WordPress 7.0 Admin Color Scheme Fix

admin-color-scheme-fix.php

<?php
/**
 * Plugin Name: WP 7.0 Admin Color Scheme Fix
 * Description: Restores Fresh as default admin color scheme; removes "Modern" option (new default); Restores contrast on notices.
 */

defined( 'ABSPATH' ) || exit;

add_filter( 'get_user_option_admin_color', function( $color, $option, $user ) {
	if ( empty( $color ) || 'modern' === $color ) {
		return 'fresh';
	}
	return $color;
}, 20, 3 );

add_action( 'admin_init', function() {
	global $_wp_admin_css_colors;
	if ( isset( $_wp_admin_css_colors['modern'] ) ) {
		unset( $_wp_admin_css_colors['modern'] );
	}
} );

add_action( 'admin_head', function() {
	?>
	<style>
	.notice,div.error,div.updated {
		background: #fff;
		border-block: 1px solid #c3c4c7;
		border-right: 1px solid #c3c4c7;
		box-shadow: 0 1px 1px rgba(0,0,0,.04);
	}
	</style>
	<?php
} );