mdb-ui-kit/scss/includes/_typography.scss

body, h1, h2, h3, h4, h5, h6, .h1, .h2, .h3, .h4 {
  //font-family: $font-family-sans-serif;
  //font-weight: 300;
}

h5, h6{
  font-weight: 400;
}

.text-warning {
  color: $brand-warning;
}
.text-primary {
  color: $brand-primary;
}
.text-danger {
  color: $brand-danger;
}
.text-success {
  color: $brand-success;
}
.text-info {
  color: $brand-info;
}