made the loading animation prettier

static/style.css

@@ -259,18 +259,23 @@ input[type="file"]::file-selector-button {
   /* Fallback color */
   background-color: rgba(0, 0, 0, 0.4);
   /* Black w/ opacity */
+  justify-content: center;
 }
 
 /* Modal Content/Box */
 .loading-content {
   background-color: #4f5977;
-  margin: 15% auto;
+  margin: auto;
   /* 15% from the top and centered */
   padding: 20px;
   /* border: 1px solid #888; */
   /* width: 80%; */
   border-radius: 15px;
+  display: flex;
+  flex-direction: column;
   /* Could be more or less, depending on screen size */
+  align-items: center;
+  text-align: center;
 }
 
 /* The Close Button */
@@ -294,6 +299,7 @@ input[type="file"]::file-selector-button {
 }
 
 .loader {
+  margin: auto;
   border: 16px solid #f3f3f3;
   /* Light grey */
   border-top: 16px solid #3498db;