:root { --bg: #f4f5f7; --panel: #fff; --text: #16181d; --muted: #5e6573; --line: #dfe2e8; --accent: #1d4ed8; --bad: #b91c1c; color-scheme: light; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #0f1115; --panel: #181b21; --text: #e8eaee; --muted: #9aa1ad; --line: #2a2f38; --accent: #6d8dfa; --bad: #f87171; color-scheme: dark; }
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center; padding: 16px; background: var(--bg); color: var(--text);
       font: 15px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
.box { width: min(380px, 100%); background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 24px; }
h1 { margin: 0 0 16px; font-size: 20px; }
form { display: grid; gap: 10px; }
label { color: var(--muted); font-size: 13px; }
input { font: inherit; color: var(--text); background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 9px 10px; }
#code { letter-spacing: 6px; font-size: 22px; text-align: center; }
button { font: inherit; border-radius: 8px; padding: 9px 14px; border: 1px solid var(--accent); background: var(--accent); color: #fff; font-weight: 600; cursor: pointer; }
button.link { background: none; border: 0; color: var(--accent); font-weight: 400; padding: 0; }
.msg { min-height: 1.4em; margin: 12px 0 0; color: var(--muted); }
.msg.bad { color: var(--bad); }
#sent-to { margin: 0; color: var(--muted); }
[hidden] { display: none !important; }