body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
}

.navbar {
  overflow: hidden;
  background-color: #333;  
  position: fixed;
  bottom: 0;
  width: 100%;
}

.navbar a {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 16px;
}

.navbar a:hover {
  background-color: #ddd;
  color: black;
}

.navbar a.active {
  background-color: #555;
  color: white;
}

.navbar .icon {
  display: none;
}

@media screen and (max-width: 600px) {
  .navbar a:not(:first-child) {display: none;}
  .navbar a.icon {
    float: right;
    display: block;
  }
}

@media screen and (max-width: 600px) {
  .navbar.responsive .icon {
    position: absolute;
    right: 0;
    bottom:0;
  }
  .navbar.responsive a {
    float: none;
    display: block;
    text-align: left;
	font-size: 20px;
  }

}

/* Style the tab content */
.tabcontent {
  float: left;
  padding: 0px 12px;
  border: 1px solid #ccc;
  width: 90%;
  border-left: none;

}

#math {
  display: none;
  padding: 20px;
  margin: 10px;
  text-align: center;
  background-color: #ccc;
}

input.number {
  width: 300px;
  padding: 12px 20px;
  margin: 8px 0;
  display: inline-block;
  border: 1px solid #ccc;
  box-sizing: border-box;
}

input[type=button] {
  background-color: #4CAF50;
  color: white;
  font-size: 16px;
  padding: 12px 20px;
  margin: 8px 5px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

.container {
  position: relative;
  width: 100%;
  overflow: hidden;
  padding-top: 56.25%; /* 16:9 Aspect Ratio */
}

.responsive-iframe {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 100%;
  border: 1px solid #ccc;
}