The simple selector matches if all of its components match.
如果它的所有内容都匹配，则简单选择符匹配。
A selector consisting of a single simple selector matches any element satisfying its requirements.
包含一个简单选择符的选择符，匹配任意符合它要求的元素。
A simple selector is either a type selector or universal selector followed immediately by zero or more attribute selectors, ID selectors, or pseudo-classes, in any order.
一个简单选择符或者是一个类型选择符，或者是一个全局选择符，紧跟在后的是零个或多个属性选择符，ID选择符或伪类，次序任意。
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