refactor: update landing page layout and styles for Schafkopf Bot

frontend/src/app.css

@@ -1,79 +1,32 @@
 :root {
-  font-family: system-ui, Avenir, Helvetica, Arial, sans-serif;
-  line-height: 1.5;
-  font-weight: 400;
+  --font-family: system-ui, Avenir, Helvetica, Arial, sans-serif;
+  --bg: #0b0b0b;
+  --surface: #121212;
+  --text: #eaeaea;
+  --muted: #9aa3b2;
+  --accent: #7c6cff;
+}
 
-  color-scheme: light dark;
-  color: rgba(255, 255, 255, 0.87);
-  background-color: #242424;
-
-  font-synthesis: none;
-  text-rendering: optimizeLegibility;
+* { box-sizing: border-box; }
+html, body { height: 100%; }
+body {
+  margin: 0;
+  font-family: var(--font-family);
+  color: var(--text);
+  background: linear-gradient(180deg, var(--bg), var(--surface));
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
 }
 
-a {
-  font-weight: 500;
-  color: #646cff;
-  text-decoration: inherit;
-}
-a:hover {
-  color: #535bf2;
-}
+a { color: var(--accent); text-decoration: none; }
+a:hover { opacity: 0.9; }
 
-body {
-  margin: 0;
-  display: flex;
-  place-items: center;
-  min-width: 320px;
-  min-height: 100vh;
-}
+/* utility container used by App.svelte */
+.container { max-width: 1100px; margin: 0 auto; padding: 1.25rem; }
 
-h1 {
-  font-size: 3.2em;
-  line-height: 1.1;
-}
-
-.card {
-  padding: 2em;
-}
-
-#app {
-  max-width: 1280px;
-  margin: 0 auto;
-  padding: 2rem;
-  text-align: center;
-}
-
-button {
-  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;
-}
-button:hover {
-  border-color: #646cff;
-}
-button:focus,
-button:focus-visible {
-  outline: 4px auto -webkit-focus-ring-color;
-}
+/* accessible focus styles */
+:focus { outline: 3px solid rgba(124,108,255,0.18); outline-offset: 2px; }
 
 @media (prefers-color-scheme: light) {
-  :root {
-    color: #213547;
-    background-color: #ffffff;
-  }
-  a:hover {
-    color: #747bff;
-  }
-  button {
-    background-color: #f9f9f9;
-  }
+  :root { --bg: #fafafa; --surface:#fff; --text:#111827; --muted:#556; }
 }