:root {
  --bg: #f3f6f9; --card: #ffffff; --text: #14212b; --muted: #4a5a68; --border: #7a8a98;
  --accent: #0b5cad; --accent-text: #ffffff; --danger: #b00020; --focus: #ffbf00;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #0e151b; --card: #17212a; --text: #f1f5f8; --muted: #b7c4cf; --border: #8da0b0;
          --accent: #6db3ff; --accent-text: #08121c; --danger: #ff8a9b; }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; min-height: 100vh; background: var(--bg); color: var(--text);
  font: 18px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  display: flex; justify-content: center; align-items: flex-start; padding: 16px; }
.card { width: 100%; max-width: 480px; margin-top: 24px; background: var(--card); border-radius: 16px;
  padding: 24px 20px 28px; box-shadow: 0 1px 4px rgba(0,0,0,.15); }
.brand { margin: 0 0 8px; font-weight: 700; color: var(--accent); letter-spacing: .02em; }
h1 { font-size: 1.6rem; line-height: 1.25; margin: 0 0 12px; }
.lead { margin: 0 0 20px; color: var(--muted); }
.field { margin-bottom: 18px; }
label { display: block; font-weight: 600; margin-bottom: 6px; }
.input-row { display: flex; gap: 8px; }
input { width: 100%; min-height: 52px; padding: 10px 12px; font: inherit; color: var(--text);
  background: var(--card); border: 2px solid var(--border); border-radius: 10px; }
input[aria-invalid="true"] { border-color: var(--danger); }
.hint { margin: 6px 0 0; font-size: .9rem; color: var(--muted); }
.error { margin: 6px 0 0; font-size: .95rem; color: var(--danger); font-weight: 600; }
button { font: inherit; min-height: 52px; border-radius: 10px; cursor: pointer; }
.toggle { min-width: 84px; padding: 0 12px; background: transparent; color: var(--accent);
  border: 2px solid var(--accent); font-weight: 600; }
.primary { width: 100%; background: var(--accent); color: var(--accent-text); border: 2px solid var(--accent);
  font-weight: 700; margin-top: 6px; }
.primary[disabled] { opacity: .6; cursor: progress; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
[hidden] { display: none !important; }