Question about inheritance

I have a question about inheritance from HTML tag. Here is my CSS code and below is HTML

html {
background-color: black;
font-size: 22px;
color: seashell;
opacity: 0.9;
font-family: Helvetica, ‘Times New Roman’, sans-serif

}

header {
height: 69px;
width: 100%;
border-bottom: 1px solid seashell;
position: fixed;
display: flex;
}

img {
margin: 10px;
height: 50px;
width: auto;
}

.navigation {
text-decoration: underline;
justify-content: flex-end;

a {
}

HTML

Tea Cozy logo of a tea company
Mission Featured Tea Locations
  </header>

The question is why color from element in CSS is not inherited by elements?

Thx!