diff --git a/lib/default-theme/Layout.vue b/lib/default-theme/Layout.vue
index df34ba7deeec4cc9beee45083380669f9b718ba6..9ee3803a3ca038d42d454e4cd51bbe4ac2c9ba5d 100644
--- a/lib/default-theme/Layout.vue
+++ b/lib/default-theme/Layout.vue
@@ -1,24 +1,6 @@
 <template>
   <div class="theme-container">
-    <div class="sidebar">
-      <ul>
-        <li v-for="item in sidebarItems">
-          <router-link v-if="item.type === 'page'" :to="item.path">
-            {{ item.title || item.path }}
-          </router-link>
-          <div class="sidebar-group" v-else-if="item.type === 'heading'">
-            <p class="sidebar-heading">{{ item.title }}</p>
-            <ul>
-              <li v-for="child in item.children">
-                <router-link v-if="child.type === 'page'" :to="child.path">
-                  {{ child.title || child.path }}
-                </router-link>
-              </li>
-            </ul>
-          </div>
-        </li>
-      </ul>
-    </div>
+    <SideBar/>
     <Index v-if="$page.path === '/index'" />
     <Page v-else />
   </div>
@@ -28,18 +10,10 @@
 import nprogress from 'nprogress'
 import Index from './Index.vue'
 import Page from './Page.vue'
-import resolveSidebar from './resolveSidebar'
+import SideBar from './SideBar.vue'
 
 export default {
-  components: { Index, Page },
-  computed: {
-    sidebarItems () {
-      return resolveSidebar(
-        this.$route,
-        this.$site
-      )
-    }
-  },
+  components: { Index, Page, SideBar },
   mounted () {
     nprogress.configure({ showSpinner: false })
 
