Source+Sans+Pro:wght@200;300&display=swap" rel="stylesheet">
</head>

<body>

<h1 style="text-align:center">Photo Gallery</h1>

<div class="container">
 <div class="row">
    <div class="column">
      <img class="demo cursor" src="01.jpg" style="width:100%" onclick="currentSlide(1)" alt="Millennium Bridge">
    </div>
    <div class="column">
      <img class="demo cursor" src="02.jpg" style="width:100%" onclick="currentSlide(2)" alt="Mountain Glacier">
    </div>
    <div class="column">
      <img class=