Kubernetes 的基本架构

枚举(Enum)类型经常被用于取值在一定范围内的场景,比如一周只能有七天,角色权限设计等。枚举类型变量使用enum
字段来定义,枚举成员的值可以是数字或者字符串,并且枚举成员是只读的。
枚举按照类型划分,主要分为以下三种:
px 像素(Pixel),相对长度单位。本来 px 还是很好理解的,但是由于 Retina 屏让 px 变得扑所迷离,也是在移动端 Web 开发的时候不得不跨越的一个坎。我们先了解一下两个概念:
独立像素 = 物理像素
独立像素 < 物理像素
Online demo: http://www.liquidapsive.com
Before introduction on responsive and adaptive design, let's start by Static and Liquid which are basis of responsive and adaptive design.
Static layouts are the traditional web: one design that sits in the center of the page and requires horizontal scrolling if the window is too small for it. M dot sites (m. site is a website that's specifically designed for mobile devices, and exists on a separate subdomain) are the traditional answer to this, providing a wholly separate site for a lower resolution - and all the work of creating a separate site.
"自适应网页设计"的核心,就是 CSS3 引入的 Media Query 模块。
它的意思就是,自动探测屏幕宽度,然后加载相应的 CSS 文件。
<link
rel="stylesheet"
type="text/css"
media="screen and (max-device-width: 400px)"
href="tinyScreen.css"
/>
上面的代码意思是如果屏幕宽度小于 400 像素,就加载 tinyScreen.css
文件。