.header {
  padding:80px; /*some padding*/
  text-align: center; /*center the text*/
  background: #1abc9c; /*green background*/
  color: white; /*white text color*/
}

.header h1{
  font-size: 40px;
}

/* Style the top navigation bar */
.navbar {
  overflow: hidden; /* Hide overflow */
  background-color: #333; /* Dark background color */
}

/* Style the navigation bar links */
.navbar a {
  float: left; /* Make sure that the links stay side-by-side */
  display: block; /* Change the display to block, for responsive reasons (see below) */
  color: white; /* White text color */
  text-align: center; /* Center the text */
  padding: 14px 20px; /* Add some padding */
  text-decoration: none; /* Remove underline */
}

/* Right-aligned link */
.navbar a.right {
  float: right; /* Float a link to the right */
}

/* Change color on hover/mouse-over */
.navbar a:hover {
  background-color: #ddd; /* Grey background color */
  color: black; /* Black text color */
}

/* Ensure proper sizing */
* {
  box-sizing: border-box;
}

/* Column container */
.row { 
  display: flex;
  flex-wrap: wrap;
}

/* Create two unequal columns that sits next to each other */
/* Sidebar/left column */
.side {
  flex: 15vw; /* Set the width of the sidebar */
  height: 100vh; /*set the height of the sidebar*/
  background-color: #f1f1f1; /* Grey background color */
  padding: 20px; /* Some padding */
  overflow: auto;
}
 
.side a{
  float: center; /* Make sure that the links stay side-by-side */
  display: block; /* Change the display to block, for responsive reasons (see below) */
  color: black; /* White text color */
  text-align: left; /* Left align the text */
  padding: 14px 20px; /* Add some padding */
  text-decoration: none; /* Remove underline */
}

/* Change color on hover/mouse-over */
.side a:hover {
  background-color: black; /* Grey background color */
  color: white; /* Black text color */
}


/* Main column */
.main { 
  flex: 70vw; /* Set the width of the main content */
  height: 100vh; /*set the height of the sidebar*/
  background-color: white; /* White background color */
  padding: 20px; /* Some padding */
  overflow: auto;
}
.main p{
  font-size:130%;
}

/* Image property setting*/
.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
  width: 800px;
}
//img {
//width 200px
//height auto
//}