104 :nth-child(3n){list-style:"Fizz"}:nth-child(5n){list-style:"Buzz"}:nth-child(15n){list-style:"FizzBuzz"}

data:text/html,<style>:nth-child(3n){list-style:"Fizz"}:nth-child(5n){list-style:"Buzz"}:nth-child(15n){list-style:"FizzBuzz"}</style><ol id=o><script>o.innerHTML='<li>'.repeat(99)</script>

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Metaboat an hour ago | parent | next [-]

103 :nth-child(3n){list-style:"Fizz"}:nth-child(5n){list-style:"Buzz"}:nth-child(15n){list-style:"FizzBuzz"

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Metaboat an hour ago | parent [-]

98 :nth-child(5n){list-style:""}:nth-child(3n){list-style:"Fizz"}:nth-child(5n)::after{content:"Buzz"

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Metaboat 32 minutes ago | parent [-]

95 :nth-child(5n){list-style:}:nth-child(3n){list-style:"Fizz"}:nth-child(5n)::after{content:"Buzz

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Metaboat 29 minutes ago | parent [-]

68 :nth-child(3n){list-style:"Fizz"}:nth-child(5n)::after{content:"Buzz

	▲	eurleif 7 minutes ago \| parent [-]
		67 :nth-child(3n){list-style:"Fizz"}:nth-child(5n):after{content:"Buzz

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cefqrn 30 minutes ago | parent | prev [-]

89: :nth-child(3n)::marker{content:"Fizz"var(--b,)}:nth-child(5n){list-style:"Buzz";--b:"Buzz

with help from @bulmenisaurus