@@ -57,6 +31,5 @@ export default {
 }
 </script>
 
-<style src="./nprogress.css"></style>
 <style src="prismjs/themes/prism-tomorrow.css"></style>
-<style src="./theme.stylus" lang="stylus"></style>
+<style src="./styles/theme.stylus" lang="stylus"></style>
diff --git a/lib/default-theme/SideBar.vue b/lib/default-theme/SideBar.vue
new file mode 100644
index 0000000000000000000000000000000000000000..af2b1a73434f0fdccda72a360ec81e457c885abc
--- /dev/null
+++ b/lib/default-theme/SideBar.vue
@@ -0,0 +1,143 @@
+<template>
+  <div class="sidebar">
+    <ul>
+      <li v-for="(item, i) in sidebarItems">
+        <router-link v-if="item.type === 'page'" :to="item.path">
+          {{ item.title || item.path }}
+        </router-link>
+        <div v-else-if="item.type === 'heading'"
+          class="sidebar-group"
+          :class="{ first: i === 0 }">
+          <p class="sidebar-heading">{{ item.title }}</p>
+          <ul>
+            <li v-for="child in item.children">
+              <router-link v-if="child.type === 'page'" :to="child.path">
+                {{ child.title || child.path }}
+              </router-link>
+            </li>
+          </ul>
+        </div>
+      </li>
+    </ul>
+  </div>
+</template>
+
+<script>
+function resolveSidebar (route, site) {
+  const { pages, themeConfig } = site
+  const sidebarConfig = themeConfig.sidebar
+  if (!sidebarConfig) {
+    return pages
+  } else {
+    const matchingConfig = Array.isArray(sidebarConfig)
+      ? sidebarConfig
+      : resolveMatchingSidebar(route, sidebarConfig)
+    return matchingConfig.map(item => resolveItem(item, site.pages))
+  }
+}
+
+function resolveMatchingSidebar (route, sidebarConfig) {
+  for (const base in sidebarConfig) {
+    if (ensureEndingSlash(route.path).indexOf(base) === 0) {
+      return sidebarConfig[base]
+    }
+  }
+}
+
+function ensureEndingSlash (path) {
+  return /(\.html|\/)$/.test(path)
+    ? path
+    : path + '/'
+}
+
+function resolveItem (item, pages) {
+  if (typeof item === 'string') {
+    return resolvePage(pages, item)
+  } else if (Array.isArray(item)) {
+    return Object.assign(resolvePage(pages, item[0]), {
+      title: item[1]
+    })
+  } else {
+    const children = item.children || []
+    return {
+      type: 'heading',
+      title: item.title,
+      children: children.map(child => resolveItem(child, pages)),
+      collapsable: children.length && item.collapsable
+    }
+  }
+}
+
+function resolvePage (pages, rawPath) {
+  const path = normalize(rawPath)
+  for (let i = 0; i < pages.length; i++) {
+    if (normalize(pages[i].path) === path) {
+      return Object.assign({}, pages[i], {
+        type: 'page',
+        path: ensureExt(rawPath)
+      })
+    }
+  }
+}
+
+const hashRE = /#.*$/
+const extRE = /\.(md|html)$/
+const slashRE = /\/$/
+
+function normalize (path) {
+  return path
+    .replace(hashRE, '')
+    .replace(extRE, '')
+}
+
+function ensureExt (path) {
+  if (slashRE.test(path)) {
+    return path
+  }
+  const hashMatch = path.match(hashRE)
+  const hash = hashMatch ? hashMatch[0] : ''
+  return normalize(path) + '.html' + hash
+}
+
+export default {
+  computed: {
+    sidebarItems () {
+      return resolveSidebar(
+        this.$route,
+        this.$site
+      )
+    }
+  }
+}
+</script>
+
+<style lang="stylus">
+@import './styles/config.stylus'
+
+.sidebar
+  ul
+    padding 0
+    margin 0
+    list-style-type none
+  a
+    display inline-block
+    color $textColor
+    border-left 0.25rem solid transparent
+    padding 0.25rem
+    padding-left 1.25rem
+    &:hover
+      color $accentColor
+    &.router-link-active
+      font-weight 600
+      color $accentColor
+      border-left-color $accentColor
+  .sidebar-group:not(.first)
+    margin-top 1.5rem
+  .sidebar-heading
+    font-size 1.1em
+    font-weight bold
+    text-transform uppercase
+    padding-left 1.5rem
+    margin-top 0
+    margin-bottom 0.5rem
+</style>
diff --git a/lib/default-theme/nprogress.css b/lib/default-theme/nprogress.css
deleted file mode 100644
index 66d782d95685d6a86cb95ff5e4588787ae0b7061..0000000000000000000000000000000000000000
--- a/lib/default-theme/nprogress.css
+++ /dev/null
@@ -1,78 +0,0 @@
-/*
-  Copied from nprogress since it doens't
-  allow programmatic configuration of color
-*/
-
-/* Make clicks pass-through */
-#nprogress {
-  pointer-events: none;
-}
-
-#nprogress .bar {
-  background: #41b883;
-
-  position: fixed;
-  z-index: 1031;
-  top: 0;
-  left: 0;
-
-  width: 100%;
-  height: 2px;
-}
-
-/* Fancy blur effect */
-#nprogress .peg {
-  display: block;
-  position: absolute;
-  right: 0px;
-  width: 100px;
-  height: 100%;
-  box-shadow: 0 0 10px #41b883, 0 0 5px #41b883;
-  opacity: 1.0;
-
-  -webkit-transform: rotate(3deg) translate(0px, -4px);
-      -ms-transform: rotate(3deg) translate(0px, -4px);
-          transform: rotate(3deg) translate(0px, -4px);
-}
-
-/* Remove these to get rid of the spinner */
