You can add stylesheet in back-office, but you need for that use the admin_enqueue_scripts action.
See Codex reference : https://codex.wordpress.org/Plugin_API/Action_Reference/admin_enqueue_scripts
Related Posts:
- Custom Plugin – CSS works, JS doesn’t
- WordPress Plugin Authoring question about jquery and css
- ajaxurl not defined on front end
- How to add a javascript snippet to the footer that requires jQuery
- How do I add CSS options to my plugin without using inline styles?
- Is it ever okay to include inline CSS in plugins?
- How to include jQuery and JavaScript files correctly?
- How to add sub-menu to a menu generated by wp_nav_menu by using plugin
- Load js/css files only on specific admin UI pages
- Get list of scripts / styles and show file which enqueued them
- jQuery in header or footer
- Enqueue script only when shortcode is used, with WP Plugin Boilerplate
- How do I conditionally enqueue script for CPT single post type with plugin?
- Where to enqueue stylesheets for plugin?
- How to prevent loading of all plugin’s resources?
- What is the best way to provide plugin users with a way to customized the styles
- When is it too late to call the action wp_enqueue_scripts?
- Use js script from one plugin in another plugin
- Script won’t load via plugin class
- Plugin Loading Scripts and Styles on Every Page – Even when not being used
- What is better way to use Bootstrap inside admin panel?
- Inserting JS snippet in the footer if there is no wp_footer?
- Can’t get JS code to work with shortcode
- How do you output enqueued scripts to an admin page?
- How do I add a javascript file to all admin pages via a plugin?
- Backslashes being stripped from CSS
- Multisite plugin development and wp_enqueue_script
- is_page() function doesnt working
- how to include javascript file and css file in wordpress
- How can I add a CSS rule to edit.php?
- How to avoid loading same script twice?
- How do I include background images in my stylesheets in a plugin?
- What parameter should I pass to wp_enqueue_style to depend on the themes stylesheet?
- Enqueue scripts in footer
- Loading scripts with wp_register_script and wp_enqueue_script
- Adding Dropbox dropin js using wp_enqueue_script
- Is there a way to ensure plugin script loads before another script?
- Is there no admin ui guide for 4.x?
- conditionally load javascript & CSS for do_action() calls from plugin
- What stylesheets are available in core?
- How to enqueue or include json file to a plugin
- How to remove default style of header in wordpress metabox
- jQuery does not enqueue for my purpose… (before an inline script in the footer)
- CSS not affecting widget output
- How can I avoid conflicts between plugin and theme?
- Enqueue script globally
- Plugin Development/ Stop CSS clashes.
- Can’t change the style of a submit input type? [closed]
- Make a plugin page out of influence of the theme’s style
- WP Plugin Running before jQuery
- wp_localize_script is not adding a global variable for javascript
- Loading Modernizr (or other JavaScript libraries) for use in a plugin
- should i be checking for jquery before enqueing it in a plugin
- How to import the css in the plugin admin area?
- Distributing Frontend Assets with Plugins
- Plugin Development – Class Constructor Not Firing wp_enqueue_style action hook
- Enqueuing scripts and styles in custom plugins
- Are there any official or unofficial guidelines for the styling of a widget?
- unable to wp_enqueue_script(‘suggest’);
- Apply styles to blockquote element with the WYSIWYG editor
- How to make my shortcode load scripts and styles, from within the plugin?
- Styles don’t load correctly. Insecure content
- How do I get rid of my inclusion race-condition on wp_enqueue_script
- Completely isolate a plugin view so it doesn’t load the theme
- Enqueue a file that’s not js or css
- Enqueueing common php scripts in a plugin
- Does WordPress default CSS have Grids?
- How To Protect Plugin Display From Being Affected By Theme’s CSS
- Enqueue scripts inside a class in a plugin
- Enqueue ONLY Plugin Styles and Scripts
- CSS not being applied using wp_enqueue_style
- wp_enqueue_scripts in a plugin’s class
- Loading Images from Javascript on the Front End
- Why my theme’s css not working on another site
- WordPress plugin development theme issue
- Add default value from selection
- Why does theme’s reset CSS have higher precedence of plugin’s CSS?
- Is “document loaded” different on admin side than public side?
- Twenty-seventy theme remove additional CSS from head
- plugin css is not being applied to the page
- Adding External Gmap JS to WordPress
- How do I ensure I can loop through every enqueued script and CSS?
- Append php file to footer
- How to avoid conflict if a plugin already have included open library?
- AJAX call of function containing javascript which is not loaded (Plugin development)
- Javascript not being loaded only in custom taxonomy template
- Ajax Response Error | just getting error as the response
- Enqueue scripts based on site.
- How to customize the size of Featured Images or Post Thumbnails in WordPress?
- How to enqueue an external Javascript file to Frontpage footer
- Publish, Save Draft and Preview buttons do not work after being moved with jQuery
- Unable to link CSS file
- How can I add the Post ID to Class Name in Jquery?
- Let user override plugin CSS
- Script work on non logged in user but not work for logged in user?
- Best practice to include custom user styles in widgets
- Why does this fail: Disabling plugins enqueue_script() in functions.php
- Enqueue Script in custom plugin before other
- How to create A – Z List with pictures?
- how to add contact form 7 shortcode in javascript variable