style.css

body {
    background-color:aliceblue;
    font-family: 'Raleway', sans-serif;
    font-family: 'Roboto Flex', sans-serif;
}


.container {
    max-width: 400px;
    margin: 10vh auto 0 auto;
    box-shadow: 0px 0px 43px 17px rgba(153, 153, 153,1);
}
.h1 {
    text-align: center;
}
#display {
    text-align: right;
    border-style:groove;
    height: 70px; /* 70px  */
    line-height: 70px;  /* 70px  */ 
    padding: 10px 6px; /* 10px 4px  */
    font-size: 30px; /* 30px  */

}

.buttons {
    display: grid;
    border-bottom: 1px solid #999;
    border-left: 1px solid #999;
    grid-template-columns: 1fr 1fr 1fr 1fr;
}

.buttons > div {
    border-top: 1px solid #999;
    border-right: 1px solid #999;
}

.button {
    border: 0.5px solid #999;
    line-height: 100px;
    text-align: center;
    font-size: 25px;
    border-radius: 15px;
    cursor: pointer;
}

#clear {
    background-color: red;
    color: white;
}

#clear:hover {
    background-color: white;
    color: black;
    transition: 0.5s ease-in-out;
}
#equal {
    background-color: green;
    color: white;
}
#equal:hover {
    background-color: #999;
    transition: 0.5s ease-in-out;
}

.button:hover {
    background-color: #323330;
    color: white;
    transition: 0.5s ease-in-out;

}