style.css

body, html{
    margin: 0;
    padding: 0;
    font-family: Roboto;
    background: #ebeff1;
}

#insert-box, #list-box, h1{
    width: 86%;
    padding: 3%;
    margin-left: auto;
    margin-right: auto;
}
.box{
    box-shadow: 0px 3px 1px -2px rgba(0, 0, 0, 0.2), 0px 2px 2px 0px rgba(0, 0, 0, 0.14), 0px 1px 5px 0px rgba(0, 0, 0, 0.12);
    margin-bottom: 20px;
    background: white;
}
#insert-box h3,
#insert-box input,
#insert-box button{
    width: 100%;
}
.box h3{
    margin-top: 0;
}
input{
    font-size: 16px;
    font-weight: lighter;
    border: 0;
    border-bottom: 1px solid #999;
    margin-bottom: 20px;
    padding-bottom: 7px;
}
input:focus{
    outline: none;
}
button{
    background-color: #009688;
    outline: none;
    border: none;
    color: white;
    font-size: 16px;
    border-radius: 4px;
    padding: 1.5%;
    cursor: pointer;
    box-shadow: 0px 3px 1px -2px rgba(0, 0, 0, 0.2), 0px 2px 2px 0px rgba(0, 0, 0, 0.14), 0px 1px 5px 0px rgba(0, 0, 0, 0.12);
}
h1{
    display: block;
    font-size: 1.17em;
    -webkit-margin-before: 1em;
    -webkit-margin-after: 1em;
    -webkit-margin-start: 0px;
    -webkit-margin-end: 0px;
    font-weight: bold;
    margin: 0 auto;
    padding: 3%;
    width: 92%;
}
h3{
    font-size: 14px;
    color: rgba(0, 0, 0, 0.54);
}
ul{
    list-style: none;
    padding: 0 2%;
    display: inline-block;
    position: relative;
    width: 96%;
}
ul#heroes-list li{
    width: 100%;
    float: left;
    margin-top: 6px;
    margin-bottom: 6px;
}
.color-box{
    width: 20px;
    height: 20px;
    float: left;
    margin-right: 11px;
    border-radius: 2px;
    border-width: 1px;
    border-style: solid;
    border-color: grey;
}