All of your menu items have the same width, 120px, so the spacing of the menu items across the page is even, even though it doesn’t look even because the amount of text in some of the menu items is longer than others. However, you’re probably right in that it would look better if there was the same amount of spacing in between each menu item.
Does your theme have a custom CSS option, or are you using a CSS plugin to add custom CSS? How did you change the link colors? You’ll probably do a similar type of thing, you’ll want to add some CSS that overrides some existing CSS:
.main-navigation li, .main-navigation ul li a {
width: auto;
}
.main-navigation li {
margin-left: 55px;
}
The first rule sets the width of all of the menu items to “auto,” meaning only use as much space as necessary to hold the text.
The second rule adds a margin (spacing) to the left of all of the menu items. I used 55px, which seems like a reasonable number. You can change the value to your liking.
