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Introduction to CSS

CSS (Cascading Style Sheets) is the language used to describe the presentation and layout of web pages. While HTML provides the structure and content of a webpage, CSS controls how that content is displayed, allowing developers to style the website’s appearance. CSS defines the colors, fonts, spacing, positioning, and overall design of the page, creating a visually appealing and consistent user experience.

CSS uses a system of selectors and declarations to apply styles to HTML elements. Selectors identify the elements on the page that you want to style. A declaration consists of a property and a value, which define how the selected element should be styled.

In addition to basic styling, CSS supports advanced features like animations, transitions, and layout models (e.g., Flexbox and Grid), allowing for complex and interactive designs. CSS can be applied to a web page in three ways:

  • Inline CSS: Directly within an HTML element using the style attribute.
  • Internal CSS: Within a <style> tag in the HTML document’s <head> section.
  • External CSS: Using an external stylesheet linked via the <link> tag.

The “cascading” nature of CSS means that styles are applied in a hierarchical manner, with rules from different sources (inline, internal, external) potentially overriding each other based on specificity and importance.

One of the key features of CSS is its ability to create responsive designs that adapt to different screen sizes. Using techniques such as media queries, CSS can adjust the layout and styling of a page based on the device or screen resolution. This makes CSS an essential tool for building modern, mobile-friendly websites.