*
{
    margin: 0;
    padding: 0;
    outline: 0;
    word-break: break-all;
    box-sizing: border-box;
}

html
{
    font-size: 100%;
    line-height: 1.5;
}

body
{
    text-align: center;
    font-family: Arial, Helvetica, sans-serif;
    background-image: radial-gradient(circle, #FFF, #AAA);
    overflow-y: scroll;
}

a
{
    text-decoration: none;
}

li
{
    list-style: none;
}

::-moz-focus-inner
{
    border: 1px solid transparent;
}


main
{
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    min-width: 320px;
    width: 96%;
    margin: 0 auto;
    padding: 20px 0;
}

main > div#container
{
    background-color: #0a3d53;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px #009DE4;
    font-size: 0;
    width: 90%;
}

main > div#container .structure-elements
{
    display: inline-block;
    vertical-align: middle;
    padding: 10px;
    font-size: initial;
}

main > div#container > p#message
{
    width: 65%;
    margin-right: 5%;
    color: white;
    font-weight: bold;
    visibility: hidden;
}

main > div#container > aside#score
{
    color: #888E5F;
    background-color: #F1FF92;
    box-shadow: 0 4px #9DA853;
}

main > div#container > div#calculation
{
    width: 80%;
    margin: 0 auto;
}

main > div#container > div#calculation > *
{
    width: 100%;
    margin-top: 10px;
}

main > div#container > div#calculation > section#question
{
    background-color: #9DA0EA;
    box-shadow: 0 4px #535AA8;
    font-size: 6.250rem;
    height: 170px;
}

main > div#container > div#calculation > p#instruction
{
    background-color: #B481D9;
    box-shadow: 0 4px #8153A8;
}

main > div#container > div#calculation > ul#choices
{
    padding: 0;
}

main > div#container > div#calculation > ul#choices > li,
main > div#container > button#start-reset
{
    border-radius: 5px;
    cursor: pointer;
    box-shadow: 0 4px rgba(0, 0, 0, 0.2);
    transition: box-shadow transform 0.2s;
}

main > div#container > div#calculation > ul#choices > li
{
    width: 100%;
    background-color: white;
    margin-bottom: 10px;
    padding: 10px;
    height: 44px;
}

main > div#container > div#calculation > ul#choices > li:active,
main > div#container > button#start-reset:active
{
    color: white;
    background-color: #9C89F6;
    box-shadow: 0 0 #6B54D3;
    transform: translateY(4px);
}

main > div#container > button#start-reset
{
    background-color: rgba(255, 255, 255, 0.5);
    border: 0;
    margin: 10px auto;
    line-height: 1.5;
    display: block;
}

main > div#container > aside#time-remaining
{
    background-color: rgba(181, 235, 36, 0.8);
    border-radius: 5px;
    box-shadow: 0 4px rgba(0, 0, 0, 0.2);
    visibility: hidden;
}

main > div#game-over
{
    color: white;
    background-image: linear-gradient(#F3CA6B, #F3706C);
    font-size: 3rem;
    text-transform: uppercase;
    position: absolute;
    padding: 20px;
    min-width: 250px;
    display: none;
}


@media all and (min-width: 768px)
{

}


@media all and (min-width: 992px)
{
    
    main
    {
        max-width: 1350px;
        width: 50%;
    }

    main > div#container
    {
        width: 75%;
    }

    main > div#container > p#message
    {
        width: 25%;
        margin: 0 25%;
    }

    main > div#container > div#calculation > ul#choices
    {
        font-size: 0;
    }

    main > div#container > div#calculation > ul#choices > li
    {
        width: 24%;
        display: inline-block;
        font-size: initial;
    }

    main > div#container > div#calculation > ul#choices > li:not(:last-of-type)
    {
        margin-right: 1%;
    }

    main > div#container > button#start-reset
    {
        display: inline-block;
        margin: 10px;
    }
}