feat: add support for embed video files (cotes2020#1558)

_includes/embed/bilibili.html

@@ -1,10 +1,9 @@
 <iframe
-  class="embed-video bilibili"
+  class="embed-video"
   loading="lazy"
   src="https://player.bilibili.com/player.html?bvid={{ include.id }}"
   scrolling="no"
-  border="0"
-  frameborder="no"
+  frameborder="0"
   framespacing="0"
   allowfullscreen="true"
-></iframe>
+></iframe>

_includes/embed/video.html

@@ -0,0 +1,38 @@
+{% assign video_url = include.src %}
+{% assign poster_url = include.poster %}
+
+{% unless video_url contains '://' %}
+  {%- capture video_url -%}
+    {% include img-url.html src=video_url img_path=page.img_path %}
+  {%- endcapture -%}
+{% endunless %}
+
+{% if poster_url %}
+  {% unless poster_url contains '://' %}
+    {%- capture poster_url -%}
+      {% include img-url.html src=poster_url img_path=page.img_path %}
+    {%- endcapture -%}
+  {% endunless %}
+  {% assign poster = 'poster="' | append: poster_url | append: '"' %}
+{% endif %}
+
+{% assign attributes = 'controls' %}
+
+{% if include.autoplay %}
+  {% assign attributes = attributes | append: ' ' | append: 'autoplay' %}
+{% endif %}
+
+{% if include.loop %}
+  {% assign attributes = attributes | append: ' ' | append: 'loop' %}
+{% endif %}
+
+{% if include.muted %}
+  {% assign attributes = attributes | append: ' ' | append: 'muted' %}
+{% endif %}
+
+<p>
+  <video class="embed-video file" src="{{ video_url }}" {{ poster }} {{ attributes }}>
+    Your browser doesn't support HTML video. Here is a <a href="{{ url }}">link to the video</a> instead.
+  </video>
+  <em>{{ include.title }}</em>
+</p>

_includes/embed/youtube.html

@@ -1,5 +1,5 @@
 <iframe
-  class="embed-video youtube"
+  class="embed-video"
   loading="lazy"
   src="https://www.youtube.com/embed/{{ include.id }}"
   title="YouTube video player"

_sass/addon/commons.scss

@@ -550,17 +550,25 @@ main {
   width: 100%;
   height: 100%;
   margin-bottom: 1rem;
+  aspect-ratio: 16 / 9;
 
   @extend %rounded;
 
-  &.youtube,
-  &.bilibili {
-    aspect-ratio: 16 / 9;
-  }
-
   &.twitch {
     aspect-ratio: 310 / 189;
   }
+
+  &.file {
+    display: block;
+    width: auto;
+    height: auto;
+    max-width: 100%;
+    max-height: 100%;
+    margin: auto;
+    margin-bottom: 0;
+  }
+
+  @extend %img-caption;
 }
 
 /* --- buttons --- */