test tube and ph strip

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>pH Strip Animation</title>
    <style>
        body {
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            background-color: #eef;
        }

        .container {
            position: relative;
            width: 100px;
            height: 250px;
        }

        .test-tube {
            position: absolute;
            bottom: 0;
            width: 60px;
            height: 150px;
            background: linear-gradient(to bottom, transparent 10%, #99d 30%, #339 100%);
            border: 3px solid #555;
            border-radius: 20px;
            display: flex;
            justify-content: center;
            align-items: flex-end;
            overflow: hidden;
        }

        .liquid {
            width: 100%;
            height: 70%;
            background: #339;
            border-radius: 0 0 20px 20px;
            transition: background-color 1s ease-in-out;
        }

        .ph-strip {
            position: absolute;
            top: -50px;
            left: 50%;
            width: 20px;
            height: 80px;
            background: #f5e663;
            border: 2px solid #ccc;
            transform: translateX(-50%);
            animation: dipAnimation 4s infinite ease-in-out;
        }

        @keyframes dipAnimation {
            0%, 100% {
                top: -50px;
                background: #f5e663;
            }
            50% {
                top: 80px;
                background: #ff5733;
            }
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="ph-strip"></div>
        <div class="test-tube">
            <div class="liquid"></div>
        </div>
    </div>
</body>
</html>