.pinlogin .pinlogin-field {
    box-sizing: border-box;
    display: inline-block;
    width: 40px;
    height: 40px;
    padding: 5px;
    margin: 0 3px;
    border: 1px solid #ccc;
    -webkit-border-radius: 2px;
    -moz-border-radius: 2px;
    border-radius: 5px;
    text-align: center;
    font-size: 20px;
    font-weight: 600;
    background-image: none;
}

.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;
}

@media only screen and (max-width : 576px) {

    .pinlogin .pinlogin-field {
        width: 45px;
        height: 45px;
    }

}