Inputmask/css/inputmask.css

mark.im-caret {
    animation: 1s blink step-end infinite !important;
}

mark.im-caret-select {
    background-color: rgba(0, 0, 0, 0.25);
}

@keyframes blink {
    from, to {
        border-right-color: black;
    }
    50% {
        border-right-color: transparent;
    }
}

span.im-static {
    color: grey;
}

div.im-colormask {
    display: inline-block;
    border-style: inset;
    border-width: 2px;
    appearance: textfield;
    cursor: text;
}

div.im-colormask > input, div.im-colormask > input:-webkit-autofill {
    position: absolute !important;
    display: inline-block;
    background-color: transparent;
    color: transparent;
    -webkit-text-fill-color: transparent;
    transition: background-color 5000s ease-in-out 0s;
    caret-color: transparent;
    appearance: caret;
    border-style: none;
    left: 0; /*calculated*/
}

div.im-colormask > input:focus {
    outline: none;
}

div.im-colormask > input::selection {
    background: none;
}

div.im-colormask > input::-moz-selection {
    background: none;
}

div.im-colormask > input:-webkit-autofill ~ div {
    background-color:  rgb(250, 255, 189);
}

div.im-colormask > div {
    color: black;
    display: inline-block;
    width: 100px; /*calculated*/
}