style.css

table,th,td{
    border: 2px solid black;
}
.tab{
    margin-top: 30px;
    text-align: center;
}

#btn{
    width: 10%;
    font-size:20px;
    padding: 15px 32px;

}
.click{
    margin-top: 20px;
}
@media only screen and (max-width: 600px){

    
#btn{
    width: 32%;
    font-size:20px;
    padding: 13px 32px;}

    img#plus{
        position:absolute;
        bottom: 0px;
        left: 20px;
        width:20px;
        height: 20px;
        top:37px;
    }
  
}

img#plus{
    position:absolute;
    bottom: 0px;
    left: 35px;
    width:20px;
    height: 20px;
    top:37px;
}

.popup{
    height:100%;
    width: 100%;
    position: absolute;
    top:0;
    display: none;
    justify-content: center;
    align-items: center;
}

.content{
    height: 250px;
    width: 500px;
    background:white;
    padding: 100px;
    border-radius: 5px;
    position: relative;
    text-align: center;
    
}

input{
    margin: 20px auto;
    display: block;
    width: 50%;
    border-color: black;
}

a.button{
    width: 10%;
    font-size:20px;
    padding: 8px 32px;
    background-color: rgb(177, 173, 167);
    color: black;

}