[breaking change] rebuild style struct (#2021)

packages/style/animation.less

@@ -0,0 +1,61 @@
+@keyframes van-slide-bottom-enter {
+  from {
+    transform: translate3d(0, 100%, 0);
+  }
+}
+
+@keyframes van-slide-bottom-leave {
+  to {
+    transform: translate3d(0, 100%, 0);
+  }
+}
+
+@keyframes van-fade-in {
+  from {
+    opacity: 0;
+  }
+
+  to {
+    opacity: 1;
+  }
+}
+
+@keyframes van-fade-out {
+  from {
+    opacity: 1;
+  }
+
+  to {
+    opacity: 0;
+  }
+}
+
+@keyframes van-rotate {
+  from {
+    transform: rotate(0deg);
+  }
+
+  to {
+    transform: rotate(360deg);
+  }
+}
+
+.van-fade {
+  &-enter-active {
+    animation: .3s van-fade-in;
+  }
+
+  &-leave-active {
+    animation: .3s van-fade-out;
+  }
+}
+
+.van-slide-bottom {
+  &-enter-active {
+    animation: van-slide-bottom-enter .3s both ease;
+  }
+
+  &-leave-active {
+    animation: van-slide-bottom-leave .3s both ease;
+  }
+}