diff --git a/tools.py b/tools.py
index 14b9d62..dc5b265 100644
--- a/tools.py
+++ b/tools.py
@@ -89,16 +89,12 @@ class MarkdownWithMath(mistune.Markdown):
 class HighlightRenderer(mistune.Renderer):
     def block_code(self, code, lang='text'):
         try:
-            lexer = get_lexer_by_name(lang, stripall=True)
+            lexer = get_lexer_by_name(lang, stripall=False)
         except:
-            lexer = get_lexer_by_name('text', stripall=True)
+            lexer = get_lexer_by_name('text', stripall=False)
 
         formatter = HtmlFormatter()
-        return "{open_block}{formatted}{close_block}".format(
-            open_block="<div class='code-highlight'>" if lang != 'text' else '',
-            formatted=highlight(code, lexer, formatter),
-            close_block="</div>" if lang != 'text' else ''
-        )
+        return highlight(code, lexer, formatter)
 
     # def table(self, header, body):
     #     return "<table class='table table-bordered table-hover'>" + header + body + "</table>"
@@ -148,7 +144,7 @@ def load_yaml(filename, default=None):
                 return yaml.load(f)
             except yaml.YAMLError as e:
                 mark = e.problem_mark
-                logger.error('In YAML file "{0}" near line {1}, column {2}.'.format(filename, mark.line, mark.column+1))
+                logger.error(f'In YAML file "{filename}" near line {mark.line}, column {mark.column+1}.')
                 return default
 
 # ---------------------------------------------------------------------------
@@ -165,11 +161,13 @@ def run_script(script, stdin='', timeout=5):
             timeout=timeout,
             )
     except FileNotFoundError:
-        logger.error(f'Script "{script}" not found.')
+        logger.error(f'Could not execute script "{script}": not found.')
     except PermissionError:
-        logger.error(f'Script "{script}" not executable. Wrong permissions?')
+        logger.error(f'Could not execute script "{script}": wrong permissions.')
+    except OSError:
+        logger.error(f'Could not execute script "{script}": unknown reason.')
     except subprocess.TimeoutExpired:
-        logger.error(f'Timeout {timeout}s exceeded while running "{script}".')
+        logger.error(f'Timeout exceeded ({timeout}s) while running "{script}".')
     else:
         if p.returncode != 0:
             logger.error(f'Script "{script}" returned error code {p.returncode}.')
@@ -177,6 +175,6 @@ def run_script(script, stdin='', timeout=5):
             try:
                 output = yaml.load(p.stdout)
             except:
-                logger.error('Error parsing yaml output of "{script}"')
+                logger.error(f'Error parsing yaml output of "{script}"')
             else:
                 return output
--
libgit2 0.21.2