Be honest—who hasn’t stepped out on a sweltering summer day only to find foundation sliding, blush faded, mascara smudged an hour later? We’ve all done emergency touch-ups, but A-list makeup artists have cracked the heat-proof makeup code. Skip thick pre-makeup moisturizer; opt for lightweight, fast-absorbing hydration or a mattifying gripping primer (some even use liquid magnesium!). Ditch heavy foundation—go for tinted SPF as base, spot-correct only where needed, layer thin. What’s your go-to heat-proof makeup hack? Drop it below!