header {
  display: flex;
  width: 100%;
  height: 100px;
  background-color: black;
  align-items: center;
}
 
.title {
  margin-right: auto;
}
 
.menu-item {
  list-style: none;
  display: inline-block;
  padding: 10px;
}

a:hover img{
  opacity: 0.6;
  transition-duration: 0.3s;
}

.background {
  width: 100%;
  height: 100vh;
  background-image: url(catastrophe1.jpg);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center;
}

.content {
  width: 45%;
  margin: 0 auto;
  padding: 50px 20px;
  background-color: rgba(0,0,0,0.8);
  color: #fff;
  float: right;
}

.others1 {
  width: 45%;
  height: 40vh;
  margin: 20px auto;
  margin-top: 40px; 
  padding: 50px 20px;
  background-image: url(catastrophe2.jpg);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center;
  float: left
}

.others2 {
  width: 45%;
  height: 40vh;
  margin: 20px auto;
  padding: 50px 20px;
  background-image: url(catastrophe3.jpg);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center;
  float: left
}

.others3 {
  width: 45%;
  height: 40vh;
  margin: 20px auto;
  padding: 50px 20px;
  background-image: url(catastrophe4.jpg);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center;
  float: left
}

.others4 {
  width: 45%;
  height: 40vh;
  margin: 20px auto;
  padding: 50px 20px;
  background-image: url(catastrophe5.jpg);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center;
  float: left
}

.others5 {
  width: 45%;
  height: 40vh;
  margin: 20px auto;
  padding: 50px 20px;
  background-image: url(catastrophe6.jpg);
  background-repeat: no-repeat;
  background-size: contain;
  background-position: center;
  float: left
}

a {
  color: gray;
  text-decoration: none;
}

a:hover {
  color: white;
  text-decoration: none;
}


footer {
  width: 100%;
  height: 40px; 
  text-align: center;
  padding: 50px 0;
  background-color: black;
  color: white;
  clear:both;
}