diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c79503e..4316139 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -70,7 +70,7 @@ jobs:
       fail-fast: false
       matrix:
         # as now the various plumed support sites use 3.9 and 3.8 (and with 3.10 starts to fail...)
-        python-version: ["3.8", "3.9"] #, "3.10", "3.11", "3.12"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12","3.13"]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
diff --git a/.gitignore b/.gitignore
index 02d5668..a23353c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,6 @@ coverage.xml
 # virtual environments
 /venv*
 /env*
+*.zip
+*.stderr.*
+/test*
diff --git a/PlumedToHTML/PlumedLexer.py b/PlumedToHTML/PlumedLexer.py
index 840dbf0..10bf93a 100644
--- a/PlumedToHTML/PlumedLexer.py
+++ b/PlumedToHTML/PlumedLexer.py
@@ -17,19 +17,19 @@ class PlumedLexer(RegexLexer):
             (r'(\w+)(=)(__FILL__)', bygroups(Name.Attribute, Text, Literal)),
             (r'__FILL__', Literal),  
             # Find LABEL=lab
-            (r'((?i)LABEL)(=)(\S+\b)', bygroups(Name.Attribute, Text, String.Double)),
+            (r'([Ll][Aa][Bb][Ee][Ll])(=)(\S+\b)', bygroups(Name.Attribute, Text, String.Double)),
             # Find special replica syntax with fill
             (r'(\w+)(=)(@\S+:)(__FILL__)', bygroups(Name.Attribute, Text, Name.Constant, Literal)), 
             # Find special replica syntax with brackets around replica command
-            (r'(\w+)(=\{)(@\S+:)((?s)\{.*?\})(\})', bygroups(Name.Attribute, Text, Name.Constant, Generic, Text)),
+            (r'(?s)(\w+)(=\{)(@\S+:)(\{.*?\})(\})', bygroups(Name.Attribute, Text, Name.Constant, Generic, Text)),
             # Find special repliica syntax with multiple brackets
-            (r'(\w+)(=)(@\S+:)((?s)\{\s*\{.*?\}\s*\})', bygroups(Name.Attribute, Text, Name.Constant, Generic)), 
+            (r'(?s)(\w+)(=)(@\S+:)(\{\s*\{.*?\}\s*\})', bygroups(Name.Attribute, Text, Name.Constant, Generic)), 
             # Find special replica syntax with brackets
-            (r'(\w+)(=)(@\S+:)((?s)\{.*?\})', bygroups(Name.Attribute, Text, Name.Constant, Generic)),  
+            (r'(?s)(\w+)(=)(@\S+:)(\{.*?\})', bygroups(Name.Attribute, Text, Name.Constant, Generic)),  
             # Find special replica syntax without brackets
             (r'(\w+)(=)(@\S+:)(\S+\b)', bygroups(Name.Attribute, Text, Name.Constant, Generic)),
             # Find KEYWORD with {} brackets around value
-            (r'(\w+)(=)((?s)\{.*?\})', bygroups(Name.Attribute, Text, Generic)),
+            (r'(?s)(\w+)(=)(\{.*?\})', bygroups(Name.Attribute, Text, Generic)),
             # Find KEYWORD=whatever with comment immediately after end of whatever
             (r'(\w+)(=)(\S+)(#.*$)', bygroups(Name.Attribute, Text, Generic, Comment)),
             # Find KEYWORD=whatever 
@@ -43,7 +43,7 @@ class PlumedLexer(RegexLexer):
             # And stuff for long versions of shortcuts
             (r'(^# PLUMED interprets the command:\n)(#.+$)', bygroups(Comment, Comment.Hashbang)),
             # Find ENDPLUMED and set everything after it to a comment
-            (r'(^\s*ENDPLUMED)((?s).*\Z)', bygroups(Keyword, Comment)),
+            (r'(?s)(^\s*)([Ee][Nn][Dd][Pp][Ll][Uu][Mm][Ee][Dd])(.*\Z)', bygroups(Text, Keyword, Comment)),
             # Find the start of shortcuts
             (r'#SHORTCUT.*?\r?\n',Comment.Preproc),
             # Find the start of a shortcut with a nested default
diff --git a/setup.py b/setup.py
index 17f690e..11c6979 100644
--- a/setup.py
+++ b/setup.py
@@ -20,6 +20,8 @@
          "Operating System :: OS Independent",
      ],
      install_requires=['lxml','pygments','requests','bs4'],
-     test_suite='nose.collector',
-     tests_require=['nose'],
+    # This adds the assets that PlumedToHTML.get_html_header() asks for ()
+     data_files=[('PlumedToHTML', ['PlumedToHTML/assets/header.html'])],
+     include_package_data=True,
  )
+# print(setuptools.find_packages())
\ No newline at end of file
diff --git a/tox.ini b/tox.ini
index 7ba1242..274b259 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,4 @@
 [testenv]
-deps = 
-    nose
-    coverage
-commands = nosetests --with-coverage --cover-inclusive --cover-xml
+deps = pytest
+       pytest-cov
+commands = pytest --cov=PlumedToHTML --cov-report=term-missing PlumedToHTML/tests