How to resize logo when in mobile view

Hi, i am new here.
Logo image does not resize when you watch it on mobile view. How can i reach this?

HTML:

<nav class="navbar"> 
 <div class="logo" href="#">
          <img src="http://placehold.it/150x50?text=Logo" alt="">
        </div>
 
   <span class="open-slide">
      <a href="#" onclick="openSlideMenu()">
        <svg width="30" height="30">
            <path d="M0,5 30,5" stroke="#fff" stroke-width="5"/>
            <path d="M0,14 30,14" stroke="#fff" stroke-width="5"/>
            <path d="M0,23 30,23" stroke="#fff" stroke-width="5"/>
        </svg>
      </a>
    </span>
    
 <ul class="navbar-nav">   
      <li><a href="#">Home</a></li>
      <li><a href="#">About</a></li>
      <li><a href="#">Services</a></li>
      <li><a href="#">Contact</a></li>
    </ul>
  </nav>
 

  <div id="side-menu" class="side-nav">
    <a href="#" class="btn-close" onclick="closeSlideMenu()">&times;</a>
    <a href="#">Home</a>
    <a href="#">About</a>
    <a href="#">Services</a>
    <a href="#">Contact</a>
  </div>

  <script>
    function openSlideMenu(){
      document.getElementById('side-menu').style.width = '250px';
      document.getElementById('main').style.marginLeft = '250px';
    }

    function closeSlideMenu(){
      document.getElementById('side-menu').style.width = '0';
      document.getElementById('main').style.marginLeft = '0';
    }
  </script>

CSS:

/* Navbar */
body{
  font-family:"Arial", Serif;
  background-color:#f4f4f4;
  overflow-x:hidden;
}

.navbar{
  background-color: #158917;
  overflow:hidden;
  height:63px;
}

.logo{
  float:left;
  width:20%;
  text-align: center;
  margin-top: 8px;
  
  
  }
.navbar a{
  float:right;
  display:block;
  color:#f2f2f2;
  text-align:center;
  padding:14px 30px;
  text-decoration:none;
  font-size:17px;
}

.navbar ul{
  margin:8px 0 0 0;
  list-style:none;
}

.navbar a:hover{
  background-color:#ddd;
  color:#000;
}

.side-nav{
  height:100%;
  width:0;
  position:fixed;
  z-index:1;
  top:0;
  left:0;
  background-color:#111;
  opacity:0.9;
  overflow-x:hidden;
  padding-top:60px;
  transition:0.5s;
}

.side-nav a{
  padding:10px 10px 10px 30px;
  text-decoration:none;
  font-size:22px;
  color:#ccc;
  display:block;
  transition:0.3s;
}

.side-nav a:hover{
  color:#fff;
}

.side-nav .btn-close{
  position:absolute;
  top:0;
  right:22px;
  font-size:36px;
  margin-left:50px;
}

#main{
  transition:margin-left 0.5s;
  padding:20px;
  overflow:hidden;
  width:100%;
}

@media(max-width:568px){
  .navbar-nav{display:none}
}

@media(min-width:568px){
  .open-slide{display:none}
}

much appreciated this efforts

You are mostly welcome