body {
    background-color: lightblue;
}
 
h1, h2, h3{
    color: blue;
    text-align: center;
    height: 15px;

}

ul{
    list-style-image: url("../img/lista.png");
   
}
ol{
    list-style-type: upper-roman;
    background-color: blue;
    list-style-position: inside;
}
 ol li{
    background-color: lightsalmon;
 }
 ol li:nth-child(2n-1){
    background-color: yellow;
 }
div ol li{
    list-style-type: upper-roman;
    background-color: purple;
    list-style-position: inside;
}