advanced-custom-fields-pro/assets/build/css/pro/acf-styles-in-iframe-for-blocks.min.css

[data-acf-inline-contenteditable="1"][contenteditable=true]:empty::before{content:attr(data-acf-placeholder);opacity:.62}[data-acf-inline-contenteditable="1"][contenteditable=true]:empty{border:1px dashed rgba(255,0,0,0)}[data-acf-inline-fields-uid]:hover,[data-acf-inline-contenteditable]:hover{outline:2px solid var(--wp-admin-theme-color);outline-offset:2px}.acf-block-has-validation-error{border:2px solid #d94f4f}