Use `::before` and `::after` to build decorations, overlays and UI details without adding extra HTML.
Without `content`, the pseudo-element does not exist.
`::before` and `::after` behave like inline elements by default.
Set `content: ""` when you want an empty box that can still be styled and positioned.
You can switch them to `block` or `inline-block` depending on the pattern you are building.
Absolute positioning unlocks overlays and more expressive decoration.
Give the parent `position: relative` so the pseudo-element has a clear anchoring context.
Use `inset` to cover the whole element when creating overlays or ambient highlights.
`pointer-events: none` helps decorative layers avoid blocking clicks or hover on the real component.
Great for lightweight labels, states and tiny tooltips.
`attr()` can read `data-*` attributes and turn them into small interface labels.
That makes it especially useful for badges, state labels or simple helper text where the real content already exists in the markup.
Keep the text short so it remains readable and does not overflow awkwardly.
Underlines, glows and separators often belong here.
Pseudo-elements are perfect for animated underlines, guide lines and small highlight treatments that would otherwise clutter the markup.
Use `transform` and `transition` for smooth movement, and combine gradients with opacity if you want a more contemporary feel.
Treat them as decoration, not as the primary source of meaning.
Important content should still live in the HTML for accessibility and SEO.
Screen readers do not reliably expose pseudo-element text as primary content.
If a pseudo-element adds color or visual emphasis, keep contrast high enough that the effect still supports readability.