-#nprogress .spinner {
-  display: block;
-  position: fixed;
-  z-index: 1031;
-  top: 15px;
-  right: 15px;
-}
-
-#nprogress .spinner-icon {
-  width: 18px;
-  height: 18px;
-  box-sizing: border-box;
-
-  border: solid 2px transparent;
-  border-top-color: #41b883;
-  border-left-color: #41b883;
-  border-radius: 50%;
-
-  -webkit-animation: nprogress-spinner 400ms linear infinite;
-          animation: nprogress-spinner 400ms linear infinite;
-}
-
-.nprogress-custom-parent {
-  overflow: hidden;
-  position: relative;
-}
-
-.nprogress-custom-parent #nprogress .spinner,
-.nprogress-custom-parent #nprogress .bar {
-  position: absolute;
-}
-
-@-webkit-keyframes nprogress-spinner {
-  0%   { -webkit-transform: rotate(0deg); }
-  100% { -webkit-transform: rotate(360deg); }
-}
-@keyframes nprogress-spinner {
-  0%   { transform: rotate(0deg); }
-  100% { transform: rotate(360deg); }
-}
diff --git a/lib/default-theme/resolveSidebar.js b/lib/default-theme/resolveSidebar.js
deleted file mode 100644
index 429f5ca4aef061acd74bd6637e10ddbbe2455ea5..0000000000000000000000000000000000000000
--- a/lib/default-theme/resolveSidebar.js
+++ /dev/null
@@ -1,53 +0,0 @@
-export default function resolveSidebar (route, site) {
-  const { pages, themeConfig } = site
-  const sidebarConfig = themeConfig.sidebar
-  if (!sidebarConfig) {
-    return pages
-  } else {
-    const matchingConfig = Array.isArray(sidebarConfig)
-      ? sidebarConfig
-      : resolveMatchingSidebar(route, sidebarConfig)
-    return matchingConfig.map(item => resolveItem(item, site.pages))
-  }
-}
-
-function resolveMatchingSidebar (route, sidebarConfig) {
-  for (const base in sidebarConfig) {
-    if (ensureEndingSlash(route.path).indexOf(base) === 0) {
-      return sidebarConfig[base]
-    }
-  }
-}
-
-function ensureEndingSlash (path) {
-  return /(\.html|\/)$/.test(path)
-    ? path
-    : path + '/'
-}
-
-function resolveItem (item, pages) {
-  if (typeof item === 'string') {
-    return Object.assign({ type: 'page' }, findPage(pages, item))
-  } else if (Array.isArray(item)) {
-    return {
-      type: 'heading',
-      title: item[0],
-      children: (item[1] || []).map(child => resolveItem(child, pages))
-    }
-  } else {
-    throw new Error(`Invalid sidebar item config: ${item}`)
-  }
-}
-
-function findPage (pages, path) {
-  path = normalize(path)
-  for (let i = 0; i < pages.length; i++) {
-    if (normalize(pages[i].path) === path) {
-      return pages[i]
-    }
-  }
-}
-
-function normalize (path) {
-  return path.replace(/\.(md|html)$/, '')
-}
diff --git a/lib/default-theme/styles/config.stylus b/lib/default-theme/styles/config.stylus
new file mode 100644
index 0000000000000000000000000000000000000000..dd47d37e50701497333163e84763fcb90356fcfe
--- /dev/null
+++ b/lib/default-theme/styles/config.stylus
@@ -0,0 +1,6 @@
+$textColor = #2c3e50
+$accentColor = darken(#41b883, 5%)
+$borderColor = #eaecef
+$codeBgColor = #282c34
+$sidebarWidth = 20rem
+$contentWidth = 760px
diff --git a/lib/default-theme/styles/nprogress.stylus b/lib/default-theme/styles/nprogress.stylus
new file mode 100644
index 0000000000000000000000000000000000000000..4fdf83a2f735098799d4edbfb517b324f65d9d4c
--- /dev/null
+++ b/lib/default-theme/styles/nprogress.stylus
@@ -0,0 +1,46 @@
+#nprogress
+  pointer-events none
+  .bar
+    background $accentColor
+    position fixed
+    z-index 1031
+    top 0
+    left 0
+    width 100%
+    height 2px
+  .peg
+    display block
+    position absolute
+    right 0px
+    width 100px
+    height 100%
+    box-shadow 0 0 10px $accentColor, 0 0 5px $accentColor
+    opacity 1.0
+    transform rotate(3deg) translate(0px, -4px)
+  .spinner
+    display block
+    position fixed
+    z-index 1031
+    top 15px
+    right 15px
+  .spinner-icon
+    width 18px
+    height 18px
+    box-sizing border-box
+    border solid 2px transparent
+    border-top-color $accentColor
+    border-left-color $accentColor
+    border-radius 50%
+    animation nprogress-spinner 400ms linear infinite
+
+.nprogress-custom-parent
+  overflow hidden
+  position relative
+
+.nprogress-custom-parent #nprogress .spinner,
+.nprogress-custom-parent #nprogress .bar
+  position absolute
+
+@keyframes nprogress-spinner
+  0% transform rotate(0deg)
+  100% transform rotate(360deg)
diff --git a/lib/default-theme/theme.stylus b/lib/default-theme/styles/theme.stylus
similarity index 60%
rename from lib/default-theme/theme.stylus
rename to lib/default-theme/styles/theme.stylus
index f470f5167aa82471bf76ce37ffa07eff4c3f99c1..9085d6151d78f668bae5bb8985d2d25f238ed856 100644
--- a/lib/default-theme/theme.stylus
+++ b/lib/default-theme/styles/theme.stylus
@@ -1,58 +1,46 @@
+@import './config.stylus'
+@import './nprogress.stylus'
+
 body
   font-family -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif
   -webkit-font-smoothing antialiased
   -moz-osx-font-smoothing grayscale
   font-size 16px
-  color #2c3e50
+  color $textColor
 
