Change font main menu

I got a problem with the font of the main menu. On my homepage I’m using a sub menu below the header (layerslider) and on my other pages I’m using a main menu on top of the page.
Homepage:
http://imageshack.com/a/img661/8020/Jlg7SL.png
Other pages:
http://imageshack.com/a/img912/4690/keFIkt.png
As you can see in the above images the font size isn’t the same.

I have added the following quick CSS:

#header_main_alternate { background-color: #f19a2f; }

#top .av-submenu-container {
background-color: #f19a2f;}

#top .av-subnav-menu li a {background-color: transparent !important;
font-size: 17px; }

#top .av-subnav-menu li a > .avia-menu-text {
color: white;}

.sub-menu .avia-menu-text {color:grey!important; }

#logoheader {background: black;}

input[type=”date”]::-webkit-inner-spin-button{
display: none;}

p {
font-family: Open Sans;}

.main_menu ul:first-child > li > a { font-family: ‘Open Sans’, ‘HelveticaNeue’, ‘Helvetica Neue’, Helvetica, Arial, sans-serif; }

.main_menu ul:first-child>li>a {
font-size: 17px;}

Can you help me out please, I’m stuck on this.