CSS Pseudo-classes and Pseudo-elements: :: vs : Explained

CSS provides powerful styling tools: pseudo-classes and pseudo-elements. They help select elements based on their state or create styles for parts of elements.

Pseudo-classes

Pseudo-classes are selectors that allow you to select elements in a specific state (for example, on hover).

Pseudo-class Syntax

selector:pseudo-class {
  /* styles */
}

Examples of Popular Pseudo-classes

• :hover — on mouse hover.
• :focus — when element receives focus.
• :nth-child(n) — to select an element by its order number.
• :checked — for checked checkboxes or radio buttons.
• :not(selector) — selects elements that don't match the selector.

Pseudo-class Example

button:hover {
  background-color: #007BFF;
  color: white;
}

Pseudo-elements

Pseudo-elements allow you to style parts of elements (for example, the first letter or add text before an element).

Pseudo-element Syntax

selector::pseudo-element {
  /* styles */
}

Examples of Popular Pseudo-elements

• ::before — inserts content before an element.
• ::after — inserts content after an element.
• ::first-letter — styles the first letter of text.
• ::first-line — styles the first line of text.
• ::placeholder — styles text inside input fields.

Pseudo-element Example

p::first-line {
  font-weight: bold;
}

button::after {
  content: " →";
}

Comparison Table