[Entry classic] Use CSS on the master page

• CSS contains the "various styles" format for pages and controls.

Therefore, when a page is displayed, all elements, text, buttons, and link styles on the page are displayed in the format defined in CSS.

• CSS can speed up page loading, because CSS is loaded only once in the browser. When used repeatedly, you can directly use the CSS stored in the client cache.

[Usage] on the master page, you should include a link similar to the following in the

CSS is the subject of HTML, not ASP. NET.