feat: add PWA and favicon assets

apple-touch-icon, android-chrome icons (192/512), PNG favicons
(16/32), ICO fallback, and site.webmanifest with heat theme color.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/css/main.css

@@ -577,6 +577,37 @@
   animation: glitch-clip 2.5s steps(1) infinite;
 }
 
+/* ── Nav & footer link hover polish ─────────────────────────── */
+
+/* Desktop nav links — lift + glow on hover */
+header nav a.label {
+  transition: color 0.2s var(--ease-sharp), transform 0.2s var(--ease-out-expo);
+}
+header nav a.label:hover {
+  transform: translateY(-1px);
+}
+
+/* Active underline — smooth width via transition */
+header nav a.label span {
+  transition: width 0.35s var(--ease-out-expo);
+}
+
+/* Footer links — subtle lift */
+footer nav a.label {
+  transition: color 0.2s var(--ease-sharp), transform 0.2s var(--ease-out-expo);
+}
+footer nav a.label:hover {
+  transform: translateY(-1px);
+}
+
+/* Footer social links — icon nudges on hover */
+footer nav a.label svg {
+  transition: transform 0.2s var(--ease-out-expo);
+}
+footer nav a.label:hover svg {
+  transform: translate(1px, -1px);
+}
+
 /* ── View Transitions ────────────────────────────────────────── */
 ::view-transition-old(main-content) {
   animation: 160ms var(--ease-sharp) both page-out;

layouts/partials/head.html

@@ -69,6 +69,11 @@
 {{- end -}}
 <link rel="stylesheet" href="{{ $css.RelPermalink }}"{{ if eq hugo.Environment "production" }} integrity="{{ $css.Data.Integrity }}"{{ end }}>
 
-<!-- Favicon -->
+<!-- Favicon & PWA -->
+<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">
+<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
+<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">
 <link rel="icon" href="/favicon.svg" type="image/svg+xml">
 <link rel="icon" href="/favicon.ico" sizes="any">
+<link rel="manifest" href="/site.webmanifest">
+<meta name="msapplication-TileColor" content="#050510">

static/site.webmanifest

@@ -0,0 +1,19 @@
+{
+  "name": "Pivoine.Art",
+  "short_name": "Pivoine",
+  "icons": [
+    {
+      "src": "/android-chrome-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/android-chrome-512x512.png",
+      "sizes": "512x512",
+      "type": "image/png"
+    }
+  ],
+  "theme_color": "#FF1A8C",
+  "background_color": "#050510",
+  "display": "standalone"
+}