Optimizing a table - Twig, CSS
Depending on your requirements (is javascript allowed, which browsers can be used), I'd go for a CSS only solution.

CSS:

table.zebra tr:nth-child(odd) {  
    background-color: #EFF4FA; 
}

table.zebra tr:nth-child(even) {  
    background-color: #F7FAFD; 
}


PHP:

&lt;table class="zebra"&gt;
  &lt;tr&gt;
    &lt;td&gt;Previous Plan:&lt;/td&gt;
    &lt;td&gt;{{ form_row(form.prev_plan) }}&lt;/td&gt;
  &lt;/tr&gt;
  &lt;tr&gt;
    &lt;td&gt;Previous Server:&lt;/td&gt;
    &lt;td&gt;{{ form_row(form.prev_srv) }}&lt;/td&gt;
  &lt;/tr&gt;
&lt;/table&gt;


Here's the catch:

You can't use these wonderfull selectors in every browser (IE &lt; 9, I'm looking at you!). Only in most of them. There's a great explanation of the selector at w3c and an overview over browsers supporting it at caniuse.

And if you still want to use CSS3 selectors and need early IE support, there's javascript providing it (e.g. selectivizr - I never used it, but it's easy to find alternatives). Just search for "css3 selectors in IE" in your favorite search engine.

I guess this still doesn't solve your text overlay issues, but for that, you'd best point to an example page.