Change Slider (t1) Caption Font Size

Go to Theme Options > Advanced > Custom CSS and paste the code given below changing the font size value as you desire.

/* Slider Height on extra small displays */
.caption .inner .t1 {
  font-size: 22px;
}

/* Slider Height on normal display */
@media only screen and (min-width: 480px) {
  .caption .inner .t1 {
    font-size: 36px;
  }
}
/* Slider Height on large displays */
@media only screen and (min-width: 768px) {
  .caption .inner .t1 {
    font-size: 56px;
  }
}