fix:更改popup类名

src/packages/popup/doc.md

@@ -48,7 +48,7 @@ export default {
 设置 round 属性后，弹窗会根据弹出位置添加不同的圆角样式
 
 ```html
-<van-popup v-model="show" round position="bottom" :style="{ height: '20%' }" />
+<nut-popup v-model="show" round position="bottom" :style="{ height: '20%' }" />
 ```
 
 ## API

src/packages/popup/mask.vue

@@ -13,10 +13,10 @@ export default {
 </script>
 <style lang="scss" scoped>
 .popup-fade-enter-active {
-  animation: 0.3s van-fade-in;
+  animation: 0.3s nut-fade-in;
 }
 .popup-fade-leave-active {
-  animation: 0.3s van-fade-out;
+  animation: 0.3s nut-fade-out;
 }
 .bg {
   position: fixed;
@@ -28,7 +28,7 @@ export default {
   z-index: 99;
 }
 
-@keyframes van-fade-in {
+@keyframes nut-fade-in {
   from {
     opacity: 0;
   }
@@ -38,7 +38,7 @@ export default {
   }
 }
 
-@keyframes van-fade-out {
+@keyframes nut-fade-out {
   from {
     opacity: 1;
   }