Thanks Nikko, I tried the suggested. Gallery is still pretty far from the logo. How would I fix?

 /*------------------------*/
/* CSS - Logo center split menu
/*------------------------*/

@media only screen and (min-width: 780px) {
/*In the below code nth-child(x) the value of x should be half the number of total menu items*/
#top #header .av-main-nav li:nth-child(3) {
    margin-right: 250px;
}

#header .main_menu {
    /*background: gold;*/
    width: 100%;
    left: 50%;
    transform: translateX(-47.4%);
}

.av-main-nav-wrap {
    left: 50%;
    transform: translateX(-50%);
}

#header .logo {
    left: 50%;
    transform: translateX(-80%);
    z-index: 999;
}

#header .logo img {    
    top: 50%;
    transform: translateY(-50%);
    max-width: 150px;  
}
}