change default theme to dtp-dark for demo tonight

app/views/layouts/main.pug

@@ -3,6 +3,7 @@ include ../components/page-sidebar
 include ../user/components/profile-icon
 doctype html
 html(lang='en')
+  - var DEFAULT_THEME = 'dtp-dark';
   head
     meta(charset='UTF-8')
     meta(name='viewport', content='width=device-width, initial-scale=1.0')
@@ -21,7 +22,7 @@ html(lang='en')
 
       block vendorcss
 
-      link(rel='stylesheet', href=`/dist/css/${user ? (user.theme || 'dtp-light') : 'dtp-light'}.css?v=${pkg.version}`)
+      link(rel='stylesheet', href=`/dist/css/${user ? (user.theme || DEFAULT_THEME) : DEFAULT_THEME}.css?v=${pkg.version}`)
   
     block js
       script(src=`/uikit/js/uikit.min.js?v=${pkg.version}`)
@@ -52,7 +53,7 @@ html(lang='en')
         }
       }
 
-  body.dtp(class= user ? user.theme : 'dtp-light', data-dtp-env= process.env.NODE_ENV, data-dtp-domain= site.domainKey, data-current-view= currentView)
+  body.dtp(class= user ? user.theme : DEFAULT_THEME, data-dtp-env= process.env.NODE_ENV, data-dtp-domain= site.domainKey, data-current-view= currentView)
 
     include ../components/site-link