Untitled

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Document</title>
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" integrity="sha384-TX8t27EcRE3e/ihU7zmQxVncDAy5uIKz4rEkgIXeMed4M0jlfIDPvg6uqKI2xXr2" crossorigin="anonymous">
    <style>
        * {
            box-sizing: border-box;
        }
    html, body {
        align-items: center;
        background: gold;
        display: flex;
        justify-content: center;
        margin: 0;
        min-height: 100%;
        padding: 0;
        width: 100%;
    }

    p:nth-of-type(1){
        width:120px;
        height:120px;
        display:block;
        background:firebrick;
        transition: 2s ease;
    }

    p:hover{
        transition: 1s linear;
        background: lightblue;
    }
  </style>
</head>
<body>
    <p></p>
</body>
</html>