* {
    box-sizing: border-box;
    page-break-inside: avoid;
}
.container{
    height: 100vh;
    padding: 20px;
}
.intro {
    height: 40%;
    width: 100%;
    background-image: url(Cubes.jpg);
    color: aliceblue;
    display: flex;
    flex-direction: row;
    justify-content: center;
    line-height: 250px;
    font-size: 45px;
}
h2 {
    text-align: center;
    font-size: 31px;
}
.explanation {
    height: 95%;
    width: 100%;
    font-size: 20px;
    color: black;
    background-image: url(download.jpeg);
}
.explanation p {
    padding: 10px;
    column-rule: 0.5px dotted black;
    column-gap: 25px;
    column-count: 2;
}
table {
    width: 100%;
}
table,th,td {
    border: 1px solid black;
    text-align: center;
}
.form {
    font-size: 25px;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative
}
ul{
    overflow: hidden;
    list-style-type:none;
    margin: 0;
    padding: 20px;
}
li {
    float: left;
}
li a {
    color: white;
    padding: 5px;
    text-decoration: none;
    display: block;
    text-align: center;
    padding: 15px 30px;
} 
.footer {
    height: 10%;
    width: 100%;
    background-color: black;
    color: whitesmoke;
    text-align: center;
    line-height: 90px;
}