style.css

body{
    text-align: center;
    font-family: Arial, Helvetica, sans-serif;
}
h1 {
    display: inline-block !important;
    width: 100px;
    font-size: 3em;
    background-color: gainsboro;
    border-radius: 5px;
}
h2{
    display: inline-block !important;
    width: 50px;
    background-color: gainsboro;
    border-radius: 5px;
}

@media (max-width: 575.98px) {
    h1 {
        width: 75px;
        font-size: 2em;
    }
    h2 {
        width: 30px;
    }
    #btn {
        font-size: medium;
        width: 40px !important;
        border-radius: 2px;
    }
    #btn1{
        font-size: medium;
        width: 40px !important;
        border-radius: 2px;
    }
    #btn2{
        font-size: medium;
        width: 40px;
        border-radius: 2px;
    }
    #lap {
        font-size: medium;
        width: 40px !important;
        
        border-radius: 2px;
    }
 }

#btn {
    font-size: large;
    color: #ffffff;
    background-color: royalblue;
    border: none;
    border-radius: 4px;
    height: 40px;
    width: 80px;
    cursor: pointer;
}
#btn:hover {
    background-color: rgb(35, 170, 35);
}

#btn1 {
    font-size: large;
    color: #ffffff;
    background-color: royalblue;
    border: none;
    border-radius: 4px;
    height: 40px;
    width: 80px;
    cursor: pointer;
}
#btn1:hover {
    background-color: rgb(238, 29, 29);
}

#btn2 {
    font-size: large;
    color: #ffffff;
    background-color: royalblue;
    border: none;
    border-radius: 4px;
    height: 40px;
    width: 80px;
    cursor: pointer;
}
#lap {
    font-size: large;
    color: #ffffff;
    background-color: royalblue;
    border: none;
    border-radius: 4px;
    height: 40px;
    width: 80px;
    cursor: pointer;
}