; --ok-bg: #19301f; --ok: #8fd6a2;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0; min-height: 100vh; background: var(--bg); color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.card {
  max-width: 400px; margin: 10vh auto; padding: 2rem;
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
}
.wide { max-width: 960px; margin: 2rem auto; padding: 0 16px; }
h1 { margin: 0 0 .25rem; font-size: 1.5rem; }
.muted { color: var(--muted); margin-top: 0; }
label { display: block; margin: 1rem 0; font-weight: 600; font-size: .9rem; }
input {
  display: block; width: 100%; margin-top: .35rem; padding: .7rem .8rem; font: inherit;
  color: var(--text); background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
}
input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
input.code { font-size: 1.6rem; letter-spacing: .4em; text-align: center; font-variant-numeric: tabular-nums; }
button {
  width: 100%; padding: .75rem; font: inherit; font-weight: 600; cursor: pointer;
  color: var(--accent-text); background: var(--accent); border: 0; border-radius: 8px;
}
button.small { width: auto; padding: .35rem .8rem; font-size: .85rem; }
button.link {
  width: auto; padding: 0; background: none; color: var(--accent); font-weight: 400; text-decoration: underline;
}
.secondary { margin-top: 1.25rem; text-align: center; font-size: .9rem; color: var(--muted); }
a { color: var(--accent); }
.error  { padding: .7rem .9rem; border-radius: 8px; background: var(--error-bg); color: var(--error); }
.notice { padding: .7rem .9rem; border-radius: 8px; background: var(--ok-bg); color: var(--ok); }
.topbar {
  display: flex; justify-content: space-between; align-items: center; gap: 1rem;
  padding: .75rem 16px; background: var(--surface); border-bottom: 1px solid var(--border);
}
.topbar form { display: flex; align-items: center; gap: .75rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1rem; margin-top: 1.5rem; }
.tile {
  display: block; padding: 1.25rem; text-decoration: none; color: inherit;
  background: var(--surface); border: 1px solid var(--border); border-radius: 12px;
}
.tile:hover { border-color: var(--accent); }
.tile h2 { margin: 0 0 .3rem; font-size: 1.1rem; }
.tile p { margin: 0; color: var(--muted); font-size: .9rem; }
@media (max-width: 480px) {
  .card { margin: 1rem 16px; padding: 1.5rem; }
  .topbar .muted { display: none; }
}