brand logo: shrink logo and logo-paddings underneath "md"-breakpoint; brand font: letter spacing++

scss/_navbar.scss

@@ -139,6 +139,12 @@
     // font-weight: bolder;
     color: $primary !important;
     font-size: 2rem;
+    letter-spacing: 0.125rem;
+
+    @include media-breakpoint-down(md) {
+      padding-left: 15vw;
+      margin-left: 5vw;
+    }
 
     &::before {
       content: ' ';
@@ -154,6 +160,11 @@
       border-radius: 50%;
       border: math.div($navbar-brand-margin-end, 2) solid $body-bg;
       box-sizing: content-box;
+
+      @include media-breakpoint-down(md) {
+        width: 15vw;
+        height: 15vw;
+      }
     }
 
     &::after {
@@ -174,6 +185,11 @@
       border-bottom-right-radius: 50%;
       border-bottom-style: dotted;
       border-color: $light;
+
+      @include media-breakpoint-down(md) {
+        width: 15vw;
+        height: 15vw;
+      }
     }
   }