:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --border: #e3e6ea;
  --text: #24292f;
  --muted: #6e7781;
  --accent: #1f6feb;
  --accent-dark: #0a4fbe;
  --chip: #eef4ff;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}
.wrap { max-width: 860px; margin: 0 auto; padding: 32px 20px 64px; }
header h1 { margin: 0 0 8px; font-size: 28px; }
header p { margin: 0 0 24px; color: var(--muted); }
header code {
  background: var(--chip); padding: 2px 6px; border-radius: 4px;
  font-size: 13px;
}
.panel {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 10px; padding: 18px 20px; margin-bottom: 16px;
}
.panel h2 { margin: 0 0 12px; font-size: 16px; }
.panel h2 small { color: var(--muted); font-weight: normal; font-size: 13px; }
.opts { display: flex; flex-wrap: wrap; gap: 10px; }
label.opt {
  display: inline-flex; align-items: center; gap: 8px;
  border: 1px solid var(--border); border-radius: 8px;
  padding: 8px 14px; cursor: pointer; user-select: none;
  background: #fff; transition: all .15s;
}
label.opt:hover { border-color: var(--accent); }
label.opt input { accent-color: var(--accent); width: 16px; height: 16px; }
label.opt.checked { background: var(--chip); border-color: var(--accent); }
label.opt small { color: var(--muted); }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 8px 0 20px; }
button {
  border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 18px; font-size: 15px; cursor: pointer;
  background: #fff; color: var(--text); transition: all .15s;
}
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
button.primary:hover { background: var(--accent-dark); }
button.ghost:hover { border-color: var(--accent); color: var(--accent); }
.preview { background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 18px 20px; }
.preview h2 { margin: 0 0 12px; font-size: 16px; }
.preview .count { color: var(--accent); font-weight: 600; }
.preview ul { list-style: none; margin: 0; padding: 0; columns: 2; column-gap: 24px; }
.preview li {
  padding: 4px 0; font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px; color: #444;
}
.preview li::before { content: "▸ "; color: var(--accent); }
footer {
  margin-top: 28px; color: var(--muted); font-size: 13px;
  display: flex; align-items: center; gap: 16px;
}
footer a { color: var(--accent); text-decoration: none; display: inline-flex; align-items: center; }
footer img { border: 0; display: block; }
@media (max-width: 640px) { .preview ul { columns: 1; } }