main.css

.overlay {
    fill: none;
    pointer-events: all;
}

.navbar {
    background-color: #e3f2fd;
}

.github-corner:hover .octo-arm {
    animation: octocat-wave 560ms ease-in-out
}

.octocat {
    color: #fff;
    position: absolute;
    top: 0;
    border: 0;
    right: 0;
    z-index: 1021;
    fill: rgba(0, 123, 255, .5);
}

.main-container {
    width: calc(100% - 300px);
    float: left;
    margin-top: 65px;
}

@keyframes octocat-wave {
    0%, 100% {
        transform: rotate(0)
    }
    20%, 60% {
        transform: rotate(-25deg)
    }
    40%, 80% {
        transform: rotate(10deg)
    }
}

@media (max-width: 500px) {
    .github-corner:hover .octo-arm {
        animation: none
    }

    .github-corner .octo-arm {
        animation: octocat-wave 560ms ease-in-out
    }
}