效果图：
van-popup背景颜色渐变
使用深度修改样式不生效，直接在 custom-style里面修改即可；
<van-popup position="bottom" custom-style="height:25%;background:linear-gradient(95deg, #F8FCFF -0.03%, #EDF5FF 64.44%, #F8FCFF 133.06%);" 在这里设置渐变背景 round show="{{ showLogin }}" bind:close="onLoginClose"> <button open-type="getPhoneNumber" open-type是微信原生自带 class="wx-login-btn wx-btn" bindgetphonenumber="wxLogin">手机号快捷登录</button> <checkbox-group class="certificate" style="width: 90%;margin:24rpx 40rpx;"> <checkbox checked="{{isagree}}" class="checkbox" value="{{sms}}"></checkbox> <view class="certificate-txt">阅读并同意<text class="txt" bindtap="openUrl" data-num='lending006'>《用户信息授权书》</text>、<text class="txt" bindtap="openUrl" data-num='lending008'>《卖家云SaaS系统服务协议》</text></view> </checkbox-group></van-popup>样式代码，包括同意协议勾选前后的样式，
.herad .wx-login-btn { margin: 80rpx 0 64rpx 0; height: 96rpx; line-height: 96rpx; font-size: 30rpx; border-radius: 6rpx; width: 90%; color: #fff; right: 0; display: flex; justify-content: center; align-items: center; position: flex; bottom: 0; left: 0; padding: 0; margin-left: 5%; text-align: center; /* padding-left: -5rpx; */ border-top-left-radius: 50rpx; border-bottom-left-radius: 50rpx; border-top-right-radius: 50rpx; border-bottom-right-radius: 50rpx; letter-spacing: 3rpx;}.wx-btn { background: var(--blue, linear-gradient(90deg, #1463FF 0%, #7214FF 100%)); box-shadow: 0rpx 8rpx 20rpx 0rpx rgba(20, 72, 255, 0.20);}.wx-btn:hover{ box-shadow: 10rpx 10rpx 32rpx #91c9f4;}.certificate { display: flex; align-items: flex-start; justify-content: space-between; margin-top: 24rpx; font-size: 30rpx; color: #666666;}.checkbox .wx-checkbox-input { border-radius: 10rpx; /* 圆角 */ width: 40rpx; /* 背景的宽 */ height: 40rpx; border: none;}.checkbox .wx-checkbox-input { background:#E7E7E7}.checkbox .wx-checkbox-input.wx-checkbox-input-checked { background:#E7E7E7}.checkbox .wx-checkbox-input.wx-checkbox-input-checked::before { width: 40rpx; height: 40rpx; line-height: 40rpx; text-align: center; font-size: 20rpx; color: #7B7B7B; background: transparent; transform: translate(-50%, -50%) scale(1); -webkit-transform: translate(-50%, -50%) scale(1);}.certificate-txt{ color: #222; font-size: 24rpx;}.txt { color: #1F6DF2; font-size: 24rpx;}