BEM solves the problem of chaos in CSS naming and improves maintainability and collaboration efficiency through structured naming. It divides components into Block (independent modules, such as .header), Element (child elements, such as .menu__item), and Modifier (variant, such as .button--primary), clarifying hierarchical relationships and scope of action, avoiding style conflicts, and improving code readability and reusability.
BEM stands for Block, Element, Modifier. It's a naming convention for CSS classes that helps you create reusable components and keep your styles organized, especially in larger projects or when working in teams.

What Problem Does BEM Solve?
Without a structure like BEM, CSS can get messy fast. You might end up with confusing class names like .red-button
or .big-text
, which are not descriptive or scalable. BEM brings clarity by clearly defining the relationship between different parts of a component.
Block – The Main Component
A Block is a standalone component that can be reused across your site. Think of it as the main container or the highest-level part of a UI element.

- Example:
.header
,.menu
,.button
- It never depends on other parts of the page
- It can be placed anywhere and still work
You can imagine a button as a block. It has its own base styles, and it doesn't care where it appears on the page.
Element – A Part of a Block
An Element is a child part of a Block. It only makes sense in the context of its parent block.

- Example:
.menu__item
,.button__text
- Uses double underscores (
__
) to separate from the block name - Elements can be nested inside other elements, but it's usually better to keep it simple
So if you have a menu block, each item in that menu would be an element. This makes it clear that .menu__item
is part of .menu
.
Modifier – Variations of a Block or Element
A Modifier is a variation of a Block or Element. It changes appear, behavior, or state.
- Example:
.button--primary
,.menu__item--active
- Uses double dashes (
--
) to separate from the block or element name - Modifiers should not create entirely new components, just variations
Let's say you have a default button and a primary button. Instead of creating two completely separate classes, you use .button--primary
to apply different styles on top of the base .button
styles.
Why Use BEM?
Here are a few reasons why BEM is useful:
- Clarity : You can look at a class name and instantly know what part of the page it belongs to
- Scalability : Makes it easier to manage large projects with many developers
- Avoids Conflicts : Reduces the chance of class name collisions
- Reusability : Encourages building reusable components
It might feel a bit verbose at first, but once you get used to it, it becomes second nature.
Using BEM doesn't require any tools or preprocessors. You can start applying it right away in your HTML and CSS. Just follow the naming pattern and be consistent.
Give it a try on your next project — it might just make your CSS easier to read, write, and maintain.
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