[audio]修改多音频同时播放示例布局

pages/API/create-inner-audio-context/inner-audio-mult.uvue

@@ -4,8 +4,8 @@
 		<view class="uni-title">
 			<text class="uni-title-text">多音频同时播放</text>
 		</view>
-		<button type="primary" @tap="play1()"> 播放/停止(进度：{{currentTime1}})</button>
-		<button type="primary" @tap="play2()"> 播放/停止(进度：{{currentTime2}})</button>
+		<button type="primary" @tap="play1()"  class="uni-btn"> 播放/停止(进度：{{currentTime1}})</button>
+		<button type="primary" @tap="play2()"  class="uni-btn"> 播放/停止(进度：{{currentTime2}})</button>
 	</view>
 </template>
 
@@ -89,4 +89,4 @@
 		height: 60px;
 		margin: 10px;
 	}
-</style>
\ No newline at end of file
+</style>