Add logo and update documentation branding

- Move logo to docs/images/logo.png
- Add logo to MkDocs theme header and as favicon
- Update README with centered logo and badges
- Apply custom green color theme (#305e3a) matching logo

Author: SmileyChris

README.md

@@ -1,7 +1,13 @@
 # Django Countries
 
-[![PyPI version](https://badge.fury.io/py/django-countries.svg)](https://badge.fury.io/py/django-countries)
-[![Build status](https://github.com/SmileyChris/django-countries/actions/workflows/tests.yml/badge.svg)](https://github.com/SmileyChris/django-countries/actions/workflows/tests.yml)
+<p align="center">
+  <img src="docs/images/logo.png" alt="Django Countries Logo" width="200">
+</p>
+
+<p align="center">
+  <a href="https://badge.fury.io/py/django-countries"><img src="https://badge.fury.io/py/django-countries.svg" alt="PyPI version"></a>
+  <a href="https://github.com/SmileyChris/django-countries/actions/workflows/tests.yml"><img src="https://github.com/SmileyChris/django-countries/actions/workflows/tests.yml/badge.svg" alt="Build status"></a>
+</p>
 
 A Django application that provides country choices for use with forms, flag icons static files, and a country field for models.
 

docs/images/logo.png

@@ -0,0 +1,11 @@
+:root {
+  --md-primary-fg-color: #305e3a;
+  --md-primary-fg-color--light: #4a8a56;
+  --md-primary-fg-color--dark: #1f3d26;
+  --md-primary-bg-color: #ffffff;
+  --md-primary-bg-color--light: #f5f5f5;
+  --md-accent-fg-color: #305e3a;
+  --md-accent-fg-color--transparent: #305e3a1a;
+  --md-accent-bg-color: #ffffff;
+  --md-accent-bg-color--light: #f5f5f5;
+}

docs/stylesheets/extra.css

@@ -5,16 +5,18 @@ repo_name: SmileyChris/django-countries
 
 theme:
   name: material
+  logo: images/logo.png
+  favicon: images/logo.png
   palette:
     - scheme: default
-      primary: indigo
-      accent: indigo
+      primary: custom
+      accent: custom
       toggle:
         icon: material/brightness-7
         name: Switch to dark mode
     - scheme: slate
-      primary: indigo
-      accent: indigo
+      primary: custom
+      accent: custom
       toggle:
         icon: material/brightness-4
         name: Switch to light mode
@@ -28,6 +30,9 @@ theme:
     - search.highlight
     - content.code.copy
 
+extra_css:
+  - stylesheets/extra.css
+
 nav:
   - Home:
       - Welcome: index.md