How to set css style

CSS (Cascading Style Sheets) is one of the basic components of web development, which allows developers to control the style and layout of web pages. For novices, CSS may be difficult to learn, but once you master the basic CSS settings, it will become easier to develop better web pages. This article will share some basic knowledge and tips on how to style CSS.

1. Choose the appropriate CSS selector

CSS selector is a syntax for locating and modifying HTML elements. It allows developers to pass tag names, class names, identifiers and Other attributes to select HTML elements. Choosing appropriate selectors can simplify CSS code and improve performance. The following are some of the most commonly used CSS selectors:

1. Tag selector

The tag selector is the most basic and simplest selector, and it can be applied to HTML documents of all elements. For example, the following code will set the font to Arial for all paragraph elements in an HTML document:

p {
  font-family: Arial;
}

2. Class selector

The class selector is a more powerful selector that makes Developers can select elements based on their class names. A class name can be applied to multiple elements so that they share the class's style. The following code will set the background color to gray for all elements with a class name of "test":

.test {
  background-color: gray;
}

3. ID Selector

The ID selector selects elements based on their unique ID attribute. ID names can only be applied to a single element. Since each ID is unique, they make it easier to target specific HTML elements. The following code will set the font color to red for the element with the element ID "header":

header {
color: red;
}

2. Use the box model to layout elements

The box model refers to treating HTML elements as content , padding, border and margin. Developers can use the box model to control the size, internal spacing, border style, and relative position of elements. The following are some basic attributes of the box model:

1. Width (width)

The width attribute defines the width of the element. It can be specified in pixels, percentages, or other units. The following code will set a fixed width to 800 pixels for the element with the ID "container":

container {
width: 800px;
}

2. Height (height)

The height attribute defines the height of the element. It can be specified in pixels, percentages, or other units. The following code will set a fixed height of 30 pixels for all paragraph elements:

p {
 height: 30px;
}

3. Padding

Padding refers to the distance between the content of the element and the border . It can be defined using pixel or percentage values. The following code will set the left padding to 20 pixels for the element with the ID "header":

header {
padding-left: 20px;
}

4. Border

The border can be used to define the size, shape and color of the element . Borders can be divided into three parts: width, style, and color. The following code will set the border width to 1 pixel, the style to solid line, and the color to black for all paragraph elements:

p {
 border: 1px solid black;
}

5. Margin (margin)

Margin refers to the distance between the element and The distance between adjacent elements. It can be defined using pixel or percentage values. The following code will set the top margin to 20 pixels for the element with the ID "container":

container {
margin-top: 20px;
}

3. Style inheritance and override

CSS styles can be set at multiple levels. These levels Including elements, classes, IDs and globals. Setting styles at these levels can affect elements at different levels. Here are some basic rules for style inheritance and overriding:

1. Style inheritance

Some styles are passed from parent elements to child elements. For example, if you apply a font style to a parent element, its child elements will also inherit that style. The following code will use the ID selector to set the font for the parent element and all child elements:

parent, #parent * {
font-size: 14px;
}

2. Style override

If multiple styles are applied to the same element at the same time, they will be pressed according to the specific Priority coverage. Here are some of the most common style override rules:

• The last style defined in the style sheet has the highest priority
• The style marked with !important has the highest priority
• ID selector has higher priority than class selector
• Inline styles have higher priority than external style sheets and internal style sheets

4. Responsive design design responsive layout

Many modern websites use responsive design to optimize web page layout on different sized screens. Fortunately, responsive design is easy to implement with CSS. The following are some CSS techniques that can be used to implement responsive design:

1. CSS media queries

CSS media queries are a CSS layout control method for different device sizes and types. Media queries allow developers to display HTML elements in different ways, effectively adapting to various screen sizes and device types. Here is a basic example:

@media screen and (max-width: 600px) {
 body {
background-color: blue;
}
}

2. Flexible layout

Flexible layout allows elements to automatically scale and rearrange between different screen sizes. It can be achieved by setting flexbox properties. Here is a basic example:

.container {
 display: flex;
 justify-content: space-between;
 align-items: center;
}
@media screen and (max-width: 600px) {
 .container {
flex-direction: column;
}
}

Summary

CSS is an important web development technology. As a developer, learning how to set CSS styles will make our web pages more professional and beautiful. We need to choose appropriate CSS selectors, use the box model to layout elements, master style inheritance and overrides, and implement responsive design, so that our web pages can not only run smoothly on PC devices, but also display better on mobile devices. Effect. I hope this article helped you learn more about how to style CSS.

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