*{
    box-sizing: border-box;
}

body{
    background-image: url("../img/pattern.gif");
}

.padre{
    width: 95%;
    height: 450px;
    margin: 20px auto;
    background-color: darkgray;
    border: 5px solid black;
    padding: 1%;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
}
h1{
    width: 100%;
    background-color: lightgray;
    text-align: center;
    padding: 1%;
    border-bottom: 8px double black;
    height: 80px;
}
.uno{
    width: 32%;
    height: 280px;
    padding: 16px;
    background-color: lightyellow;
}
.dos{
    width: 32%;
    height: 280px;
    padding: 16px;
    background-color: lightseagreen;
    text-align: center;
}
.tres{
    width: 32%;
    height: 280px;
    padding: 16px;
    background-color: pink;
    text-align: right;
}


/*
.padre > div{
    width: 33%;
}