win/lose feedback, mobile kb style

src/App.css

@@ -25,6 +25,19 @@ body {
   font-weight: bold;
 }
 
+.App {
+  display: flex;
+  flex-direction: column;
+  max-width: 500px;
+  margin: 0 auto;
+  justify-content: center;
+}
+
+.Game {
+  display: flex;
+  flex-direction: column;
+}
+
 .Game-keyboard {
   display: flex;
   flex-direction: column;
@@ -33,22 +46,31 @@ body {
 .Game-keyboard-row {
   display: flex;
   flex-direction: row;
-  justify-content: center;
+  justify-content: stretch;
 }
 
 .Game-keyboard-button {
   margin: 2px;
   background-color: #cdcdcd;
-  padding: 4px;
+  padding: 2px;
   text-transform: capitalize;
   border-radius: 4px;
-  min-width: 25px;
+  min-height: 40px;
+  display: flex;
+  flex: 1;
+  align-items: center;
+  justify-content: center;
+  font-size: 20px;
   color: inherit;
   text-decoration: inherit;
   border: inherit;
   cursor: pointer;
 }
 
+.Game-keyboard-button-wide {
+  flex: 2;
+}
+
 .Game-keyboard-button:focus {
   outline: none;
 }