diff --git a/browser/components/MarkdownPreview.js b/browser/components/MarkdownPreview.js
index 5376a773..493b1fc4 100755
--- a/browser/components/MarkdownPreview.js
+++ b/browser/components/MarkdownPreview.js
@@ -738,10 +738,17 @@ export default class MarkdownPreview extends React.Component {
         try {
           const chartConfig = JSON.parse(el.innerHTML)
           el.innerHTML = ''
-          var canvas = document.createElement('canvas')
+
+          const canvas = document.createElement('canvas')
           el.appendChild(canvas)
-          /* eslint-disable no-new */
-          new Chart(canvas, chartConfig)
+
+          const height = el.attributes.getNamedItem('data-height')
+          if (height && height.value !== 'undefined') {
+            el.style.height = height.value + 'vh'
+            canvas.height = height.value + 'vh'
+          }
+
+          const chart = new Chart(canvas, chartConfig)
         } catch (e) {
           console.error(e)
           el.className = 'chart-error'
diff --git a/browser/components/markdown.styl b/browser/components/markdown.styl
index fb30742d..ea46b0b6 100644
--- a/browser/components/markdown.styl
+++ b/browser/components/markdown.styl
@@ -213,10 +213,12 @@ pre
   margin 0 0 1em
   display flex
   line-height 1.4em
-  &.flowchart, &.sequence, &.chart
-    display flex
-    justify-content center
-    background-color white
+  code
+    background-color inherit
+    margin 0
+    padding 0
+    border none
+    border-radius 0
   &.CodeMirror
     height initial
     flex-wrap wrap
@@ -230,12 +232,12 @@ pre
     border none
     border-radius 0
   &>span.filename
-    width 100%
-    border-radius: 5px 0px 0px 0px
-    margin -8px 100% 8px -8px
-    padding 0px 6px
+    margin -8px -7px 8px -8px
+    padding 2px 6px
     background-color #777;
     color white
+    &:empty
+      display none
   &>span.lineNumber
     display none
     font-size 1em
@@ -361,7 +363,7 @@ for name, val in admonition_types
     .admonition.{name}
         @extend $admonition
         border-left-color: val[color]
-    
+
     .admonition.{name}>.admonition-title
         @extend $admonition-title
         border-bottom-color: .1rem solid rgba(val[color], 0.2)
@@ -372,6 +374,18 @@ for name, val in admonition_types
         color: val[color]
         content: val[icon]
 
+pre.fence
+  flex-direction column
+
+  .chart, .flowchart, .mermaid, .sequence
+    display flex
+    justify-content center
+    background-color white
+    max-width 100%
+
+    canvas, svg
+      max-width 100% !important
+
 themeDarkBackground = darken(#21252B, 10%)
 themeDarkText = #f9f9f9
 themeDarkBorder = lighten(themeDarkBackground, 20%)
diff --git a/browser/components/render/MermaidRender.js b/browser/components/render/MermaidRender.js
index bac52b2c..f04d8cd0 100644
--- a/browser/components/render/MermaidRender.js
+++ b/browser/components/render/MermaidRender.js
@@ -2,8 +2,8 @@ import mermaidAPI from 'mermaid'
 
 // fixes bad styling in the mermaid dark theme
 const darkThemeStyling = `
-.loopText tspan { 
-  fill: white; 
+.loopText tspan {
+  fill: white;
 }`
 
 function getRandomInt (min, max) {
@@ -11,9 +11,9 @@ function getRandomInt (min, max) {
 }
 
 function getId () {
-  var pool = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
-  var id = 'm-'
-  for (var i = 0; i < 7; i++) {
+  const pool = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
+  let id = 'm-'
+  for (let i = 0; i < 7; i++) {
     id += pool[getRandomInt(0, 16)]
   }
   return id
@@ -21,14 +21,18 @@ function getId () {
 
