OpportunityHeaderInlineVF

<apex:page standardController="Opportunity">
    <style type="text/css">
        * {
          font-family: Roboto;
        }

        div.message {
          position: relative;
          padding: 1px;
          padding-left: 35px;
          margin: 20px 10px;
          box-shadow: 0 2px 5px rgba(0, 0, 0, .3);
          background: #BBB;
          color: #FFF;
        }

        div.message.lost {
            color: white;
            background: red;
        }
        
        div.message.won {
            color: white;
            background: green;
        }
    </style>

    <link href="//fonts.googleapis.com/css?family=Roboto:300italic,400italic,400,300,600,700" rel="stylesheet" type="text/css" />
    <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css" rel="stylesheet" />

   <div class="lost message" style="display: {!IF(Opportunity.Stagename = 'Closed Lost', '', 'none')}" >
      <h2>Opportunity: This Opportunity is Closed Lost</h2>
    </div>
    
    <div class="won message" style="display: {!IF(Opportunity.StageName = 'Closed Won', '', 'none')}" >
      <h2>Opportunity: This Opportunity is Closed Won</h2>
    </div>
</apex:page>