diff --git a/docs/administrator.md b/docs/administrator.md
index 844a86bf70f2e2fb05ef28dcf29f2d4e6f555005..d613917e9bc40e65854fce3ce8fb230a5d162bff 100644
--- a/docs/administrator.md
+++ b/docs/administrator.md
@@ -1,4 +1,4 @@
-# Administrator Guide
+<h1>Administrator Guide</h1>
 
 Learn how to configure and manage the Postgres Operator in your Kubernetes (K8s)
 environment.
diff --git a/docs/developer.md b/docs/developer.md
index 178fa1b7430e730b990026191c885effd4a7e956..86b01bbfb4fc68379453a88623cb40e874547fe4 100644
--- a/docs/developer.md
+++ b/docs/developer.md
@@ -1,4 +1,4 @@
-# Developer Guide
+<h1>Developer Guide</h1>
 
 Read this guide if you want to debug the operator, fix bugs or contribute new
 features and tests.
diff --git a/docs/gsoc-2019/ideas.md b/docs/gsoc-2019/ideas.md
index 23a3e3eb72298e52542591017034d4c97d4f52cb..456a5a0ffa6e059763744703b0ff4c23fe4d1168 100644
--- a/docs/gsoc-2019/ideas.md
+++ b/docs/gsoc-2019/ideas.md
@@ -1,18 +1,17 @@
+<h1>Google Summer of Code 2019</h1>
 
-# Google Summer of Code 2019
+## Applications steps
 
-## Applications steps 
-
-1. Please carefully read the official [Google Summer of Code Student Guide](https://google.github.io/gsocguides/student/) 
+1. Please carefully read the official [Google Summer of Code Student Guide](https://google.github.io/gsocguides/student/)
 2. Join the #postgres-operator slack channel under [Postgres Slack](https://postgres-slack.herokuapp.com) to introduce yourself to the community and get quick feedback on your application.
 3. Select a project from the list of ideas below or propose your own.
 4. Write a proposal draft.  Please open an issue with the label `gsoc2019_application` in the [operator repository](https://github.com/zalando/postgres-operator/issues)  so that the community members can publicly review it. See proposal instructions below for details.
 5. Submit proposal and the proof of enrollment before April 9 2019 18:00 UTC through the web site of the Program.
 
-## Project ideas 
+## Project ideas
 
 
-### Place database pods into the "Guaranteed" Quality-of-Service class 
+### Place database pods into the "Guaranteed" Quality-of-Service class
 
 * **Description**: Kubernetes runtime does not kill pods in this class on condition they stay within their resource limits, which is desirable for the DB pods serving production workloads.  To be assigned to that class, pod's resources must equal its limits. The task is to add the `enableGuaranteedQoSClass` or the like option to the Postgres manifest and the operator configmap that forcibly re-write pod resources to match the limits.
 * **Recommended skills**: golang, basic Kubernetes abstractions
@@ -21,7 +20,7 @@
 
 ### Implement the kubectl plugin for the Postgres CustomResourceDefinition
 
-* **Description**: [kubectl plugins](https://kubernetes.io/docs/tasks/extend-kubectl/kubectl-plugins/) enable extending the Kubernetes command-line client `kubectl`  with commands to manage custom resources. The task is to design and implement a plugin for the `kubectl postgres` command, 
+* **Description**: [kubectl plugins](https://kubernetes.io/docs/tasks/extend-kubectl/kubectl-plugins/) enable extending the Kubernetes command-line client `kubectl`  with commands to manage custom resources. The task is to design and implement a plugin for the `kubectl postgres` command,
 that can enable, for example, correct deletion or major version upgrade of Postgres clusters.
 * **Recommended skills**: golang, shell scripting, operational experience with Kubernetes
 * **Difficulty**: moderate to medium, depending on the plugin design
@@ -29,36 +28,36 @@ that can enable, for example, correct deletion or major version upgrade of Postg
 
 ### Implement the openAPIV3Schema for the Postgres CRD
 
-* **Description**: at present the operator validates a database manifest on its own. 
+* **Description**: at present the operator validates a database manifest on its own.
 It will be helpful to reject erroneous manifests before they reach the operator using the [native Kubernetes CRD validation](https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/#validation). It is up to the student to decide whether to write the schema manually or to adopt existing [schema generator developed for the Prometheus project](https://github.com/ant31/crd-validation).
 * **Recommended skills**: golang, JSON schema
 * **Difficulty**: medium
-* **Mentor(s)**: Sergey Dudoladov [@sdudoladov](https://github.com/sdudoladov) 
+* **Mentor(s)**: Sergey Dudoladov [@sdudoladov](https://github.com/sdudoladov)
 * **Issue**: [#388](https://github.com/zalando/postgres-operator/issues/388)
 
