Improve side navigation spacing in relation to masthead

_sass/minimal-mistakes/_masthead.scss

@@ -18,8 +18,10 @@
     padding: 1em;
     max-width: 100%;
     display: -webkit-box;
+    display: -ms-flexbox;
     display: flex;
     -webkit-box-pack: justify;
+    -ms-flex-pack: justify;
     justify-content: space-between;
     font-family: $sans-serif-narrow;
 
@@ -39,11 +41,10 @@
 
 .site-title {
   display: -webkit-box;
+  display: -ms-flexbox;
   display: flex;
-  padding: 0.5rem 0;
-  align-self: stretch;
-  -webkit-box-align: center;
-  align-items: center;
+  -ms-flex-item-align: center;
+  align-self: center;
   font-weight: bold;
   z-index: 20;
 }