Customize posts' contents with your own styles

[Canapin (Coin-coin le Canapin)]

@UnitedFreedom

to complicated

Of course, it depends on what you intend to put in it, but to achieve the same exact visual as your example, you can optimize your code a lot:

[wrap="card-header"]**Card Header**[/wrap]
[wrap="card-body"]
**Card Title**

Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text, Card Text
[/wrap]

[data-wrap="card-header"] {
    padding: 0.5em 1em;
    border: 1px solid rgba(0,0,0,.125);
    border-bottom: 0;
    background: #007bff;
    color: #fff;
    border-radius: 5px 5px 0 0;
}

[data-wrap="card-body"] {
    padding: 1em;    
    border: 1px solid rgba(0,0,0,.125);
    border-radius: 0 0 5px 5px;
}