diff --git a/click_log/core.py b/click_log/core.py
index 722f092..fe70e20 100644
--- a/click_log/core.py
+++ b/click_log/core.py
@@ -49,7 +49,6 @@ class ClickHandler(logging.Handler):
     def emit(self, record):
         try:
             msg = self.format(record)
-            level = record.levelname.lower()
             click.echo(msg, err=self._use_stderr)
         except Exception:
             self.handleError(record)
diff --git a/docs/conf.py b/docs/conf.py
index b8085bc..893b802 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-import sys
 import os
 
 import click_log
@@ -28,7 +27,6 @@
 try:
     import sphinx_rtd_theme
     html_theme = 'sphinx_rtd_theme'
-    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 except ImportError:
     html_theme = 'default'
     if not on_rtd:
@@ -37,7 +35,7 @@
               'theme.')
         print('-' * 74)
 
-html_static_path = ['_static']
+# html_static_path = ['_static']
 htmlhelp_basename = 'click-logdoc'
 
 latex_elements = {}
diff --git a/docs/index.rst b/docs/index.rst
index f3e22f3..9e47220 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -9,6 +9,11 @@ Click-log: Simple and beautiful logging for click applications
 
 .. module:: click_log
 
+
+.. contents:: Table of contents
+
+----
+
 Getting started
 ===============
 
@@ -83,13 +88,50 @@ The output will look like this::
     error: Failed to divide by zero.
 
 
-The ``error:``-prefix will be red, unless the output is piped to another
+----
+
+Customization
+=============
+
+Output colors
++++++++++++++
+
+In the Getting started example, the ``error:`` prefix will be red, unless the output is piped to another
 command.
 
-The :py:func:`simple_verbosity_option` decorator adds a ``--verbosity`` option
-that takes a (case-insensitive) value of ``DEBUG``, ``INFO``, ``WARNING``,
-``ERROR``, or ``CRITICAL``, and calls ``setLevel`` on the given logger
-accordingly.
+Default colors:
+
++------------+---------+
+| Log level  | Color   |
++============+=========+
+| critical   | red     |
++------------+---------+
+| debug      | blue    |
++------------+---------+
+| error      | red     |
++------------+---------+
+| exception  | red     |
++------------+---------+
+| warning    | yellow  |
++------------+---------+
+
+To customize colors used by each level of log, it's possible to pass a dict with the foreground color for each log level.
+Color code must be `one of those included into click  <https://github.com/pallets/click/blob/master/examples/colors/colors.py>`_
+
+For example:
+
+.. code-block:: python
+
+    import logging
+    import click_log
+
+    click_log.ColorFormatter.colors['info'] = dict(fg="bright_black")
+
+
+Simple verbosity
+++++++++++++++++
+
+In the Getting started example, the :py:func:`simple_verbosity_option` decorator adds a ``--verbosity`` option that takes a (case-insensitive) value of ``DEBUG``, ``INFO``, ``WARNING``, ``ERROR``, or ``CRITICAL``, and calls ``setLevel`` on the given logger accordingly.
 
 .. note::
 
@@ -97,6 +139,8 @@ accordingly.
     Otherwise logging setup will not be early enough for some of your other
     eager options.
 
+----
+
 API
 ===
 
diff --git a/setup.py b/setup.py
index 13528f1..980fb57 100644
--- a/setup.py
+++ b/setup.py
@@ -44,4 +44,7 @@
     install_requires=[
         'click',
     ],
+    extras_require={
+        "doc": ["sphinx>=3.2,<3.3", "sphinx-rtd-theme>=0.5,<0.6"],
+    },
 )