fix(design-v2): make body bg transparent so harbor pseudo shows through

body had opaque background: var(--color-bg) which sat at z-index 0 and
covered the body::before harbor at z-index -3. Switched body to
transparent and put the fallback color on html instead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

public/css/wevisto-design.css

@@ -98,10 +98,14 @@
  */
 [data-design="v2"] body {
   color: var(--color-text);
-  background: var(--color-bg);
+  background: transparent;
   position: relative;
   min-height: 100dvh;
 }
+[data-design="v2"] html {
+  /* Below body's pseudo-elements; shows through if anything has alpha */
+  background: var(--color-bg);
+}
 [data-design="v2"] body::before {
   content: '';
   position: fixed;