feat: enhance LongTextGuideCard with detailed layout and improved styles; update mocks and add padding utility

src/static/scss/padding.scss

@@ -231,6 +231,10 @@
   padding-bottom: 16px;
 }
 
+.p-18 {
+  padding: 18px;
+}
+
 .p-20 {
   padding: 20px;
 }