fix(theme): remove extra padding from top when navbar is hidden (#2575)

Co-authored-by: Divyansh Singh <40380293+brc-dd@users.noreply.github.com>

Author: buqiyuan

src/client/theme-default/Layout.vue

@@ -35,7 +35,7 @@ provide('hero-image-slot-exists', heroImageSlotExists)
     <slot name="layout-top" />
     <VPSkipLink />
     <VPBackdrop class="backdrop" :show="isSidebarOpen" @click="closeSidebar" />
-    <VPNav v-if="frontmatter.navbar !== false">
+    <VPNav>
       <template #nav-bar-title-before><slot name="nav-bar-title-before" /></template>
       <template #nav-bar-title-after><slot name="nav-bar-title-after" /></template>
       <template #nav-bar-content-before><slot name="nav-bar-content-before" /></template>

src/client/theme-default/components/VPNav.vue

@@ -1,16 +1,29 @@
 <script setup lang="ts">
-import { provide } from 'vue'
+import { inBrowser } from 'vitepress'
+import { computed, provide, watchEffect } from 'vue'
+import { useData } from '../composables/data'
 import { useNav } from '../composables/nav'
 import VPNavBar from './VPNavBar.vue'
 import VPNavScreen from './VPNavScreen.vue'
 
 const { isScreenOpen, closeScreen, toggleScreen } = useNav()
+const { frontmatter } = useData()
+
+const hasNavbar = computed(() => {
+  return frontmatter.value.navbar !== false
+})
 
 provide('close-screen', closeScreen)
+
+watchEffect(() => {
+  if (inBrowser) {
+    document.documentElement.classList.toggle('hide-nav', !hasNavbar.value)
+  }
+})
 </script>
 
 <template>
-  <header class="VPNav">
+  <header v-if="hasNavbar" class="VPNav">
     <VPNavBar :is-screen-open="isScreenOpen" @toggle-screen="toggleScreen">
       <template #nav-bar-title-before><slot name="nav-bar-title-before" /></template>
       <template #nav-bar-title-after><slot name="nav-bar-title-after" /></template>

src/client/theme-default/styles/vars.css

@@ -426,6 +426,14 @@
   --vp-nav-logo-height: 24px;
 }
 
+.hide-nav {
+  --vp-nav-height: 0px;
+}
+
+.hide-nav .VPSidebar {
+  --vp-nav-height: 22px;
+}
+
 /**
  * Component: Local Nav
  * -------------------------------------------------------------------------- */