.header-div {
  width: 100%;
  margin: 0 auto;
  padding: 15px 0px 15px 0px;
}

.thumbnail-img {
  height: 150px;
  margin: auto;
  display: flex;
}

.thumbnail-text {
  text-align: center;
  font-family: "Courier New", Courier, monospace;
  font-size: 14px;
  padding-bottom: 12px;
  margin-top: 15px;
}

.header-nav-list {
  display: flex;
  justify-content: center;
  gap: 12px;
  transition: transform 0.3s ease;
}

.header-nav-list.is-fixed {
  position: fixed;
  top: 0;
  z-index: 9999;
  background: rgba(252, 240, 235, 0.625);
  width: 280px;
  left: calc(50% - 140px);
  box-shadow: 0 0 25px rgba(255, 0, 0, 0.1);
  padding: 10px 0;
  backdrop-filter: blur(5px);
  transform: translateY(15px);
  border-radius: 45px;
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.15);
  transition: all 0.3s ease;
}

.header-nav-list a {
  padding: 6px 8px;
  color: black;
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.header-nav-list-illustration,
.header-nav-list-projects {
  padding: 6px 8px;
  border: none;
  background-color: transparent;
  font: inherit;
  cursor: pointer;
  position: relative;
  /* so ::after positions relative to the button */
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

/* the animated underline */
.header-nav-list-illustration::after,
.header-nav-list-projects::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: .05rem;
  /* thickness of the bar */
  background-color: black;
  transform: scaleX(0);
  /* start hidden */
  transform-origin: left;
  /* animates left→right */
  transition: transform 0.3s ease;
}

/* when activated, scale to full width */
.header-nav-list-illustration.activated::after,
.header-nav-list-projects.activated::after {
  transform: scaleX(1);
}

@media (max-aspect-ratio: 1/1) {
  .header-div {
    padding: 5px 0px 10px 0px;
  }

  .thumbnail-img {
    height: 7rem;
  }

  .thumbnail-text {
    padding-bottom: 5px;
    font-size: 0.6rem;
    font-weight: bold;
  }

  .header-nav-list a,
  .header-nav-list-illustration,
  .header-nav-list-projects {
    font-size: 0.8rem;
    padding: 3px 3px 3px 3px;
  }

  .header-nav-list.is-fixed {
    top: 10px;
    width: 250px;
    left: calc(50% - 125px);
    box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.15);
  }
}