.sekstito
{
content-align:center;
  text-align:center;
z-index:999; 
height:25vh;
min-height:250px;
max-height:300px;  
}

.flexbox-container
{
  padding: 15px 15px 15px 25px;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -ms-flex-align: center;
    -webkit-align-items: center;
    -webkit-box-align: center;
    align-items: center;
}

.bold
{
font-size:270%;
font-weight:bold;

}

 <div id="bg">