Working on the search problem....

docs/extra.css

@@ -0,0 +1,5 @@
+.bs-sidebar {
+    padding: 0;
+    max-height:90vh;
+    overflow-y: auto;
+}

mkdocs.yml

@@ -4,5 +4,5 @@ theme:
     custom_dir: docs_modification/
 plugins:
   - search:
-        prebuild_index: true
-  
+      prebuild_index: true
+extra_css: [extra.css]

readthedocs.yml

@@ -2,6 +2,8 @@ version: 2
 
 python:
   version: 3.6
+  install:
+    - requirements: docs/requirements.txt
 
 mkdocs:
   configuration: mkdocs.yml