.pinbox-wrapper {
    display: flex;
}

.pinbox-wrapper .pinbox-input {
    box-shadow: none;
    flex-basis: 0;
    -webkit-box-flex: 1;
    -ms-flex-positive: 1;
    flex-grow: 1;
    max-width: 100%;
    text-align: center;
    font-family: "password-mask";
    font-size: 20px;
}

.pinbox-wrapper .pinbox-input:not(:first-child) {
    margin-left: 2px;
}

.pinbox-wrapper .pinbox-input:not(:last-child) {
    margin-right: 2px;
}