diff --git a/lib/default-theme/NotFound.vue b/lib/default-theme/NotFound.vue
index 6aefe797c4..ed2c0e27c5 100644
--- a/lib/default-theme/NotFound.vue
+++ b/lib/default-theme/NotFound.vue
@@ -1,6 +1,6 @@
 <template>
   <div class="theme-container">
-    <div class="content">
+    <div id="content">
       <h1>404</h1>
       <blockquote>{{ getMsg() }}</blockquote>
       <router-link to="/">Take me home.</router-link>
diff --git a/lib/default-theme/styles/code.styl b/lib/default-theme/styles/code.styl
index fb5a8037f0..880b9fb3da 100644
--- a/lib/default-theme/styles/code.styl
+++ b/lib/default-theme/styles/code.styl
@@ -1,6 +1,6 @@
 @require './config'
 
-.content
+#content
   code
     color lighten($textColor, 20%)
     padding 0.25rem 0.5rem
@@ -9,7 +9,7 @@
     background-color rgba(27,31,35,0.05)
     border-radius 3px
 
-.content
+#content
   pre, pre[class*="language-"]
     line-height 1.4
     padding 1.25rem 1.5rem
diff --git a/lib/default-theme/styles/mobile.styl b/lib/default-theme/styles/mobile.styl
index b35e59c588..d939b584b9 100644
--- a/lib/default-theme/styles/mobile.styl
+++ b/lib/default-theme/styles/mobile.styl
@@ -31,7 +31,7 @@ $mobileSidebarWidth = $sidebarWidth * 0.82
 @media (max-width: $MQMobileNarrow)
   h1
     font-size 1.9rem
-  .content
+  #content
     div[class*="language-"]
       margin 0.85rem -1.5rem
       border-radius 0
diff --git a/lib/default-theme/styles/theme.styl b/lib/default-theme/styles/theme.styl
index a733861fa6..9443b3c830 100644
--- a/lib/default-theme/styles/theme.styl
+++ b/lib/default-theme/styles/theme.styl
@@ -54,7 +54,7 @@ body
   border-right 1px solid $borderColor
   overflow-y auto
 
-.content:not(.custom)
+#content:not(.custom)
   @extend $wrapper
   > *:first-child
     margin-top $navbarHeight
@@ -67,7 +67,7 @@ body
   img
     max-width 100%
 
-.content.custom
+#content.custom
   padding 0
   margin 0
   img
@@ -105,7 +105,7 @@ strong
 h1, h2, h3, h4, h5, h6
   font-weight 600
   line-height 1.25
-  .content:not(.custom) > &
+  #content:not(.custom) > &
     margin-top (0.5rem - $navbarHeight)
     padding-top ($navbarHeight + 1rem)
     margin-bottom 0
@@ -171,7 +171,7 @@ th, td
     .sidebar-mask
       display: block
   &.no-navbar
-    .content:not(.custom) > h1, h2, h3, h4, h5, h6
+    #content:not(.custom) > h1, h2, h3, h4, h5, h6
         margin-top 1.5rem
         padding-top 0
     .sidebar
diff --git a/lib/webpack/markdownLoader.js b/lib/webpack/markdownLoader.js
index 3c49b747f6..b12bf12f70 100644
--- a/lib/webpack/markdownLoader.js
+++ b/lib/webpack/markdownLoader.js
@@ -82,7 +82,7 @@ module.exports = function (src) {
 
   const res = (
     `<template>\n` +
-      `<div class="content">${html}</div>\n` +
+      `<div id="content">${html}</div>\n` +
     `</template>\n` +
     (hoistedTags || []).join('\n')
   )