In a mixing bowl, combine the graham cracker crumbs, sugar, and melted butter. Mix until well combined and press into the bottom of a 9-inch springform pan. Chill for 30 minutes.

Sprinkle gelatin over cold water and let it bloom for 5 minutes. Microwave until melted and let cool slightly.

Beat cream cheese and powdered sugar until smooth. Mix in lime zest, lime juice, and vanilla extract until combined.

Pour the cooled gelatin into the cream cheese mixture, mixing continuously. Whip the cream until soft peaks form and fold it gently into the mousse.

Pour the mousse over the chilled crust, smooth the top, and refrigerate for at least 4 hours or overnight to set.

Remove from the pan, garnish with lime slices or zest, and serve chilled.