UI improve of recipes section

In the Recipes section, I noticed some UI improvements could be made:

1. The `Random` picker box takes up too much width; it would be better if we adjusted the Hero section layout to make it more balanced.

2. The selected recipe cards don't look polished; they should be centered within the cards and given a more refined, polished appearance.

### Screenshot:

從 Recipes 區段開始，檢查 Hero layout、Random picker box 和 selected recipe card components。將目前的 UI 與附上的螢幕截圖進行比較，然後調整 layout 平衡和卡片對齊方式，使 picker 使用較少的寬度，並讓卡片呈現置中且精緻的效果。確認 Recipes 區段在相關 viewport sizes 下能正確渲染。

由索引模型根據 Issue 內容生成。