Revert to static JS site (Svelte built, but no CSR); Optimize images

src/app.css

@@ -44,6 +44,66 @@ body {
     color: var(--fg);
 }
 
+/* Lightbox (structure may be created by script.js; ensures styles apply to injected content) */
+.lightbox {
+    align-items: stretch;
+    background: var(--surface-elevated);
+    border: none;
+    border-radius: 8px;
+    box-shadow: var(--lightbox-shadow);
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+    justify-content: center;
+    max-width: 90vw;
+    padding: 0.5rem 1rem;
+    opacity: 0;
+    transition: opacity 0.3s;
+}
+
+.lightbox::backdrop {
+    background: var(--lightbox-backdrop);
+}
+
+.lightbox[open] {
+    opacity: 1;
+}
+
+.lightbox header {
+    display: flex;
+    justify-content: flex-end;
+    padding: 0.25rem 0.25rem 0 0;
+}
+
+.lightbox .lb-close {
+    background: none;
+    border: none;
+    font-size: 2rem;
+    color: var(--fg);
+    cursor: pointer;
+}
+
+.lightbox .lb-content {
+    flex: 1;
+    display: flex;
+    justify-content: center;
+    align-items: center;
+}
+
+.lightbox .lb-content img,
+.lightbox .lb-content video {
+    max-width: 90vw;
+    max-height: 80vh;
+    border-radius: 8px;
+}
+
+.lightbox .lb-caption {
+    color: var(--fg);
+    margin-top: 0.5rem;
+    text-align: center;
+    max-width: 90vw;
+}
+
 .lightbox-open {
     overflow: hidden;
 }