[Vuejs]-Vue custom webpack css does not take effect, but it is normal in the vuecli project

It looks like your CSS loader doesn’t support the space-separated syntax of rgb() (introduced in CSS Colors Level 4).

As a workaround, switch to the classic comma-separated syntax:

box-shadow: 0 2px 12px 0 rgb(0, 0, 0, 10%);

h1 {
  box-shadow: 0 2px 12px 0 rgb(0, 0, 0, 10%);
}

<h1>Hello world</h1>