.base__header {
  position: sticky;
  top: 0;
  display: flex;
  justify-content: space-between;
  background: var(--main-blue);
  padding: 1rem 4rem;
}

@media (max-width: 900px) {
  .base__header {
    padding: 1rem;
  }
}

.base__header nav {
  display: flex;
  align-items: center;
}

.base__header-logo {
  width: 12rem;
  transition: opacity 0.1s;
}

@media (max-width: 900px) {
  .base__header-logo {
    width: 8rem;
  }
}

.base__header-logo:hover {
  opacity: 0.8;
}

.base__header ul {
  display: flex;
  align-items: center;
  list-style-type: none;
  height: 100%;
}

.base__header li {
  display: flex;
  align-items: center;
  margin-right: 2rem;
  height: 100%;
}

@media (max-width: 900px) {
  .base__header li {
    display: none;
  }

  .base__header li:last-child {
    display: flex;
  }
}

.base__header li:last-child {
  margin-right: 0;
}

.base__header-anchor {
  position: relative;
  display: flex;
  align-items: center;
  opacity: 0.85;
  background: transparent;
  font-weight: 500;
  text-decoration: none;
  color: var(--main-dark-blue);
  height: 100%;
}

.base__header-anchor--researchers {
  font-weight: normal;
}

.base__header-anchor:hover:before {
  height: 50%;
}

.base__header-anchor:before {
  position: absolute;
  content: "";
  height: 0;
  left: 0;
  bottom: 0;
  background: #f3f6f9;
  width: 100%;
  transition: 0.2s height cubic-bezier(0.75, 0.01, 0.58, 1);
  z-index: -1;
}