Create a default state for tiles without a colored border

apps/block_scout_web/assets/css/components/_tile.scss

@@ -3,7 +3,6 @@
   color: $text-muted;
   line-height: 1.4rem;
   border: 1px solid $border-color;
-  border-left: 4px solid $primary;
   border-radius: 2px;
   padding: 1rem;
   box-shadow: 0 1px 5px rgba($black, 0.15);
@@ -18,6 +17,10 @@
 
   &-type {
 
+    &-block {
+      border-left: 4px solid $primary;
+    }
+
     &-transaction {
       border-left: 4px solid $blue;
 

apps/block_scout_web/lib/block_scout_web/templates/block/_tile.html.eex

@@ -1,4 +1,4 @@
-<div class="tile fade-up">
+<div class="tile tile-type-block fade-up">
   <div class="row">
     <div class="col-md-8 col-lg-9">
       <!-- block height -->

apps/block_scout_web/lib/block_scout_web/templates/chain/_block.html.eex

@@ -1,5 +1,5 @@
 <div class="col-sm-3 fade-up-blocks-chain mb-3 mb-sm-0" data-selector="chain-block" data-block-number="<%= @block.number %>">
-  <div class="tile d-flex flex-column">
+  <div class="tile tile-type-block d-flex flex-column">
     <%= link(@block, to: block_path(BlockScoutWeb.Endpoint, :show, @block), class: "tile-title") %>
     <div>
       <span class="mr-2"> <%= Enum.count(@block.transactions) %> Transactions </span>