feat: UI animation enhancements across all major pages

P1 - Critical UX feedback:
- Add scale-in + slide-up-in entrance animations to profile popover and notification panel
- Port SmoothedProgressBar to EcommercePage (4 generation tools: clone, detail, tryOn, productSet)
- Add result-reveal stagger animation to ecommerce result grids
- Add heart-pop spring animation to CommunityPage favorite toggle

P2 - Visual polish:
- Add scroll-entrance IntersectionObserver animations for HomePage feature sections and experience section
- Add chat-message-in entrance animation to WorkbenchPage message rows
- Fix prefers-reduced-motion accessibility in WelcomeSplash canvas (skip animation, instant entry)

P3 - CSS consolidation:
- Remove conflicting .page-motion definition from legacy-pages.css (keep translateY version from legacy-components.css)
- Consolidate skeleton-shimmer: remove opacity-pulse keyframe from primitives.css, unify with gradient sweep
- Wire up --ease-spring token for heart-pop animation
- Add :active press states (scale 0.97) to topbar buttons, brand lockup

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/styles/components/legacy-components.css

@@ -48,6 +48,9 @@
   background: var(--surface-elevated);
   box-shadow: var(--shadow-elevated);
   backdrop-filter: none;
+  transform-origin: top right;
+  animation: scale-in 150ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both,
+             slide-up-in 150ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;
 }
 
 .profile-popover__head {

src/styles/components/motion.css

@@ -39,6 +39,78 @@
   to { opacity: 1; }
 }
 
+/* Popover / panel entrance utilities */
+.panel-enter {
+  animation: scale-in 150ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both,
+             slide-up-in 150ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;
+}
+
+.backdrop-enter {
+  animation: backdrop-in 140ms ease both;
+}
+
+/* Heart toggle spring animation */
+@keyframes heart-pop {
+  0% { transform: scale(1); }
+  40% { transform: scale(1.3); }
+  70% { transform: scale(0.9); }
+  100% { transform: scale(1); }
+}
+
+.heart-animate {
+  animation: heart-pop 420ms var(--ease-spring, cubic-bezier(0.34, 1.2, 0.64, 1)) both;
+}
+
+/* Result reveal stagger for generation output grids */
+.result-reveal > * {
+  opacity: 0;
+  animation: slide-up-in 320ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;
+}
+
+.result-reveal > *:nth-child(1) { animation-delay: 0ms; }
+.result-reveal > *:nth-child(2) { animation-delay: 80ms; }
+.result-reveal > *:nth-child(3) { animation-delay: 160ms; }
+.result-reveal > *:nth-child(4) { animation-delay: 240ms; }
+.result-reveal > *:nth-child(5) { animation-delay: 320ms; }
+.result-reveal > *:nth-child(n+6) { animation-delay: 400ms; }
+
+/* Scroll-triggered entrance: hidden until revealed by IntersectionObserver */
+.scroll-entrance {
+  opacity: 0;
+  transform: translateY(16px);
+  transition: opacity 480ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)),
+              transform 480ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1));
+}
+
+.scroll-entrance.is-visible {
+  opacity: 1;
+  transform: translateY(0);
+}
+
+.scroll-entrance.is-visible > * {
+  animation: slide-up-in 380ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;
+}
+
+.scroll-entrance.is-visible > *:nth-child(1) { animation-delay: 60ms; }
+.scroll-entrance.is-visible > *:nth-child(2) { animation-delay: 140ms; }
+.scroll-entrance.is-visible > *:nth-child(3) { animation-delay: 220ms; }
+
+/* Chat message entrance animation */
+@keyframes chat-message-in {
+  from {
+    opacity: 0;
+    transform: translateY(10px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
+}
+
+.chat-message-enter {
+  animation: chat-message-in 220ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;
+}
+
 /* Stagger utility: apply to parent, children get delayed entrance */
 .motion-stagger > * {
   animation: list-item-in 280ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;

src/styles/components/primitives.css

@@ -29,7 +29,8 @@
   width: 40%;
   height: 24px;
   border-radius: 8px;
-  background: var(--surface-elevated, #222);
+  background: linear-gradient(90deg, rgba(255,255,255,0.04), rgba(255,255,255,0.1), rgba(255,255,255,0.04));
+  background-size: 220% 100%;
   animation: skeleton-shimmer 1.4s ease infinite;
 }
 
