小程序筛选，向下展开的动效

参考升学规划小程序，提交记录： 下载资料弹窗标题 June 20, 2023 at 15:27:35 GMT+8
实现效果如下

关键代码：
动效css:

.fbContent {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  border-radius: 0px 0px 40rpx 40rpx;
	background: #EFF3F7;
	padding-bottom: 40rpx;

  position: absolute;
  animation: moveon 0.5s forwards;
}

@keyframes moveon {
  0% {}
  100% {
    transform: translateY(100%);
  }
}

wxml:

<view class="fbContent" catchtap="hold" style="bottom: calc(100vh - {{topBoxH}}px)"></view>

初始位置是这样的：

需要设置顶部的层级：

.topBox {
	display: flex;
	width: 100%;
	flex-direction: column;
	align-items: center;
	justify-content: flex-end;

	background-repeat: no-repeat;
	background-size: 100% auto;	

	z-index: 1;
}

完整xml:

<view class="topFilterBox">
		<view class="topBox" style="background-image: url('https://resource.gximg.cn/4604e3_fAztFSdjGK.png'); padding-top: {{navH}}px;">
			<view class="filterItemBox" wx:if="{{hasFilter}}" style="width: {{navList.length > 2 ? '94vw' : '62vw'}};">
				<view class="fiItem" wx:for="{{navList}}" wx:key="fibKey" bindtap="sectionTap" data-idx="{{index}}">
					<text class="fiiText">{{item.selectTitle ? item.selectTitle : item.title}}</text>
					<image src="../../images/list/[email protected]" mode="" class="arrowDown" />
				</view>
			</view>
		</view>
		<view class="filterBox" wx:if="{{showFilter}}" style="height: calc(100vh - {{topBoxH}}px);" bindtap="filterBgTap" catchtouchmove="hold">
			<view class="fbContent" catchtap="hold" style="bottom: calc(100vh - {{topBoxH}}px)">
				<view class="trangle" style="left: {{trangleleftArr[sectionIdx]}}px;"></view>

				<view class="fbSecontBox">

					<block wx:if="{{navList[sectionIdx].type == 'date'}}">
						<!-- 分组样式 -->
						<view class="timeSection" wx:for="{{navList[sectionIdx].list}}" wx:for-index='bigidx'>
							<text class="fbcTitle">{{item.title}}</text>
							<view class="fbsItemBox">
								<text class="fbsItem {{item.is_select ? 'fbsActive' : ''}}" wx:for="{{item.list}}" bindtap="timeSectionTextTap" data-idx="{{index}}" data-outidx="{{bigidx}}">{{item.title}}</text>
							</view>
						</view>
					</block>
					<block wx:else="">
						<text class="fbcTitle">{{navList[sectionIdx].title}}</text>
						<view class="fbsItemBox">
							<text class="fbsItem {{item.is_select ? 'fbsActive' : ''}}" wx:for="{{navList[sectionIdx].list}}" wx:key="fbsKey" bindtap="sectionTextTap" data-idx="{{index}}">{{item.title}}</text>
						</view>
					</block>

				</view>
			</view>
		</view>
	</view>

关注topBox和filterBox