Front and center, illustrate a cartoonish anthropomorphic heart character that is vibrant and muscular, symbolizing the core of the gym family. This heart is adorned with a cheeky grin and sports a sweatband around its top, reminiscent of an 80s fitness icon. It stands proudly, flexing cartoonishly buff arms, with gym gloves and tiny sneakers at the bottom of its ventricles.

Surrounding the heart, integrate whimsical and exaggerated gym equipment to emphasize the fitness theme: colorful dumbbells, a tiny treadmill, a skipping rope, and a yoga mat. Each piece of equipment should be slightly oversized and comically animated, giving them their own personality as if they are part of the gym family too.

In the background, add a hand-drawn gym setting with a whimsical twist. Think of a gym designed by Maurice Sendak: instead of typical walls, depict a forest of leafy vines curling around and over gym apparatus, where the vines bear little hearts as fruit. The walls could be illustrated as a giant open storybook with pages that have escaped the confines of the cover, unfolding into scenes of various fitness activities like Zumba, yoga, and weightlifting.

Add details such as a water bottle with a cheeky face leaning against a heart-shaped weight bench, and a clock on the wall with numbers replaced by tiny hearts, its hands stuck at 2 o'clock (to signify it's always time for love).

Color the scene with vibrant reds, pinks, and purples to reflect the Valentine's theme, while balancing with earthy greens and soft browns for the background. Use dynamic, flowing lines akin to Aubrey Beardsley's work, giving the whole scene an elegant yet lively movement.

At the top of the card, hand-letter the phrase "You are the heart to our gym family!" in bold, playful, Quentin Blake-inspired typography, incorporating small hand-drawn heart motifs around the letters. Below, in a smaller, charming script, add "Happy Valentine's Day" to tie the theme together.

Generated with these themes: You are the heart to our gym family! Happy Valentines day.

Made with ❤️ by AI.