React Core Concepts

What is React?

React is a JavaScript library for building user interfaces. It’s focused on UI development and separates concerns – you build the components, and React manages the updates and rendering.

It uses a virtual DOM to efficiently update the UI without re-rendering the whole thing.

Key Concepts

Why Use React?

React’s component-based approach makes it easy to manage complex UIs. It has a large and active community, and it provides a lot of libraries and tools.

Example

This is a simple example that utilizes React's components, JSX, and state.

``` ```css /* style.css */ body { font-family: sans-serif; margin: 0; padding: 0; background-color: #f4f4f4; color: #333; line-height: 1.6; } header { background-color: #344040; color: #fff; padding: 20px; text-align: center; box-shadow: 0 0 10px #ccc; } nav { background-color: #344040; color: #fff; padding: 10px; text-align: center; border-bottom: 1px solid #ccc; } nav ul { list-style: none; padding: 0; } nav ul li { display: block; margin: 0; padding: 10px; } .container { width: 80%; margin: 0 auto; padding: 20px; background-color: #fff; border-radius: 8px; box-shadow: 0 0 10px rgba(0, 0, 0, 0.1); } main { padding: 20px; background-color: #f4f4f4; border-radius: 8px; max-width: 800px; } section { padding: 20px; margin-bottom: 20px; border-bottom: 1px solid #ccc; background-color: #f4f4f4; border-radius: 8px; } section h2 { font-size: 24px; margin-bottom: 10px; color: #344040; } h3 { font-size: 18px; margin-bottom: 5px; color: #fff; } ul { list-style: none; padding: 0; } ul li { margin-bottom: 10px; } footer { text-align: center; padding: 10px; background-color: #344040; color: #fff; border-bottom: 1px solid #ccc; }