.overlay {
  height: 0%;
  width: 100%;
  position: fixed;
  color: white;
  z-index: 1;
  top: 0;
  left: 0;
  overflow-y: hidden;
  transition: 0.75s;
}

.panel-menu {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s ease-out;
}

.accordion-menu,
.accordion-menu:hover {
  background-color: var(--skobeloff);
  color: white;
  cursor: pointer;
  width: 100%;
  text-align: left;
  border: none;
  transition: 0.4s;
}

/* Mantiene la sottolineatura sugli elementi del menu */
a.overlay-link:hover,
a.overlay-link:focus,
a.overlay-link:active,
a.panel-link:hover,
a.panel-link:focus,
a.panel-link:active {
  transform: none !important;
  font-family: inherit !important;
  font-size: inherit !important;
  text-decoration: underline !important;
}

/*
 * Indicatore di focus visibile per navigazione da tastiera.
 * Importante: non utilizzare outline: none.
 */
.header-menu a:focus-visible,
.header-menu button:focus-visible {
  outline: 3px solid #FFFFFF;
  outline-offset: 4px;
}

/* Focus specifico per link e accordion dell'overlay */
a.overlay-link:focus-visible,
a.panel-link:focus-visible,
.accordion-menu:focus-visible {
  outline: 3px solid #FFFFFF;
  outline-offset: 4px;
  text-decoration: underline !important;
}

/*
 * Fallback per browser che non supportano :focus-visible.
 * Il @supports evita di mostrare inutilmente il focus al click
 * nei browser moderni.
 */
@supports not selector(:focus-visible) {
  .header-menu a:focus,
  .header-menu button:focus {
    outline: 3px solid #FFFFFF;
    outline-offset: 4px;
  }
}