.fourth {
  height: 75%;
  width: 100%;
  display: flex;
  position: relative;
}

.form-background {
  position: absolute;
  filter: sepia(66%);
  object-fit: cover;
  box-sizing: border-box;
  display: flex;

  width: 100%;
  height: 80%;
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 1), rgba(0, 0, 0, 0));
  -webkit-mask-image: linear-gradient(
    to bottom,
    rgba(0, 0, 0, 1),
    rgba(0, 0, 0, 0)
  );
  z-index: 0;
  flex-direction: column;
  justify-content: center;
  align-items: flex-end;
  overflow: hidden;
}

.form-background .video-style {
  pointer-events: none;
  filter: sepia(80%);
}

.form-container.submitted {
  transition: transform 0.5s ease, opacity 0.5s ease;
  transform: scale(0.5);
  opacity: 0;
}

.thankyou-box {
  opacity: 0;
  transition: opacity 0.5s ease;
}

.thankyou-box.visible {
  opacity: 1;
}

@media screen and (max-width: 768px) {
  .fourth {
    height: auto;
    flex-direction: column;
    padding-bottom: 32px;
  }
  .form-background {
    position: relative;
    height: 200px; /* ggf. anpassen */
    mask-image: none;
    -webkit-mask-image: none;
  }
}