chore: upgrade tailwind css from 3.4 to 4.3

assets/styles/app.css

@@ -1,7 +1,34 @@
-@import "tailwindcss/base";
-@import "_base.css";
+@import "tailwindcss";
+@import "./_base.css" layer(base);
+@import "./_components.css" layer(components);
 
-@import "tailwindcss/components";
-@import "_components.css";
+@plugin "@tailwindcss/forms";
 
-@import "tailwindcss/utilities";
+@source inline("rotate-90");
+
+@theme {
+    --font-sans: Lato, sans-serif;
+    --font-weight-semibold: 700;
+    --font-weight-bold: 900;
+    --color-primary: #3d8ccb;
+    --color-secondary: #f9c700;
+}
+
+/*
+ * Tailwind 3 defaults that Tailwind 4 changed: borders were gray-200 instead of currentColor,
+ * and buttons had a pointer cursor.
+ */
+@layer base {
+    *,
+    ::after,
+    ::before,
+    ::backdrop,
+    ::file-selector-button {
+        border-color: var(--color-gray-200, currentcolor);
+    }
+
+    button:not(:disabled),
+    [role="button"]:not(:disabled) {
+        cursor: pointer;
+    }
+}