.hover-image {
  display: none;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 300px;
  height: auto;
  z-index: 100;
  pointer-events: none;
}

li:hover .hover-image {
  display: block;
}

.menu ul li {
  position: relative;
  list-style: none;
}

html, body {
  height: 100%;
  margin: 0;
}

body {
  margin: 0;
  background-color: #fff;
  font-family: "Times New Roman", Times, serif;
  font-size: 15px;
  line-height: 1.4;
  display: flex;
  min-height: 100vh;
  padding: 15px;
  flex-direction: column;
  box-sizing: border-box;
}

main {
  flex: 1 0 auto;
}

footer {
  margin-top: 30px; 
  padding-bottom: 15px;
}

img {
  width: 100%;
  display: block;
  height: auto;
  margin-bottom: 15px;
}

.header-info {
  display: block;
  width: 100%;
  padding-bottom: 30px;
}


.gallery,
.exhibitiontext {
  width: 100%; 
  margin-bottom: 15px;
}



.exhibitiontext {
    margin-top: 15px;
    margin-bottom: 300px; 
}


a:link,
a:visited {
  text-decoration: none;
  color: black; 
}

a:hover,
a:active {
  text-decoration: none;
  color: grey; 
}

.menu ul {
  list-style-type: none;
  padding: 0;
  margin-top: 15px;
  margin-bottom: 15px;
}

@media screen and (min-width: 769px) {
  img, 
  .header-info, 
  .exhibitiontext {
    width: 60%;
    max-width:900px;
    margin-left: 0; 
  }
}