/* RESET */

*{
    margin: 0;
    padding: 0;
}

/* LAYOUT */

html{
    font-size: 20px
}

body{
    display: grid;
    grid-template-rows: 10vh 10vh 1fr 5vh;
    width: 100vw;
    height: 100vh;
    font-family: sans-serif;
}

nav{
    background-color: #FFF;
    display : flex;
    flex-flow: row nowrap;
    padding: 2vh;
}   

button{
    border: none;
    border-bottom: .25rem solid  #2B8EAD;
    border-right: .15rem solid  #2B8EAD;
    border-radius: 5px;
    padding: .25rem;
    margin: .5vh;
    background-color: #72c3dc;
    color: #FFF;
    font-size: calc(1.25vw + 1.25vh);
    min-width: 2.1vh;
    min-height:2.1vh;
    max-height:2.1rem;
    flex: 1 0 auto;
}


.numberContainer{
    display: flex;
    flex-flow: column wrap;
    justify-content: center;
}

.square{
    background-color:#EFEFEF; 
    font-size: 20px;
    text-align: center;
    margin: 0 1rem calc(15vh/9);
    height: calc(60vh/9);
    vertical-align: middle;
    line-height: calc(60vh/9);
    flex-grow: 100%;
    border-left: 1rem solid;
}

header{
    background-color: #333333;
    text-align: center;
    vertical-align: middle;
    line-height: 10vh;
}

h1{
    color: #FFF;
    font-size: calc(.75rem + 2vw);
}

footer{
    background-color: #FFF;
    text-align: center;
    vertical-align: middle;
    line-height: 5vh;
    font-size: calc(.5rem + 1vw);
}

@media (max-width: 480px) {
    .square{
        background-color:#EFEFEF !important; 
    }
}
@media (min-width: 481px) {
    body{
        grid-template-areas:
              "h h h h"
              "m m m n"
              "f f f f";
        grid-template-columns: repeat(4,1fr);
        grid-template-rows: 15vh 1fr 15vh;
    }
    nav{
        grid-area: n;
        background-color: #EFEFEF;
        flex-flow: column nowrap;
    }
    
    main{
        grid-area: m;
    }

    .numberContainer{
        flex-flow: row wrap;
    }
          
    .square{
        margin: 0;
        border: none;
        font-size: calc(1rem + 4vw);
        color: #FFF;
        width: calc(100vw/4);
        height: calc(70vh/3);
        line-height: calc(70vh/3);
        flex: 1 1 auto;
    }

    header{
        grid-area: h;
        background-color: #FFF;
        line-height: 15vh;
    }

    h1{
        color: #000;
    }

    footer{
        grid-area: f;
        background-color: #EFEFEF;
        line-height: 15vh;
    }
}