:root {
  --bg: #f3f6fb;
  --card: #fff;
  --text: #0f172a;
  --muted: #475569;
  --ok: #065f46;
  --bad: #991b1b;
  --line: #dbe3ee;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Noto Sans SC", "PingFang SC", sans-serif;
  background: linear-gradient(140deg, #eaf2ff, #f7fbff 45%, #eefaf2);
  color: var(--text);
}
header {
  padding: 14px 20px;
  border-bottom: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  background: #ffffffd9;
  backdrop-filter: blur(6px);
  position: sticky;
  top: 0;
}
main { padding: 16px; max-width: 1200px; margin: 0 auto; }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 14px;
}
.grid2 { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 12px; }
@media (max-width: 900px) { .grid2 { grid-template-columns: 1fr; } }
.row { display: flex; gap: 8px; flex-wrap: wrap; margin: 8px 0; }
button {
  border: 1px solid #b8c9e3;
  background: #f8fbff;
  padding: 8px 10px;
  border-radius: 8px;
  cursor: pointer;
}
button:hover { background: #eef6ff; }
input, textarea {
  width: 100%;
  border: 1px solid #c8d6ea;
  border-radius: 8px;
  padding: 8px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}
pre {
  background: #0b1220;
  color: #d7e3ff;
  padding: 12px;
  border-radius: 10px;
  min-height: 180px;
  overflow: auto;
}
.hint { color: var(--muted); }
.ok { color: var(--ok); font-weight: 700; }
.bad { color: var(--bad); font-weight: 700; }
.hidden { display: none; }
.item { border: 1px dashed #d1dcec; border-radius: 8px; padding: 8px; margin: 8px 0; }
.small { font-size: 12px; color: var(--muted); }