Bootstrap CSS -background颜色属性在Safari中有* - 警告

Question

我在Safari浏览器中收到很多警告，

[Warning] Invalid CSS property declaration at: * (bootstrap.min.css, line 11)
[Warning] Invalid CSS property declaration at: * (bootstrap.min.css, line 47)
[Warning] Invalid CSS property declaration at: * (bootstrap.min.css, line 48)

错误是由于背景颜色前面的*。

.btn-danger:hover,.btn-danger:focus,.btn-danger:active,.btn-danger.active,.btn-danger.disabled,.btn-danger[disabled] {
    color: #ffffff;
    background-color: #bd362f;
    *background-color: #a9302a;
}