/* When the checkbox is checked, add a blue background */
.container4 input:checked ~ .checkmark4 {
background-image: linear-gradient(#255CD2,#1D52C1)
}
/* Create the checkmark4/indicator (hidden when not checked) */
.checkmark4:after {
content: "";
position: absolute;
display: none;
}
/* Show the checkmark4 when checked */
.container4 input:checked ~ .checkmark4:after {
display: block;
}