refactor: update landing page

Author: piotrpdev

landing/assets/demo.webp

@@ -244,7 +244,7 @@ <h5>("eye" in Polish)</h5>
                 <header id="btn-container">
                     <a id="about-btn" class="selected" role="button" tabindex="0">About</a>
                     <a id="poster-btn" role="button" tabindex="0">Poster</a>
-                    <a target="_blank" href="https://www.youtube.com/watch?v=Ijt94tO9f5o">Demo</a>
+                    <a target="_blank" href="https://youtu.be/pLrvvLToVLg">Demo</a>
                     <a target="_blank" href="https://github.com/piotrpdev/oko">GitHub</a>
                 </header>
                 <ul>
@@ -256,9 +256,8 @@ <h5>("eye" in Polish)</h5>
             </div>
         </div>
         <div id="img-col">
-            <!-- TODO: Replace placeholder images -->
-            <img id="demo-img" src="assets/demo_placeholder.webp" width="3284" height="2016" alt="Oko demo">
-            <img id="poster-img" src="assets/poster_placeholder.webp" width="1357" height="1920" alt="Oko poster" style="display: none;">
+            <img id="demo-img" src="assets/demo.webp" width="2386" height="1160" alt="Oko demo">
+            <img id="poster-img" src="assets/poster.webp" width="1684" height="2384" alt="Oko poster" style="display: none;">
         </div>
     </div>
     <script>