 ###  Design a solution for the local testing of the operator
 
 * **Description**: The current way of testing is to run minikube, either manually or with some tooling around it like `/run-operator_locally.sh` or Vagrant. This has at least three problems:
-First, minikube is a single node cluster, so it is unsuitable for testing vital functions such as pod migration between nodes. Second, minikube starts slowly; that prolongs local testing. 
+First, minikube is a single node cluster, so it is unsuitable for testing vital functions such as pod migration between nodes. Second, minikube starts slowly; that prolongs local testing.
 Third, every contributor  needs to come up with their own solution for local testing. The task is to come up with a better option which will enable us to conveniently and uniformly  run e2e tests locally / potentially in Travis CI.
 A promising option is the Kubernetes own [kind](https://github.com/kubernetes-sigs/kind)  
 * **Recommended skills**: Docker, shell scripting, basic Kubernetes abstractions
 * **Difficulty**: medium to hard depending on the selected desing
-* **Mentor(s)**: Dmitry Dolgov [@erthalion](https://github.com/erthalion), Sergey Dudoladov [@sdudoladov](https://github.com/sdudoladov) 
+* **Mentor(s)**: Dmitry Dolgov [@erthalion](https://github.com/erthalion), Sergey Dudoladov [@sdudoladov](https://github.com/sdudoladov)
 * **Issue**: [#475](https://github.com/zalando/postgres-operator/issues/475)
 
 ### Detach a Postgres cluster from the operator for maintenance
 
-* **Description**: sometimes a Postgres cluster requires manual maintenance. During such maintenance the operator should ignore all the changes manually applied to the cluster. 
-  Currently the only way to achieve this behavior is to shutdown the operator altogether, for instance by scaling down the operator's own deployment to zero pods. That approach evidently affects all Postgres databases under the operator control and thus is highly undesirable in production Kubernetes clusters. It would be much better to be able to detach only the desired Postgres cluster from the operator for the time being and re-attach it again after maintenance. 
+* **Description**: sometimes a Postgres cluster requires manual maintenance. During such maintenance the operator should ignore all the changes manually applied to the cluster.
+  Currently the only way to achieve this behavior is to shutdown the operator altogether, for instance by scaling down the operator's own deployment to zero pods. That approach evidently affects all Postgres databases under the operator control and thus is highly undesirable in production Kubernetes clusters. It would be much better to be able to detach only the desired Postgres cluster from the operator for the time being and re-attach it again after maintenance.
 * **Recommended skills**: golang, architecture of a Kubernetes operator
 * **Difficulty**: hard - requires significant modification of the operator's internals and careful consideration of the corner cases.
-* **Mentor(s)**: Dmitry Dolgov [@erthalion](https://github.com/erthalion), Sergey Dudoladov [@sdudoladov](https://github.com/sdudoladov) 
+* **Mentor(s)**: Dmitry Dolgov [@erthalion](https://github.com/erthalion), Sergey Dudoladov [@sdudoladov](https://github.com/sdudoladov)
 * **Issue**: [#421](https://github.com/zalando/postgres-operator/issues/421)
 
 ### Propose your own idea
 
-Feel free to come up with your own ideas.  For inspiration, 
-see [our bug tracker](https://github.com/zalando/postgres-operator/issues), 
-the [official `CustomResouceDefinition` docs](https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/) 
-and [other operators](https://github.com/operator-framework/awesome-operators).
\ No newline at end of file
+Feel free to come up with your own ideas.  For inspiration,
+see [our bug tracker](https://github.com/zalando/postgres-operator/issues),
+the [official `CustomResouceDefinition` docs](https://kubernetes.io/docs/tasks/access-kubernetes-api/custom-resources/custom-resource-definitions/)
+and [other operators](https://github.com/operator-framework/awesome-operators).
diff --git a/docs/index.md b/docs/index.md
index c128de7fcd3a96fd2e266854151e624bd3ec56ed..a61fc5dd53e472cb23315696e837dc5cf2205cbf 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -1,4 +1,4 @@
-# Concepts
+<h1>Concepts</h1>
 
 The Postgres [operator](https://coreos.com/blog/introducing-operators.html)
 manages PostgreSQL clusters on Kubernetes (K8s):
diff --git a/docs/operator-ui.md b/docs/operator-ui.md
index c8e2a4b8c24468432c1b33eea999e0467af3c271..99526bb5c5679125615e54b2ebdb2a15980d2f52 100644
--- a/docs/operator-ui.md
+++ b/docs/operator-ui.md
@@ -1,4 +1,4 @@
-# Postgres Operator UI
+<h1>Postgres Operator UI</h1>
 
 The Postgres Operator UI provides a graphical interface for a convenient
 database-as-a-service user experience. Once the operator is set up by database
diff --git a/docs/quickstart.md b/docs/quickstart.md
index 965e96a362813bb85d0036092aeb541d7d546fc1..b8b97c94e9588dcc986791536c5510c4d079f51b 100644
--- a/docs/quickstart.md
+++ b/docs/quickstart.md
@@ -1,4 +1,4 @@
-# Quickstart
+<h1>Quickstart</h1>
 
