.nav_fix {
  position: sticky;
  top: 0;
  z-index: 3;
}

.custom_mt {
  margin-top: 10%;
}

.banner {
  height: 500px;
  background: rgba(0, 0, 0, 0.75)
    url("https://media.istockphoto.com/photos/landscape-on-planet-mars-scenic-desert-scene-on-the-red-planet-picture-id1142542838?k=20&m=1142542838&s=612x612&w=0&h=63P3SJZjC8BvPncrPyuoMlfFcK1EnOBVmsjRWyZgqVY=")
    center center fixed;
  background-size: cover;
}
.custom_img {
  height:300px;
  width: 100%;
}

.custom_shadow {
  background-color: #f0f0f0;
}