StayFocus 是一款免费的 Chrome 扩展，用于替代收费版的 BlockSite，支持自定义阻塞站点，在工作和学习中保持专注并提高生产力。 StayFocusd is a free Chrome extension designed to replace the paid version of BlockSite, featuring customizable site blocking to help maintain focus and increase productivity during work and study.