Can't change the editor CSS style

Hi everyone,

I want to modify the editor style to match my colors and font. I'm using Wordpress and I'm not a developer. So far I have:

  1. Created a php file and uploaded it to /wp-content/plugins/ to install the plugin h5pmods.
  2. Created the following CSS:

<code>html.h5p-iframe .h5p-content {

   font-size: 20px; /* size of the font used in H5P content */

  color: #5a5a5a; /* color of the H5P content */ 


and uploaded it to /wp-content/uploads/h5p/

Nothing has happened to my already created and embeded content. Can someone guide me? Any help would be appreciated.