 This guide aims to give you a quick look and feel for using the Postgres
 Operator on a local Kubernetes environment.
@@ -55,7 +55,7 @@ kubectl create -f manifests/postgres-operator.yaml  # deployment
 ```
 
 There is a [Kustomization](https://github.com/kubernetes-sigs/kustomize)
-manifest that [combines the mentioned resources](../manifests/kustomization.yaml) - 
+manifest that [combines the mentioned resources](../manifests/kustomization.yaml) -
 it can be used with kubectl 1.14 or newer as easy as:
 
 ```bash
diff --git a/docs/reference/cluster_manifest.md b/docs/reference/cluster_manifest.md
index 44500bc66c3493b29e977583edbd3d5d6915d223..ac609e6d1332304d4a5c95e86a2e2e1126510c15 100644
--- a/docs/reference/cluster_manifest.md
+++ b/docs/reference/cluster_manifest.md
@@ -1,4 +1,4 @@
-# Cluster manifest reference
+<h1>Cluster manifest reference</h1>
 
 Individual Postgres clusters are described by the Kubernetes *cluster manifest*
 that has the structure defined by the `postgresql` CRD (custom resource
diff --git a/docs/reference/command_line_and_environment.md b/docs/reference/command_line_and_environment.md
index 8caf7b898be7d8a3d65f7b6165a2eff2f033de55..ec5da5ceb69f81aaa534cdca0be94e9992172062 100644
--- a/docs/reference/command_line_and_environment.md
+++ b/docs/reference/command_line_and_environment.md
@@ -28,7 +28,7 @@ flags](https://godoc.org/github.com/golang/glog) are also supported. For
 instance, one may want to add `-alsologtostderr` and `-v=8` to debug the
 operator REST calls.
 
-## Environment variables
+# Environment variables
 
 The following environment variables are accepted by the operator:
 
diff --git a/docs/reference/operator_parameters.md b/docs/reference/operator_parameters.md
index f3fe96b6b97c32891e941dc2b492416a705032a8..0528147ab9592c6ab70f561d54fc95c5bbaec195 100644
--- a/docs/reference/operator_parameters.md
+++ b/docs/reference/operator_parameters.md
@@ -1,4 +1,4 @@
-# Configuration parameters
+<h1>Configuration parameters</h1>
 
 There are two mutually-exclusive methods to set the Postgres Operator
 configuration.
diff --git a/docs/user.md b/docs/user.md
index dae252fa85a35758662ddd6d697898e847233d43..ee8e7183c7099b1a6cee0954e8476764c85332b5 100644
--- a/docs/user.md
+++ b/docs/user.md
@@ -1,4 +1,4 @@
-# User Guide
+<h1>User Guide</h1>
 
 Learn how to work with the Postgres Operator in a Kubernetes (K8s) environment.
 
diff --git a/manifests/postgres-operator.yaml b/manifests/postgres-operator.yaml
index 6860316cf38d71dd41d204383405cbda94c6851c..f6b73561df1c0ae82680e00b31124163d129aefd 100644
--- a/manifests/postgres-operator.yaml
+++ b/manifests/postgres-operator.yaml
@@ -29,10 +29,9 @@ spec:
           runAsNonRoot: true
           readOnlyRootFilesystem: true
         env:
-        # provided additional ENV vars can overwrite individual config map entries  
+        # provided additional ENV vars can overwrite individual config map entries
         - name: CONFIG_MAP_NAME
           value: "postgres-operator"
         # In order to use the CRD OperatorConfiguration instead, uncomment these lines and comment out the two lines above
         # - name: POSTGRES_OPERATOR_CONFIGURATION_OBJECT
         #  value: postgresql-operator-default-configuration
-          
diff --git a/mkdocs.yml b/mkdocs.yml
index eca88559fd33db3c329d9c9f269f94078863f0d0..34f55fac8c6d9d8ad2b258f91bf011652419878b 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -3,13 +3,14 @@ repo_url: https://github.com/zalando/postgres-operator
 theme: readthedocs
 
 nav:
-  - index.md
-  - quickstart.md
-  - operator-ui.md
-  - administrator.md
-  - user.md
-  - developer.md
+  - Concepts: 'index.md'
+  - Quickstart: 'quickstart.md'
+  - Postgres Operator UI: 'operator-ui.md'
+  - Admin guide: 'administrator.md'
+  - User guide: 'user.md'
+  - Developer guide: 'developer.md'
   - Reference:
-    - reference/operator_parameters.md
-    - reference/cluster_manifest.md
-    - reference/command_line_and_environment.md
+    - Config parameters: 'reference/operator_parameters.md'
+    - Manifest parameters: 'reference/cluster_manifest.md'
+    - CLI options and environment: 'reference/command_line_and_environment.md'
+  - Google Summer of Code 2019: 'gsoc-2019/ideas.md'