css command_html/css_WEB-ITnose

Test whether there is css in the web page: change the font size

No need to have attributes with different compatibility

1. For future css code For optimization, it is recommended that all attribute values ​​be followed by ";"

2. What should I do if I want to use a special font? --Convert it to a picture 3. When it is divided into Chinese and English fonts, English is in front and Chinese is in the back

4. If you want the text to be centered vertically, set the line height to The height of the element, that is, line height == element height, but the content of the text cannot exceed the height of the element, that is, it cannot wrap lines

5. The way css is applied to web pages is equivalent to how people Go to wear clothes Inline style: applied to an embedded style: applied to a type of tag If we have many web pages that use the same css, we will write these css into a separate file. This is the external link style, recommended Using imported styles also writes the styles into a file and then imports them into the web page. In fact, it is similar to the embedded styles. They both add the styles to the web page

6. css selector 1) Classification of selectors 1---label selector--for html tags 2---ID selector--for a certain ID 3---class selector--for a certain category or some elements, their styles are the same (multiple classes are applied to the same element, and the class names are separated by spaces class="Class 1 Class 2 Class 3" 4---If we target the sub-elements in an element For control, you can use the nesting method, and you no longer need to set IDs for child elements. Parent element child element {attribute: value} 5---Multiple selectors will have the same style. At this time, we can combine these selectors. A group selector 1, selector 2, ... {attribute: value}

7.css features 1. Inheritance: Child elements will inherit some styles of the parent element, and some children The element itself has a default value, so it does not use the parent element. 2. Cascading: If the child element defines the same style as the parent element, it will overwrite the style of the parent element, that is, the later style will overwrite the previous style

8.css controls a certain state of the element---pseudo class pseudo class syntax: element name: pseudo class name {attribute: value} For example: hyperlink, mouse over Status a:hover{text-decoration:underline;} a:link{text-decoration:none;} a:active{text-decoration:overline;} a:visited{text-decoration:line-through;} If the mouse is placed The effect does not work, please modify the order of link status L -V -H -A