button.css

/* this is used to style the toggle button */
.dark input {
    -webkit-appearance: none;
    position: relative;
    width: 50px;
    height: 25px;
    background-image: url(https://i.postimg.cc/857jHw2q/Screenshot-2020-04-16-at-1-07-06-PM.png);
    background-size: cover;
    border-radius: 50px;
    outline: none;
    transition: background-image .90s;
    box-shadow: 0px 2px 5px 1px gray;
    float: left; 
  }
  
.dark input:before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    height: 25px;
    width: 25px;
    background-color: navy;
    border-radius: 50px;
    transition: all .9s;
    background-color: #F7CA33;
  }
  
.dark  input:checked {
    background-image: url(https://i.postimg.cc/Hn0nstVK/Screenshot-2020-04-16-at-1-07-19-PM.png);
    transition: background-image .90s;
  
  }
  
.dark input:checked:before {
    transform: translate(100%);
    transition: all .9s;
    background-color: #ECF0F3;
  }