css style modification

CSS style is an indispensable part of web design. It can be used to beautify the page, increase interactivity and improve user experience. For designers who want to create excellent web pages, how to modify CSS styles is a skill that must be mastered. This article will discuss how to modify CSS styles, including common CSS properties and selectors, as well as some practical case applications.

1. Modification of CSS attributes

1. Color attribute

First of all, we need to understand the most commonly used attribute in CSS-color. Color can bring different atmospheres and feelings to the page, and plays a vital role in the aesthetics of the entire page. In CSS, we can modify the color attributes in the following ways:

(1) Use specific color values, such as red can be represented by "red", or use RGB color values ​​(such as rgb(255 ,0,0)) or hexadecimal value (such as #FF0000).

(2) Use the gradient effect in CSS3. For example, linear gradients can be implemented through the "linear-gradient()" function, and radial gradients can be implemented through the "radial-gradient()" function.

(3) Use transparency. Transparency changes the opacity of an element, making it appear more translucent. Transparency is represented by the "opacity" attribute, which ranges from 0 to 1.

2. Font attribute

The font attribute is also one of the commonly used attributes in CSS. Font properties can be modified by adjusting the font, size, weight, style, etc.

(1) Modifying the font type can be achieved through the "font-family" attribute. We can set a specific font name in this attribute, such as "Arial" or "Songti", or we can set a general font category, such as "sans-serif" (sans serif font) or "serif" (serif font) .

(2) Modifying the font size can be achieved through the "font-size" attribute. Font size can be set as pixel value, em value or percentage.

(3) Modifying the font thickness can be achieved through the "font-weight" attribute. Common values ​​include "normal", "bold" and "bolder".

(4) Modifying the font style can be achieved through the "font-style" attribute. Common values ​​include "normal", "italic" and "oblique".

3. Box model attribute

The box model attribute is the most important attribute in CSS layout. It controls the size, position and padding of elements. The box model attributes are as follows:

(1) Width and height: The width and height of the element can be set through the "width" and "height" attributes.

(2) Margin: The distance between an element and other elements can be set through the "margin" attribute.

(3) Padding: The distance between the inside of the element and the border can be set through the "padding" attribute.

(4) Border: The border width, style and color of the element can be set through the "border" attribute.

4. Background attribute

The background attribute allows us to add background images, background colors, or background gradient effects to elements.

(1) To set the background image, you can use the "background-image" attribute. In this attribute, we can put a URL address and specify the background image to be used.

(2) To set the background color, you can use the "background-color" attribute. Inside this property, we can set any color value.

(3) To set the background gradient, you can use the "background-image" attribute in CSS3, which supports two gradient methods: linear and radial.

2. Modification of CSS selectors

In CSS, selectors are a method used to select HTML elements that need to be modified. Common selectors include the following:

1. Element selector

The element selector is the most commonly used selector, which uses the name of the HTML element as the selector. For example, to change the style of all paragraphs, use "p" as the selector.

2. Class selector

The class selector is represented by a dot (.), which can select all elements using a specific class name and apply them to CSS styles. For example, to modify all elements with the class name "nav", you can use ".nav" as the selector.

3. ID selector

The ID selector is represented by a pound sign (#), which selects an HTML element with a unique ID and applies it to in CSS styles. For example, to modify the element with the ID "header", you can use "#header" as the selector.

4. Descendant selector

The descendant selector is implemented through the hierarchical relationship of selectors. For example, you can use the "ul li" selector to modify all "li" elements nested within the "ul" element.

5. Pseudo-element selector

The pseudo-element selector is used to select content created in a certain position of the element. For example, you can use the "::before" pseudo-element selector to add content in front of the element, or use the "::first-letter" pseudo-element selector to control the style of the first letter.

3. Application of actual cases

In addition to the common CSS properties and selectors mentioned above, there are many things that need attention in practical applications. Below we will further explore how to modify CSS styles through several practical cases.

1. Modify the style of the button

Button is one of the commonly used elements in websites. In practical applications, we need to modify the button style through CSS. For example, we can modify the following HTML code:

<button>Click Me</button>

to:

<button class="my-button">Click Me</button>

Then add the following style in CSS:

.my-button {
  padding: 10px 20px;
  background-color: #007bff;
  border: none;
  color: #fff;
  font-weight: bold;
  border-radius: 5px;
}

In this way, the button style can be modified. More beautiful.

2. Modify the style of the navigation bar

The navigation bar is a very important part of the website. In practical applications, we need to modify the style of the navigation bar through CSS. For example, we can modify the following HTML code:

<nav>
  <a href="#">Home</a>
  <a href="#">About Us</a>
  <a href="#">Contact Us</a>
</nav>

to:

<nav>
  <a href="#" class="active">Home</a>
  <a href="#">About Us</a>
  <a href="#">Contact Us</a>
</nav>

and then add the following style in CSS:

nav {
  background-color: #fff;
  border-bottom: 1px solid #ddd;
}

nav a {
  display: inline-block;
  padding: 10px 20px;
  color: #333;
  text-decoration: none;
}

nav a:hover {
  background-color: #ddd;
}

nav a.active {
  background-color: #007bff;
  color: #fff;
}

This way you can change the style of the navigation bar Modified to be more beautiful and easier to use.

3. Modify the style of the picture

In actual design, we often need to modify the style of the picture to achieve a more beautiful effect. For example, we can modify the following HTML code:

<img src="/static/imghwm/default1.png"  data-src="http://example.com/image.jpg"  class="lazy" alt="example image">

to:

  <img src="/static/imghwm/default1.png"  data-src="http://example.com/image.jpg"  class="lazy" alt="example image">

and then add the following style in CSS:

.image-container {
  width: 50%;
  margin: 0 auto;
}

.image-container img {
  width: 100%;
  border-radius: 5px;
  box-shadow: 0 0 10px #aaa;
}

This way you can modify the style of the image In order to make it more beautiful, some shadow effects are added to the picture to make the picture look more three-dimensional.

Summary

Through the introduction of this article, we have learned about the basic modification methods of CSS styles, as well as common selectors and attributes. We put some practical use cases into use and gained some key points. To be proficient in CSS styles, you need to continue to practice and try, and constantly expand your knowledge and skills, so as to create a more beautiful, practical and user-friendly web design.

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