* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.header {
  height: 10vh;
  background-image: linear-gradient(to right bottom, rgba(126, 213, 111, 0.4), rgba(40, 180, 131, 0.4)),
    url('../img/pixabay_waves-g9a31aaaec_640.jpg');
  background-size: cover;
  background-position: center;

  clip-path: polygon(0 0, 100% 0, 100% 55%, 0 100%);
}

.section_a {
  height: 20vh;
  background-image: linear-gradient(to right bottom, rgba(126, 213, 111, 0.4), rgba(40, 180, 131, 0.4)),
    url('../img/pixabay_waves-g9a31aaaec_640.jpg');
  background-size: cover;
  background-position: center;

  /* triangle: */
  clip-path: polygon(0 0, 100% 50%, 100% 50%, 0 100%);
}

.section_b {
  height: 20vh;
  background-image: linear-gradient(to right bottom, rgba(126, 213, 111, 0.4), rgba(40, 180, 131, 0.4)),
    url('../img/pixabay_waves-g9a31aaaec_640.jpg');
  background-size: cover;
  background-position: center;

  /* triangle: */
  clip-path: polygon(50% 0, 50% 0, 100% 100%, 0 100%);
}

.section_c {
  height: 20vh;
  background-image: linear-gradient(to right bottom, rgba(126, 213, 111, 0.4), rgba(40, 180, 131, 0.4)),
    url('../img/pixabay_waves-g9a31aaaec_640.jpg');
  background-size: cover;
  background-position: center;

  /* Right arrow */
  clip-path: polygon(0% 20%, 60% 20%, 60% 0%, 100% 50%, 60% 100%, 60% 80%, 0% 80%);
}

.section_d {
  height: 40vh;
  background-image: linear-gradient(to right bottom, rgba(126, 213, 111, 0.4), rgba(40, 180, 131, 0.4)),
    url('../img/pixabay_waves-g9a31aaaec_640.jpg');
  background-size: cover;
  background-position: center;

  clip-path: polygon(0% 20%, 100% 0%, 100% 80%, 0% 100%);
}