:root {
  --bg: #f4f5f7;
  --card: #fff;
  --text: #1c1e21;
  --muted: #65676b;
  --border: #d0d4da;
  --accent: #2563eb;
  --ok-bg: #e7f6ec;
  --ok-text: #14632f;
  --err-bg: #fdecec;
  --err-text: #9b1c1c;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #17181a;
    --card: #222326;
    --text: #e8e9eb;
    --muted: #a0a3a8;
    --border: #3a3c40;
    --accent: #5b8cff;
    --ok-bg: #173523;
    --ok-text: #8fe0a8;
    --err-bg: #3d1c1c;
    --err-text: #f3a5a5;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 16px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
main {
  width: 100%;
  max-width: 360px;
  padding: 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
}
h1 { margin: 0 0 8px; font-size: 22px; }
.ip { margin: 0 0 16px; color: var(--muted); font-size: 14px; }
.state { margin: 0 0 16px; }
.msg { margin: 0 0 16px; padding: 10px 12px; border-radius: 8px; font-size: 14px; }
.ok { background: var(--ok-bg); color: var(--ok-text); }
.err { background: var(--err-bg); color: var(--err-text); }
form { display: grid; gap: 12px; }
label { display: grid; gap: 4px; font-size: 14px; color: var(--muted); }
input {
  width: 100%;
  padding: 10px 12px;
  font: inherit;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
}
input:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
button {
  margin-top: 4px;
  padding: 11px;
  font: inherit;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: 0;
  border-radius: 8px;
  cursor: pointer;
}
button.secondary { color: var(--text); background: transparent; border: 1px solid var(--border); }