*,
*::after,
*::before{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    color: rgb(0, 0, 0);
    background: rgb(235, 235, 235);
}

header,
footer {
    background: black;
    justify-content: center;
    text-align: center;
    display: flex;
}

header a,
footer a {
    background: green;
    color: white;
    text-decoration: none;
    display: flex;
    width: 12rem;
    height: 3rem;
    margin: 1.2rem;
    border-radius: 8px;
    align-items: center;
    justify-content: center;
}

svg {
    height: 2rem;
}

main {
    width: 100%;
    padding: 1rem 15rem;
}

main span {
    float: right;
}

h1 {
    text-align: center;
}
h1, h2, h3 {
    margin: 1rem 0;
}
@media screen and (max-width: 768px) {
    main {
        padding: 1rem 1rem;
    }
}