refactor: enhance UI components and improve styling consistency across chat interface

web/styles/main.scss

@@ -4,31 +4,6 @@
 $thumb: #cbd5e1;
 $thumb-hover: #94a3b8;
 
-textarea.cs-agent-scrollbar {
-  scrollbar-width: thin;
-  scrollbar-color: $thumb transparent;
-
-  &::-webkit-scrollbar {
-    width: 8px;
-  }
-
-  &::-webkit-scrollbar-track {
-    background: transparent;
-  }
-
-  &::-webkit-scrollbar-thumb {
-    border: 2px solid transparent;
-    border-radius: 999px;
-    background: $thumb;
-    background-clip: padding-box;
-  }
-
-  &::-webkit-scrollbar-thumb:hover {
-    background: $thumb-hover;
-    background-clip: padding-box;
-  }
-}
-
 .cs-agent-scrollbar {
   scrollbar-width: thin;
   scrollbar-color: $thumb transparent;
@@ -54,73 +29,6 @@ textarea.cs-agent-scrollbar {
   }
 }
 
-.cs-agent-shell {
-  /* 与 widget 保持一致：容器本身不额外加 padding。 */
-}
-
-.cs-agent-panel {
-  border-radius: 28px;
-  box-shadow:
-    0 24px 80px rgba(15, 23, 42, 0.14),
-    0 10px 24px rgba(15, 23, 42, 0.08);
-  backdrop-filter: blur(16px);
-}
-
-.cs-agent-grid-bg,
-.\.cs-agent-grid-bg {
-  background-image:
-    radial-gradient(circle at top, rgba(255, 255, 255, 0.72), transparent 32%),
-    linear-gradient(180deg, rgba(247, 249, 252, 0.92) 0%, rgba(238, 244, 251, 0.94) 100%),
-    linear-gradient(rgba(148, 163, 184, 0.08) 1px, transparent 1px),
-    linear-gradient(90deg, rgba(148, 163, 184, 0.08) 1px, transparent 1px);
-  background-size:
-    auto,
-    auto,
-    22px 22px,
-    22px 22px;
-  background-position:
-    center top,
-    center,
-    center,
-    center;
-}
-
-.cs-agent-fade-up {
-  animation: cs-agent-fade-up 220ms ease-out;
-}
-
-.cs-agent-status-dot {
-  animation: cs-agent-pulse 1.8s ease-in-out infinite;
-}
-
-@keyframes cs-agent-fade-up {
-  from {
-    opacity: 0;
-    transform: translate3d(0, 8px, 0);
-  }
-
-  to {
-    opacity: 1;
-    transform: translate3d(0, 0, 0);
-  }
-}
-
-@keyframes cs-agent-pulse {
-  0%,
-  100% {
-    transform: scale(1);
-  }
-
-  50% {
-    transform: scale(1.08);
-  }
-}
-
-/* 图片预览：遮罩在 dialog 内部绘制，避免与原生 ::backdrop 叠色 */
-.cs-agent-image-lightbox::backdrop {
-  background: transparent;
-}
-
 .dark .cs-agent-scrollbar {
   scrollbar-color: hsl(var(--border)) transparent;