What are the differences between Flexbox in the browser and Flexbox in React Native?

CSS Flexbox is used to design responsive layouts easily, without relying on float or position CSS properties, which can be cumbersome. Introduced in CSS3, Flexbox ensures consistent layouts across different screen sizes. 

In React Native, you typically use a combination of flexDirection, alignItems, and justifyContent to achieve the desired layout. There are some differences in the default values of certain flex-based CSS properties between React Native and web browsers: 

• flexDirection: Defaults to row on the web, but to column in React Native. 
• flex: In React Native, the flex parameter supports only a single number. 

Flexbox properties like alignItems and justifyContent help position elements: 

• alignItems: Values like flex-start align elements from the start, while flex-end places the first child element at the end. 
• justifyContent: Similar to alignItems, it positions elements along the main axis. 

These properties allow for easy and flexible layout designs, ensuring responsive and adaptive UIs across different devices.