:root {
  --bg: #f4f5f7;
  --card: #ffffff;
  --ink: #111827;
  --muted: #6b7280;
  --line: #e5e7eb;
  --accent: #3b5bdb;
  --bad: #dc2626;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #0f1115; --card: #181b22; --ink: #f3f4f6; --muted: #9ca3af; --line: #2a2f3a; --accent: #6b8cff; --bad: #f87171; }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 16px;
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
.card { width: 100%; max-width: 400px; background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 28px; }
.brand { display: flex; align-items: center; gap: 10px; font-size: 13px; color: var(--muted); letter-spacing: .5px; text-transform: uppercase; }
.logo { width: 28px; height: 28px; border-radius: 50%; background: var(--accent); color: #fff; display: grid; place-items: center; font-weight: 600; }
h1 { font-size: 20px; margin: 18px 0 6px; }
.lead { color: var(--muted); margin: 0 0 20px; }
label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 6px; }
input { width: 100%; padding: 11px 12px; border: 1px solid var(--line); border-radius: 8px; background: transparent; color: var(--ink); font-size: 16px; }
input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
#code { letter-spacing: 6px; text-align: center; font-size: 20px; }
button { width: 100%; margin-top: 12px; padding: 11px; border: 0; border-radius: 8px; background: var(--accent); color: #fff; font-size: 15px; font-weight: 500; cursor: pointer; }
button:disabled { opacity: .6; cursor: default; }
button.link { background: none; color: var(--muted); margin-top: 6px; }
.msg { min-height: 22px; margin: 14px 0 0; font-size: 14px; color: var(--muted); }
.msg.bad { color: var(--bad); }
.note { margin: 18px 0 0; padding-top: 14px; border-top: 1px solid var(--line); font-size: 12px; color: var(--muted); }