Make the modal button use flex instead

diff --git a/index.html b/index.html
index d7d2b3e..838c201 100644
--- a/index.html
+++ b/index.html
@@ -107,7 +107,7 @@
                 <img src="" alt="">
               </div>
               <video muted="" playsinline="" autoplay="" loop="" preload="metadata">
-				<source src="videos/bliss-phone-demo.webm" type="video/webm">
+                <source src="videos/bliss-phone-demo.webm" type="video/webm">
                 <source src="videos/bliss-phone-demo.mp4" type="video/mp4">
               </video>
             </div>
@@ -290,7 +290,7 @@
                       <p class="text-center"><b>Bootable Installer supports BIOS/CSM and UEFI boot. We recommend using Rufus to flash the ISO to a USB drive, and boot into that to test by running in Live mode. If that works, use the USB drive and boot into the installer to install/upgrade</b></p>
                       <div class="modal-social text-right">
                         <div class="row">
-                          <div class="col-sm-12">
+                          <div style="" class="d-flex justify-content-center align-items-center flex-grow-1">
                             <a class="btn btn-primary btn-block" target="”_blank”" href="https://forum.xda-developers.com/bliss-roms/bliss-roms-development/bliss-os-pie-beta-preview-t3855917">Bliss OS XDA Thread</a>
                           </div>
                         </div>