DevTools: polish the MQ ruler, move zoom controls to the top.

Source/devtools/front_end/responsiveDesignView.css

Index: Source/devtools/front_end/responsiveDesignView.css
diff --git a/Source/devtools/front_end/responsiveDesignView.css b/Source/devtools/front_end/responsiveDesignView.css
index 8bbc2cd0ca79734361205f2a9a6bd6d99d0911bd..104e31a43bd7725b723a36f7b9d57e04714c6476 100644
--- a/Source/devtools/front_end/responsiveDesignView.css
+++ b/Source/devtools/front_end/responsiveDesignView.css
@@ -72,7 +72,7 @@
 
 .responsive-design-page-scale-container {
     position: absolute !important;
-    bottom: 0;
+    top: 0;
     right: 0;
     padding: 10px;
     background-color: rgba(0, 0, 0, 0.3);
@@ -82,7 +82,7 @@
 .responsive-design-page-scale-label {
     display: block;
     height: 20px;
-    margin: 2px 0;
+    margin: 0 4px;
     padding-top: 3px;
     color: white;
     cursor: default !important;
@@ -476,8 +476,6 @@
     right: 0;
     top: 0;
     padding-bottom: 5px;
-    background-color: rgb(43, 43, 43);
-    box-shadow: inset 0px 5px 7px rgba(0, 0, 0, 0.7);
     overflow: hidden;
 }
 
@@ -487,17 +485,12 @@
     position: relative;
     height: 14px;
     margin: 2px 0;
-    z-index: 1;
-}
-
-.media-inspector-marker-container:hover {
-    z-index: 2;
 }
 
 .media-inspector-marker {
     position: absolute;
-    top: 0px;
-    bottom: 0px;
+    top: 1px;
+    bottom: 1px;
     white-space: nowrap;
     border-radius: 2px;
 }
@@ -506,7 +499,9 @@
     -webkit-filter: brightness(80%);
 }
 
-.media-inspector-marker-highlight {
+.media-inspector-marker:hover {
+    top: -1px;
+    bottom: -1px;
     -webkit-filter: brightness(115%) !important;
 }
 
@@ -523,20 +518,19 @@
     border-right: 2px solid rgb(80, 226, 40);
 }
 
+.media-inspector-marker-min-max-width:hover {
+    z-index: 1;
+}
+
 .media-inspector-marker-min-width {
     background: linear-gradient(to right, rgba(255, 255, 255, 0.27), rgba(0,0,0,0) 30px), linear-gradient(to bottom, rgb(222, 129, 30), rgb(204, 104, 31));
     border-radius: 2px 0 0 2px;
     border-left: 2px solid rgb(255, 181, 142);
 }
 
-.media-inspector-marker-under-highlighted {
-    background: transparent !important;
-    border: none !important;
-}
-
 /* Media query labels */
 
-.media-inspector-marker:not(.media-inspector-marker-highlight) .media-inspector-marker-label-container {
+.media-inspector-marker:not(:hover) .media-inspector-marker-label-container {
     display: none;
 }
 
@@ -552,25 +546,6 @@
     right: -2px;
 }
 
-.media-inspector-marker-serif {
-    position: absolute;
-    top: -60px;
-    bottom: -60px;
-    width: 1px;
-}
-
-.media-inspector-marker-max-width .media-inspector-marker-serif {
-    background-color: rgb(26, 113, 233);
-}
-
-.media-inspector-marker-min-max-width .media-inspector-marker-serif {
-    background-color: rgb(4, 166, 0);
-}
-
-.media-inspector-marker-min-width .media-inspector-marker-serif {
-    background-color: rgb(204, 104, 31);
-}
-
 .media-inspector-marker-label {
     color: rgb(230, 230, 230);
     position: absolute;
@@ -578,6 +553,7 @@
     bottom: 0;
     font-size: 10px;
     text-shadow: rgba(0, 0, 0, 0.6) 1px 1px;
+    pointer-events: none;
 }
 
 .media-inspector-label-right {