I want to remove the yellow frame around the logo

(Look in the right side column – Body style). Its properties are allocated, but not deleted (in Chrome developer tools), and in which of CSS files this style is not specified, but written – User Agent StyleSheet . How can I reset Margin Body ?

Answer 1, Authority 100%

body {
 margin: 0;
}

PS: I do not even know how this answer is up to 30 characters to enlarge.

Answer 2, Authority 100%

User Agent StyleSheet – Browser Styles

You need to create a child style file for the topic to override them as described here Saving CSS Styles in the STYLE.CSS WordPress-A file