feat: 优化全局样式与组件视觉升级

- 更新 globals.css 全局样式
- 优化 not-found 404 页面
- 升级 footer, mega-dropdown, mobile-tab-bar 布局组件
- 改进 challenge, cta, hero 等核心 section 组件
- 优化 challenge-card, ink-glow-card, product-card 等 UI 组件
- 更新产品常量配置

src/components/sections/methodology-section.tsx

@@ -7,12 +7,7 @@ import { METHODOLOGY } from '@/lib/constants/methodology';
 import { CheckCircle2 } from 'lucide-react';
 import { InkGlowCard } from '@/components/ui/ink-glow-card';
 
-const phaseAccents: { rgb: string; glowStart: string; glowEnd: string }[] = [
-  { rgb: '196, 30, 58', glowStart: 'var(--color-brand-primary)', glowEnd: 'var(--color-warning)' },
-  { rgb: '217, 119, 6', glowStart: 'var(--color-warning)', glowEnd: 'var(--color-success)' },
-  { rgb: '22, 163, 74', glowStart: 'var(--color-success)', glowEnd: 'var(--color-accent-cyan)' },
-  { rgb: '37, 99, 235', glowStart: 'var(--color-accent-blue)', glowEnd: 'var(--color-accent-purple)' },
-];
+const phaseBgOpacities = [0.1, 0.08, 0.12, 0.06];
 
 export function MethodologySection() {
   const ref = useRef(null);
@@ -41,19 +36,16 @@ export function MethodologySection() {
 
           <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-6 md:gap-8">
             {METHODOLOGY.map((phase, idx) => {
-              const accent = phaseAccents[idx % phaseAccents.length]!;
+              const bgOpacity = phaseBgOpacities[idx % phaseBgOpacities.length];
               return (
                 <InkGlowCard
                   key={phase.id}
                   index={idx}
-                  accentColorRgb={accent.rgb}
-                  glowStart={accent.glowStart}
-                  glowEnd={accent.glowEnd}
                 >
                   <div className="p-6 md:p-8">
                     <div
                       className="w-10 h-10 rounded-full flex items-center justify-center mb-5 text-sm font-bold"
-                      style={{ backgroundColor: accent.glowStart, color: 'var(--color-bg-primary)' }}
+                      style={{ backgroundColor: `rgba(var(--color-brand-primary-rgb), ${bgOpacity})`, color: 'var(--color-brand-primary)' }}
                     >
                       {phase.number}
                     </div>