Update landing pages and fonts (#1872)

* Update landing pages and fonts.

* Update the avatar.

ru/docs/index.html

@@ -5,7 +5,7 @@
     <div class="starfield">
         <div class="starfield-origin"></div>
     </div>
-    <div class="hero-div">
+    <div class="hero-div hero-div--ru">
         <img src="../assets/hero/ground.png" alt="" style="position: absolute; width: auto; height: 26.445%; left: 28.211%; top: 54.145%;">
         <img src="../assets/hero/links.png" alt="" style="position: absolute; width: auto; height: 78.751%; left: 10.545%; top: 7.326%;">
         <a href="chapter_introduction/">
@@ -247,7 +247,7 @@
                     <br><b>И. А. Шевкун</b>
                 </div>
                 <div class="profile-cell translator-profile-cell">
-                    <img class="profile-img" src="../assets/avatar/avatar_xxx.jpg" alt="Translator: yuyanhuang" />
+                    <img class="profile-img" src="../assets/avatar/avatar_yuyanhuang.jpg" alt="Translator: yuyanhuang" />
                     <br><b>Yuyan Huang</b>
                 </div>
             </div>

ru/mkdocs.yml

@@ -16,7 +16,7 @@ theme:
   custom_dir: ../build/overrides
   language: ru
   font:
-    text: Noto Sans
+    text: PT Sans
   palette:
     - scheme: default
       primary: white