In your snippet call you should be adding:
This removes the Adv.Search default style sheet - it is corrupting the original design by overriding the pre-defined CSS
I would also suggest removing the javascript files, by adding:
&addJs=`0` &addJQuery=`0`
The above removes the "advsearchform.min.js" and the default jQuery version that comes with the snippet, which in your case is 1.7.1
[ed. note: iusemodx last edited this post 10 years, 6 months ago.]