:root {
  --bg: #0f1419;
  --card: #1a212b;
  --border: #2b3644;
  --text: #e6edf3;
  --muted: #8b98a8;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --error: #f87171;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f3f5f8;
    --card: #ffffff;
    --border: #d5dbe3;
    --text: #18202a;
    --muted: #5d6b7c;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --error: #dc2626;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.card {
  width: 100%;
  max-width: 560px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
}
h1 { margin: 0 0 8px; font-size: 1.4rem; }
.sub { margin: 0 0 16px; color: var(--muted); }
textarea, input[type="text"], select, pre {
  width: 100%;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font: inherit;
}
textarea { resize: vertical; font-family: ui-monospace, Menlo, Consolas, monospace; }
pre {
  margin: 0 0 12px;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: ui-monospace, Menlo, Consolas, monospace;
  max-height: 300px;
  overflow: auto;
}
.row { display: flex; align-items: center; gap: 12px; margin: 12px 0; }
.row label { color: var(--muted); white-space: nowrap; }
.row select { width: auto; flex: 1; }
button {
  background: var(--accent);
  color: #fff;
  border: 0;
  border-radius: 8px;
  padding: 10px 16px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  margin-top: 8px;
  margin-right: 8px;
}
button:hover { background: var(--accent-hover); }
button:disabled { opacity: .6; cursor: default; }
button.secondary { background: transparent; color: var(--text); border: 1px solid var(--border); }
button.secondary:hover { background: var(--bg); }
.error { color: var(--error); }
a { color: var(--accent); }
footer { margin-top: 24px; font-size: .8rem; color: var(--muted); }
[hidden] { display: none !important; }