Issue #2207391 by LewisNyman, emma.maria, lokapujya: Style select elements in Webkit only.

core/misc/icons/333333/caret-down.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16"><path fill="#333333" d="M3.8 5.4c-.165-.22-.075-.4.2-.4h8.002c.275 0 .365.18.199.4l-3.898 5.2c-.166.221-.436.221-.6 0l-3.903-5.2z"/></svg>

core/themes/seven/css/style.css

@@ -831,8 +831,7 @@ input.form-color,
 input.form-file,
 input.form-date,
 input.form-time,
-textarea.form-textarea,
-select.form-select {
+textarea.form-textarea {
   -webkit-box-sizing: border-box;
   -moz-box-sizing:    border-box;
   box-sizing:         border-box;
@@ -861,8 +860,7 @@ select.form-select {
 .form-file:focus,
 .form-textarea:focus,
 .form-date:focus,
-.form-time:focus,
-.form-select:focus {
+.form-time:focus {
   border-color: #40b6ff;
   outline: 0;
   box-shadow: inset 0 1px 3px rgba(0, 0, 0, .05), 0 0 8px #40b6ff;
@@ -888,6 +886,39 @@ select.form-select {
 }
 
 
+/**
+ * Select elements - Webkit only
+ */
+@media screen and (-webkit-min-device-pixel-ratio: 0) {
+  select {
+    cursor: pointer;
+    -webkit-appearance: none;
+    padding: 1px 1.571em 1px 0.5em; /* LTR */
+    border: 1px solid #a6a6a6;
+    border-radius: 0.143em;
+    background:
+      url("../../../misc/icons/333333/caret-down.svg") no-repeat 99% 63%,
+      -webkit-linear-gradient(top, #f6f6f3, #e7e7df); /* LTR */
+    text-shadow: 0 1px hsla(0, 0%, 100%, 0.6);
+    font-size: 0.875rem;
+    transition: all 0.1s;
+    -webkit-font-smoothing: antialiased;
+  }
+  [dir="rtl"] select {
+    padding: 1px 0.714em 1px 1.571em;
+    background-position: 1% 63%, 0 0;
+  }
+  select:focus,
+  select:hover {
+    background-image: url("../../../misc/icons/333333/caret-down.svg"),
+    -webkit-linear-gradient(top, #fcfcfa, #e9e9dd);
+    color: #1a1a1a;
+  }
+  select:hover {
+    box-shadow: 0 1px 2px hsla(0, 0%, 0%, 0.125);
+  }
+}
+
 /**
  * Improve spacing of cancel link.
  */