header.css

.umami-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 4%;
}

/* Medium */
@media screen and (min-width: 48rem) {
  /* 768px */
  .umami-header {
    padding-top: 0;
  }
}

/* Extra large + side margins */
@media screen and (min-width: 80rem) {
  /* 1200px (large) + 80px (side margins) = 1280px */
  .umami-header {
    padding: 0;
  }
}

.umami-header__burger {
  width: 41px;
  height: 41px;
  margin-right: -9px;
  /* the padding, margin & transparent border means the hamburger doesn't move on focus/hover */
  padding: 0 6px;
  text-align: left;
  border: 3px solid transparent;
  border-radius: 0;
  background-color: transparent;
  line-height: 1;
}

.umami-header__burger:hover {
  background-color: transparent;
}

.umami-header__burger svg {
  display: block;
}

@media screen and (min-width: 48em) {
  .umami-header__burger {
    display: none;
  }
}

.umami-header__dropdown {
  overflow: hidden;
  flex-basis: 100%;
  max-height: 0;
  transition: max-height 0.5s ease-in;
}

@media screen and (min-width: 48em) {
  .umami-header__dropdown {
    overflow: auto;
    flex-basis: auto;
    max-height: none;
  }
}

.umami-header__burger[aria-expanded="true"] ~ .umami-header__dropdown {
  overflow-y: auto;
  /**
   * An exact max-height value must be set to make possible to animate the menu display.
   * It my not be much larger than the content because that would break the animation.
   * See: https://css-tricks.com/using-css-transitions-auto-dimensions/
   */
  max-height: 18.75rem;
}

.umami-header__logo {
  flex: 0 1 40%;
}

@media screen and (min-width: 48em) {
  .umami-header__logo {
    flex: 0 1 220px;
    margin: 2.5rem 0;
  }
}

File

core/profiles/demo_umami/themes/umami/components/header/header.css

.umami-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 4%;
}

/* Medium */
@media screen and (min-width: 48rem) {
  /* 768px */
  .umami-header {
    padding-top: 0;
  }
}

/* Extra large + side margins */
@media screen and (min-width: 80rem) {
  /* 1200px (large) + 80px (side margins) = 1280px */
  .umami-header {
    padding: 0;
  }
}

.umami-header__burger {
  width: 41px;
  height: 41px;
  margin-right: -9px;
  /* the padding, margin & transparent border means the hamburger doesn't move on focus/hover */
  padding: 0 6px;
  text-align: left;
  border: 3px solid transparent;
  border-radius: 0;
  background-color: transparent;
  line-height: 1;
}

.umami-header__burger:hover {
  background-color: transparent;
}

.umami-header__burger svg {
  display: block;
}

@media screen and (min-width: 48em) {
  .umami-header__burger {
    display: none;
  }
}

.umami-header__dropdown {
  overflow: hidden;
  flex-basis: 100%;
  max-height: 0;
  transition: max-height 0.5s ease-in;
}

@media screen and (min-width: 48em) {
  .umami-header__dropdown {
    overflow: auto;
    flex-basis: auto;
    max-height: none;
  }
}

.umami-header__burger[aria-expanded="true"] ~ .umami-header__dropdown {
  overflow-y: auto;
  /**
   * An exact max-height value must be set to make possible to animate the menu display.
   * It my not be much larger than the content because that would break the animation.
   * See: https://css-tricks.com/using-css-transitions-auto-dimensions/
   */
  max-height: 18.75rem;
}

.umami-header__logo {
  flex: 0 1 40%;
}

@media screen and (min-width: 48em) {
  .umami-header__logo {
    flex: 0 1 220px;
    margin: 2.5rem 0;
  }
}