144, using css variables, with fallback and p instead of li

https://codepen.io/dsmmcken/pen/WbwYOEQ?editors=0100

p{counter-increment:n;--n:counter(n)}p:nth-child(3n){--f:"Fizz"}p:nth-child(5n){--b:"Buzz";--n:''}p::after{content:var(--f,var(--n))var(--b,'')}