Add OG tags and TODO for favicon/og image

Author: lemonadern

TODO.md

@@ -0,0 +1,16 @@
+# TODO
+
+## Favicon
+
+- Prepare `favicon-32x32.png` and `favicon-16x16.png`
+- Place them in `static/img/`
+
+## OG Image
+
+- Prepare an OG image (recommended size: 1200×630px)
+- Place it in `static/`
+- Add to `templates/_head_extend.html`:
+  ```html
+  <meta property="og:image" content="{{ get_url(path='YOUR_IMAGE.png') }}">
+  <meta name="twitter:image" content="{{ get_url(path='YOUR_IMAGE.png') }}">
+  ```

templates/_head_extend.html

@@ -291,3 +291,12 @@
     }
   }
 </style>
+
+<meta property="og:title" content="{% if page.title %}{{ page.title }} | {{ config.title }}{% elif section.title %}{{ section.title }} | {{ config.title }}{% else %}{{ config.title }}{% endif %}">
+<meta property="og:description" content="{{ page.description | default(value=section.description | default(value=config.description)) }}">
+<meta property="og:url" content="{{ current_url | default(value=config.base_url) }}">
+<meta property="og:type" content="{% if page %}article{% else %}website{% endif %}">
+<meta property="og:site_name" content="{{ config.title }}">
+<meta name="twitter:card" content="summary">
+<meta name="twitter:title" content="{% if page.title %}{{ page.title }} | {{ config.title }}{% elif section.title %}{{ section.title }} | {{ config.title }}{% else %}{{ config.title }}{% endif %}">
+<meta name="twitter:description" content="{{ page.description | default(value=section.description | default(value=config.description)) }}">