diff --git a/app/assets/javascripts/app.js b/app/assets/javascripts/app.js
index 35fc7f5..4e16a35 100644
--- a/app/assets/javascripts/app.js
+++ b/app/assets/javascripts/app.js
@@ -33,4 +33,11 @@ $(function(){
       $('img').css('transform', 'rotate(180deg)');
     }
   });
+  $('pre code').each(function() {
+    if ($(this).attr("class")) {
+      $(this).parent().attr("lang", $(this).attr("class").replace("hljs", "").trim());
+    } else {
+      $(this).parent().attr("lang", "(language unknown)")
+    }
+  });
 });
\ No newline at end of file
diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index 650ac36..a2e29b5 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -3,5 +3,5 @@
  *= require style.css
  *= require screen.css
  *= require mobi.css
- *= require highlight/default.css
+ *= require highlight/tomorrow-night.css
  */
\ No newline at end of file
diff --git a/app/assets/stylesheets/screen.css.scss b/app/assets/stylesheets/screen.css.scss
index 83dc9ce..4616849 100644
--- a/app/assets/stylesheets/screen.css.scss
+++ b/app/assets/stylesheets/screen.css.scss
@@ -230,11 +230,9 @@ and (min-width: 0px) //TODO
   }
 
   pre {
-    background: #3F3F3F;
     border-radius: 2px;
-    box-shadow: 0 0 16px #222 inset;
     position: relative;
-    padding: 1em;
+    background: #3F3F3F;
     &:after {
       color: #fff;
       content: attr(lang); // show language on top right
@@ -252,17 +250,20 @@ and (min-width: 0px) //TODO
       right: 0;
     }
     code {
-      background: transparent;
       padding: 0;
+      box-shadow: 0 0 16px #222 inset;
+      background: #3F3F3F !important;
+      border: none;
+      border-radius: 3px;
     }
   }
 
   code {
-    background: #3F3F3F;
-    padding: 0 2px;
-    border-radius: 3px;
-    color: #ddd;
-    text-shadow: 1px 1px #000;
+    background: #A2A2A2;
+    padding: 2px 5px 2px 2px;
+    border-radius: 0 3px 3px 0;
+    color: #000;
+    border-left: 3px solid #3F3F3F;
   }
 
   table, tr, td, th {
@@ -271,10 +272,10 @@ and (min-width: 0px) //TODO
 
   blockquote {
     background: #F9F9F9;
-    border-left: 10px solid #3F3F3F;
+    border-left: 3px solid #3F3F3F;
     display: inline-block;
-    margin: 0 0 0 2em;
-    padding: 0.5em 3em 0 10px;
+    margin: 0;
+    padding: 2px 5px 2px 2px;
   }
 
   blockquote p {
@@ -598,8 +599,17 @@ and (min-width: 0px) //TODO
     font-weight: bold;
   }
 
-  del {
-    background: rgba(255, 200, 200, 0.5);
+  iframe.youtube {
+    border: none;
+    width: 640px;
+    max-width: 100%;
+    height: 360px;
+  }
+
+  mark {
+    background: #faa;
+    padding: 0 2px;
+    border-radius: 3px;
   }
 
   .comment-counter {
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 89b444d..5444ac9 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -32,11 +32,12 @@ module ApplicationHelper
       lax_spacing: true,
       disable_indented_code_blocks: false,
       space_after_headers: false,
+      superscript: true,
       underline: true,
       highlight: true,
       footnotes: true
     })
-    md.render(content)
+    render_youtube(md.render(content))
   end
 
   def render_mini_md(content)
@@ -57,10 +58,23 @@ module ApplicationHelper
       lax_spacing: false,
       disable_indented_code_blocks: true,
       space_after_headers: true,
+      superscript: true,
       underline: true,
       highlight: true,
       footnotes: false
     })
-    md.render(content)
+    md.render(content.gsub(/([\r\n]+\s*?){3,}/, "\n\n").gsub(/^\s*#/, "\\#"))
+  end
+
+
+  private
+
+  def render_youtube(content)
+    # TODO: render only in text blocks, not in code/quotes/etc
+    return content.gsub(
+      /\[yt:([a-zA-Z0-9\-_]+)\]/,
+      "<iframe class='youtube' allowfullscreen src='
+        https://www.youtube-nocookie.com/embed/\\1?theme=light&vq=hd720&hd=1&iv_load_policy=3&showinfo=1&showsearch=0&rel=0&modestbranding&hd=1&autohide=1&html5=1'>
+      </iframe>")
   end
 end
\ No newline at end of file
diff --git a/app/models/user.rb b/app/models/user.rb
index 81a60fe..1880027 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -15,12 +15,12 @@ class User < ActiveRecord::Base
   validates_length_of :password, in: 8..256, :on => :create
   validates_length_of :name, in: 2..30
   validates_length_of :about, maximum: 5000
-  validates_length_of :ign, minimum: 2, maximum: 16
+  validates_length_of :ign, minimum: 1, maximum: 16
 
