CSS <time> Data Type
The CSS <time> data type denotes time dimensions expressed in seconds or milliseconds.
Here are some valid <time> values:
Time values are dimensions denoted by <time>. A dimension is a number immediately followed by a unit identifier, which is an identifier. 
The unit identifiers for <time> are:
- s
 - Seconds.
 - ms
 - Milliseconds. There are 1000 milliseconds in a second.
 
A <time> Example
When you see <time> (including the < and >) anywhere in the CSS specifications, this refers to the fact that the value can be a valid time.
For example, the transition-duration property accepts the following value/s.
So you could write something like this:
Here's a working example:
CSS Specifications
- The 
<time>data type is defined in CSS Values and Units Module Level 3 (W3C Candidate Recommendation, 29 September 2016) - It is also defined in Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification (W3C Recommendation 07 June 2011)