#forkongithub a {
    background: #171717;
    color: #f0db4f;
    text-decoration: none;
    font-family: arial, sans-serif;
    text-align: center;
    font-weight: bold;
    padding: 5px 40px;
    font-size: 1rem;
    line-height: 2rem;
    position: relative;
    transition: 0.5s;
}

#forkongithub a:hover {
    background: #f0db4f;
    color: #fff;
}

#forkongithub a::before,#forkongithub a::after {
    content: "";
    width: 100%;
    display: block;
    position: absolute;
    top: 1px;
    left: 0;
    height: 1px;
    background: #fff;
}

#forkongithub a::after {
    bottom: 1px;
    top: auto;
}

@media screen and (min-width:800px) {
    #forkongithub {
        position: absolute;
        display: block;
        top: 0;
        right: 0;
        width: 200px;
        overflow: hidden;
        height: 200px;
    }

    #forkongithub a {
        width: 200px;
        position: absolute;
        top: 60px;
        right: -60px;
        transform: rotate(45deg);
        -webkit-transform: rotate(45deg);
        box-shadow: 4px 4px 10px rgba(0,0,0,0.8);
    }
}

@media screen and (max-width:799px) {
    #forkongithub {
        position: absolute;
        display: block;
        top: 0;
        right: 0;
        width: 200px;
        overflow: hidden;
        height: 200px;
    }

    #forkongithub a {
        width: 200px;
        position: absolute;
        top: 60px;
        right: -60px;
        transform: rotate(45deg);
        -webkit-transform: rotate(45deg);
        box-shadow: 4px 4px 10px rgba(0,0,0,0.8);
    }
}