:root {
  --bg: #f4f6f8;
  --card: #ffffff;
  --text: #1c2430;
  --muted: #637083;
  --border: #dde3ea;
  --accent: #1f6feb;
  --accent-text: #ffffff;
  --ok: #1a7f37;
  --off: #b42318;
  --code-bg: #eef2f6;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f141a;
    --card: #171e26;
    --text: #e4e9ef;
    --muted: #8b98a8;
    --border: #2a3440;
    --accent: #4c8dff;
    --accent-text: #0b1220;
    --ok: #3fb950;
    --off: #f85149;
    --code-bg: #212b36;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.top {
  display: flex; align-items: center; justify-content: space-between;
  max-width: 760px; margin: 0 auto; padding: 16px;
}
.brand { font-weight: 700; font-size: 1.25rem; color: var(--text); text-decoration: none; }
nav a { color: var(--muted); text-decoration: none; margin-left: 16px; }
nav a:hover { color: var(--text); }
main { max-width: 760px; margin: 0 auto; padding: 0 16px; }
footer { max-width: 760px; margin: 32px auto; padding: 0 16px; color: var(--muted); font-size: .85rem; }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 20px; margin-bottom: 16px;
}
h1, h2 { margin: 0 0 8px; line-height: 1.25; }
h1 { font-size: 1.5rem; }
h2 { font-size: 1.15rem; }
ol { padding-left: 20px; margin: 0; }
li { margin-bottom: 6px; }
.statusbar { display: flex; flex-wrap: wrap; gap: 8px 20px; align-items: center; color: var(--muted); margin-bottom: 16px; font-size: .9rem; }
.statusbar b { color: var(--text); }
.pill { padding: 2px 10px; border-radius: 999px; font-weight: 600; border: 1px solid currentColor; }
.pill.ok { color: var(--ok); }
.pill.off { color: var(--off); }
button {
  font: inherit; cursor: pointer; border-radius: 8px; padding: 10px 18px;
  border: 1px solid var(--border); background: var(--card); color: var(--text);
}
button.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-text); font-weight: 600; }
button:disabled { opacity: .5; cursor: default; }
.code {
  font: 700 clamp(2rem, 9vw, 3rem)/1.1 ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: .08em; margin: 12px 0; user-select: all;
}
.step { font-size: 1.1rem; font-weight: 600; }
.muted { color: var(--muted); }
.error { color: var(--off); }
code { background: var(--code-bg); padding: 1px 6px; border-radius: 4px; font-size: .92em; word-break: break-all; }
.facts { display: grid; grid-template-columns: max-content 1fr; gap: 4px 16px; margin: 0 0 12px; }
.facts dt { color: var(--muted); }
.facts dd { margin: 0; }
table { width: 100%; border-collapse: collapse; font-size: .95rem; }
th, td { text-align: left; padding: 8px 6px; border-bottom: 1px solid var(--border); }
th { color: var(--muted); font-weight: 600; }
.result { overflow-x: auto; }
form.row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
form.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-items: end; }
form.grid .wide { grid-column: 1 / -1; }
label { display: flex; flex-direction: column; gap: 4px; color: var(--muted); font-size: .9rem; }
input {
  font: inherit; padding: 9px 10px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); min-width: 0;
}
.actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 12px; }
.spinner { display: inline-block; width: 1em; height: 1em; border: 2px solid var(--border); border-top-color: var(--accent); border-radius: 50%; animation: spin 1s linear infinite; vertical-align: -2px; margin-right: 8px; }
@keyframes spin { to { transform: rotate(360deg); } }
@media (max-width: 520px) {
  form.grid { grid-template-columns: 1fr; }
}