Casco literally translates to "helmet". It's a word you'd use for safety gear when riding a motorcycle or bicycle.
However, in this song, Rauw Alejandro uses it as creative slang for "head" in the phrase "me vuelve loco desde el casco hasta los pedales" (she drives me crazy from the helmet to the pedals). This unique metaphor, comparing a person to a vehicle, is a fresh and modern way of saying "from head to toe".
Rauw Alejandro's "Todo De Ti" is a full-on love letter to someone he's completely obsessed with. It's not about deep, complicated feelings; it's about pure, head-over-heels attraction. He's into every single detail, from her hair in the wind to her pink lipstick. He says it all in the chorus: "Y es que me gusta todo de ti" (It's that I like everything about you). He's so overwhelmed by how much he likes her that he can't even pick a favorite part: "De toda tus partes, ¿cuál decido?" (Of all your parts, which do I choose?).
This song has a perfect summer vibe, with him telling her, "Tú combinas con el mar / Ese bikini se ve fenomenal" (You go with the sea / That bikini looks phenomenal). He feels like she's all he needs and wants to spend all his time with her, from waking up in the morning to partying at night. He's totally captivated, and his heart races whenever she's around: "Aceleras to' mis latidos" (You speed up all my heartbeats).