diff --git a/doc/source/codestyle.rst b/doc/source/codestyle.rst
index 5a015a5b25b2929a7c19b3718840b3bdd6eab223..6a2c2023cebc819eee81ab83284eb652dc15bb2d 100644
--- a/doc/source/codestyle.rst
+++ b/doc/source/codestyle.rst
@@ -2,7 +2,7 @@ Code Style
 ==========
 
 
-PEP 8 : The Base Python style
+PEP 8 : the base Python style
 -----------------------------
 Python code should follow **PEP 8**
 
diff --git a/doc/source/csst_common/csst_common.rst b/doc/source/csst_common/csst_common.rst
index 54f6872488688d450e77db4e2c826f5575f4b352..7ee0313c00734fef1e8340f5c11dfd02cf6f7921 100644
--- a/doc/source/csst_common/csst_common.rst
+++ b/doc/source/csst_common/csst_common.rst
@@ -20,13 +20,19 @@ A class that helps developers to access simulation files.
         assert_all_detectors=False,     # if True, assert all detectors are available
         datatype="mbi",                 # "mbi" or "sls"
     )
-    # for a quick start
+
+.. code-block:: python
+
+    # for a quick start ()
     dm_mbi = CsstMsDataManager.quickstart(
         ver_sim="C5.2",
         datatype="mbi",
         dir_l1=".",
         exposure_id=100                 # the 100th exposure
     )
+
+.. code-block:: python
+
     # access L0 directory
     dm_mbi.dir_l0
     # access L1 directory
@@ -46,6 +52,8 @@ A class that helps developers to access simulation files.
     # define an L1 file (non-detector-specified)
     dm_mbi.l1_file("flipped_image.fits")
 
+.. code-block:: python
+
     # to get bias
     dm_mbi.get_bias()
     # to get dark
diff --git a/doc/source/csst_common/example_interface.py b/doc/source/csst_common/example_interface.py
index 6edc923b5089caa0a24b099aa3207158e7d130e1..2411d8ae6b2ee0dfc545ed901702f2bd31ff8203 100644
--- a/doc/source/csst_common/example_interface.py
+++ b/doc/source/csst_common/example_interface.py
@@ -143,7 +143,7 @@ def process_multiple_images(
             return CsstStatus.PERFECT
         else:
             # not all images are properly processed
-            return CsstStatus.WARNING
+            return CsstStatus.ERROR
     except DeprecationWarning:
         # this will be written into the log file
         logger.warning("Suffered DeprecationWarning!")
diff --git a/doc/source/packaging.rst b/doc/source/packaging.rst
index d76bfb2732f47888ccc18eef6114527c840eb070..6d971cf5d3fe336d79b73a1b1d33780ca5eb861c 100644
--- a/doc/source/packaging.rst
+++ b/doc/source/packaging.rst
@@ -7,7 +7,7 @@ official `Python Packaging User Guide`_, and more specifically `here`_.
 .. _Python Packaging User Guide: https://packaging.python.org/en/latest/
 
 
-Project Structure
+Project structure
 -----------------
 An example code structure is shown below.
 Files/directories with asterisks (``*``) marks are optional.
diff --git a/doc/source/unittest.rst b/doc/source/unittest.rst
index e5f13f3d06a07202d5d2b0f4fb3ce0df4369a509..43cca9277b8299888ee68b7ad4a9d80389c891f4 100644
--- a/doc/source/unittest.rst
+++ b/doc/source/unittest.rst
@@ -15,7 +15,7 @@ Here we show an example of an example unit test on ``csst_proto.top_level_interf
 
 
 
-Run Unit Tests
+Run unit tests
 --------------
 
 To run unit tests
diff --git a/doc/source/vcs.rst b/doc/source/vcs.rst
index abb3c791b923248004849a4623fffd17bdd423bf..5cb10b7b5bfba4843ea5bc3e6a4d12cbb16b6a37 100644
--- a/doc/source/vcs.rst
+++ b/doc/source/vcs.rst
@@ -14,15 +14,15 @@ which provides several advantages.
     4. Code safety
         the approve-merge mechanism, etc.
 
-`git`
------
-`git` is probably the most widely used version control system presently.
+``git``
+-------
+``git`` is probably the most widely used version control system presently.
 
     - official website: https://git-scm.com/
     - **Pro Git** (2nd Ed.): https://git-scm.com/book/en/v2
 
 
-Basic Usages
+Basic usages
 ------------
 To initialize a repository:
 
@@ -111,8 +111,8 @@ You can also store your credentials on disk via
     ``*.py~`` (temporary files generated by text editor).
 
 
-Work Flow with Git
-------------------
+Work flow with ``git``
+----------------------
 In CSST DAS pipeline development, each developer registers an account at the
 `CSST DAS GitLab`_, which is a self self-managed `GitLab`_ instance
 to host data processing pipelines at NAOC.