SharePoint 2013 Global Navigation Menu Alignment and Display

Add below CSS to Content Editor WebPart and it will resolve problem.

<style>
.ms-core-listMenu-horizontalBox .menu-item, .ms-core-listMenu-horizontalBox  

.menu-item .additional-background, .ms-core-listMenu-horizontalBox  

.menu-item .additional-background .menu-item-text { display:block; }
ul.dynamic { min-width:175px; }
span.menu-item-text:hover { 
background-color:rgba(205,230,247,0.5);
padding:2px;
}
span.menu-item-text{ 
padding:2px;
}
</style>