I love the Drupal Admin Menu module (in fact, I almost can't live without it!), but I guess I'm getting old because I find the microscopic font hard to read ;) Others have this problem as well, but it hasn't been made configurable yet, so here are your options:

0. Use the Admin Menu Toolbar

Admin Menu comes with 2 options. If you just enable the main Admin Menu module, then the font is small. If you enable the Admin Menu Toolbar module, then the font is bigger and matches the core Toolbar better. The Admin Menu Toolbar module used to be kind of buggy but I tried it recently and it was working pretty well. Just make sure to disable the core Toolbar module afterwards or you'll have 2 toolbars.

Pros:

• Easy to do.
• No CSS required.

Cons:

• Requires enabling an additional module. (It really should be the default configuration!)

1. Change the font size in the browser

Most browsers let you adjust your font size. For example, Control + will increase your font in Firefox, Chrome, and others.

Pros:

• Easy to do.
• No CSS required.

Cons:

• Must repeat steps when starting new browser windows.
• Other things on the page increase as well which may or may not be desirable.

2. Modify your custom theme

If you have a custom theme and only need the Admin Menu to be adjusted for that theme only, you can add some CSS to your theme like:


#admin-menu-wrapper a {
font-size:16px;
}


and then refresh your caches. Where the CSS goes depends on your theme.

Pros:

• Change will affect any page using that theme.

Cons:

• Requires a CSS change.
• You must know how to update your theme.
• Change will ONLY affect any page using that theme. Other themes are not affected.

3. Modify a custom module

If you have a custom module and want the Admin Menu to be adjusted for all themes, you can add some CSS to your module as follows:

Create mymodule.css

Put this in your mymodule.css file:


#admin-menu-wrapper a {
font-size:16px;
}


Update your module code

Update mymodule.module to add the css file upon init:


function mymodule_init() {
drupal_add_css(drupal_get_path('module', 'mymodule') . '/mymodule.css');
}


and then refresh your caches.

Pros:

• Change will affect any page using any theme.

Cons:

• Requires coding.
• You must know how to update your module.

4. Use CSS Injector

If you want the Admin Menu to be adjusted for all themes without a custom module, you can use the CSS Injector module as follows:

1. Install and enable CSS Injector
2. Clear the cache
3. Go to: [yourdomain]/admin/config/development/css-injector
4. Click create a new rule
5. Add a Title (e.g. Admin Menu Font Size Adjustment) and the CSS, e.g.

   
#admin-menu-wrapper a {
font-size:16px;
}


6. Click the Save button.

Pros:

• Change will affect any page using any theme.
• No custom theme or module is required.

Cons:

• Requires an extra module.

5. Get a magnifying glass!

:P

Pros:

• Low tech.

Cons:

• You might lose it.

Cheers and happy eyes!