Adding a :checked pseudo class to an embedded mailchimp form - css

Question

First of all I'm not really a web developer, so bear with me.
I'm trying to embed a mailchimp signup form on my site. I have a set check-boxes that I'd like to keep hidden unless a certain radio button is selected.
<!-- Begin MailChimp Signup Form -->
<link href="//cdn-images.mailchimp.com/embedcode/classic-10_7.css" rel="stylesheet" type="text/css">
<style type="text/css">
.reveal{
display: none !important;
}
#radio-2:checked ~ .reveal {
display: inline;
}
</style>
<div id="mc_embed_signup">
<form action="n/a" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
<div id="mc_embed_signup_scroll">
<div class="mc-field-group input-group">
<strong>Radio Buttons</strong>
<ul>
<li><input type="radio" id="radio-1" value="Radio 1" name="MMERGE6" id="mce-MMERGE6-0"><label for="mce-MMERGE6-0">Radio 1</label></li>
<li><input type="radio" id="radio-2" value="Part Time" name="MMERGE6" id="mce-MMERGE6-1"><label for="mce-MMERGE6-1">Part Time</label></li>
</ul>
</div>
<div class="mc-field-group input-group reveal">
<ul>
<li><input type="checkbox" value="1" name="group[18657][1]" id="mce-group[18657]-18657-0"><label for="mce-group[18657]-18657-0">1</label></li>
<li><input type="checkbox" value="2" name="group[18657][2]" id="mce-group[18657]-18657-1"><label for="mce-group[18657]-18657-1">2</label></li>
<li><input type="checkbox" value="4" name="group[18657][4]" id="mce-group[18657]-18657-2"><label for="mce-group[18657]-18657-2">3</label></li>
<li><input type="checkbox" value="8" name="group[18657][8]" id="mce-group[18657]-18657-3"><label for="mce-group[18657]-18657-3">4</label></li>
</ul>
</div>
<div id="mce-responses" class="clear">
<div class="response" id="mce-error-response" style="display:none"></div>
<div class="response" id="mce-success-response" style="display:none"></div>
</div> <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
<div style="position: absolute; left: -5000px;" aria-hidden="true"><input type="text" name="b_e7f52c90ee3d55370f2c41bac_8ea8200d35" tabindex="-1" value=""></div>
<div class="clear"><input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button"></div>
</div>
</form>
</div>
<script type='text/javascript' src='//s3.amazonaws.com/downloads.mailchimp.com/js/mc-validate.js'></script><script type='text/javascript'>(function($) {window.fnames = new Array(); window.ftypes = new Array();fnames[0]='EMAIL';ftypes[0]='email';fnames[1]='FNAME';ftypes[1]='text';fnames[2]='LNAME';ftypes[2]='text';fnames[4]='MMERGE4';ftypes[4]='phone';fnames[6]='MMERGE6';ftypes[6]='radio';}(jQuery));var $mcj = jQuery.noConflict(true);</script>
<!--End mc_embed_signup-->
I want the set of checkboxes here to only reveal when the second radio button is selected.
I can get :checked to work when I write my own form, but I can't seem to get it to work within an embedded mailchimp form, and I can't figure out why. Does anyone have any ideas?

Answer 1

There are a few issues here:
A style with the !important rule cannot be overridden with another style that doesn't include !important. You can just remove it from your first style to resolve this.
The ~ sibling CSS selector locates elements with the same parent. Because the radio and .reveal elements don't share the same parent, it doesn't display the .reveal element.
The radio buttons shouldn't have two id attributes. Only the second id is set when more than one exists.
In order to make the sibling selector work, you can remove the <ul> and <li> elements from the radio buttons, and add line breaks before them so they're still on separate lines. Also put the .reveal class <div> inside the first .mc-field-group one. This will make the radio buttons have the same parent as the hidden element.
Here's what the updated code looks like:
<!-- Begin MailChimp Signup Form -->
<link href="//cdn-images.mailchimp.com/embedcode/classic-10_7.css" rel="stylesheet" type="text/css">
<style type="text/css">
.reveal {
display: none;
}
#mce-MMERGE6-1:checked ~ .reveal {
display: inline;
}
</style>
<div id="mc_embed_signup">
<form action="n/a" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
<div id="mc_embed_signup_scroll">
<div class="mc-field-group input-group">
<strong>Radio Buttons</strong>
<br>
<input type="radio" value="Radio 1" name="MMERGE6" id="mce-MMERGE6-0"><label for="mce-MMERGE6-0">Radio 1</label>
<br>
<input type="radio" value="Part Time" name="MMERGE6" id="mce-MMERGE6-1"><label for="mce-MMERGE6-1">Part Time</label>
<div class="reveal">
<ul>
<li><input type="checkbox" value="1" name="group[18657][1]" id="mce-group[18657]-18657-0"><label for="mce-group[18657]-18657-0">1</label></li>
<li><input type="checkbox" value="2" name="group[18657][2]" id="mce-group[18657]-18657-1"><label for="mce-group[18657]-18657-1">2</label></li>
<li><input type="checkbox" value="4" name="group[18657][4]" id="mce-group[18657]-18657-2"><label for="mce-group[18657]-18657-2">3</label></li>
<li><input type="checkbox" value="8" name="group[18657][8]" id="mce-group[18657]-18657-3"><label for="mce-group[18657]-18657-3">4</label></li>
</ul>
</div>
</div>
<div id="mce-responses" class="clear">
<div class="response" id="mce-error-response" style="display:none"></div>
<div class="response" id="mce-success-response" style="display:none"></div>
</div>
<!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
<div style="position: absolute; left: -5000px;" aria-hidden="true"><input type="text" name="b_e7f52c90ee3d55370f2c41bac_8ea8200d35" tabindex="-1" value=""></div>
<div class="clear"><input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button"></div>
</div>
</form>
</div>
<script type='text/javascript' src='//s3.amazonaws.com/downloads.mailchimp.com/js/mc-validate.js'></script><script type='text/javascript'>(function($) {window.fnames = new Array(); window.ftypes = new Array();fnames[0]='EMAIL';ftypes[0]='email';fnames[1]='FNAME';ftypes[1]='text';fnames[2]='LNAME';ftypes[2]='text';fnames[4]='MMERGE4';ftypes[4]='phone';fnames[6]='MMERGE6';ftypes[6]='radio';}(jQuery));var $mcj = jQuery.noConflict(true);</script>
<!--End mc_embed_signup-->