我终于明白了，我没有选择正确的属性.

I got it finnaly, i was not selecting the right attribute.

这里有什么效果:

page-login {
    .sample-modal-page {
        padding: 30px;
        background: rgba(0,0,0,0.5);
    }
}

感谢 varun aaruru 帮助我，感谢他为出色的编辑提供的所有特点

Thank you to varun aaruru for helping me and all the caracteristic he gave for nice editing

在这里您还可以找到一篇很好的帖子，讨论如何设计它:https://forum.ionicframework.com/t/custom-modal-alert-with-html-form/47980/19

here you can also find a nice post talking about how to nicely design it : https://forum.ionicframework.com/t/custom-modal-alert-with-html-form/47980/19