:root { --bg: #f4f5f7; --card: #fff; --fg: #1b1d22; --muted: #6b7280; --line: #d9dce3; --accent: #2b6cff; --err: #d33; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #111317; --card: #1b1e24; --fg: #e8eaee; --muted: #9aa1ad; --line: #2f343d; --err: #ff6b6b; }
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center; padding: 16px;
  background: var(--bg); color: var(--fg); font: 15px/1.5 system-ui, -apple-system, "Segoe UI", "Malgun Gothic", sans-serif; }
.card { width: 100%; max-width: 340px; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 28px 24px; display: grid; gap: 10px; }
h1 { margin: 0 0 8px; font-size: 20px; }
label { font-size: 13px; color: var(--muted); }
input { width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px; background: transparent; color: inherit; font: inherit; }
input:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
button { margin-top: 6px; padding: 10px; border: 0; border-radius: 8px; background: var(--accent); color: #fff; font: inherit; font-weight: 600; cursor: pointer; }
.error { margin: 0; color: var(--err); font-size: 13px; }