Code issue folder

Hello I have issue with some code.
1. Can you give me an additional code so that when I hover over the project folder it shows the red line on the subcategories?
2. Also my client sent me a screenshot of the site where when he is on one page for example home there is a red line beneath but when he clicks on "projekte" there is another line and when he hovers over a third title there a 3 red lines even though you can't open a page when you are on "projekte". Is it possible to remove that red line from the projects main title because there is no page on the main title
3. Is it possible that the text underneath the project folder are left aligned?

4. On the phone view there is a red button for some reason that I can't get rid off

the website password is: password 

website url: https://www.invest-bau.ch

this is the code

/* Fix dropdown menu */
.header-nav-item--active a {
  background-image: none !important;
}

/* Change the underline color of the top menu links */
.header-nav-item a {
  position: relative;
  text-decoration: none !important;
  color: #FFFFFF; /* Set the color of the link */
}

.header-nav-item a::after, .header-nav-folder-item.header-nav-folder-item--active a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px; /* Adjust the positioning of the underline */
  width: 100%;
  height: 2px; /* Adjust the height of the underline */
  background-color: #D60001; /* Set the color of the underline */
  visibility: hidden;
  opacity: 0;
  transition: opacity 0.4s;
}

.header-nav-item>a:hover::after,
.header-nav-item>a:focus::after,
.header-nav-item--active>a::after, .header-nav-folder-item.header-nav-folder-item--active a::after {
  visibility: visible;
  opacity: 1;
}

/* Optional: Change the underline color when the link is active or focused */
.header-nav-item--active>a::after, .header-nav-folder-item.header-nav-folder-item--active a::after {
  background-color: #D60001; /* Set the color of the underline when the link is active */
}
div.header-nav-item a {
    display: inline-block;
}
span.header-nav-folder-item-content {
    background-image: none !important;
}