A negative radius inside a linear gradient becomes invalid CSS after running it through LightningCSS:
https://lightningcss.dev/playground/#%7B%22minify%22%3Atrue%2C%22customMedia%22%3Atrue%2C%22cssModules%22%3Afalse%2C%22analyzeDependencies%22%3Afalse%2C%22targets%22%3A%7B%22chrome%22%3A6684672%7D%2C%22include%22%3A0%2C%22exclude%22%3A0%2C%22source%22%3A%22.foo%20%7B%5Cn%20%20background%3A%20linear-gradient(-1.42109e-14deg%2C%20rgba(10%2C%20132%2C%20255%2C%200.14)%200%25%2C%20rgba(112%2C%20183%2C%20255%2C%200.14)%20100%25)%3B%5Cn%7D%22%2C%22visitorEnabled%22%3Afalse%2C%22visitor%22%3A%22%7B%5Cn%20%20Color(color)%20%7B%5Cn%20%20%20%20if%20(color.type%20%3D%3D%3D%20'rgb')%20%7B%5Cn%20%20%20%20%20%20color.g%20%3D%200%3B%5Cn%20%20%20%20%20%20return%20color%3B%5Cn%20%20%20%20%7D%5Cn%20%20%7D%5Cn%7D%22%2C%22unusedSymbols%22%3A%5B%5D%2C%22version%22%3A%22local%22%7D

background: linear-gradient(-1.42109e-14deg, rgba(10, 132, 255, 0.14) 0%, rgba(112, 183, 255, 0.14) 100%); is perfectly valid when used in a browser, however --1.42109e-14deg is not.