HTML Guide for transition-delay

CSS: “transition-delay”: “0” is not a “transition-delay” value.

Change the transition-delay value from 0 to 0s to specify a time unit.

CSS properties dealing with time, like transition-delay, require a time unit to be compliant with standards. The transition-delay property specifies when the transition effect will start after being triggered. Valid values for transition-delay include time values such as 100ms (milliseconds) or 0s (seconds). Specifying just 0 is not compliant because it lacks a time unit, which is why the validator flags this as an error.

Here is an example of how to correctly define transition-delay using proper time units in your CSS:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Transition Delay Example</title>
  <style>
    .example {
      transition-delay: 0s; /* Correctly includes time unit */
      transition-property: opacity;
      transition-duration: 1s;
      opacity: 0;
    }

    .example:hover {
      opacity: 1;
    }
  </style>
</head>
<body>
  <div class="example">Hover over me!</div>
</body>
</html>

In this corrected example, the transition-delay is set to 0s, ensuring compliance with CSS standards by including the necessary time unit.