@@ -42,7 +43,8 @@
   flex: 1;
   height: 140px;
   border-radius: 14px;
-  background: var(--surface-elevated, #222);
+  background: linear-gradient(90deg, rgba(255,255,255,0.04), rgba(255,255,255,0.1), rgba(255,255,255,0.04));
+  background-size: 220% 100%;
   animation: skeleton-shimmer 1.4s ease infinite;
   animation-delay: 0.15s;
 }
@@ -51,16 +53,12 @@
   width: 100%;
   height: 200px;
   border-radius: 14px;
-  background: var(--surface-elevated, #222);
+  background: linear-gradient(90deg, rgba(255,255,255,0.04), rgba(255,255,255,0.1), rgba(255,255,255,0.04));
+  background-size: 220% 100%;
   animation: skeleton-shimmer 1.4s ease infinite;
   animation-delay: 0.3s;
 }
 
-@keyframes skeleton-shimmer {
-  0%, 100% { opacity: 0.4; }
-  50% { opacity: 0.7; }
-}
-
 .page-transition-wrap {
   width: 100%;
   height: 100%;

src/styles/pages/ecommerce.css

@@ -9,6 +9,48 @@
   font-family: Inter, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
 }
 
+/* Ecommerce generation progress bar */
+.ecommerce-progress-bar {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  padding: 10px 16px;
+  border-radius: var(--radius-sm, 10px);
+  background: rgba(var(--accent-rgb, 0, 255, 136), 0.08);
+  border: 1px solid rgba(var(--accent-rgb, 0, 255, 136), 0.18);
+  margin: 8px 0;
+}
+
+.ecommerce-progress-bar__label {
+  font-size: 13px;
+  font-weight: 700;
+  color: var(--fg-muted, #aeb8b1);
+  white-space: nowrap;
+}
+
+.ecommerce-progress-bar__track {
+  flex: 1;
+  height: 6px;
+  border-radius: 999px;
+  background: rgba(var(--accent-rgb, 0, 255, 136), 0.12);
+  overflow: hidden;
+}
+
+.ecommerce-progress-bar__fill {
+  height: 100%;
+  border-radius: 999px;
+  background: var(--accent, #00ff88);
+  transition: width 80ms linear;
+}
+
+.ecommerce-progress-bar__value {
+  font-size: 12px;
+  font-weight: 900;
+  color: var(--accent, #00ff88);
+  min-width: 40px;
+  text-align: right;
+}
+
 /* Product set page: target dark two-column workspace with floating detail input. */
 .product-clone-page[data-tool="set"] {
   display: block;

src/styles/pages/legacy-pages.css

@@ -14271,19 +14271,6 @@
 }
 
 /* ─── Page Motion Animation ─── */
-.page-motion {
-  animation: pixel-page-enter 0.3s ease-out;
-}
-
-@keyframes pixel-page-enter {
-  from {
-    opacity: 0;
-  }
-  to {
-    opacity: 1;
-  }
-}
-
 /* ─── Workbench Page Layout Overrides ─── */
 .ai-workbench-page.is-active .ai-workbench-shell {
   grid-template-columns: 1fr auto;
@@ -14865,6 +14852,8 @@
   display: flex;
   flex-direction: column;
   overflow: hidden;
+  animation: scale-in 150ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both,
+             slide-up-in 150ms var(--ease-out-expo, cubic-bezier(0.16, 1, 0.3, 1)) both;
 }
 
 .notification-center__header {

src/styles/shell/app-shell.css

@@ -135,6 +135,11 @@
   font-size: 15px;
   font-weight: 900;
   cursor: pointer;
+  transition: opacity 160ms ease;
+}
+
+.brand-lockup:active {
+  opacity: 0.85;
 }
 
 .brand-lockup__mark {
@@ -303,6 +308,15 @@
   background: var(--bg-hover);
 }
 
+.creator-button:active,
+.member-button:active,
+.profile-button:active,
+.icon-button:active,
+.theme-toggle:active {
+  transform: scale(0.97);
+  transition-duration: 80ms;
+}
+
 .profile-button--guest:hover {
   background: rgba(var(--accent-rgb), 0.88);
   color: #07100b;