payment-form.css

h1{
    margin-bottom: 0;
}
ul{
    margin:0;
    padding: 0;
    list-style-type: none;
}
form{
    margin: 0 auto;
    width: 420px;
    padding: 1em;
    border:2px double goldenrod;
    border-radius: 1em;
}
label span{
    /*Align inputs vertically*/
    display: inline-block;
    width: 120px; 
    text-align: right;
}
input{
    font: 1em sans-serif;
    width: 250px;
    box-sizing: border-box;
    border: 2px solid rgb(190, 209, 16);
}
input[type=radio] {
    width: auto;
    border: none;
}
input:focus {
    border-color: rgb(11, 235, 97);
}
fieldset{
    width: 250px;
    box-sizing: border-box;
    margin-left: 136px;
    border: 2px solid rgb(190, 209, 16);
}
button {
    margin: 20px 0 0 124px;
}

/* =================
Validation
====================== */
div{
    
    position: relative;
}
input+.validation{
    padding-right: 30px;
}
input:invalid+.validation:after{
   position: absolute;
  content: '✖';
  padding-left: 5px;
}
input:valid+.validation:after {
 position: absolute;
    content: '✓';
    padding-left:5px;
  }