   validates :email, uniqueness: {case_sensitive: false}, format: {with: /\A.+@.+\..{2,}\z/i, message: "That doesn't look like an email adress."}
-  validates :ign, uniqueness: {case_sensitive: false}, format: {with: /\A[a-z\d_]+\z/i, message: "That is probably not your username."}
+  validates :ign, uniqueness: {case_sensitive: false}, format: {with: /\A[a-z\d_]+\z/i, message: "Username is invalid (a-z, 0-9, _)."}
 
-  validate :has_paid, :if => lambda {|user| user.ign_changed? }
+  validate :account_exists?, :if => lambda {|user| user.ign_changed? }
 
   has_many :blogposts
   has_many :comments
@@ -96,31 +96,31 @@ class User < ActiveRecord::Base
     end
   end
 
-  def haspaid?
-    begin
-      response = open("https://sessionserver.mojang.com/session/minecraft/profile/#{CGI.escape(self.uuid)}", read_timeout: 0.5)
-      if response.status[0] == "200"
-        session_profile = JSON.load(response.read)
-        # unpaid accounts are called 'demo' accounts
-        return session_profile["demo"] == true
-      elsif response.status[0] == "204"
-        # user doesn't exist
-        return false
-      else
-        puts "---"
-        puts "ERROR: unexpected response code while checking '#{self.uuid}' for premium account"
-        puts "code: #{reponse.status}, body: '#{reponse.read}'"
-        puts "---"
-      end
-    rescue => e
-      puts "---"
-      puts "ERROR: failed to check for premium account for '#{self.uuid}'. Minecraft servers down?"
-      puts e.message
-      puts "---"
-    end
-    # mojang servers have trouble
-    return true
-  end
+  # def haspaid?
+  #   begin
+  #     response = open("https://sessionserver.mojang.com/session/minecraft/profile/#{CGI.escape(self.uuid)}", read_timeout: 0.5)
+  #     if response.status[0] == "200"
+  #       session_profile = JSON.load(response.read)
+  #       # unpaid accounts are called 'demo' accounts
+  #       return session_profile["demo"] == true
+  #     elsif response.status[0] == "204"
+  #       # user doesn't exist
+  #       return false
+  #     else
+  #       puts "---"
+  #       puts "ERROR: unexpected response code while checking '#{self.uuid}' for premium account"
+  #       puts "code: #{reponse.status}, body: '#{reponse.read}'"
+  #       puts "---"
+  #     end
+  #   rescue => e
+  #     puts "---"
+  #     puts "ERROR: failed to check for premium account for '#{self.uuid}'. Minecraft servers down?"
+  #     puts e.message
+  #     puts "---"
+  #   end
+  #   # mojang servers have trouble
+  #   return true
+  # end
 
   # def correct_case?(ign)
   #   begin
@@ -183,8 +183,11 @@ class User < ActiveRecord::Base
     self.role ||= Role.get(:normal)
   end
 
-  def has_paid
-    errors.add(:ign, "'#{self.ign}' is not a paid account!") unless self.haspaid?
+  def account_exists?
+    profile = self.get_profile
+    if !profile || profile["demo"] == true
+      errors.add(:ign, "'#{self.ign}' is not a paid account!")
+    end
   end
 
