Изучаем Gutenberg — https://wpgutenberg.top
Gallery Block – https://gogutenberg.com/blocks/gallery/
Remove block styles in the Block Editor – https://wordpress.stackexchange.com/questions/352559/remove-block-styles-in-the-block-editor
Understanding WordPress Block CSS – https://kraftner.com/en/blog/understanding-wordpress-block-css/
Building your own WordPress Core Block CSS – https://kraftner.com/en/blog/building-your-own-wordpress-core-block-css/