When the mercury begins to climb, makeup artist Fiona Stiles fills her kit with products that won’t melt, smudge or smear. A particular challenge? Dark eye makeup. To ensure clients like Jessica Chastain, Halle Berry and Jennifer Garner don’t turn up on the red carpet with a statement eye that’s more raccoon than cat, Stiles relies on a handful of foolproof products. Below, she divulges her list, along with a few tips and tricks.