* { box-sizing: border-box; }
body {
  font-family: system-ui, sans-serif;
  background: #f3f4f6;
  display: flex;
  min-height: 100vh;
  margin: 0;
  align-items: center;
  justify-content: center;
}
.card {
  background: #fff;
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 1px 4px rgba(0,0,0,.1);
  width: 360px;
}
h1 { font-size: 1.2rem; margin-top: 0; }
label { display: block; margin-bottom: .4rem; font-size: .9rem; }
input {
  width: 100%;
  padding: .6rem;
  border: 1px solid #d1d5db;
  border-radius: 6px;
  margin-bottom: 1rem;
}
button {
  width: 100%;
  padding: .6rem;
  border: 0;
  border-radius: 6px;
  background: #2563eb;
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
}
button:disabled { background: #9ca3af; cursor: default; }
.banner { padding: .6rem; border-radius: 6px; margin-bottom: 1rem; font-size: .9rem; }
.banner.success { background: #dcfce7; color: #166534; }
.banner.error { background: #fee2e2; color: #991b1b; }