*{
    box-sizing: border-box;
    margin: 0;
    padding: 0
}

body {
    background-color: aqua;
}

.uno{
    height: 200px;
    background-color: yellow;
}

.dos{
    height: 200px;
    background-color: blue;
}

.tres{
    height: 200;
    background-color: red;
}

.caja1{
    height: 200px;
    background-color: rgb(117, 79, 79);
}