CSS snippet from this article https://wptips.dev/gutenberg-custom-styles

my-editor.css

/* ADMIN CSS */

/* Media Text: Half Bg */

.wp-block-media-text.is-style-half-bg {
  --columnMedia: 4fr;
  --columnContent: 3fr;

  background-color: transparent !important;
  padding-top: 2rem;
  padding-bottom: 2rem;
}

.wp-block-media-text.is-style-half-bg::before {
  content: "";
  position: absolute;
  top: 0;
  left: -2rem;
  bottom: 0;
  width: calc(50% + 2rem);
  background-color: var(--bgColor, rgba(0,0,0,.1));
}

.wp-block-media-text.is-style-half-bg.has-media-on-the-right::before {
  left: auto;
  right: -2rem;
}


/* Heading: Stars */

.is-style-stars {
  display: flex;
  flex-wrap: wrap;

  background-color: transparent !important;
  padding: 0 !important;
}

.is-style-stars::before {
  content: "\2605 \2605 \2605 \2605 \2605";
  order: 2;
  display: block;
  width: 100%;
  font-size: 14px;
  letter-spacing: 2px;
  color: var(--bgColor, currentColor);
}


/* Button: Outline arrow */

.wp-block-button.is-style-outline-arrow .wp-block-button__link {
  position: relative;
  overflow: visible;
  background-color: transparent;
  border: 2px solid;
  border-radius: 4px;
  padding-right: 2rem;
  margin-right: 1.5rem;

  letter-spacing: 1px;
  text-transform: uppercase;
}

.wp-block-button.is-style-outline-arrow .wp-block-button__link::after {
  content: "";
  position: absolute;
  top: 50%;
  right: 0;
  transform: translateX(50%) translateY(-50%);
  display: inline-block;
  width: 40px;
  height: 10px;
  background: url('https://raw.github.com/hrsetyono/cdn/master/wptips/2020-12/button-arrow.svg') center center no-repeat;
  background-size: 100% auto;
}

my-style.css

/* FRONTEND CSS */

/* Media Text: Half Bg */

.wp-block-media-text.is-style-half-bg {
  position: relative;
  position: relative;
  background-color: transparent !important;
  padding-top: 2rem;
  padding-bottom: 2rem;
  column-gap: 2rem;
}

@media (min-width: 768px) {
  .wp-block-media-text.is-style-half-bg {
    grid-template-columns: 4fr 3fr;
  }

  .wp-block-media-text.is-style-half-bg.has-media-on-the-right {
    grid-template-columns: 3fr 4fr;
  }
}

.wp-block-media-text.is-style-half-bg .wp-block-media-text__media,
.wp-block-media-text.is-style-half-bg .wp-block-media-text__content {
  position: relative;
  z-index: 2;
  padding: 0;
}

.wp-block-media-text.is-style-half-bg::before {
  content: "";
  position: absolute;
  top: 0;
  left: -2rem;
  bottom: 0;
  width: calc(50% + 2rem);
  background-color: var(--bgColor, rgba(0,0,0,.1));
}

.wp-block-media-text.is-style-half-bg.has-media-on-the-right::before {
  left: auto;
  right: -2rem;
}

@media (max-width: 768px) {
  .wp-block-media-text.is-style-half-bg::before,
  .wp-block-media-text.is-style-half-bg.has-media-on-the-right::before {
    width: calc(100% + 2rem);
    bottom: auto;
    height: 300px;
    left: -1rem;
    right: -1rem;
  }
}

/* Heading: Stars */

.is-style-stars {
  display: flex;
  flex-wrap: wrap;

  background-color: transparent !important;
  padding: 0 !important;
}

.is-style-stars::before {
  content: "\2605 \2605 \2605 \2605 \2605";
  order: 2;
  display: block;
  width: 100%;
  font-size: 14px;
  letter-spacing: 2px;
  color: var(--bgColor, currentColor);
}


/* Button: Outline arrow */

.wp-block-button.is-style-outline-arrow .wp-block-button__link {
  position: relative;
  overflow: visible;
  background-color: transparent;
  border: 2px solid;
  border-radius: 4px;
  padding: 0.5rem 1.5rem;
  margin-right: 1.5rem;

  letter-spacing: 1px;
  text-transform: uppercase;
}

.wp-block-button.is-style-outline-arrow .wp-block-button__link::after {
  content: "";
  position: absolute;
  top: 50%;
  right: 0;
  transform: translateX(50%) translateY(-50%);
  display: inline-block;
  width: 40px;
  height: 10px;
  background: url('https://raw.github.com/hrsetyono/cdn/master/wptips/2020-12/button-arrow.svg') center center no-repeat;
  background-size: 100% auto;
}