v0.38.0

Last release of 2023

• Update bundle format from umd to iife.
• Add @x, @y selectors.
• Add support for function inside@keyframes step names.
• Fix @cycle() grouping.
• Fix shader background resize.
• Improve calc speed inside @nth.
• Improve performance of @once.
• Optimize initial styles update when there's delay or animation.
• Remove @canvas() because I barely used it.
• Reduce preset-size list.
• Remove compatible fix for old Safari.