SaeedTJ

You create a dynamic.css and set the permissions so the server can write to it. You do not do anything else, OT will automatically enqueue the file. If the file is empty and you have values saved in your CSS option type then the permissions are not allowing you to save to the file.

you mean the permission is the problem?
im using xampp how can I solve it?

What do you mean nothing happened, are any values being saved to dynamic.css?

as documentation says, just I made a dynamic.css and linked it to the header.php then I made a field with the id that I mentioned.
and put the code
body {
{{bg_color}}
}
in the dynamic.css.
now I change the color in panel admin but it doesnt change in the real.
if it is needed I can take a screenshot of the job ??

aloo??

ok I should use echo