body {
  background-color: black;
  color: white;
  font-family: "Courier New", Courier, monospace;
}

.sidenav {
  height: 100%;
  width: 200px;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: black;
  overflow-x: hidden;
  text-align: center
}

.main {
  margin-left: 200px; /*(sidenav width)*/
  padding: 50px;
}

.blog11132020 {
   display: flex;
}
.blog11132020 div {
  -ms-flex: 1;
  flex: 1;
}

.blog09182009 {
   display: flex;
}
.blog09182009 div {
  -ms-flex: 1;
  flex: 1;
}

.a {
  flex: 50%;
  padding: 10px;
}
.b {
  flex: 50%;
  padding: 10px;
  margin-right: 500px;
}

.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 50%;
}

a:link {
  color: white;
  }
a:visited {
  color: white;
  }
a:hover {
  color: gray;
  }
a:active {
  color: gray;
  }

img.hover {
  display: none;
  }
img.default {
  display: inherit
  ;}
a:hover img.hover {
  display: inherit;
  }
a:hover img.default {
  display: none;}

button{
  width: 150px;
  text-align: center;
}