.field--name-field-banner {
  display: flex;
  flex-wrap: wrap;
}

.field--name-field-banner > .field--item {
  width: 20%;
}

.banner-item {
  position: relative;
  text-align: center;
}

.banner-item .field--name-field-text {
  position: absolute;
  top: calc(50% - 6px);
  left: 0;
  width: 100%;
  font-size: 12px;
  color: white;
  text-shadow: 1px 1px 2px black;
  font-weight: bold;
}

.banner-item img {
  width: 100%;
}

@media screen and (max-width: 768px) {
  .field--name-field-banner > .field--item {
    width: 50%;
  }
}