[NIFI-6548] add min width to raised and flat buttons

This closes #49
diff --git a/platform/core/common/styles/_buttons.scss b/platform/core/common/styles/_buttons.scss
index 859e7f1..7193636 100644
--- a/platform/core/common/styles/_buttons.scss
+++ b/platform/core/common/styles/_buttons.scss
@@ -73,6 +73,7 @@
     line-height: normal;
     box-shadow: 0 0 0 0 rgba(0, 0, 0, 0.2), 0 0 0 0 rgba(0, 0, 0, 0.14), 0 0 0 0 rgba(0, 0, 0, 0.12);
     border-radius: 2px;
+    min-width: 88px;
   }
 
   body[fds] .mat-button {
@@ -83,6 +84,7 @@
     text-transform: uppercase;
     line-height: normal;
     border-radius: 2px;
+    min-width: 88px;
   }
 
   body[fds] .mat-button-toggle-button {