Reduce Specificity of Input Styles

[mikeselander]

Describe the bug
This is in-kind with #10067; I am opening this ticket as a distinct example of over-specificity needing to be fixed.

The specificity of the block input styles causes custom styles which are correctly using simple classnames to get trampled over.

For example, let's say that I have a custom stylesheet which I have loaded in via add_editor_style. This stylesheet defines how inputs should look within a custom block, but uses a company-wide design library, and therefore has styles which cannot be modified just for the G'berg editor.

This stylesheet has well-written selectors that only use classes such as .client-input {...}. This then gets converted to .editor-styles-wrapper .client-input {...} after being passed through add_editor_style. Core has an (ahem) comprehensive set of selectors for every single (or just about) type of input which are compiled to .block-editor-block-list__block input[type="number"].

These appear to be defined here:

gutenberg/packages/base-styles/_mixins.scss

Lines 378 to 557 in 995aa3a

	@mixin reset {
	box-sizing: border-box;
	*,
	*::before,
	*::after {
	box-sizing: inherit;
	}
	.input-control, // Upstream name is `.regular-text`.
	input[type="text"],
	input[type="search"],
	input[type="radio"],
	input[type="tel"],
	input[type="time"],
	input[type="url"],
	input[type="week"],
	input[type="password"],
	input[type="checkbox"],
	input[type="color"],
	input[type="date"],
	input[type="datetime"],
	input[type="datetime-local"],
	input[type="email"],
	input[type="month"],
	input[type="number"],
	select,
	textarea {
	font-family: $default-font;
	padding: 6px 8px;
	@include input-style__neutral();
	/* Fonts smaller than 16px causes mobile safari to zoom. */
	font-size: $mobile-text-min-font-size;
	/* Override core line-height. To be reviewed. */
	line-height: normal;
	@include break-small {
	font-size: $default-font-size;
	/* Override core line-height. To be reviewed. */
	line-height: normal;
	}
	&:focus {
	@include input-style__focus();
	}
	}
	input[type="number"] {
	padding-left: 4px;
	padding-right: 4px;
	}
	select {
	padding: 2px;
	font-size: $default-font-size;
	color: $dark-gray-500;
	&:focus {
	border-color: $blue-medium-600;
	// Windows High Contrast mode will show this outline
	outline: 2px solid transparent;
	outline-offset: 0;
	}
	}
	input[type="checkbox"],
	input[type="radio"] {
	border: $border-width + 1 solid $dark-gray-300;
	margin-right: 12px;
	transition: none;
	&:focus {
	border-color: $dark-gray-300;
	box-shadow: 0 0 0 1px $dark-gray-300;
	}
	&:checked {
	background: theme(toggle);
	border-color: theme(toggle);
	}
	&:checked:focus {
	box-shadow: 0 0 0 2px $dark-gray-500;
	}
	}
	input[type="checkbox"] {
	border-radius: $radius-round-rectangle / 2;
	&:checked::before,
	&[aria-checked="mixed"]::before {
	margin: -3px -5px;
	color: $white;
	@include break-medium() {
	margin: -4px 0 0 -5px;
	}
	}
	&[aria-checked="mixed"] {
	background: theme(toggle);
	border-color: theme(toggle);
	&::before {
	// Inherited from `forms.css`.
	// See: https://github.com/WordPress/wordpress-develop/tree/5.1.1/src/wp-admin/css/forms.css#L122-L132
	content: "\f460";
	float: left;
	display: inline-block;
	vertical-align: middle;
	width: 16px;
	/* stylelint-disable */
	font: normal 30px/1 dashicons;
	/* stylelint-enable */
	speak: none;
	-webkit-font-smoothing: antialiased;
	-moz-osx-font-smoothing: grayscale;
	@include break-medium() {
	float: none;
	font-size: 21px;
	}
	}
	&:focus {
	box-shadow: 0 0 0 2px $dark-gray-500;
	}
	}
	}
	// We provide explicit pixel dimensions to ensure a crisp appearance.
	// This radio button style should be ported upstream.
	input[type="radio"] {
	border-radius: $radius-round;
	&:checked::before {
	width: 6px;
	height: 6px;
	margin: 6px 0 0 6px;
	background-color: $white;
	@include break-medium() {
	margin: 3px 0 0 3px;
	}
	}
	}
	// Placeholder colors
	input,
	textarea {
	// Use opacity to work in various editor styles.
	&::-webkit-input-placeholder {
	color: $dark-opacity-300;
	}
	&::-moz-placeholder {
	opacity: 1; // Necessary because Firefox reduces this from 1.
	color: $dark-opacity-300;
	}
	&:-ms-input-placeholder {
	color: $dark-opacity-300;
	}
	.is-dark-theme & {
	&::-webkit-input-placeholder {
	color: $light-opacity-300;
	}
	&::-moz-placeholder {
	opacity: 1; // Necessary because Firefox reduces this from 1.
	color: $light-opacity-300;
	}
	&:-ms-input-placeholder {
	color: $light-opacity-300;
	}
	}
	}
	}

This leaves our custom styles with a specificity of 0,0,2,0, whereas core has a specificity of 0,0,2,1 which just barely overrides a well-written selector. This means that the inputs on my custom block are no longer in sync with the frontend and I have confused editors. My only options are to start a specificity war with G'berg's styles or use !important. Both are terrible options and should be unnecessary.

Expected behavior
I would expect the inputs to be styled only with a tag selector and a parent class. For example, .block-editor-block-list__block input or potentially apply the styles only to specific core blocks or to core input components.

[talldan]

@mikeselander This is a fair point and I think it also affects the reusability of the components in @wordpress/components that various styles are mixins instead of part of the components themselves.