:root {
  --bg: #000; --surface: #0d0d0f; --border: #26262b; --text: #ececee; --muted: #9a9aa3;
  --accent: #4da3ff; --ok: #4cd38a; --err: #ff6b6b; --warn: #f5c451;
}
@media (prefers-color-scheme: light) {
  :root { --bg: #f6f6f8; --surface: #fff; --border: #d9d9e0; --text: #16161a; --muted: #62626c;
          --accent: #0a62c9; --ok: #0d7a45; --err: #b3261e; --warn: #8a5b00; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
main { max-width: 34rem; margin: 0 auto; padding: 2.5rem 1rem 3rem; }
.brand { margin: 0; letter-spacing: .18em; font-weight: 700; font-size: .85rem; color: var(--accent); }
h1 { margin: .4rem 0 .5rem; font-size: 1.9rem; line-height: 1.2; }
.lead { margin: 0 0 1.5rem; color: var(--muted); }
.step { background: var(--surface); border: 1px solid var(--border); border-radius: 14px;
  padding: 1.25rem; margin-bottom: 1rem; }
h2 { margin: 0 0 .25rem; font-size: 1.1rem; display: flex; align-items: center; gap: .6rem; }
.num { display: inline-grid; place-items: center; width: 1.6rem; height: 1.6rem; border-radius: 50%;
  border: 1px solid var(--accent); color: var(--accent); font-size: .85rem; }
.hint { margin: 0 0 1rem; color: var(--muted); font-size: .95rem; }
label { display: block; margin-bottom: .35rem; font-size: .9rem; color: var(--muted); }
input { width: 100%; padding: .75rem .85rem; margin-bottom: .9rem; border-radius: 10px; font: inherit;
  letter-spacing: .04em; background: var(--bg); color: var(--text); border: 1px solid var(--border); }
input:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
input:disabled { opacity: .5; }
button { padding: .75rem 1.1rem; border-radius: 10px; border: 0; font: inherit; font-weight: 600;
  background: var(--accent); color: #fff; cursor: pointer; min-height: 2.75rem; }
button:disabled { opacity: .45; cursor: not-allowed; }
.device { margin: 1rem 0 0; display: grid; gap: .4rem; }
.device div { display: flex; justify-content: space-between; gap: 1rem; border-top: 1px solid var(--border); padding-top: .4rem; }
dt { color: var(--muted); font-size: .9rem; }
dd { margin: 0; font-variant-numeric: tabular-nums; word-break: break-all; text-align: right; }
.msg { min-height: 1.5rem; margin: .8rem 0 0; font-size: .95rem; }
.msg.ok { color: var(--ok); } .msg.err { color: var(--err); }
.notice { border: 1px solid var(--warn); color: var(--warn); border-radius: 10px; padding: .75rem 1rem; margin-bottom: 1rem; }
footer { margin-top: 1.5rem; color: var(--muted); font-size: .85rem; }
a { color: var(--accent); }
.crosslink { margin: -.5rem 0 1.5rem; color: var(--muted); font-size: .95rem; }
[hidden] { display: none !important; }