fix(readme): center-align inline SVG logos with captions

SVGs were `display:block` and ignored `text-align:center`, causing captions
to appear off-center. Added `margin: 0 auto` (and kept width/height) on
`.logo-item svg` (including `.wide`) so icons and captions align.

README.md

@@ -39,10 +39,11 @@ short_description: keeper-security org card
     border-radius: 6px 6px 0 0;
   }
 
-  /* Size Keeper logo to 250 wide; keep aspect ratio */
+  /* Size Keeper logo to 300 wide; keep aspect ratio */
   .keeper-header svg {
-    height: 250px;
+    width: 300px;
     display: block;
+    margin: 0 auto;
   }
 
   .keeper-logo {
@@ -168,12 +169,14 @@ short_description: keeper-security org card
     width: 60px;
     height: 60px;
     display: block;
+    margin: 0 auto;
   }
 
   /* Wider marks (PCI, TRUSTe, etc.) get a wider box */
   .logo-item.wide svg {
     width: 90px;
     height: 60px;
+    margin: 0 auto;
   }
 </style>