噪点渐变背景

Create a dark section with a slow-shifting gradient background and a semi-transparent noise texture overlay. The gradient should move between deep purple, blue, and black tones. The noise should add analog grain without reducing readability. Use CSS gradients, SVG filters for noise, and keyframes for the gradient animation. Use Tailwind CSS. Center a short headline and paragraph.

创建一个深色区域，带有缓慢变化的渐变背景和半透明噪点纹理叠加。渐变应在深紫、蓝和黑色调之间移动。噪点应添加模拟颗粒感而不降低可读性。使用 CSS 渐变、SVG 滤镜生成噪点、keyframes 实现渐变动画。使用 Tailwind CSS。居中放置短标题和段落。