remove lightmode. (it was broken)

src/app.css

@@ -26,6 +26,7 @@ a {
   color: #646cff;
   text-decoration: inherit;
 }
+
 a:hover {
   color: #535bf2;
 }
@@ -54,9 +55,11 @@ button {
   cursor: pointer;
   transition: border-color 0.25s;
 }
+
 button:hover {
   border-color: #646cff;
 }
+
 button:focus,
 button:focus-visible {
   outline: 4px auto -webkit-focus-ring-color;
@@ -71,16 +74,3 @@ button:focus-visible {
   margin: 0 auto;
   text-align: center;
 }
-
-@media (prefers-color-scheme: light) {
-  :root {
-    color: #213547;
-    background-color: #ffffff;
-  }
-  a:hover {
-    color: #747bff;
-  }
-  button {
-    background-color: #f9f9f9;
-  }
-}