body{
font-family: Arial, sans-serif;
margin: 0;
padding: 0;
}
header{
background-color: aqua;
color: blueviolet;
padding: 12px;
text-align: center;
}
header h1 {
font-size: 2.5em;
text-shadow: 5px 5px 3px gray;
}
.promo{
    background-image: url(../images/phonebgrd.jpg);
    background-size: 100%;
    opacity: 0.5;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    /*text-align: center
    line-height: 300px*/
    font-size: 4em;
    color: white;
    text-shadow: 3px 3px 2px black;
    color: cadetblue;
}
.description{
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    padding: 20px;
    justify-content: center;
}
.feature{
    flex: 1 1 200px; /*flex-grow,flex-shrink,flex-basis*/
    border: 1px solid #ccc;
    padding: 12px;
    border-radius: 8px;
}
.action{
    background-color: aquamarine;
    color: blanchedalmond;
    padding: 30px;
    text-align: center;
}
.action button{
padding: 15px 30px;
border-radius: 10px;
padding-left: 50px;
padding-right: 50px;
}
.button :hover{
background-color: brown;
}