 function render (element, content, theme) {
   try {
+    const height = element.attributes.getNamedItem('data-height')
+    if (height && height.value !== 'undefined') {
+      element.style.height = height.value + 'vh'
+    }
     let isDarkTheme = theme === 'dark' || theme === 'solarized-dark' || theme === 'monokai'
     mermaidAPI.initialize({
       theme: isDarkTheme ? 'dark' : 'default',
-      themeCSS: isDarkTheme ? darkThemeStyling : ''
+      themeCSS: isDarkTheme ? darkThemeStyling : '',
+      useMaxWidth: false
     })
     mermaidAPI.render(getId(), content, (svgGraph) => {
       element.innerHTML = svgGraph
-      element.style.height = element.attributes.getNamedItem('data-height').value + 'vh'
     })
   } catch (e) {
     console.error(e)
diff --git a/browser/lib/markdown-it-fence.js b/browser/lib/markdown-it-fence.js
new file mode 100644
index 00000000..040ac540
--- /dev/null
+++ b/browser/lib/markdown-it-fence.js
@@ -0,0 +1,130 @@
+'use strict'
+
+module.exports = function (md, renderers, defaultRenderer) {
+  function fence (state, startLine, endLine) {
+    let pos = state.bMarks[startLine] + state.tShift[startLine]
+    let max = state.eMarks[startLine]
+
+    if (state.sCount[startLine] - state.blkIndent >= 4 || pos + 3 > max) {
+      return false
+    }
+
+    const marker = state.src.charCodeAt(pos)
+    if (!(marker === 96 || marker === 126)) {
+      return false
+    }
+
+    let mem = pos
+    pos = state.skipChars(pos, marker)
+
+    let len = pos - mem
+    if (len < 3) {
+      return false
+    }
+
+    const markup = state.src.slice(mem, pos)
+    const params = state.src.slice(pos, max)
+
+    let nextLine = startLine
+    let haveEndMarker = false
+
+    while (true) {
+      nextLine++
+      if (nextLine >= endLine) {
+        break
+      }
+
+      pos = mem = state.bMarks[nextLine] + state.tShift[nextLine]
+      max = state.eMarks[nextLine]
+
+      if (pos < max && state.sCount[nextLine] < state.blkIndent) {
+        break
+      }
+      if (state.src.charCodeAt(pos) !== marker || state.sCount[nextLine] - state.blkIndent >= 4) {
+        continue
+      }
+
+      pos = state.skipChars(pos, marker)
+
+      if (pos - mem < len) {
+        continue
+      }
+
+      pos = state.skipSpaces(pos)
+
+      if (pos >= max) {
+        haveEndMarker = true
+        break
+      }
+    }
+
+    len = state.sCount[startLine]
+    state.line = nextLine + (haveEndMarker ? 1 : 0)
+
+    const parameters = {}
+    let langType = ''
+    let fileName = ''
+    let firstLineNumber = 0
+
+    let match = /^(\w[-\w]*)?(?:\(((?:\s*\w[-\w]*(?:=(?:'(?:.*?[^\\])?'|"(?:.*?[^\\])?"|(?:[^'"][^\s]*)))?)*)\))?(?::([^:]*)(?::(\d+))?)?\s*$/.exec(params)
+    if (match) {
+      if (match[1]) {
+        langType = match[1]
+      }
+      if (match[3]) {
+        fileName = match[3]
+      }
+      if (match[4]) {
+        firstLineNumber = parseInt(match[4], 10)
+      }
+
+      if (match[2]) {
+        const params = match[2]
+        const regex = /(\w[-\w]*)(?:=(?:'(.*?[^\\])?'|"(.*?[^\\])?"|([^'"][^\s]*)))?/g
+
+        let name, value
+        while ((match = regex.exec(params))) {
+          name = match[1]
+          value = match[2] || match[3] || match[4] || null
+
+          const height = /^(\d+)h$/.exec(name)
+          if (height && !value) {
+            parameters.height = height[1]
+          } else {
+            parameters[name] = value
+          }
+        }
+      }
+    }
+
+    let token
+    if (renderers[langType]) {
+      token = state.push(`${langType}_fence`, 'div', 0)
+    } else {
+      token = state.push('_fence', 'code', 0)
+    }
+
+    token.langType = langType
+    token.fileName = fileName
+    token.firstLineNumber = firstLineNumber
+    token.parameters = parameters
+
+    token.content = state.getLines(startLine + 1, nextLine, len, true)
+    token.markup = markup
+    token.map = [startLine, state.line]
+
+    return true
+  }
+
+  md.block.ruler.before('fence', '_fence', fence, {
+    alt: ['paragraph', 'reference', 'blockquote', 'list']
+  })
+
+  for (let name in renderers) {
+    md.renderer.rules[`${name}_fence`] = (tokens, index) => renderers[name](tokens[index])
+  }
+
+  if (defaultRenderer) {
+    md.renderer.rules['_fence'] = (tokens, index) => defaultRenderer(tokens[index])
+  }
+}
diff --git a/browser/lib/markdown.js b/browser/lib/markdown.js
index d4bc72e4..40c47aac 100644
--- a/browser/lib/markdown.js
+++ b/browser/lib/markdown.js
@@ -27,32 +27,6 @@ class Markdown {
       html: true,
       xhtmlOut: true,
       breaks: config.preview.breaks,
-      highlight: function (str, lang) {
-        const delimiter = ':'
-        const langInfo = lang.split(delimiter)
-        const langType = langInfo[0]
-        const fileName = langInfo[1] || ''
-        const firstLineNumber = parseInt(langInfo[2], 10)
-
-        if (langType === 'flowchart') {
-          return `<pre class="flowchart">${str}</pre>`
-        }
-        if (langType === 'sequence') {
-          return `<pre class="sequence">${str}</pre>`
-        }
-        if (langType === 'chart') {
-          return `<pre class="chart">${str}</pre>`
-        }
-        if (langType === 'mermaid') {
-          return `<pre class="mermaid" data-height="${fileName}">${str}</pre>`
-        }
-        return '<pre class="code CodeMirror">' +
-          '<span class="filename">' + fileName + '</span>' +
-          createGutter(str, firstLineNumber) +
-          '<code class="' + langType + '">' +
-          str +
-          '</code></pre>'
-      },
       sanitize: 'STRICT'
     }
 
