style.css

/* Created by The Young Programmer aka NemoNet */

@import url('https://fonts.googleapis.com/css2?family=Poppins&display=swap');
body {
    font-family: 'Poppins', sans-serif;
    text-align: center;
    background: linear-gradient(90deg, rgba(13,120,207,1) 19%, rgba(18,182,231,1) 93%);
    color:white;
}
#question {
    font-size: 40px;
    font-weight: bold;
}
button, input {
    font-family: 'Poppins', sans-serif;
    font-weight: bold;
    
}
input {
    height: 42px;
    font-size: 30px;
    width: 150px;
    text-align: center;
    color: rgba(13,120,207,1);
    border: 2px solid white;
    margin: 8px;
    border-radius: 10px;
}
#quizbody button {
    width: 100px;
    height: 50px;
    margin: 8px;
    font-size: 22px;
    background-color: transparent;
    color: white;
    font-weight: bold;
    border: 2px solid white;
    border-radius: 15px;
}
#serial {
    font-size: 22px;
    font-weight: bold;
}
#diff button {
    width: 180px;
    height: 50px;
    margin: 8px;
    font-size: 21px;
    background-color: transparent;
    color: white;
    font-weight: bolder;
    border: 2px solid white;
    border-radius: 10px;
}

#result {
    font-size: 25px;
    font-weight: bold;
}
.titlebar {
    margin: 10px;
}
.titlebar img {
    height: 25px;
    width: 25px;
    float:left;
    padding-top: 7px;
}
#count {
    padding: 2px;
    background-color: white;
    margin: 2px;
    color: rgba(13,120,207,1);
    border-radius: 10px;
    width: 65px;
    display: inline-block;
    height: 35px;
    text-align:right;
    padding-bottom: 5px;
    padding-left: 5px;
    background-color: #dbdbdb;
    font-weight: bold;
}
#count span {
    font-size: 27px;
    font-weight: bold;
}
#logo {
    font-size: 30px;
    font-weight: bold;
}
#nums button {
    height: 44px;
    width: 44px;
    font-size: 23px;
}
#timer, #bar {
    height: 10px;
    width: 220px;
}
#timer {
    background-color: transparent;
    border: 1px solid white;
}
#bar {
    background-color: white;
    position: relative;
    float: left;
}
input:focus, button:focus {
    outline: 0;
    outline-color: transparent;
    outline-style: none;
}