fix(canvas): 画布交互 - 优化节点视觉、分镜列与滑动性能

web/src/components/canvas/canvas-node-prompt-panel.tsx

@@ -113,7 +113,7 @@ export function CanvasNodePromptPanel({ node, isRunning, onPromptChange, onConfi
     } as CSSProperties;
     const composerSurfaceStyle = {
         ...composerTokens,
-        border: `1px solid ${theme.node.edge}`,
+        border: `1px solid color-mix(in srgb, ${theme.node.edge} 42%, transparent)`,
         background: theme.node.panel,
         color: theme.node.text,
         boxShadow: theme.node.shadow,