Add fade-out effect on the last visible paragraph of access-restricted posts

Uses a CSS mask gradient on the last <p> child of .gh-content, scoped via
:has() to only apply when a .gh-post-upgrade-cta sibling is present.

This gives readers a visual cue that the article continues beyond the
preview, a common pattern on paywalled content (Medium, Substack, NYT…).
No HTML changes, no new files.

Author: bst1n

assets/built/screen.css

@@ -2266,6 +2266,15 @@ unless a heading is the very first element in the post content */
     font-family: var(--font-mono);
 }
 
+/* Fade out the last visible paragraph on access-restricted posts so it's
+   obvious to the reader that the article continues beyond the preview.
+   Scoped via :has() to only apply when the upgrade CTA is present, so
+   regular posts are unaffected. */
+.gh-content:has(> .gh-post-upgrade-cta) > p:last-of-type {
+    -webkit-mask-image: linear-gradient(to bottom, var(--color-black) 1%, transparent 100%);
+    mask-image: linear-gradient(to bottom, var(--color-black) 1%, transparent 100%);
+}
+
 /* 16. Cards
 /* ---------------------------------------------------------- */