   def strip_whitespaces
diff --git a/app/views/blogposts/index.atom.builder b/app/views/blogposts/index.atom.builder
index 5f1c05e..25eab0b 100644
--- a/app/views/blogposts/index.atom.builder
+++ b/app/views/blogposts/index.atom.builder
@@ -11,7 +11,7 @@ atom_feed do |feed|
       end
       entry.url blogpost_url(post)
       entry.title post.title
-      entry.content Sanitize.clean(render_md(post.content), Sanitize::Config::RELAXED).html_safe, :type => 'html'
+      entry.content render_md(post.content).html_safe, :type => 'html'
     end
   end
 end
\ No newline at end of file
diff --git a/app/views/blogposts/index.html.erb b/app/views/blogposts/index.html.erb
index e973d02..b3bc1aa 100644
--- a/app/views/blogposts/index.html.erb
+++ b/app/views/blogposts/index.html.erb
@@ -13,7 +13,7 @@
       <div class="items">
         <div class="item content post">
           <h2 class="headline"><%= link_to truncate(p.title, length: 60, omission: " …"), p %></h2>
-          <%= Sanitize.clean(render_md(p.content), Sanitize::Config::RELAXED).html_safe %>
+          <%= render_md(p.content).html_safe %>
         </div>
       </div>
     </div>
diff --git a/app/views/blogposts/show.html.erb b/app/views/blogposts/show.html.erb
index 8941018..87905cd 100644
--- a/app/views/blogposts/show.html.erb
+++ b/app/views/blogposts/show.html.erb
@@ -8,7 +8,7 @@
   <div class="items">
     <div class="item content">
       <h2 class="headline"><%= link_to truncate(@post.title, length: 60, omission: " …"), p %></h2>
-      <%= Sanitize.clean(render_md(@post.content), Sanitize::Config::RELAXED).html_safe %>
+      <%= render_md(@post.content).html_safe %>
     </div>
   </div>
 </div>
diff --git a/app/views/comments/_comment.html.erb b/app/views/comments/_comment.html.erb
index 7f77747..21be5f9 100644
--- a/app/views/comments/_comment.html.erb
+++ b/app/views/comments/_comment.html.erb
@@ -6,7 +6,7 @@
   </div>
   <div class="items">
     <div class="item content">
-      <%= Sanitize.clean(render_mini_md(c.content.gsub(/([\r\n]+\s*?){3,}/, "\n\n")), Sanitize::Config::BASIC).html_safe %>
+      <%= render_mini_md(c.content).html_safe %>
     </div>
   </div>
 </div>
\ No newline at end of file
diff --git a/app/views/comments/_new.html.erb b/app/views/comments/_new.html.erb
index 67729ba..d1c0125 100644
--- a/app/views/comments/_new.html.erb
+++ b/app/views/comments/_new.html.erb
@@ -1,7 +1,7 @@
 <% if current_user %>
   <h3>New comment</h3>
   <%= simple_form_for [@post, @comment] do |f| %>
-    <p>> quote | _underline_ | *italic* | **bold** | `code` | [link](https://example.com)
+    <p><blockquote>&gt; quote</blockquote> | _underline_ | <i>*italic*</i> | <b>**bold**</b> | <code>`code`</code> | <mark>==mark==</mark> | <a>[link](https://example.com)</a>
     <%= f.input :content, :label => false, :as => "text", :placeholder => "Comment", input_html: {class: "comment"} %>
     <%= f.submit class: "btn blue" %>
   <% end %>
diff --git a/app/views/forumthreads/show.html.erb b/app/views/forumthreads/show.html.erb
index 9821d0a..4b9c9ba 100644
--- a/app/views/forumthreads/show.html.erb
+++ b/app/views/forumthreads/show.html.erb
@@ -8,7 +8,7 @@
   <div class="items">
     <div class="item content">
       <h2 class="headline"><%= link_to truncate(@thread.title, length: 60, omission: " …"), p %></h2>
-      <%= Sanitize.clean(render_md(@thread.content), Sanitize::Config::RELAXED).html_safe %>
+      <%= render_md(@thread.content).html_safe %>
     </div>
   </div>
 </div>
diff --git a/app/views/users/show.html.erb b/app/views/users/show.html.erb
index 39bff81..be736ec 100644
--- a/app/views/users/show.html.erb
+++ b/app/views/users/show.html.erb
@@ -82,5 +82,5 @@
     </tbody>
   </table>
   About:<br>
-  <%= @user.about.blank? ? "<span class=\"no-about\">nothing</span>".html_safe : @user.about %>
+  <%= @user.about.blank? ? "<span class=\"no-about\">nothing</span>".html_safe : render_mini_md(@user.about).html_safe %>
 </div>
\ No newline at end of file