Heat oven to 350°F (175°C). Line a 9x13-inch pan with parchment paper.
In a bowl, mix graham cracker crumbs, brown sugar, salt, and melted butter. Add vanilla. Stir until it looks like wet sand.
Press the mixture firmly into the pan. Make it tight and even.
Bake for 10 minutes. Remove from oven.
Sprinkle chocolate chips over the hot crust. Wait 2 minutes until soft, then spread gently.
Sprinkle toffee bits evenly on top. Add chopped pecans.
Bake again for 12–15 minutes, until the topping looks set but not dark.
Let cool completely before cutting into bars.