feat: Initialize Svelte frontend with Vite, TailwindCSS, custom theme, and a basic "Hello World" component.

Provider/frontend/src/app.css

@@ -1,31 +1,19 @@
-:root {
-  --bg-primary: #0f172a;
-  --bg-card: #1e293b;
-  --text-primary: #f1f5f9;
-  --text-secondary: #94a3b8;
-  --accent: #38bdf8;
-  --accent-hover: #7dd3fc;
-  --border: #334155;
-}
+@import "tailwindcss";
 
-* {
-  margin: 0;
-  padding: 0;
-  box-sizing: border-box;
-}
-
-body {
-  font-family: system-ui, -apple-system, sans-serif;
-  background-color: var(--bg-primary);
-  color: var(--text-primary);
-  min-height: 100vh;
-  display: flex;
-  justify-content: center;
-  align-items: center;
-}
-
-#app {
-  width: 100%;
-  max-width: 640px;
-  padding: 1rem;
-}
+/*
+ * Custom theme overrides for Calendink ESP32 dashboard.
+ * TailwindCSS v4 uses CSS-based configuration via @theme.
+ */
+@theme {
+  --color-bg-primary: #0f172a;
+  --color-bg-card: #1e293b;
+  --color-bg-card-hover: #263548;
+  --color-text-primary: #f1f5f9;
+  --color-text-secondary: #94a3b8;
+  --color-accent: #38bdf8;
+  --color-accent-hover: #7dd3fc;
+  --color-border: #334155;
+  --color-success: #22c55e;
+  --color-danger: #ef4444;
+  --color-danger-hover: #f87171;
+}