:root { color-scheme: dark; }
* { box-sizing: border-box; }
body {
  margin: 0; min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  background: #0f1117; color: #e6e8ef;
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
.card {
  width: min(92vw, 360px);
  background: #171a23; border: 1px solid #262b38; border-radius: 16px;
  padding: 28px 24px; box-shadow: 0 10px 40px rgba(0,0,0,.45);
}
h1 { font-size: 18px; margin: 0 0 6px; letter-spacing: .2px; }
.sub { margin: 0 0 18px; color: #9aa3b5; font-size: 13px; }
input {
  width: 100%; padding: 14px; font-size: 17px; border-radius: 10px;
  border: 1px solid #2c3346; background: #0d1017; color: #fff; outline: none;
}
input:focus { border-color: #4f7cff; }
button {
  width: 100%; margin-top: 12px; padding: 14px; font-size: 16px; font-weight: 600;
  border: 0; border-radius: 10px; background: #4f7cff; color: #fff; cursor: pointer;
}
button:active { background: #3b63d8; }
.err { margin: 12px 0 0; color: #ff7b7b; font-size: 13px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
[hidden] { display: none !important; }