Add basic styles for the landing page

src/css/main.css

@@ -1,3 +1,50 @@
 @tailwind base;
 @tailwind components;
 @tailwind utilities;
+
+@layer base {
+    h1,
+    h2,
+    h3,
+    h4,
+    h5,
+    h6 {
+        @apply block w-full font-bold;
+    }
+    h1 {
+        @apply text-4xl;
+    }
+    h2 {
+        @apply text-2xl;
+    }
+    h3 {
+        @apply text-xl;
+    }
+    h4 {
+        @apply text-lg;
+    }
+    h5 {
+        /* NA */
+    }
+    h6 {
+        @apply text-sm;
+    }
+
+    .main-body {
+        @apply bg-black;
+    }
+
+    .main-container {
+        @apply w-1/2 lg:w-3/4 h-full
+            my-4 mx-auto p-4
+            flex flex-row flex-wrap justify-center
+            border border-black rounded bg-gray-100 space-y-4;
+    }
+
+    .btn {
+        @apply inline-block rounded-lg border text-center font-bold;
+    }
+    .btn--try-now {
+        @apply w-44 py-2 border-blue-700 bg-blue-200 text-xl font-mono;
+    }
+}