diff --git a/demo/questions/questions-tutorial.yaml b/demo/questions/questions-tutorial.yaml
index ea43cb2..9cee83a 100644
--- a/demo/questions/questions-tutorial.yaml
+++ b/demo/questions/questions-tutorial.yaml
@@ -264,7 +264,28 @@
     ```
 
     Neste caso, as respostas aceites são `azul`, `Azul` ou `AZUL`.
-  correct: ['azul', 'Azul', 'AZUL']
+
+    Em alguns casos pode ser conveniente transformar a resposta antes de a
+    comparar, por exemplo para remover espaços ou converter para maiúsculas ou
+    maiúsculas.
+    A opção `transform` permite dar uma sequência de transformações a aplicar à
+    resposta do aluno, por exemplo:
+
+    ```yaml
+      transform: ['trim', 'lower']
+      correct: ['azul']
+    ```
+
+    Neste momento estão disponíveis as seguintes transformações:
+
+    * `trim` remove os espaços do início e fim da resposta, os do meio mantêm-se
+      inalterados.
+    * `remove_space` remove todos os espaços (início, meio e fim).
+    * `normalize_space` remove espaços do início e fim (trim), e substitui
+      múltiplos espaços por um único espaço (no meio).
+    * `lower` e `upper` convertem respectivamente para minúsculas e maiúsculas.
+  transform: ['remove_spaces', 'lower']
+  correct: ['azul']
 
 # ---------------------------------------------------------------------------
 - type: text-regex
diff --git a/perguntations/questions.py b/perguntations/questions.py
index cb15512..d66c2c6 100644
--- a/perguntations/questions.py
+++ b/perguntations/questions.py
@@ -234,7 +234,8 @@ class QuestionText(Question):
 
         self.set_defaults(QDict({
             'text': '',
-            'correct': [],
+            'correct': [],  # no correct answers, always wrong
+            'transform': [],  # transformations applied to the answer, in order
             }))
 
         # make sure its always a list of possible correct answers
@@ -244,12 +245,36 @@ class QuestionText(Question):
         # make sure all elements of the list are strings
         self['correct'] = [str(a) for a in self['correct']]
 
+        # make sure that the answers are invariant with respect to the filters
+        if any(c != self.transform(c) for c in self['correct']):
+            logger.warning(f'in "{self["ref"]}", correct answers are not '
+                           'invariant wrt transformations')
+
+    # ------------------------------------------------------------------------
+    # apply optional filters to the answer
+    def transform(self, ans):
+        for f in self['transform']:
+            if f == 'remove_space':
+                ans = ans.replace(' ', '')
+            elif f == 'trim':
+                ans = ans.strip()
+            elif f == 'normalize_space':
+                ans = re.sub(r'\s+', ' ', ans.strip())
+            elif f == 'lower':
+                ans = ans.lower()
+            elif f == 'upper':
+                ans = ans.upper()
+            else:
+                logger.warning(f'in "{self["ref"]}", unknown transform "{f}"')
+        return ans
+
     # ------------------------------------------------------------------------
     def correct(self) -> None:
         super().correct()
 
         if self['answer'] is not None:
-            self['grade'] = 1.0 if self['answer'] in self['correct'] else 0.0
+            answer = self.transform(self['answer'])  # apply transformations
+            self['grade'] = 1.0 if answer in self['correct'] else 0.0
 
 
 # ============================================================================
diff --git a/perguntations/static/css/test.css b/perguntations/static/css/test.css
index ad56d4f..25dbd39 100644
--- a/perguntations/static/css/test.css
+++ b/perguntations/static/css/test.css
@@ -1,6 +1,6 @@
 /* Fixes navigation panel overlaying content */
 html {
-    font-size: 13px;
+    font-size: 11pt;
 }
 
 body {
@@ -15,9 +15,12 @@ body {
 }
 
 .card {
-    margin-top: 5em;
+    margin-bottom: 1em;
 }
 
+.alert {
+    margin-top: 3em;
+}
 
 textarea {
     font-family: monospace !important;
diff --git a/perguntations/templates/question.html b/perguntations/templates/question.html
index c666ccf..3482416 100644
--- a/perguntations/templates/question.html
+++ b/perguntations/templates/question.html
@@ -1,7 +1,7 @@
 {% autoescape %}
 
 {% block question %}
-<div class="card border-dark mb-3">
+<div class="card border-dark">
   <h5 class="card-header text-white bg-dark">
     {{ q['number'] }}.  {{ q['title'] }}
     <div class="float-right">
diff --git a/perguntations/test.py b/perguntations/test.py
index e3f407e..d85f9db 100644
--- a/perguntations/test.py
+++ b/perguntations/test.py
@@ -1,7 +1,6 @@
 
 # python standard library
-from os import path, listdir
-import fnmatch
+from os import path
 import random
 from datetime import datetime
 import logging
--
libgit2 0.21.2