CSS Basics | Building Blocks

CSS, or Cascading Style Sheets, serves as the backbone of web design, allowing developers to control the presentation and layout of HTML elements. At its core, CSS relies on selectors to target specific elements on a webpage. Basic selectors include the element selector, targeting all instances of a particular HTML element, the ID selector, pinpointing elements with a unique identifier, and the class selector, which applies styles to elements with a shared class attribute. Additionally, the universal selector can be used to select all elements on a page.

CSS Selectors

Selectors can be combined to target more specific elements through various relationships. Descendant selectors target elements nested within another element, while child selectors specifically target direct children. Adjacent sibling selectors target elements that share the same parent and appear immediately after one another, and general sibling selectors target elements that share the same parent but can appear anywhere in relation to each other. Moreover, pseudo-classes and pseudo-elements offer additional styling capabilities, such as targeting elements based on user interaction (:hover, :active, :focus) or manipulating specific parts of an element (::before, ::after, ::first-line, ::first-letter).

CSS Box Model

Understanding the CSS box model is fundamental for controlling the layout of elements on a webpage. This model consists of properties such as width, height, padding, border, and margin, which collectively determine the size and spacing of an element. The box-sizing property can be adjusted to control how these properties interact, ensuring consistent layouts across different elements. Furthermore, the box display property dictates how elements are rendered in relation to one another, with options including block, inline, inline-block, and none, each influencing the flow and positioning of elements on the page.

CSS Layout and Structure

In addition to layout and structure, CSS allows for the styling of text, backgrounds, and borders. Text can be customized with various fonts, colors, spacing, and transformations to enhance readability and visual appeal. Backgrounds and borders can be adorned with colors, images, and properties to create visually engaging designs. By applying styles using properties like display, margin, and padding, developers can further refine the appearance and behavior of elements, ensuring a seamless and aesthetically pleasing user experience.


CSS serves as the cornerstone of web design, enabling precise control over element presentation through selectors, including basic ones like element, ID, and class, as well as advanced ones like pseudo-classes and pseudo-elements. Understanding the CSS box model is crucial for managing element layout, encompassing properties like width, height, padding, and margin, while the box display property dictates how elements are rendered. Additionally, CSS empowers designers to style text, backgrounds, and borders, enhancing the visual appeal and user experience of web pages.