Here is a suggestion for your CSS styling:
nav {
padding-left: 5px;
}
nav .main-nav {
height: 80px;
width: 100%;
margin-top: 64px;
background: url(../images/navHeader.png) no-repeat top;
position: relative;
}
nav .main-nav > ul {
list-style-type: none;
}
nav .main-nav ul a,
nav .main-nav ul li {
display: inline-block;
padding: 5px;
height: 80px;
margin: 5px;
align-content:center;
}
nav .main-nav .dropdown-content a {
height: auto;
line-height: initial;
padding: 5px 0;
}
nav .main-nav ul a {
text-align: center;
font-weight: 700;
font-size: 15px;
color: #84827d;
text-shadow: 1px 1px 1px #000;
text-transform: uppercase;
-webkit-transition: all .2s ease-in-out;
transition: all .2s ease-in-out;
}
nav .main-nav ul a:hover {
text-decoration: none;
color: #7289da;
}
.nav .main-nav li.dropdown {
position: relative;
}
nav .main-nav .dropdown-content {
position: absolute;
display: none;
z-index: 10;
-webkit-box-shadow: 0 3px 5px 0 #999;
-moz-box-shadow: 0 3px 5px 0 #999;
box-shadow: 0 3px 5px 0 #999;
border: 1px solid #CCC;
background: #0d2638;
color: #656161;
opacity: .8;
top : 35px;
}
nav .main-nav .dropdown-content a {
font-size: 8px;
text-decoration: none;
display: block;
text-align: center;
}
nav .main-nav .dropdown:hover .dropdown-content {
display: inline-block;
}
nav .main-nav ul.left {
float: left;
margin-left: 5px;
}
.dropdown-content ul {
padding: 0;
width: auto !important;
display: flex;
flex-direction: column;
}
.dropdown-content ul li {
height: auto !important;
position: relative;
}
.dropdown-content-second {
position: absolute;
display: none;
float: left;
z-index: 10;
-webkit-box-shadow: 0 3px 5px 0 #999;
-moz-box-shadow: 0 3px 5px 0 #999;
box-shadow: 0 3px 5px 0 #999;
border: 1px solid #CCC;
background: #0d2638;
color: #656161;
opacity: .8;
min-width: 30px;
top: 0px;
margin-top: -1px;
margin-left: 1px;
left: 100%;
}
nav .main-nav ul.right {
float: right;
margin-right: 25px;
}