body {
    font-family: Arial, sans-serif;
    background: #f3f4f6;
    margin: 0;
    padding: 40px 16px;
}
.box {
    max-width: 420px;
    margin: 60px auto;
    background: white;
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,.08);
}
h1 { margin-top: 0; }
label {
    display: block;
    margin-top: 16px;
    margin-bottom: 6px;
}
input {
    width: 100%;
    box-sizing: border-box;
    padding: 12px;
    border: 1px solid #bbb;
    border-radius: 6px;
    font-size: 16px;
}
button, .button {
    display: inline-block;
    margin-top: 20px;
    padding: 12px 18px;
    border: 0;
    border-radius: 6px;
    background: #164a8a;
    color: white;
    text-decoration: none;
    font-size: 16px;
    cursor: pointer;
}
.error { color: #b00020; }
.success { color: #176b2c; }