Revise defaults and UI for baseball cost estimator

- Updated initial values for teams, games per team, umpire costs, and team size to reflect a smaller league.
- Expanded fixed cost list with items such as "Umpire Admin", "Digital", and "Trophies".
- Simplified field configuration to a single field covering 100% of games.
- Removed redundant background and text color utility classes for a cleaner and more uniform UI.
- Added derived metrics in the Summary section for improved clarity and budgeting transparency.

src/index.css

@@ -5,8 +5,6 @@
   font-weight: 400;
 
   color-scheme: light dark;
-  color: rgba(255, 255, 255, 0.87);
-  background-color: #242424;
 
   font-synthesis: none;
   text-rendering: optimizeLegibility;
@@ -37,13 +35,14 @@ h1 {
 }
 
 button {
+  @apply text-white;
   border-radius: 8px;
   border: 1px solid transparent;
   padding: 0.6em 1.2em;
   font-size: 1em;
   font-weight: 500;
   font-family: inherit;
-  background-color: #1a1a1a;
+
   cursor: pointer;
   transition: border-color 0.25s;
 }
@@ -53,17 +52,4 @@ button:hover {
 button:focus,
 button:focus-visible {
   outline: 4px auto -webkit-focus-ring-color;
-}
-
-@media (prefers-color-scheme: light) {
-  :root {
-    color: #213547;
-    background-color: #ffffff;
-  }
-  a:hover {
-    color: #747bff;
-  }
-  button {
-    background-color: #f9f9f9;
-  }
-}
+}