Site name bg color and support box bg color overwritten by wordpress 4.6

Hello,

Please, help me, after the wordpress update (4.6) the Site name background section and the support box background section had been overwritten with the load-styes.php “body” part.

wp-admin/load-styles.php?c=0&dir=ltr&load%5B%5D=dashicons,admin-bar,common,forms,admin-menu,dashboard,list-tables,edit,revisions,media,themes,about,nav-menus,widgets,site-icon,&load%5B%5D=l10n,buttons,wp-auth-check,media-views,wp-color-picker,wp-jquery-ui-dialog,wp-pointer&ver=4.6

body {
background: #f1f1f1;
}

Thank you for your help.

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