Print Preview: Fading in/out printing options.

chrome/browser/resources/print_preview.css

 html {
   height: 100%;
 }
 
 body {
   background: white;
   display: -webkit-box;
   height: 100%;
   margin: 0;
   overflow: hidden;
@@ skipping 464 matching lines @@
 
 span.hint.closing {
   -webkit-transition: margin 100ms, height 100ms, opacity 200ms;
   background: transparent;
   height: 0 !important;
   margin-bottom: 0;
   margin-top: 0;
   opacity: 0;
 }
 
+.option {
+  -webkit-transition: color 200ms;
+  background: white;
+  display: block;
+  height: 0;
+  margin-bottom: 0;
+  margin: 0;
+  overflow: hidden;
+}
+
+.option.visible {
+  -webkit-animation-duration: 200ms;
+  -webkit-animation-fill-mode: forwards;
+  height: auto;
+  margin-bottom: -10px;
+  margin-top: 5px;
+  padding-bottom: 5px;
+}
+
+.option:not(.visible) + hr {
+  display: none;
+}
+
+.option.closing {
+  -webkit-transition: margin 100ms, height 100ms, opacity 200ms;
+  background: transparent;
+  height: 0 !important;
+  margin-bottom: 0;
+  margin-top: 0;
+  opacity: 0;
+}
+
+
 select {
   -webkit-box-shadow: inset 0 1px 2px white,
                       0 1px 2px rgba(0, 0, 0, .2);
   -webkit-appearance: none;
   -webkit-margin-end: -2px;
   -webkit-padding-end: 34px;
   -webkit-padding-start: 14px;
   -webkit-user-select: none;
   background-image: url('./print_preview/black_arrow.png'),
                     -webkit-linear-gradient(#fafafa, #dcdcdc);
@@ skipping 165 matching lines @@
 
 #dancing-dots.invisible {
   -webkit-transition: opacity 0.7s linear;
   opacity: 0;
   pointer-events: none;
 }
 
 #messages {
   color: #404040;
   font-size: 15px;
-  left: 25%;
   position: relative;
   text-align: center;
   text-shadow: 1px 1px 0 rgba(255, 255, 255, .7);
   top: 50%;
-  width: 50%;
 }
 
 html[dir='rtl'] .messages {
   right: 25%;
 }
 
 @-webkit-keyframes dancing-dots-jump {
   0% { top: 0; }
   55% { top: 0; }
   60% { top: -10px; }
@@ skipping 23 matching lines @@
   -webkit-animation-delay: 300ms;
 }
 
 #two-sided-div {
   margin-top: 10px;
 }
 
 input[disabled] + label {
   color: gray;
 }