body {
    font-family: Arial, Helvetica, sans-serif;
}
h1 {
    color: #673232; 
    border-bottom: 5px solid green; 
    font-size: 12px; 
    text-transform: uppercase; 
}
p.rameczka {
    border: 1px solid gray; 
    border-left: 10px solid gray; 
    font-size: 1.2em; 
    padding: 10px; 
    background: #aabb55; 
}

section.introduction {
    background: #eee; 
    width: 300px; 
}

section.introduction h1 {
    font-family: serif; 
    font-size: 3em; 
    border: 0; 
    text-transform: unset; 
}