css - 为什么 Bootstrap 用 darken() 定义@brand-primary？

Question

在 Bootstrap 文件 variable.less 中，一些颜色是这样定义的:

@brand-primary:         darken(#428bca, 6.5%); // #337ab7
@brand-success:         #5cb85c;
@brand-info:            #5bc0de;
@brand-warning:         #f0ad4e;
@brand-danger:          #d9534f;

@brand-primary使用darken()有什么意义，为什么不直接写#337ab7呢？

Answer 1

为了链接颜色的可访问性对比，原始颜色变暗了。它是在 this commit 中完成的通过 Mark Otto .来自讨论:

The @brand-primary could have been simply replaced with the default value, but I wanted the source of the new color value to be left there for context. The darker primary blue increases accessibility across the board; the link change was merely the focus and impetus for this change.