:root {
  --bg: #f6f7fb; --card: #ffffff; --text: #171a26; --dim: #5d6478; --border: #e1e4ee;
  --accent: #4f5dff; --accent-text: #ffffff; --ok: #138a52; --bad: #c62f3f; --field: #ffffff;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11131a; --card: #1a1d27; --text: #eef0f7; --dim: #9aa1b5; --border: #2a2e3b;
    --accent: #7380ff; --accent-text: #0d0f16; --ok: #43c98a; --bad: #ff6b7a; --field: #12141c;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif; }
main { max-width: 440px; margin: 0 auto; padding: 40px 16px 48px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 20px; margin-bottom: 20px; }
.logo { color: var(--accent); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 20px; margin-bottom: 14px; }
h1 { font-size: 20px; margin: 0 0 6px; }
h2 { font-size: 16px; margin: 0 0 10px; }
.hint { color: var(--dim); font-size: 14px; margin: 0 0 12px; }
label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 12px; }
input { display: block; width: 100%; margin-top: 6px; padding: 10px 12px; font: inherit; color: var(--text);
  background: var(--field); border: 1px solid var(--border); border-radius: 10px; }
input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
button { font: inherit; cursor: pointer; }
.primary { width: 100%; padding: 11px 14px; border: 0; border-radius: 10px; background: var(--accent); color: var(--accent-text); font-weight: 700; }
.primary:disabled { opacity: .6; cursor: progress; }
.tabs { display: grid; grid-template-columns: 1fr 1fr; gap: 4px; padding: 4px; background: var(--bg); border-radius: 10px; margin-bottom: 18px; }
.tabs button { padding: 8px; border: 0; border-radius: 8px; background: transparent; color: var(--dim); font-weight: 600; }
.tabs button[aria-selected="true"] { background: var(--card); color: var(--text); box-shadow: 0 1px 2px rgb(0 0 0 / .08); }
.error { color: var(--bad); font-size: 14px; min-height: 1.2em; margin: 0 0 10px; }
.code-row { display: flex; gap: 8px; }
.code-row input { margin: 0; font-size: 24px; letter-spacing: .18em; text-align: center; font-variant-numeric: tabular-nums; }
.code-row .primary { width: auto; flex: none; }
#code-msg { margin: 10px 0 0; font-size: 14px; min-height: 1.2em; }
#code-msg.ok { color: var(--ok); } #code-msg.bad { color: var(--bad); }
.meter { height: 10px; background: var(--bg); border-radius: 99px; overflow: hidden; margin-bottom: 8px; }
#meter-fill { height: 100%; width: 0; background: var(--accent); transition: width .3s ease; }
.devices { list-style: none; margin: 0; padding: 0; }
.devices li { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 10px 0; border-top: 1px solid var(--border); }
.devices li:first-child { border-top: 0; }
.devices small { display: block; color: var(--dim); font-size: 13px; }
.devices button, .link { border: 0; background: none; color: var(--bad); font-weight: 600; padding: 4px; }
.link { color: var(--dim); text-decoration: underline; }
.tag { font-size: 12px; font-weight: 600; color: var(--dim); border: 1px solid var(--border); border-radius: 99px; padding: 1px 8px; margin-left: 6px; vertical-align: 2px; }
#pv-video { display: block; width: 100%; border-radius: 10px; background: #000; margin-bottom: 12px; aspect-ratio: 16 / 10; object-fit: contain; }
.pv-status { margin: 10px 0 0; min-height: 1.2em; }
.pv-status.ok { color: var(--ok); } .pv-status.bad { color: var(--bad); }
.secondary { width: 100%; padding: 11px 14px; border: 1px solid var(--border); border-radius: 10px; background: transparent; color: var(--text); font-weight: 700; }
.prose ul { padding-left: 20px; margin: 0 0 14px; }
.prose li { margin-bottom: 6px; }
.prose p { margin: 0 0 14px; }
.prose h2 { margin-top: 18px; }
.brand a, .footer a, .prose a { color: inherit; }
.footer { text-align: center; color: var(--dim); font-size: 14px; }