diff --git a/.vscode/launch.json b/.vscode/launch.json
index a7b7add4..c349b76f 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -1,6 +1,12 @@
 {
   "version": "0.2.0",
   "configurations": [
+    {
+      "name": "dev",
+      "request": "launch",
+      "type": "node-terminal",
+      "command": "pnpm run dev"
+    },
     {
       "name": "docs:dev",
       "type": "node-terminal",
diff --git a/packages/theme/package.json b/packages/theme/package.json
index a29170e8..686e406f 100644
--- a/packages/theme/package.json
+++ b/packages/theme/package.json
@@ -53,6 +53,7 @@
     "nanoid": "^3.3.2",
     "sass": "^1.49.9",
     "sass-loader": "^12.6.0",
+    "ts-debounce": "^4.0.0",
     "vue": "^3.2.33",
     "vue-router": "^4.0.14",
     "vuepress-plugin-comment2": "2.0.0-beta.47",
diff --git a/packages/theme/src/client/components/BackToTop.vue b/packages/theme/src/client/components/BackToTop.vue
index 29c88f4c..725e2059 100644
--- a/packages/theme/src/client/components/BackToTop.vue
+++ b/packages/theme/src/client/components/BackToTop.vue
@@ -1,29 +1,23 @@
 <script lang="ts" setup>
-import { onMounted, onUnmounted, ref } from 'vue'
-import { scrollTo } from '../utils'
+import { debounce } from 'ts-debounce'
+import { onMounted, ref } from 'vue'
+import { getScrollTop, scrollTo } from '../utils'
 import { BackTopIcon } from './icons'
 
 const opacity = ref<number>(0)
 const MAX_TOP = 300
 
-const canShow = (): void => {
-  if (__VUEPRESS_SSR__) return
-  opacity.value = document.documentElement.scrollTop >= MAX_TOP ? 1 : 0
-}
+const canShow = debounce((): void => {
+  opacity.value = getScrollTop(document) >= MAX_TOP ? 1 : 0
+})
 
 const scrollToTop = (): void => {
   scrollTo(document, 0)
 }
 
 onMounted(() => {
-  if (__VUEPRESS_SSR__) return
   canShow()
-  window.addEventListener('scroll', canShow, false)
-})
-
-onUnmounted(() => {
-  if (__VUEPRESS_SSR__) return
-  window.removeEventListener('scroll', canShow)
+  window.addEventListener('scroll', () => canShow(), false)
 })
 </script>
 <template>
@@ -32,10 +26,11 @@ onUnmounted(() => {
   </div>
 </template>
 <style lang="scss">
+@import '../styles/variables';
 .btn-back-top {
   position: fixed;
   right: 3rem;
-  bottom: 3rem;
+  bottom: 4.35rem;
   width: 3rem;
   height: 3rem;
   text-align: center;
@@ -60,4 +55,10 @@ onUnmounted(() => {
     }
   }
 }
+@media (max-width: $MQMobile) {
+  .btn-back-top {
+    right: 1.25rem;
+    bottom: 2rem;
+  }
+}
 </style>
diff --git a/packages/theme/src/client/utils/dom.ts b/packages/theme/src/client/utils/dom.ts
index 0b2eabe0..df97a0d4 100644
--- a/packages/theme/src/client/utils/dom.ts
+++ b/packages/theme/src/client/utils/dom.ts
@@ -11,7 +11,12 @@ export function getScrollTop(
   target: Document | HTMLElement = document
 ): number {
   if (target === document || !target) {
-    return document.documentElement.scrollTop || document.body.scrollTop
+    return (
+      window.pageYOffset ||
+      document.documentElement.scrollTop ||
+      document.body.scrollTop ||
+      0
+    )
   } else {
     return (target as HTMLElement).scrollTop
   }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 64052f57..53c3fe9e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -30,6 +30,7 @@ importers:
       nanoid: ^3.3.2
       sass: ^1.49.9
       sass-loader: ^12.6.0
+      ts-debounce: ^4.0.0
       vue: ^3.2.33
       vue-router: ^4.0.14
       vuepress-plugin-comment2: 2.0.0-beta.47
@@ -65,6 +66,7 @@ importers:
       nanoid: 3.3.3
       sass: 1.51.0
       sass-loader: 12.6.0_sass@1.51.0
+      ts-debounce: 4.0.0
       vue: 3.2.33
       vue-router: 4.0.14_vue@3.2.33
       vuepress-plugin-comment2: 2.0.0-beta.47