.pinlogin .pinlogin-field {
    box-sizing: border-box;
    display: inline-block;
    width: 40px;
    height: 40px;
    padding: 5px;
    margin: 0 10px;
    border: 1px solid #ccc;

    -webkit-border-radius: 2px;
    -moz-border-radius: 2px;
    border-radius: 2px;
    text-align: center;
}

.pinlogin .pinlogin-field:first-of-type {
    margin-left: 0;
}

.pinlogin .pinlogin-field:last-of-type {
    margin-right: 0;
}

.pinlogin .pinlogin-field:read-only {
    border: 1px solid #ddd;
    background: #fafafa;
    cursor: default;
}

.pinlogin .pinlogin-field.invalid {
    border: 1px solid red;
    color: red;
}