> For the complete documentation index, see [llms.txt](https://docs.codelessly.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.codelessly.com/editor-basics/working-with-size-fits.md).
# Working with Size Fits
Size Fits form the basis of Codelessly's auto-layout system. It's a fundamental concept that helps you achieve that pixel-perfect responsiveness.
To summarize, Size Fits let you define how a node **fits** inside a frame, row, or column. Whether it takes up all the available space or wraps around its children, taking the minimum space possible. Or, you can even provide it a fixed size manually.
Size Fits can be defined per axis, **horizontal** and **vertical**. Simply select the desired Size Fit from the dropdown, or, use the *Size Fit Selector*.
## Fixed Size
By default, nodes are **fixed in size**. This means that they do not adjust their size according to the parent layout.
So, if a node is fixed size on the horizontal axis, it retains its width.
If a node is fixed size on the vertical axis, it retains its height.
## Fill Parent
This fit expands the node to the size of its direct parent.
So, if a node is set to fill parent on the horizontal axis, it expands its width to that of its parent.
If a node is set to fill parent on the vertical axis, it expands its height to that of its parent.
## Wrap Content
Contrary to ***fill parent***, this fit depends on a node's children rather than its parent. If a node has children, ***wrap content*** sets the node's dimensions to that of its children.
So, if a node wraps content horizontally, its width shrinks to that of its children.
If a node wraps content vertically, its height shrinks to that of its children.