 .page
-  padding-left 300px
+  padding-left $sidebarWidth
 
 .sidebar
-  width 300px
+  font-size 15px
+  width $sidebarWidth
   position fixed
   margin 0
   top 0
   left 0
   bottom 0
-  padding 2em 0
+  padding 2rem 0
   box-sizing border-box
-  border-right 1px solid #eaecef
+  border-right 1px solid $borderColor
   overflow-y scroll
-  ul
-    padding 0
-    margin 0
-    list-style-type none
-  a
-    display inline-block
-    color #2c3e50
-    border-left 4px solid transparent
-    padding 0.25em
-    padding-left 1.25em
-    &:hover
-      color darken(#41b883, 5%)
-    &.router-link-active
-      font-weight 600
-      color darken(#41b883, 5%)
-      border-left-color darken(#41b883, 5%)
 
 .markdown
   max-width 760px
-  margin 2em auto
-  padding 0 2em
+  margin 2rem auto
+  padding 0 2rem
 
 blockquote
-  font-size 1.25em
+  font-size 1.25rem
   color #999
-  border-left .25em solid #dfe2e5
+  border-left .25rem solid #dfe2e5
   margin-left 0
-  padding-left 1em
+  padding-left 1rem
 
 ul, ol
-  padding-left 1.5em
+  padding-left 1.5rem
 
 a, p a code
-  color darken(#41b883, 5%)
+  color $accentColor
   text-decoration none
 
 strong
@@ -62,20 +50,20 @@ h1, h2, h3, h4, h5, h6
   font-weight 600
   line-height 1.25
   &:not(:first-child)
-    margin-top 1.5em
+    margin-top 1.5rem
   &:hover .header-anchor
     opacity: 1
 
 h1
-  font-size 2.3em
+  font-size 2.3rem
 
 h2
-  font-size 1.8em
-  padding-bottom .3em
-  border-bottom 1px solid #eaecef
+  font-size 1.8rem
+  padding-bottom .3rem
+  border-bottom 1px solid $borderColor
 
 h3
-  font-size 1.4em
+  font-size 1.4rem
 
 a.header-anchor
   font-size 0.85em
@@ -93,42 +81,43 @@ p, ul, ol
 
 p, h1, h2, h3, h4, h5, h6
   code
-    padding 0.2em 0.5em
+    padding 0.2rem 0.5rem
     margin 0
-    font-size 0.85em
+    font-size 0.85rem
     background-color rgba(27,31,35,0.05)
     border-radius 3px
 
 p code
-  color lighten(#2c3e50, 20%)
+  color lighten($textColor, 20%)
 
 pre, pre[class*="language-"]
-  background-color #2d2d2d
-  color white
+  background-color $codeBgColor
+  color #fff
   line-height 1.4
   border-radius 6px
-  padding 1.4em 1.6em
+  padding 1.25rem 1.5rem
   white-space pre-wrap
   word-break break-word
   overflow auto
   code
-    font-size 0.85em
+    font-size 0.85rem
 
 .highlighted-line
-  background-color #14161a
+  background-color rgba(0, 0, 0, 66%)
   display block
-  margin 0 -1.6em
-  padding 0.2em 1.6em 0
+  margin 0.1rem -1.8rem 0
+  padding 0.1rem 1.8rem
 
 .custom-block
   .custom-block-title
     font-weight 600
     text-transform uppercase
+    margin-bottom -0.4rem
   &.tip, &.warning, &.danger
-    padding .1em 1.4em
-    border-left-width .5em
+    padding .1rem 1.5rem
+    border-left-width .5rem
     border-left-style solid
-    margin 1em 0
+    margin 1rem 0
   &.tip
     background-color #f3f5f7
     border-color #42b983
@@ -147,30 +136,41 @@ pre, pre[class*="language-"]
 
 p
   &.demo
-    padding 1rem
+    padding 1rem 1.5rem
     border 1px solid #ddd
     border-radius 4px
 
+$mobileSidebarWidth = $sidebarWidth * 0.82
+
+// narrow desktop / iPad
 @media (max-width: 959px)
   body
     font-size 15px
   .sidebar
     font-size 14px
-    width 250px
+    width $mobileSidebarWidth
   .page
-    padding-left 250px
+    padding-left $mobileSidebarWidth
   .markdown
-    margin 1.5em 0
-    padding 0 1.5em
+    margin 1.5rem 0
+    padding 0 1.5rem
 
+// wide mobile
 @media (max-width: 719px)
   body
     font-size 15px
   .sidebar
-    width 275px
+    font-size 14px
+    width $mobileSidebarWidth
     display none
   .page
     padding-left 0
   .markdown
-    margin 1em 0
-    padding 0 1em
+    margin 1rem 0
+    padding 0 1rem
+
+// narrow mobile
+@media (max-width: 419px)
+  pre, pre[class*="language-"]
+    margin 0 -1.5rem
+    border-radius 0