body{
  margin:0;
  min-height:100vh;
  display:grid;
  place-items:center;
  background:radial-gradient(circle at 20% 20%, #0f2c3f, #0b0d13 45%, #09090b);
  color:#fff;
  font-family:system-ui,sans-serif;
}
.login-box{
  width:min(420px,92vw);
  background:#121820;
  border:1px solid #243040;
  border-radius:14px;
  padding:24px;
  box-shadow:0 30px 80px rgba(0,0,0,.5);
}
.brand{font-size:1.6rem;font-weight:700;margin-bottom:14px}
.brand span{color:#00a8ff}
.form-control,.btn{width:100%;padding:10px;border-radius:8px;border:1px solid #2f3f55;background:#0f141d;color:#fff}
.btn{background:#0077b8;border-color:#0077b8;font-weight:700;cursor:pointer}
.error{background:#7a1f1f;border:1px solid #a43d3d;border-radius:8px;padding:8px 10px;margin:0 0 10px}
.help{color:#8aa0b8;font-size:.85rem;margin-top:10px}