:root {
    --color-light: #fff;
    --color-dark: #000;
    --page-bg-color: #555;
    --button-bg-color: #aaa;
    --button-bg-color-hover: #888;
    --button-fg-color: #fff;
    --info: rgb(0, 211, 0);
    --warning: rgb(224, 153, 0);
    --error: rgb(192, 0, 0);
}
body {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}
* {
    font-family: sans-serif;
}
.flex-row {
    display: flex;
    flex-direction: row;
}
.flex-col {
    display: flex;
    flex-direction: column;
}
.flex-grow {
    display: flex;
    flex-grow: 1;
}
.flex-shrink {
    display: flex;
    flex-shrink: 1;
}
.page_bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--page-bg-color);
    overflow: auto;
}
.page {
    background-color: var(--color-light);
    margin: 0;
    padding: .5in;
    width: 8.5in;
    height: 11in;
    flex-grow: 0;
    flex-shrink: 0;
    margin: .25in
}
.overlay {
    position: absolute;
    left: 0;
    bottom: 0;
    backdrop-filter: blur(5px);
    padding: 1vmin;
    margin: 1vmin;
    border-radius: 1vmin;
}
.button {
    user-select: none;
    border: none;
    border-radius: 0.5vmin;
    color: var(--button-fg-color);
    background-color: var(--button-bg-color);
    padding: 1vmin;
    margin: 0.5vmin;
    text-align: center;
    font-weight: bold;
    cursor: pointer;
    flex-basis: 100%;
}
.button:hover {
    background-color: var(--button-bg-color-hover);
}
.num-container {
    flex-wrap: wrap;
}
.num {
    font-family: "Courier New", Courier, monospace;
    padding: .5px;
    padding-left: 4px;
    padding-right: 4px;
    margin: 1px;
    border: 1px solid var(--color-dark);
}
input {
    background-color: transparent;
    border: none;
    color: var(--color-light);
    text-align: right;
    width: 8ch;
}
@media print {
    body, .page_bg {
        width: auto;
        height: auto;
    }
    body * {
        visibility: hidden;
        position: absolute;
    }
    .page, .page * {
        visibility: visible;
        position: static;
    }
}
#otp-canvas {
    background-color: var(--color-light);
}
#message-box {
    color: var(--color-light);
    background-color: var(--error);
    padding: 5px;
}