diff --git a/content/static/style/default.css b/content/static/style/default.css
index f373cdd3d..6d3ac4515 100644
--- a/content/static/style/default.css
+++ b/content/static/style/default.css
@@ -455,6 +455,9 @@ abbr.dtstart, abbr.dtend {
   text-shadow: none;
   transition: all 0.1s ease-in;
 }
+#portal .wiki {
+    background-color: #CFDFEF;
+}
 #portal .wiki h4 {
   text-align: justify;
   word-break: break-all;
diff --git a/xsl/ical.xsl b/xsl/ical.xsl
index d9c8cb6cc..bf0044945 100644
--- a/xsl/ical.xsl
+++ b/xsl/ical.xsl
@@ -2,7 +2,7 @@
 <xsl:stylesheet version="1.0"
                 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                 xmlns:date="http://exslt.org/dates-and-times"
-                xmlns:crypto="http://exslt.org/crypto">
+                xmlns:str="http://exslt.org/strings">
 
 <xsl:output method="text" encoding="utf-8"/>
 
@@ -75,7 +75,7 @@
   </xsl:template>
 
   <xsl:template name="uid">
-    <xsl:text>UID:</xsl:text><xsl:value-of select="crypto:sha1(concat(title,start))"/><xsl:text>@www.c3d2.de</xsl:text>
+    <xsl:text>UID:https://www.c3d2.de/#</xsl:text><xsl:value-of select="str:encode-uri(concat(title,start),false())"/>
     <xsl:text>&#13;&#10;</xsl:text>
   </xsl:template>
 
diff --git a/xsl/xcal.xsl b/xsl/xcal.xsl
index cec74c9ad..ae931236b 100644
--- a/xsl/xcal.xsl
+++ b/xsl/xcal.xsl
@@ -7,8 +7,8 @@
 <xsl:stylesheet version="1.0"
                 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                 xmlns:date="http://exslt.org/dates-and-times"
-                xmlns:crypto="http://exslt.org/crypto"
-                exclude-result-prefixes="xsl crypto date">
+                xmlns:str="http://exslt.org/strings"
+                exclude-result-prefixes="xsl str date">
 
 <xsl:output method="xml"
             version="1.0"
@@ -54,7 +54,7 @@
   </xsl:template>
 
   <xsl:template name="uid">
-    <uid><xsl:value-of select="crypto:sha1(concat(title,start))"/>@www.c3d2.de</uid>
+    <uid>https://www.c3d2.de/#<xsl:value-of select="str:encode-uri(concat(title,start),false())"/></uid>
   </xsl:template>
     
   <xsl:template match="start">
diff --git a/xsl/xhtml5.xsl b/xsl/xhtml5.xsl
index 706d0853d..7c047c96a 100644
--- a/xsl/xhtml5.xsl
+++ b/xsl/xhtml5.xsl
@@ -3,8 +3,8 @@
   xmlns="http://www.w3.org/1999/xhtml"
   xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
   xmlns:date="http://exslt.org/dates-and-times"
-  xmlns:crypto="http://exslt.org/crypto"
-  exclude-result-prefixes="xsl date crypto">
+  xmlns:str="http://exslt.org/strings"
+  exclude-result-prefixes="xsl date str">
 
 
 <xsl:include href="common.xsl" />
@@ -391,21 +391,6 @@
 	    background-image: url('<xsl:value-of select="content-image"/>');
 	  </xsl:attribute>
 	</xsl:if>
-	<xsl:if test="@class = 'wiki'">
-	  <xsl:variable name="number"
-			select="translate(
-				crypto:md5(content-text),
-				'abcdefABCDEF', '123456123456')"/>
-	  <xsl:attribute name="style">
-	    <xsl:text>background-color: rgb(</xsl:text>
-	    <xsl:value-of select="255 - number(substring($number, 1, 2))"/>
-	    <xsl:text>, </xsl:text>
-	    <xsl:value-of select="255 - number(substring($number, 3, 2))"/>
-	    <xsl:text>, </xsl:text>
-	    <xsl:value-of select="255 - number(substring($number, 5, 2))"/>
-	    <xsl:text>);</xsl:text>
-	  </xsl:attribute>
-	</xsl:if>
 
 	<xsl:apply-templates select="header"/>
 	<xsl:apply-templates select="footer"/>