body {
    background-image: url("https://downloops.com/wp-content/uploads/edd/2018/03/MosaicBlue-Flowing-Mosaic-Pattern-Free-Download-Motion-Background-Video-Loop-Sample2.jpg");
}

.title {
    text-align: center;
    padding-top: 150px;
    font-size: 35px;
    font-family: 'Roboto Mono', monospace;
    font-weight: 200;
}
.container {
    margin: 0 auto;
    margin-top: 50px;
    width: 380px;
    height: 420px;
    border:  gray;
    border-style: solid;
    border-radius: 4px;
    background-color: gray;
    box-shadow: 0 0 20px black;
    display: grid;
    grid-template: repeat(6, 1fr) / repeat(4, 1fr);
    grid-gap: 1px;
    grid-template-areas: 
        "x x x x"
        "a b c d"
        "e f g r"
        "h i j q"
        "k l m q"
        "n o p q"
}

button {
    background-color: #4d4b4b; /* Green */
    border: none;
    border-radius: 4px;
    outline: none;
    color: white;
    text-align: center;
    font-size: 18px;
    font-family: 'Roboto Mono', monospace;
    margin: 3px 3px;
    cursor: pointer;
    box-shadow: 0 0 2px black;
}

button:active {
    box-shadow: 0 0 3px #666;
    transform: translateY(2px);
  }

.display {
    grid-area: x;
    height: 70px;
    padding-top: 10px;
    border: none;
    border-radius: 4px;
    color: rgb(126, 138, 141);
    padding-right: 20px;
    font-size: 18px;
    font-family: 'Roboto Mono', monospace;
    margin: 3px 3px;
    background-color: rgb(58, 53, 53);
    text-align: right;
    cursor: default;
    position: relative;
}

#downNumber {
    position: absolute;
    right: 20px;
    top: 38px;
    font-size: 22px;
    color: rgb(201, 207, 209);
}

.special { 
    background-color: rgb(50, 74, 90);
}

.one {
    grid-area: k;
}

.two {
    grid-area: l;
}

.three {
    grid-area: m;
}

.four {
    grid-area: h;
}

.five {
    grid-area: i;
}

.six {
    grid-area: j;
}

.seven {
    grid-area: e;
}

.eight {
    grid-area: f;
}

.nine {
    grid-area: g;
}

.zero {
    grid-area: o;
}

.plus {
    grid-area: a;
}

.minus {
    grid-area: b;
}

.times {
    grid-area: c;
}

.divisor {
    grid-area: d;
}

.equal {
    grid-area: q;
    font-size: 30px;
    background-color: rgb(51, 108, 146);
}

.point {
    grid-area: n;
}

.clear {
    grid-area: p;
}

.backspace {
    grid-area: r;
}