Add SSO+2FA and outbound-exposure posts with Excalidraw architecture diagrams; Diagram component serves outlined SVGs

src/pages/blog/[slug].astro

@@ -85,4 +85,16 @@ const { Content } = await render(entry);
   .post__body {
     margin-top: var(--space-7);
   }
+  /* Diagram images (Markdown `![](/diagrams/*.svg)`) sit on a constant light card so the
+     fixed-colour SVGs stay legible in dark mode — mirrors the Diagram.astro component. */
+  .post__body :global(img[src^="/diagrams/"]) {
+    display: block;
+    width: 100%;
+    height: auto;
+    margin: var(--space-6) auto;
+    padding: var(--space-5);
+    background: #f6f8fb;
+    border: 1px solid rgba(2, 6, 23, 0.1);
+    border-radius: var(--radius);
+  }
 </style>