方式1：半圆的颜色和主内容的颜色一样
css: 这是小程序的样式，在网页上把rpx换成px
.nav-top{ text-align: center; background: #FFE6E6; width:530rpx; margin: 0 auto; border-radius: 30rpx; .btn-nav { width: 170rpx; text-align: center; height: 60rpx; border-radius: 30rpx; line-height: 60rpx; color: #F97777; position: relative; display: inline-block; padding-right: 30rpx; padding-left: 30rpx; z-index: 100; } .btn-nav:nth-child(2){ margin-left: 10rpx; margin-right:10rpx; } .activated{ border-radius: 30rpx; background: linear-gradient(to right,#F83A3A,#F7C18B); color:#fff; z-index: 1000; } } .na
