Fix spacing and alignment in different block placeholders

[youknowriad]

Before

After

[github-actions]

Size Change: +355 B (0%)

Total Size: 864 kB

Filename	Size	Change
build/block-editor/style-rtl.css	10.5 kB	+8 B (0%)
build/block-editor/style.css	10.5 kB	+9 B (0%)
build/block-library/editor-rtl.css	7.36 kB	+98 B (1%)
build/block-library/editor.css	7.36 kB	+98 B (1%)
build/block-library/index.js	115 kB	+9 B (0%)
build/editor/editor-styles-rtl.css	381 B	+56 B (14%)	⚠️
build/editor/editor-styles.css	382 B	+55 B (14%)	⚠️
build/editor/index.js	43.8 kB	+22 B (0%)

ℹ️ View Unchanged

Filename	Size	Change
build/a11y/index.js	1.01 kB	0 B
build/annotations/index.js	3.43 kB	0 B
build/api-fetch/index.js	3.39 kB	0 B
build/autop/index.js	2.58 kB	0 B
build/blob/index.js	620 B	0 B
build/block-directory/index.js	6.02 kB	0 B
build/block-directory/style-rtl.css	760 B	0 B
build/block-directory/style.css	760 B	0 B
build/block-editor/index.js	104 kB	0 B
build/block-library/style-rtl.css	7.5 kB	0 B
build/block-library/style.css	7.51 kB	0 B
build/block-library/theme-rtl.css	669 B	0 B
build/block-library/theme.css	671 B	0 B
build/block-serialization-default-parser/index.js	1.65 kB	0 B
build/block-serialization-spec-parser/index.js	3.1 kB	0 B
build/blocks/index.js	57.7 kB	0 B
build/components/index.js	191 kB	0 B
build/components/style-rtl.css	15.5 kB	0 B
build/components/style.css	15.5 kB	0 B
build/compose/index.js	5.75 kB	0 B
build/core-data/index.js	10.6 kB	0 B
build/data-controls/index.js	1.03 kB	0 B
build/data/index.js	8.22 kB	0 B
build/date/index.js	5.36 kB	0 B
build/deprecated/index.js	772 B	0 B
build/dom-ready/index.js	569 B	0 B
build/dom/index.js	3.06 kB	0 B
build/edit-post/index.js	91.3 kB	0 B
build/edit-post/style-rtl.css	8.71 kB	0 B
build/edit-post/style.css	8.71 kB	0 B
build/edit-site/index.js	4.64 kB	0 B
build/edit-site/style-rtl.css	2.48 kB	0 B
build/edit-site/style.css	2.48 kB	0 B
build/edit-widgets/index.js	4.42 kB	0 B
build/edit-widgets/style-rtl.css	2.59 kB	0 B
build/edit-widgets/style.css	2.58 kB	0 B
build/editor/style-rtl.css	3.98 kB	0 B
build/editor/style.css	3.98 kB	0 B
build/element/index.js	4.45 kB	0 B
build/escape-html/index.js	734 B	0 B
build/format-library/index.js	7.11 kB	0 B
build/format-library/style-rtl.css	502 B	0 B
build/format-library/style.css	502 B	0 B
build/hooks/index.js	1.92 kB	0 B
build/html-entities/index.js	622 B	0 B
build/i18n/index.js	3.48 kB	0 B
build/is-shallow-equal/index.js	710 B	0 B
build/keyboard-shortcuts/index.js	2.3 kB	0 B
build/keycodes/index.js	1.68 kB	0 B
build/list-reusable-blocks/index.js	2.99 kB	0 B
build/list-reusable-blocks/style-rtl.css	226 B	0 B
build/list-reusable-blocks/style.css	226 B	0 B
build/media-utils/index.js	4.85 kB	0 B
build/notices/index.js	1.57 kB	0 B
build/nux/index.js	3.01 kB	0 B
build/nux/style-rtl.css	616 B	0 B
build/nux/style.css	613 B	0 B
build/plugins/index.js	2.54 kB	0 B
build/primitives/index.js	1.49 kB	0 B
build/priority-queue/index.js	780 B	0 B
build/redux-routine/index.js	2.84 kB	0 B
build/rich-text/index.js	14.3 kB	0 B
build/server-side-render/index.js	2.55 kB	0 B
build/shortcode/index.js	1.7 kB	0 B
build/token-list/index.js	1.27 kB	0 B
build/url/index.js	4 kB	0 B
build/viewport/index.js	1.61 kB	0 B
build/warning/index.js	1.14 kB	0 B
build/wordcount/index.js	1.18 kB	0 B

_{compressed-size-action}

[jasmussen]

Nice!

Desktop breaktpoint is a vast improvement. I see the same before and after. Before:

After:

But the is-small (and potentially is-medium) breakpoints need a little love. You can test these in a columns block.

Before:

After:

Once those are fixed, ship it!

[youknowriad]

I think I fixed those but I noticed that there is a fundamental problem in Placeholder component (should be fixed separately). It styles things that are not rendered by the component itself.

For example it assumes that there's potentially a "form" inside it. It shouldn't try to style the form, it should just leave it for the place where a form is used. If there are things in common between these places, then a new component might be needed but Placeholder shouldn't be responsible for it.

Its stylesheet also has classnames that are rendered elsewhere (like the error one)

I also noticed that some placeholders (embeds) use internal Placeholder classnames in other components.

These issues are the main reasons why we keep regressing in terms of placeholder design/alignment...