*{
    box-sizing: border-box;
    margin: 10px auto;
}

body{
    background-color: aquamarine;
    display: flex;
    flex-wrap: wrap;
    /*
    PARA COLOCAR IMAGENES EN EL FONDO:
    background-image: url(../img/picachu.png);
    background-repeat:no-repeat;
    background-size: 50%;
    background-position: 10%;
    */
}   

h1:nth-of-type(1){
    color: red;
    background-color: black;
    width: 70%;
    text-align: center;
    letter-spacing: 20px;
    text-decoration: underline dotted 5px red;
    padding: 20px;
    transition: 3s;
}

#uno{
    color: green;
    background-color: pink;
    width: 50%;
}    

.dos{
    color: rgb(152, 57, 136);
    background-color: blue;
    width: 80%;
}
h1:nth-of-type(4){
    color:pink ;
    background-color: darkgray;
    padding: 40px;
    margin: 50px auto;
}
h1:hover{
    background-color: aquamarine;
    color: brown;
    transition: 3s;
}

h1:active{
    background-color: rgb(236, 87, 19);
  
    transition: 3s;
}

div{
    width: 80%;
    background-color: chartreuse;
}