.outlined-text {
  color: white; /* The color of your font */
  text-shadow: 
    -1px -1px 0 black,  /* Top-left */
    1px -1px 0 black,   /* Top-right */
    -1px 1px 0 black,   /* Bottom-left */
    1px 1px 0 black;    /* Bottom-right */
}