feat(website): 官网企业版视觉升级

- 引入 Geist 字体，去除紫色渐变，克制阴影与交互态
- 导航/卡片/按钮统一企业风格，各区块视觉收敛

website/src/sections/Features.tsx

@@ -59,10 +59,10 @@ export default function Features() {
                 />
               </div>
               <div className="p-6">
-                <div className="mb-3 flex h-10 w-10 items-center justify-center rounded-xl border border-primary/25 bg-primary/10 text-primary">
+                <div className="icon-chip mb-3">
                   <Icon className="h-5 w-5" weight="duotone" />
                 </div>
-                <h3 className="mb-2 text-lg font-semibold">{f.title}</h3>
+                <h3 className="mb-2 text-lg font-semibold tracking-tight">{f.title}</h3>
                 <p className="text-sm leading-relaxed text-muted-foreground">
                   {f.desc}
                 </p>