Create an enchanting birthday invitation with a Frozen cartoon theme. The invitation should feature a magical winter wonderland setting, sparkling with snowflakes and ice crystals, reminiscent of the movie's iconic scenes. In the center, there should be an elegant, icy-blue castle with ornate frozen spires, glowing softly under a starry night sky. Surrounding the castle, a magical forest of snow-covered trees and a frozen lake can be seen, adding to the mystical ambiance. The foreground should include beloved characters from Frozen, like Elsa and Anna, cheerfully welcoming guests. Elsa, in her shimmering blue gown, is creating a trail of magical ice, while Anna, in her signature green and pink attire, is playfully interacting with a snowman, possibly Olaf, who is wearing a party hat. The characters should exhibit a joyful and inviting demeanor, evoking the warm, celebratory spirit of a birthday party. Incorporate elegant, swirling fonts in icy blue and white tones, prominently displaying the text, 'Join us for a Magical Birthday Adventure!' Additional details like the date, time, and location of the party can be elegantly integrated into the design, perhaps appearing as if they are etched in ice or snow. The overall design should be vibrant and colorful, capturing the enchantment and joy of Frozen, while conveying the warmth and excitement of a birthday celebration. | Anything