body {
  /* background: #ecf0f1;
  color: #050620; */
  background: #050620;
  background: -webkit-radial-gradient(rgba(5,6,32,0.79), rgba(5,6,32,0.91));
  background:    -moz-radial-gradient(rgba(5,6,32,0.79), rgba(5,6,32,0.91));
  background:         radial-gradient(rgba(5,6,32,0.79), rgba(5,6,32,0.91));
  color: #ecf0f1;
  border-bottom: none;
  transition: all 0.3s ease-out;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  height: 100%;
  height: auto;
}

p, li, a {
  font-size: 18px;
  text-decoration: none;
  color: #ecf0f1;
}

nav {
  position: sticky;
  top: 0;
  padding: 40px;
}

ul {
  width: 400px;

  display: flex;
  justify-content: space-between;
}

.section {
  max-width: 700px;
  min-height: 1000px;
  border: 2px solid aqua;
}

.active::after {
  content: '';
  display: block;
  width: 100%;
  height: 4px;
  border-radius: 2px;
  background: yellowGreen;
}