nav {
    display: table;
    margin: auto;
    margin-top: 30px;
    margin-bottom: 30px;
}

nav a {
    margin: 5px;
    background: url("../img/button1.png") no-repeat center;
    width: 50px;
    height: 50px;
    cursor: pointer;
    border-radius: 50px;
    display: inline-block;
    vertical-align: middle;
    font-size: 0px;
    border: 1px solid #808080;
    transition-duration: 0.5s;
    transition-timing-function: ease;
    position: relative;
}

nav a:first-child {
    margin-right: 15px;
}

nav a:last-child {
    margin-left: 15px;
}

#ButtonFacebook {
    background: url("../img/Facebook-color.svg") no-repeat center;
    background-size: 22px;
    border: 1px solid #43619c;
}

#ButtonTwitter {
    background: url("../img/Twitter-color.svg") no-repeat center;
    border: 1px solid #24a9e6;
    background-size: 22px;
}

#ButtonInstagram {
    background: url("../img/Instagram-color.svg") no-repeat center;
    border: 1px solid #C42C66;
    background-size: 22px;
}

#ButtonLinkedin {
    background: url("../img/LinkedIn-color.svg") no-repeat center;
    border: 1px solid #187FB8;
    background-size: 22px;
}

#Button20pourcent {
    background: url("../img/button3.png") no-repeat center;
}

nav a:after {
    position: absolute;
    z-index: -10;
    width: 0px;
    height: 0px;
    cursor: pointer;
    background: #FFFFFF;
    content: "";
    border-radius: 50px;
    margin: 25px;
    display: block;
    transition-duration: 0.5s;
    transition-timing-function: ease;
}

nav a:hover:after {
    width: 50px;
    height: 50px;
    border-radius: 50px;
    margin: 0px;
}

nav a:before {
    position: absolute;
    z-index: -10;
    width: 0px;
    height: 0px;
    cursor: pointer;
    background: #bdccd4;
    content: "";
    border-radius: 50px;
    margin: 25px;
    display: block;
    transition-duration: 0.3s;
    transition-timing-function: ease;
}

nav a:hover:before {
    width: 50px;
    height: 50px;
    border-radius: 50px;
    margin: 0px;
}

nav a:hover {
    border: 1px solid #ffffff !important;
}