Remove use of background color style on the logger's input fields

Related feedback from the following issue:
- https://github.com/gorhill/uBlock/issues/787#issuecomment-449531979

src/css/logger-ui.css

@@ -10,9 +10,6 @@ body {
     padding: 0;
     width: 100vw;
     }
-input:focus {
-    background-color: #ffe;
-    }
 textarea {
     box-sizing: border-box;
     direction: ltr;
@@ -128,9 +125,6 @@ textarea {
 #netInspector #filterInput > input {
     min-width: 18em;
     }
-#netInspector #filterInput.bad > input {
-    background-color: #fee;
-    }
 #netInspector #maxEntries {
     margin: 0 2em;
     }