article{
    text-align: center;
    margin-bottom: 3em;

}
.secsobre{
    text-align: center;
    margin-top: 3em;
}
.hr1 {
    border: none;
    height: 2px;
    width: 50%;                /* só metade da tela */
    margin: 20px auto;         /* centraliza */
    background-color: #222;
}
.h2sobre{
    margin-top: 3em;
    margin-bottom: 3em;
}
.bttsobre{
    margin-bottom: 3em;
}
.botaosobre{
    text-align: center;
}
@media (prefers-color-scheme: dark){
    body{
      
    .hr1{
        background-color: aliceblue;
    }
}
}