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

html {
    height: 100%;
}


body {
    font: 1em/1.5 'Varela Round', arial, helvetica, sans-serif;
    background-color: seagreen;
    color: #ffffff;
    height: 100%;
    overflow-x: hidden;
    -webkit-user-select: none;  /* Chrome all / Safari all */
    -moz-user-select: none;     /* Firefox all */
    -ms-user-select: none;      /* IE 10+ */
    user-select: none;          /* Likely future */
}

h1 {
    font-size: 48px;
    text-align: center;
    margin: 3rem auto;
}

a {
    color: inherit;
    text-decoration: none;
}


.field {
    background-color: rgba(0,0,0,0.2);
    border-radius: 8px;
    box-shadow: inset 0 0 8px 2px rgba(0,0,0,0.2), 0 2px 5px rgba(255,255,255,0.2);
}

#restart {
    margin-top: 1.5rem;
    border: 3px solid;
    border-radius: 8px;
    padding: 1rem;
    display: inline-block;
}

#restart img {
    width: 35px;
    vertical-align: text-top;
}

.show #restart img {
    -webkit-animation: spin 2.5s ease-out;
            animation: spin 2.5s ease-out;
}


#site {
    margin: 0 auto;
    display: flex;
    min-height: 100%;
    position: relative;
}

#memorycard-wrap {
    width: 100%;
    padding: 3rem 3rem 1.5rem;
    position: relative;
}

.gameboard {
    padding: 0 4.5rem 3rem;
    flex-grow: 1;
}

.gameboard__inner {
    max-width: 1000px;
    margin: 0 auto;
}

.sidebar {
    padding: 0 4.5rem;
    background-color: #333;
    box-shadow: inset 12px 0px 15px -6px rgba(0,0,0,0.2);
}
    
#site:after,   
#memorycard-container:after,
#memorycard-wrap:after,
.sidebar:after,
.gameboard:after {
    content: "";
    display: block;
    clear: both;
}

#memorycard-container {
    list-style-type: none;
    
}

#memorycard-container li img {
    max-width: 85%;
    display: inline-block;
    margin: 0 auto;
    vertical-align: middle;
}

#memorycard-container li {
    float: left;
    width: 23.5%;
    margin-left: 2%;
    margin-bottom: 2%;
    text-align: center;
    line-height: 150px;
    color: #333;
    cursor: pointer;
    position: relative;
    -webkit-perspective: 1200px;
            perspective: 1200px;
}

#memorycard-container li .card__inner {
    padding-bottom: 100%;
    box-shadow: 1px 1px 2px rgba(0,0,0,0.25);
    -webkit-transition: -webkit-transform 800ms cubic-bezier(.55,-.62, .27, 1.2);
    transition: -webkit-transform 800ms cubic-bezier(.55,-.62, .27, 1.2);
    transition: transform 800ms cubic-bezier(.55,-.62, .27, 1.2);
    transition: transform 800ms cubic-bezier(.55,-.62, .27, 1.2), -webkit-transform 800ms cubic-bezier(.55,-.62, .27, 1.2);
    -webkit-transform-style: preserve-3d;
            transform-style: preserve-3d;
}

#memorycard-container li .card__backside {    
    background-color: #4183D7;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 100;
    -webkit-backface-visibility: hidden;
            backface-visibility: hidden;
}

#memorycard-container li .card__image {
    background-color: darkslategray;
    border: 8px solid white;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    -webkit-transform: rotateY(180deg);
            transform: rotateY(180deg);
    -webkit-backface-visibility: hidden;
            backface-visibility: hidden;
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -webkit-flex-direction: column;
        -ms-flex-direction: column;
            flex-direction: column;
    -webkit-box-pack: center;
    -webkit-justify-content: center;
        -ms-flex-pack: center;
            justify-content: center;
}


#memorycard-container li.open .card__inner,
#memorycard-container li.matched .card__inner,
#memorycard-container li.debug .card__inner {
    -webkit-transform: rotateY(-180deg);
            transform: rotateY(-180deg);
}


#memorycard-container li:nth-child(4n+1) {
    margin-left: 0;
}

#results {
    position: absolute;
    top: -120px;
    left: 0;
    padding: 12px 24px;
}

#game-over {
    font-size: 2em;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    text-align: center;
    background-color: rgba(0,0,0,0.85);
    opacity: 0;
    z-index: -1;
    -webkit-transition: 500ms;
    transition: 500ms;
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
        -webkit-box-orient: vertical;
        -webkit-box-direction: normal;
        -webkit-flex-direction: column;
            -ms-flex-direction: column;
                flex-direction: column;
        -webkit-box-pack: center;
        -webkit-justify-content: center;
                  -ms-flex-pack: center;
                justify-content: center;
}


#game-over.show {
    opacity: 1;
    z-index: 10;
}

.game-over__card {
    background-color: #fff;
    color: #333;
    margin: 3rem auto;
    padding: 3rem;
    width: 80%;
    max-width: 750px;
}


.matched {
    animation: matched 1s forwards;
}




@-webkit-keyframes spin {
    100% {
        -webkit-transform: rotate(1800deg);
                transform: rotate(1800deg);
    }
}





@keyframes spin {
    100% {
        -webkit-transform: rotate(1800deg);
                transform: rotate(1800deg);
    }
}


@keyframes matched {
    100% { 
        transform: translateX(-400px) translateY(-400px) rotate(-45deg); 
        opacity: 0; 
        visibility: hidden; 
    }
}