background-color {
    color: whitesmoke;
}

h1 {
    color: black;
    font-size: large;
    text-align: center;
}

p {
    align-content: center;
}

.rotate {
    -webkit-animation: rotation 2s infinite linear;
}

@-webkit-keyframes rotation {
    from {
        -webkit-transform: rotate(0deg);
    }
    to {
        -webkit-transform: rotate(359deg);
    }
}

s1.S1 {
    display: inline-block;
    padding: 0.1em 0.1em;
    border: 0.1em solid #cf1727;
    font-weight: 700;
    font-family: center;
    box-sizing: border-box;
}

s1.S1:hover {
    color: whitesmoke;
    background-color: red;
}

@media all and (max-width: 0.1em) {
    s1.S1 {
        display: block;
        margin: 0.1em;
    }
}

s4.S4 {
    display: inline-block;
    padding: 0.1em 0.1em;
    border: 0.1em solid greenyellow;
    font-weight: 700;
    font-family: center;
    box-sizing: border-box;
}

s4.S4:hover {
    color: whitesmoke;
    background-color: greenyellow;
}

@media all and (max-width: 0.1em) {
    s4.S4 {
        display: block;
        margin: 0.1em;
    }
}

s2.S2 {
    display: inline-block;
    padding: 0.1em 0.1em;
    border: 0.1em solid blue;
    font-weight: 700;
    font-family: center;
    box-sizing: border-box;
    transition: all 0.1s;
    text-align: center;
    margin: 0 auto;
}

s2.S2:hover {
    color: whitesmoke;
    background-color: blue;
}

@media all and (max-width: 0.1em) {
    s2.S2 {
        display: block;
        margin: 0.1em;
    }
}

s3.S3 {
    display: inline-block;
    padding: 0.1em 0.1em;
    border: 0.1em solid orange;
    font-weight: 700;
    font-family: center;
    box-sizing: border-box;
}

s3.S3:hover {
    color: whitesmoke;
    background-color: orange;
}

@media all and (max-width: 0.1em) {
    s3.S3 {
        display: block;
        margin: 0.1em;
    }
}

footer {
    position: fixed;
    left: 0;
    bottom: 0;
    width: 100%;
    background-color: gainsboro;
    color: rgb(241, 14, 14);
    text-align: center;
}

.btn {
    border: solid blanchedalmond;
    background-color: inherit;
    padding: 14px 28px;
    font-size: 16px;
    cursor: pointer;
    display: inline-block;
}

.btn:hover {
    background: #eee;
}

.Previous {
    color: orange;
}

.Next {
    color: Black;
}