address comments

Author: mmalerba

src/lib/input/input-container.scss

@@ -42,11 +42,19 @@ $mat-input-wrapper-padding-bottom:
 // Applies a floating placeholder above the input itself.
 @mixin mat-input-placeholder-floating {
   display: block;
+
   transform: translateY(-$mat-input-infix-margin-top - $mat-input-infix-padding)
-             // fixes text blurriness, see
-             // https://css-tricks.com/forums/topic/transforms-cause-font-smoothing-weirdness-in-webkit/
-             perspective(1px)
-             scale($mat-input-subscript-font-scale);
+             scale($mat-input-subscript-font-scale)
+             // We use perspecitve to fix the text blurriness as described here:
+             // http://www.useragentman.com/blog/2014/05/04/fixing-typography-inside-of-2-d-css-transforms/
+             // This results in a small jitter after the label floats on Firefox, which the
+             // translateZ fixes.
+             perspective(1px) translateZ(0.001px);
+  // The tricks above used to smooth out the animation on chrome and firefox actually make things
+  // worse on IE, so we don't include them in the IE version.
+  -ms-transform: translateY(-$mat-input-infix-margin-top - $mat-input-infix-padding)
+                 scale($mat-input-subscript-font-scale);
+
   width: 100% / $mat-input-subscript-font-scale;
 }
 
@@ -59,6 +67,7 @@ $mat-input-wrapper-padding-bottom:
   // TODO(mmalerba): should this come from typography settings? If so a lot of this CSS needs to go
   // into some sort of typography mixin.
   line-height: $mat-input-line-height;
+  font-size: 16px;
 
   // To avoid problems with text-align.
   text-align: left;
@@ -213,6 +222,10 @@ $mat-input-wrapper-padding-bottom:
   text-overflow: ellipsis;
   overflow: hidden;
 
+  // The perspective helps smooth out animations on Chrome and Firefox but isn't needed on IE.
+  transform: perspective(1px);
+  -ms-transform: none;
+
   transform-origin: 0 0;
   transition: transform $swift-ease-out-duration $swift-ease-out-timing-function,
               color $swift-ease-out-duration $swift-ease-out-timing-function,