style.css

body{
  background-color: #99cc00;
  font-family: "Lucida Console", Courier, monospace;
}

input{
  font-family: "Lucida Console", Courier, monospace;
  color:  #263300;
}

button{
  font-family: "Lucida Console", Courier, monospace;
  color:  #263300;
;
}

#app{
  background-color:  #f2ffcc;
  color:  #263300;
  padding: 1rem;

}

#app h1{
    color:  #263300;
}

#app ul li{
    color:  #263300;
    padding: 1rem;
}

#app input{
    background-color:  #f9ffe6;
    color:  #263300;
}

#app input[type=checkbox]:before {
         content: "";
         display: block;
         width: inherit;
         height: inherit;
         border: 2px solid #555555;
         border-radius: 2px;
         background-color: #f9ffe6;
         position: absolute;
         top: inherit;
         left: inherit;
}

#app input[type=checkbox]:checked:after{
    background-color:  #99cc00;
    color:  #99cc00;
    content: "";
    display: block;
    border: solid #263300;
    border-top: solid #99cc00;
    border-left: solid #99cc00;
    border-width: 2px;
    width: inherit;
    height: inherit;
    border-radius: 3px;
    position: absolute;
    top: inherit;
    left: inherit;
}

#app button{
    background-color:  #f9ffe6;
    color:  #263300;
}