Docs > Styling & Customization > Rules > Rules 6

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingSoft Demo</title>

  <script nonce="undefined" src="https://cdn.zingchart.com/zingchart.min.js"></script>
  <style>
    html,
    body,
    #myChart {
      height: 100%;
      width: 100%;
    }
  </style>
</head>

<body>
  <div id='myChart'></div>
  <script>
    ZC.LICENSE = ["569d52cefae586f634c54f86dc99e6a9", "b55b025e438fa8a98e32482b5f768ff5"];
    var myConfig = {
      "graphset": [{
        "type": "line",
        "scale-y": {
          "guide": {
            "rules": [{
              "rule": "%v < 0",
              "line-color": "red",
              "alpha": "0.6"
            }]
          }
        },
        "scale-x": {
          "line-color": "red"
        },
        "series": [{
            "values": [11, 16, 7, -20, -22, -3, 14, 11, 24, 5, -5, -10, -8, -2, 3]
          },
          {
            "values": [28, 19, -5, -20, -2, 30, 35, 30, -10, -5, -25, -40, -5, 46, 30]
          }
        ]
      }]
    };

    zingchart.render({
      id: 'myChart',
      data: myConfig,
      height: "100%",
      width: "100%"
    });
  </script>
</body>

</html>

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingSoft Demo</title>

  <script src="https://cdn.zingchart.com/zingchart.min.js"></script>
</head>

<body>
  <div id='myChart'></div>
</body>

</html>

html,
body,
#myChart {
  height: 100%;
  width: 100%;
}

var myConfig = {
  "graphset": [{
    "type": "line",
    "scale-y": {
      "guide": {
        "rules": [{
          "rule": "%v < 0",
          "line-color": "red",
          "alpha": "0.6"
        }]
      }
    },
    "scale-x": {
      "line-color": "red"
    },
    "series": [{
        "values": [11, 16, 7, -20, -22, -3, 14, 11, 24, 5, -5, -10, -8, -2, 3]
      },
      {
        "values": [28, 19, -5, -20, -2, 30, 35, 30, -10, -5, -25, -40, -5, 46, 30]
      }
    ]
  }]
};

zingchart.render({
  id: 'myChart',
  data: myConfig,
  height: "100%",
  width: "100%"
});