You may try it with GPT if you want to use richtext with HTML. Here is the code for custom CSS for Hint component:
.oneColumn-hint > div > div > div > div {
display: block;
}
.oneColumn-hint button {
width: 100%;
margin-bottom:10px;
}
.oneColumn-hint p {
width: 100%;
padding-bottom:20px;
}