@@ -150,6 +124,39 @@ class Markdown {
     this.md.use(require('markdown-it-kbd'))
     this.md.use(require('markdown-it-admonition'))
 
+    this.md.use(require('./markdown-it-fence'), {
+      chart: token => {
+        return `<pre class="fence">
+          <span class="filename">${token.fileName}</span>
+          <div class="chart" data-height="${token.parameters.height}">${token.content}</div>
+        </pre>`
+      },
+      flowchart: token => {
+        return `<pre class="fence">
+          <span class="filename">${token.fileName}</span>
+          <div class="flowchart" data-height="${token.parameters.height}">${token.content}</div>
+        </pre>`
+      },
+      mermaid: token => {
+        return `<pre class="fence">
+          <span class="filename">${token.fileName}</span>
+          <div class="mermaid" data-height="${token.parameters.height}">${token.content}</div>
+        </pre>`
+      },
+      sequence: token => {
+        return `<pre class="fence">
+          <span class="filename">${token.fileName}</span>
+          <div class="sequence" data-height="${token.parameters.height}">${token.content}</div>
+        </pre>`
+      }
+    }, token => {
+      return `<pre class="code CodeMirror">
+        <span class="filename">${token.fileName}</span>
+        ${createGutter(token.content, token.firstLineNumber)}
+        <code class="${token.langType}">${token.content}</code>
+      </pre>`
+    })
+
     const deflate = require('markdown-it-plantuml/lib/deflate')
     this.md.use(require('markdown-it-plantuml'), '', {
       generateSource: function (umlCode) {