<div class="alert success">
    <span class="closebtn" onclick="this.parentElement.style.display='none';"><i class="fas fa-times"></i></span> 
    <i class="fas fa-check-circle"></i>
    <strong>Success!</strong> <span class="alert-des">This is a success message.</span>
</div>

<div class="alert info">
    <span class="closebtn" onclick="this.parentElement.style.display='none';"><i class="fas fa-times"></i></span> 
    <i class="fas fa-info-circle"></i>
    <strong>Info!</strong> <span class="alert-des">This is an info message.</span>
</div>

<div class="alert warning">
    <span class="closebtn" onclick="this.parentElement.style.display='none';"><i class="fas fa-times"></i></span> 
    <i class="fas fa-exclamation-triangle"></i>
    <strong>Warning!</strong> <span class="alert-des">This is a warning message.</span>
</div>

<div class="alert danger">
    <span class="closebtn" onclick="this.parentElement.style.display='none';"><i class="fas fa-times"></i></span> 
    <i class="fas fa-times-circle"></i>
    <strong>Danger!</strong> <span class="alert-des">This is a danger message.</span>
</div>

/*  Alert css start  */
.alert {
  padding: 20px;
  color: #4f4f4f;
  border-radius: 5px;
  margin-bottom: 15px;
  position: relative;
  display: flex;
  align-items: center;
}

.alert:hover {
    background-color: white;
}

.alert strong {
    padding-right: 10px;
}

.closebtn {
  position: absolute;
  top: 10px;
  right: 0;
  color: rgb(59, 59, 59);
  font-size: 12px;
  cursor: pointer;
}

.fa, .fas {
  margin-right: 10px;
}

.success {
  background-color: #def0d8;
}

.info {
  background-color: #daecf8;
}

.warning {
  background-color: #fbf9e4;
}

.danger {
  background-color: #f3dfe0;
}

.fa-check-circle, .fas fa-check-circle {
  color: #4CAF50;
}

.fa-info-circle, .fas fa-info-circle {
  color: #2196F3;
}

.fa-exclamation-triangle, .fas fa-exclamation-triangle {
  color: #ff9800;
}

.fa-times-circle, .fas fa-times-circle {
  color: #f44336;
}

.closebtn:hover {
  color: black;
}

@media only screen and (max-width: 600px) {
  .alert {
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
  }
  
  .fa, .fas {
    margin-right: 10px;
    margin-bottom: 10px;
  }
  
}
/*  Alert css end  */

<script>
// Get all alert elements
var alerts = document.getElementsByClassName("alert");

// Show all alerts
for (var i = 0; i < alerts.length; i++) {
  alerts[i].style.display = "flex";
}
</script>

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css"/>