html {
  margin:0;
  padding:0;
}

body {
  margin:0;
  padding:0;
}

.container {			
  max-width:900px;
  margin:0 auto 0 auto;
  margin-top:25px;
  /*margin-bottom:25px;*/
  padding:10px;
  border:5px solid;
  border-radius:25px;
}

.topnav {
  text-align: center;
  width:100%;
  border-top:4px solid;
  border-bottom:4px solid;
}

.topnav ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
}

.topnav li {
  float: left;
}

.topnav li a {
  display: block;
  color: black;
  font-weight: bold;
  font-family: arial, sans-serif;
  font-size: 18px;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.outer-video-container {
  margin: 0 auto;
}

.video-container {
  position: relative;
  height: 0;
}

.video-16-9-padding {
  padding-bottom: 56.25%; /* 16:9 */
}

.video-4-3-padding {
  padding-bottom: 75%; /* 4:3 */
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

@media only screen and (max-width: 900px) {
  .container {
    max-width: none;
    width: auto;
  }
}

@media only screen and (max-width: 500px) {
  .topnav li a {
    padding: 10px 12px;
  }
}