Untitled

body{
   margin: 0%;
 }
 .topnav {
 background-color: whitesmoke;
 overflow: hidden;
 }
 .topnav a {
 float: right;
 color: green; 
 text-align: center;
 padding: 15px 18px;
 text-decoration: none;
 font-size: 17px;
   }
 .topnav a:hover {
   background-color: aquamarine;
   color: black;
 }
 .topnav a.active {
 background-color: whitesmoke;
 color:green;
 }
 .topnav input[type=text] {
  float: center;
  padding: 6px;
  border: none;
  margin-top: 8px;
  margin-right: 16px;
  font-size: 17px;
 }
 form {    
   background-color:black;
   width: 200px;
   height: 44px;
   border-radius: 5px;
   display: right;
   flex-direction: row;
   align-items: center;
 }
 input {
 all: unset;
 font: 16px;
 color: #fff;
 height: 100%;
 width: 100%;
 padding: 6px 10px;
 }
 ::placeholder {
   color: #fff;
   opacity: 0.7;
 }
 button {
   color: #fff;
   cursor: pointer;
   width: 24px;
   height: 24px;
   padding: 10px;
 }