Is it possible to apply CSS transitions inline? Yes

README.md

https://x.com/JLarky/status/1798237763650888101

snippet.ts

const links = document.querySelectorAll('a');
links.forEach((link) => {
  link.style.outline = '10px solid #52c5ea';
  link.style.outlineOffset = '5px';
  link.animate(
    [
      { outlineColor: '#448c4a', outlineOffset: '5px' },
      {
        outlineColor: '#52c5ea',
        outlineOffset: '10px',
        outlineWidth: '15px',
      },
      { outlineColor: '#448c4a', outlineOffset: '5px' },
    ],
    {
      duration: 1000,
      iterations: 30,
    },
  );
});