:root{--navy:#1F3864;--ink:#1d1d1f;--line:#e3e3e8}
*{box-sizing:border-box}
body{margin:0;font:16px/1.5 -apple-system,"PingFang HK","Helvetica Neue",sans-serif;
  color:var(--ink);background:#f7f7f9;display:flex;min-height:100vh;align-items:center;justify-content:center}
.box{background:#fff;border:1px solid var(--line);border-radius:14px;padding:24px;width:min(92vw,360px);
  box-shadow:0 6px 24px #0001}
h1{margin:0 0 2px;font-size:20px;color:var(--navy)}
.sub{margin:0 0 16px;color:#6e6e73;font-size:13px}
label{display:block;margin:0 0 12px;font-size:13px;color:#6e6e73}
input{display:block;width:100%;margin-top:4px;padding:12px;font-size:16px;border:1px solid var(--line);border-radius:10px}
button{width:100%;padding:13px;font-size:16px;font-weight:600;color:#fff;background:var(--navy);
  border:0;border-radius:10px;cursor:pointer}
.err{background:#fde8e8;color:#b02020;padding:10px 12px;border-radius:8px;margin-bottom:12px;font-size:14px}