yes the logic is different, it use bootstrap awesome checkboxes:
https://github.com/flatlogic/awesome-bootstrap-checkbox

You can change it background color (it's yet different in the 3 core templates).

The empty label is because in LimeSurvey Admin interface, you can enter whatever you want in the question label : text, pictures, div, table, etc. So we can't push that content inside an inline element.

Having an empty label doesn't any problem.

The empty label broke all CSS system : you can not have a clean way to
use
li.radio-item input.radio:checked + label, li.checkbox-item input.checkbox:checked + label {
background: #6789a0 none repeat scroll 0 0;
color: #fff;
}

I try this morning : really no clean way ..... due toi empty label.

When i want to change bg color :
different color with hover/focus + not-checked + checked : there are no solution for this in any of the template

Send screenshit : able to do it in 2.06, not able to do it in 2.50

yes, you can do it:

http://www.cssscript.com/demo/pretty-checkbox-radio-inputs-with-bootstrap-and-awesome-bootstrap-checkbox-css/

No : BACKGROUND of whole "answer" part ..... not only the "radio"

Example : set disable option : your example show text grey.

Not in LimeSurvey : because it apply to label , not after ....

In fact : tehre are 2 solutions:

1 : Do or fix awesome-bootstrap-checkbox-css with .label-clickable and remove the empty label
2 : put the answer/question in lable like before : feature request 11449

removing the empty label is not related to being able to change the background of anything.

Mais si :

li.radio-item input.radio:checked + label, li.checkbox-item input.checkbox:checked + label {
background: #6789a0 none repeat scroll 0 0;
color: #fff;
}
Don't work

li.radio-item input.radio:checked + .label-clickable, li.checkbox-item input.checkbox:checked + .label-clickable {
background: #6789a0 none repeat scroll 0 0;
color: #fff;
}
Don't work

Second solution work if you remove the empty label .....

Louis : i can do the pull request :

• Remove this empty label OR readd a real label
• Fix the core template to show the awesome checkbox like before

BUT : i don't want to work without your agreement on one or other of the methods

The only alternative is

• Forking LimeSurvey
• Do a plugin to fork all views

Because really : this empty label broke a lot of css things.

Can be done now

Version 3.0.0-beta.1 released