Hello!
Can you send your site link?
Thanks!
many themes have body_class() incorparated into the body tag, which outputs page specific CSS classes on which you can base the width formatting.
http://codex.wordpress.org/Function_Reference/body_class
what theme are you using?
Hello gays, and thanks for your support.
The theme I use is ThemeStarta: http://www.planetstarta.com/products/themestarta-framework-wordpress-theme-framework
The page I want to have narrower than the main page is this one: http://leccionesdeatraccion.com/privados
unfortunately, your theme does not use body_class() so there are no page specific CSS classes.
as your theme is not one of the supported themes from https://wordpress.org/themes/ please contact the developer of your theme directly for support.
Hello Again 🙂
Check this site out to learn how to insert the body_class() to your theme:
http://www.wpbeginner.com/wp-themes/wordpress-body-class-101-tips-and-tricks-for-theme-designers/
Let me know when you done this.