blender exports turn blackish,fbx when imported into unity turns blackish/dark

why do blender exports turn blackish when i import hem in unity.,I created materials and assigned them to objects. everything was looking good so i decided to export it as fbx and then imported that fbx into unity. upon importing all the materials turned dark/blackish. can anyone tell me why this is happening and how can i solve this.?169846-capture.png

Select your model in your Assets folder, in the Inspector Panel you see new tab called “Materials”. It will allow you to extract the materials and the textures. Clikc"Extract Textures" there. It is going to ask you where to put them after that. Put them in a new folder like Materials and click okay. And it will create all the textures and image files for you. There might be a message window about fixing the normals just click “Fix Now”. If you select your Material Folder you’ve created in your Assets folder you see all of the textures. If there is another problem about looking of your model, it is probably about shader problem. But in first, Unity does not allow you to modify the “Shader Component”. So you can fix it by again clicking on your model in assets folder and in the Inspector again in the Materials tab, you should click on the “Extract Materials” button. Then you are allowed to change shader of your model in the inspector. If there is a weird looking of your model, like bulging eyes, in your “Shader Component”, click the options begin with “Standart” and change it to “Legacy Shaders” then “Difuse Shader”, It might fix the problem though.