Fix admonitions styling and spacing (#172)

Closes #164 

Make sure fonts and spacing is consistent for all admonitions, and
cleans up unnecessary definitions in the css source.

Before:

![Captura de
imagem_20240718_200025](https://github.com/user-attachments/assets/d5f5ce40-dd73-4317-bf25-ee380593e577)

After:

![Captura de
imagem_20240718_200040](https://github.com/user-attachments/assets/e63266f9-8f67-4b6e-ae9d-7ff91b6293e3)
![Captura de
imagem_20240718_200009](https://github.com/user-attachments/assets/a00ea471-c89a-4216-ad0e-216aef61e420)

docs/test1.rst

@@ -1,4 +1,71 @@
 Test 1
 ======
 
-A bunch of words.
+A bunch of words.
+
+.. note::
+
+    This is how an admonition with multiple paragraphs looks like.
+
+    It can include many words.
+
+There is also some text between admonitions.
+
+.. warning::
+
+    * How is the padding in this list?
+    * Is it consistent?
+    * Does it look good with other elements?
+
+.. attention::
+
+    Keep track of spacing and margins in admonitions.
+
+    * This is how they look like;
+    * Rely on upstream as much as possible.
+
+And this is how an admonition with a title looks like:
+
+.. admonition:: You can use titles!
+
+    Sometimes they are helpful.
+
+Admonition colors
+-----------------
+
+.. attention::
+
+    This is an attention admonition.
+
+.. caution::
+
+    This is a caution admonition.
+
+.. warning::
+
+    This is a warning admonition.
+
+.. danger::
+
+    This is a danger admonition.
+
+.. error::
+
+    This is an error admonition.
+
+.. hint::
+
+    This is a hint admonition.
+
+.. tip::
+
+    This is a tip admonition.
+
+.. important::
+
+    This is an important admonition.
+
+.. note::
+
+    This is a note admonition.
+