/* Main Navigation */
nav {
     display: inline-block; 
    background: #444;
    width: 50%;   /*100%  50%*/

nav ul {
     display: flex; 
    padding: 8px;
    margin: 0;
    
}

nav ul li {
    position: relative;
    display: inline-block;     /*inline-block;  block    none        */
    list-style-type: none;
    margin: 0;
    padding: 8px 0;              /*10             */
}
nav ul li:hover {
        background: #008B8B;        /*old03ADDF; */ 
    }

nav ul li a {
    color: #fff;
    text-decoration: none;
    padding: 8px;                   /*12px               */
}
    nav ul li a:hover {
        color: #fff;
        text-decoration: none;
    }

/* Sub Menu */
nav ul li.parent ul.child {
    float: left;
    display: inline;    
    padding: 8px;                         /* Hide Sub Menu */
}
nav ul li.parent:hover ul.child {
    display: inline-block;                /* Show Sub Menu on Hover */
    float: left; 
    position: absolute;      
    top: 40px;                    /*40px  80px   */
    background: #008B8B;           /* old 03ADDF;*/
}

nav ul li.parent ul.child li {
    width: 9em;
    padding: 0;
}
nav ul li.parent ul.child li:hover {
    background: #008B8B                /* old 008FBA;           */
}
nav ul li.parent ul.child li a {
    display:inline-block;
}   
    
 


/*css for button use next*/


a {
  text-decoration: none;
  display: inline-block;
  padding: 8px 16px;
}

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

.previous {
  background-color: #f1f1f1;
  color: black;
}

.next {
  background-color: #4CAF50;
  color: white;
}

.round {
  border-radius: 50%