Master the CSS cascade: Say goodbye to chaos and embrace control! This article will explore how to use new CSS features to control cascades to write more concise and efficient CSS code. In the past, styles from different sources often made cascades difficult to manage and eventually produced redundant code. Even with methods like ITCSS and BEM, we still face challenges posed by cascades, such as the need to precisely control the position of the @import
statement or have to resort to !important
. Fortunately, some new tools have come out, allowing us to effectively control the cascade.
Drive :where
pseudo selector
:where
pseudo-selectror allows us to remove the particularity of the selector so that it is only higher than the user agent default style, regardless of the CSS loading order. This means that the selector's particularity is actually zero, which is very useful for general-purpose components.
For example, use :where
to define a common table style:
:where(table) { background-color: tan; }
Even if other table styles were defined before this:
table { background-color: hotpink; } :where(table) { background-color: tan; }
The table background color is still tan
because :where
eliminates the particularity of the selector. This makes :where
perfect for CSS reset.
:where
's brother selector :is
has the opposite effect:
The particularity of the
:is()
pseudo-class is determined by the particularity of its most special parameters. Therefore, selectors written with:is()
do not necessarily have the same speciality as equivalent selectors written without:is()
. ——Selector Level 4 Specification
Continue with the previous example:
:is(table) { --tbl-bgc: orange; } table { --tbl-bgc: tan; } :where(table) { --tbl-bgc: hotpink; background-color: var(--tbl-bgc); }
The background color of the table will be tan
because :is
has the same particularity as table
, and table
is located behind it. But if we change it to:
:is(table, .c-tbl) { --tbl-bgc: orange; }
The background color will be orange
because :is
has the same weight as its most special selector.c .c-tbl
.
Example: Configurable table components
Let's build a table component with the following HTML:
Next, we wrap .c-tbl
in :where
selector and add the rounded corners:
:where(.c-tbl) { border-collapse: separate; border-spacing: 0; table-layout: auto; width: 99.9%; }
Table cells use different styles:
:where(.c-tbl thead th) { /* ... */ } :where(.c-tbl tbody td) { /* ... */ }
Due to rounded corners and border-collapse: separate
, we need to add extra styles:
:where(.c-tbl tr td:first-of-type) { /* ... */ } /* ... */
Now we can create variations of the table component by injecting other styles before or after the general style (benefits from :where
's speciality elimination):
.c-tbl--purple th { background-color: hsl(330, 50%, 40%) } /* ... */
CSS custom properties
We will use data-component
property to define the component:
The above is the detailed content of Don't Fight the Cascade, Control It!. For more information, please follow other related articles on the PHP Chinese website!

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