/* --------------------------------- Layout ---------------------------------*/

.container {
    width: 320px;
    padding: 12px;
    background: #fff;
}

/* vertically center .container */
body {
  min-height: 100%;
  min-height: 100vh;
  display: flex;
  align-items: center;
}

button {
    width: 65px;
    height: 45px;
    font-family: 'Roboto', sans-serif;
    border: none;
    border-radius: 5px;
    outline: none !important;
    position:relative;
    transition: all 0.1s;
}

button.operator-group, button#equal {
    font-size: 30px !important;
}

button.operand-group, button#ans {
    font-size: 20px !important;
}

#display1 {
    font-family: 'Roboto', sans-serif;
    font-weight: 400 !important;
    font-size: 20px !important;
    height: 50px;
}

.button-row {
    margin-top: 12px;
}

form {
    width: 100%;
    border-radius: .25rem;
}

form input {
    background-color: inherit;
    border: none;
    width: 294px;
    margin: 0 auto;
    display: block;
}

/*--------------------------- Light & Dark System ---------------------------*/

/* Light Theme */
.container-light {
    background-color: white;
    border: 1px solid #999;
    border-radius: 10px;
    padding: 10px;
}

.form-light {
    background-color: #f5f5f5;
    border: 1px solid #999;
    font-size: 38px;
    margin-bottom: 15px;
    text-align: right;
    padding-right: 3px;
}

.form-input-light {
    color: #263238;
}

.operand-group-light {
    display: inline-block;
    padding: 4px 12px;
    margin-bottom: 0;
    font-size: 14px;
    line-height: 20px;
    text-align: center;
    vertical-align: middle;
    cursor: pointer;
    color: #333333;
    text-shadow: 0 1px 1px rgba(255, 255, 255, 0.75);
    background-color: #f5f5f5;
    background-image: -moz-linear-gradient(top, #ffffff, #e6e6e6);
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#ffffff), to(#e6e6e6));
    background-image: -webkit-linear-gradient(top, #ffffff, #e6e6e6);
    background-image: -o-linear-gradient(top, #ffffff, #e6e6e6);
    background-image: linear-gradient(to bottom, #ffffff, #e6e6e6);
    background-repeat: repeat-x;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffffff', endColorstr='#ffe6e6e6', GradientType=0);
    border-color: #e6e6e6 #e6e6e6 #bfbfbf;
    border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
    filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
    border: 1px solid #cccccc;
    border-bottom-color: #b3b3b3;
    -webkit-border-radius: 4px;
    -moz-border-radius: 4px;
    border-radius: 4px;
    -webkit-box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05);
    -moz-box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05);
    box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 1px 2px rgba(0,0,0,.05);
}

.operand-group-light:hover {
    color: #333333;
    text-decoration: none;
    background-position: 0 50px;
    -webkit-transition: background-position 0.1s linear;
    -moz-transition: background-position 0.1s linear;
    -o-transition: background-position 0.1s linear;
    transition: background-position 0.1s linear;
}

.operand-group-light:active {
    background-image: none;
    outline: 0;
    -webkit-box-shadow: inset 0 2px 4px rgba(0,0,0,.15), 0 1px 2px rgba(0,0,0,.05);
    -moz-box-shadow: inset 0 2px 4px rgba(0,0,0,.15), 0 1px 2px rgba(0,0,0,.05);
    box-shadow: inset 0 2px 4px rgba(0,0,0,.15), 0 1px 2px rgba(0,0,0,.05);
}

.operator-group-light {
    color: #ffffff;
    cursor: pointer;
    text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
    background-color: #363636;
    background-image: -moz-linear-gradient(top, #444444, #222222);
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#444444), to(#222222));
    background-image: -webkit-linear-gradient(top, #444444, #222222);
    background-image: -o-linear-gradient(top, #444444, #222222);
    background-image: linear-gradient(to bottom, #444444, #222222);
    background-repeat: repeat-x;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ff444444', endColorstr='#ff222222', GradientType=0);
    border-color: #222222 #222222 #000000;
    border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
    filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
}

.operator-group-light:hover {
    text-decoration: none;
    background-position: 0 50px;
    -webkit-transition: background-position 0.1s linear;
    -moz-transition: background-position 0.1s linear;
    -o-transition: background-position 0.1s linear;
    transition: background-position 0.1s linear;
}

.operator-group-light:active {
    background-color: #080808;
}

.equal-light {
    color: #ffffff;
    cursor: pointer;
    text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
    background-color: #006dcc;
    background-image: -moz-linear-gradient(top, #0088cc, #0044cc);
    background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#0088cc), to(#0044cc));
    background-image: -webkit-linear-gradient(top, #0088cc, #0044cc);
    background-image: -o-linear-gradient(top, #0088cc, #0044cc);
    background-image: linear-gradient(to bottom, #0088cc, #0044cc);
    background-repeat: repeat-x;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ff0088cc', endColorstr='#ff0044cc', GradientType=0);
    border-color: #0044cc #0044cc #002a80;
    border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
    filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
}

.equal-light:hover {
    text-decoration: none;
    background-position: 0 50px;
    -webkit-transition: background-position 0.1s linear;
    -moz-transition: background-position 0.1s linear;
    -o-transition: background-position 0.1s linear;
    transition: background-position 0.1s linear;
}

.equal-light:active {
    background-color: #003399;
}