默认状态是在标签中没有指定属性，这对于定义文本域和label中的颜色和字体已经足够了，因为这两种组件的状态不会改变。

The default state, where no attribute is specified in the tag, is sufficient for defining the colors and fonts in a text field and in labels, because their states won't change.

youdao

我见过的许多基于CSS的导航标签大都具有一类的特征：矩形的色块，也许仅仅是一个轮廓，对于当前选中的标签则没有边框，标签在鼠标指针游至其上时改变颜色。

Many of the CSS-based tabs I've seen suffer from the same generic features: blocky rectangles of color, maybe an outline, a border disappears for the current TAB, a color changes for the hover state.

youdao