How to do css

CSS (Cascading Style Sheets) is an important part of front-end development that separates the appearance, layout, and style of an HTML document from its content. Learning CSS is one of the necessary steps to get started with front-end development. In this article, I’ll cover how to get started with CSS, as well as some common CSS tips and best practices.

1. Getting Started with CSS

Understanding the basic syntax and rules of CSS is the first step to getting started. CSS uses selectors and declarations to style HTML elements. The basic syntax is as follows:

selector {

property: value;
property: value;
...

}

Among them, selector is the HTML element to be styled, such as div, p, h1, etc.; property is the CSS attribute, Such as color, background, font-size, etc.; value is the specific value or value range of the attribute, for example, the value of red is red.

In CSS, you can use multiple selectors to select the same element, and multiple attributes can also be styled at the same time. You will gradually learn and become familiar with the specific writing methods of selectors and attributes.

2. Box model

The box model is a very important concept in CSS. All HTML elements can be regarded as a box. The box model consists of four parts: element content, padding, border and margin. In order to better understand and apply the box model, you can refer to the following picture:

In CSS, the box model can be defined by width, height, inner edge Adjust the margins, borders, and margins. When an element's size changes, its internal and external effects should be considered.

3. Positioning and layout

Positioning and layout in CSS determine the position and size of elements. Among them, there are four main methods of positioning: relative positioning, absolute positioning, fixed positioning and sticky positioning. Layout mainly includes float (float) and flexible layout (flexbox).

Relative positioning uses the position of relative elements to position elements and generally does not affect the positions of other elements.

Absolutely positioned elements will be positioned relative to their ancestor elements, generally used in conjunction with the positioning attributes top, bottom, left and right. When using absolute positioning, care should be taken to consider the size and position of the element.

Fixed positioning is fixed at a certain position on the screen and will not move as the page scrolls.

Sticky positioning is mainly to keep the position of elements fixed when the page scrolls. Generally used in navigation bars and other locations.

In terms of layout, floating can be used to remove elements from the document flow; elastic layout is a more complex and flexible layout method.

4. Responsive Design

With the popularity of mobile devices, responsive design has become an essential skill. Developers need to ensure that the website or application can be used on various screen sizes and Display effectively on the device. The implementation of responsive design requires the use of CSS media queries, which can be styled for different screen sizes.

For example, on the iPad, you can use the following code:

@media (min-width: 768px) {

/*针对 iPad 屏幕的样式*/

}

On iPhone , you can set it to:

@media (max-width: 480px) {

/*针对 iPhone 屏幕的样式*/

}

Responsive design needs to be used in conjunction with other CSS technologies, such as elasticity Layout and media nesting etc.

5. Common CSS techniques and best practices

In addition to the CSS techniques introduced above, there are many common techniques and best practices, including:

• Avoid nesting too deeply and keep the code clean and easy to read.
• Use concise selectors as much as possible to reduce page loading time.
• Avoid using too many !important, which may cause style confusion.
• Avoid setting styles directly in HTML and use external style sheets whenever possible.
• Set comments for styles to facilitate later modification and maintenance.
• For complex CSS code, it can be broken into multiple modules or files.
• Test CSS across different devices and browsers to ensure compatibility and relatively consistent display.

Summary

In this article, we discussed how to get started with CSS and introduced the box model, positioning and layout, responsive design, and some common CSS tips and best practices . Learning CSS is one of the necessary steps in front-end development. It requires continuous practice and exploration to improve your skills and efficiency.

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