하이퍼링크 코드

https://ibb.co/G03LnJJ

I am trying to design hyperlinks in letters.
How did you apply it, but today I can’t see the CSS code.
So when I try to apply it again, it doesn’t work. Please review the code to see if it is incorrect.

https://ibb.co/2MhCLMm

Is it correct to put the code here?
I applied it to Custom → CSS, is it okay to apply it here in the future?

/* 하이퍼링크 Link */
.post p a{
word-break: break-all;
color: #3e5898;
transition: color .25s ease-in;
color: #3E5898;
background-repeat: no-repeat;
background-size: 100% 0.2em;
background-position: 0 100%;
background-image: linear-gradient(to right,#00BCD4,#5C6BC0);
transition: all .25s ease-in;
padding: 2px 0;
}
.post p a:hover {
background-size: 100% 100% !important;
color: #fff !important;
border-radius: 10px !important;
}