further improve ui contrast and consistency

src/components/UI/card/Card.css

@@ -1,9 +1,9 @@
 @import '../theme.css';
 
 .card {
-  composes: base container rounded depth;
+  composes: base container rounded;
   overflow: hidden;
-  border: 1px solid #f7f8f8;
+  border: 2px solid var(--textFieldBorderColor);
   transition: all .1s ease-in-out;
   transform: translateY(0);
   padding: 16px 24px;

src/components/UI/theme.css

@@ -17,7 +17,7 @@
   --topmostZindex: 99999;
   --foregroundAltColor: #fff;
   --backgroundAltColor: #232528;
-  --textFieldBorderColor: #e7e7e7;
+  --textFieldBorderColor: #e6e6e6;
   --highlightFGColor: #fff;
   --highlightBGColor: #3ab7a5;
   --highlightFGAltColor: #eee;
@@ -40,10 +40,6 @@
   border-radius: var(--borderRadius);
 }
 
-.depth {
-  box-shadow: var(--dropShadow);
-}
-
 .clearfix:after {
   content: '';
   display: table;