Introduction to CSS: Cascading Style Sheets
Nwoha Martins
Software Engineer | Web3 Content & Technical Writer - Simplifying Blockchain & Tech for All | Graphics Designer | Special Needs Advocate(Autism)
CSS (Cascading Style Sheets) is a style sheet language used to describe the presentation of a document written in HTML (HyperText Markup Language) or XML (Extensible Markup Language). CSS is responsible for how a webpage looks, from the font size and color to the layout and spacing.
In the early days of the web, designers used HTML to style their websites. However, as websites became more complex, it became difficult to maintain consistent styles across different pages. CSS was developed to solve this problem by separating the content of a webpage from its presentation.
How CSS Works
CSS works by selecting elements in an HTML document and applying styles to them. The styles are defined in a separate CSS file or in the HTML document itself. The CSS file is linked to the HTML document using the <link> tag in the <head> section.
CSS rules consist of a selector and one or more declarations. The selector is the HTML element that the style applies to, and the declarations specify the style properties and their values. For example, the following CSS rule sets the font size of all <p> elements to 16 pixels:
p {
font-size: 16px;
}
CSS selectors can be based on element type, class, ID, or other attributes. For example, the following CSS rule sets the font size of all elements with the class "intro" to 18 pixels:
.intro {
font-size: 18px;
}
Inline Styles
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In addition to external CSS files, styles can also be applied inline using the style attribute. Inline styles are defined directly in the HTML element using the style attribute. For example, the following HTML code sets the font size of a <p> element to 14 pixels:
<p style="font-size: 14px;">This is a paragraph.</p>
Inline styles should be used sparingly because they can be difficult to maintain and override. It's generally better to use external CSS files and apply styles using selectors.
CSS Box Model
The CSS box model is used to define the layout of elements on a webpage. Every HTML element is treated as a box, with a content area, padding, border, and margin. The content area is the space inside the box where the element's content is displayed. The padding is the space between the content area and the border. The border is the line that surrounds the element, and the margin is the space between the border and the neighboring elements.
CSS Layout
CSS can be used to control the layout of a webpage using positioning, floats, and the display property. Positioning can be used to place elements in specific locations on the page, while floats can be used to create columns or wrap text around images. The display property can be used to control how elements are displayed, such as turning an element into a block-level or inline-level element.
Conclusion
CSS is an essential part of modern web design, allowing designers to separate content and presentation and maintain consistent styles across different pages. With CSS, designers can control every aspect of a webpage's appearance, from the font size and color to the layout and spacing. By understanding the basics of CSS, you can create beautiful and responsive websites that look great on all devices.