align-items is used to set the default cross-axis alignment of all items in the entire flex container, while align-self is used to cover an item individually. 1. align-items is a container attribute, affecting all child elements. The default value is stretch. You can choose flex-start, flex-end, and center; 2. align-self is an attribute of individual child elements, which can override container settings and allow specific elements to adopt different alignment methods; 3. When using it, align-items should be set to unified control, and then individual exceptions should be adjusted through align-self. Both must be effective in the parent container of display:flex.

When working with CSS Flexbox, align-self and align-items both control how items are aligned along the cross axis — but they're used in different contexts and have distinct purposes.

What's the basic difference?

• align-items is a property applied to the flex container and affects all flex items inside it.
• align-self is applied directly to an individual flex item , allowing it to override the container's align-items setting.

Now let's break this down further with practical usage scenarios.

How align-items works

This property sets the default alignment for all items inside a flex container. Think of it as a global rule for vertical alignment (assuming a row-based flex layout).

Common values ??include:

• flex-start
• flex-end
• center
• stretch (default)

For example:

 .container {
  display: flex;
  align-items: center;
}

All items inside .container will be vertically centered by default. This saves you from having to set alignment individually on each item.

Use align-items when you want consistent alignment across all child elements.

When to use align-self

Sometimes you want one or two items to behave differently. That's where align-self comes in.

It works just like align-items , but apply only to a single item. It lets that item ignore the container's alignment rule and define its own.

Example:

 .item-special {
  align-self: flex-end;
}

Even if the container says align-items: center , this special item will align to the end.

So think of align-self as a way to create exceptions. It gives you more fine-grained control without needing extra wrappers or changing the parent's settings.

Common pitfalls and tips

• If you forget that align-self overrides align-items , you might spend time debugging why one item isn't aligning like the others.
• Use align-items first to set a base alignment, then apply align-self only when needed.
• Both properties only work in flex containers — so make sure display: flex is set on the parent.

A good mental model:

• align-items : "How should I line up my kids by default?"
• align-self : "I know the rules, but I want to stand somewhere else."

In short, align-items controls the group, while align-self controls individuals. Use them together for flexible and precise layouts.

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