styles.css

* {
    position: relative;
    box-sizing: border-box;
}

html {
    font-family: ".AppleSystemUIFont", Avenir, "Helvetica Neue", sans-serif;
    font-size: 62.5%;
    background: #333B4F;
}

html, body {
    margin: 0;
    padding: 0;
    color: #CCCED3;
    overflow: hidden;
}

body {
    /*border: 1px solid #191D27;*/
    /*background: #333B4F;*/
    padding: 20px;
    user-select: none;
}

main {
    padding: 0 10px;
}

h1, h2 {
    margin-top: 0;
    padding: 0;
}

header,
footer {
    padding: 20px 10px;
}

header {
    padding-top: 10px;
}

header p {
    margin-top: 40px;
}

hr {
    border-color: #191D27;
    margin: 15px 0;
}

footer {
    padding: 20px 0;
    font-size: 1.3rem;
    text-align: center;
}

footer i {
    font-style: normal;
    margin: 0 10px;
}

a, a:hover, a:visited {
    color: #699ce8;
}

body {
    padding: 2rem;
    font-size: 1.6rem;
}

h1 img,
h2 img {
    height: 32px;
    vertical-align: bottom;
    margin-right: 4px;
}

figure {
    display: inline-block;
    margin-left: 0;
    margin-right: 0;
    vertical-align: top;
    font-weight: bold;
}

.big-arrow {
    width: 140px;
    display: block;
    top: 25%;
}

#uploader-input {
    cursor: pointer;
}

img, canvas {
    image-rendering: -moz-crisp-edges;
    image-rendering: -webkit-crisp-edges;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

#composer-pic,
#uploader-pic {
    display: block;
}

.checkerboard-bg {
    background-image: linear-gradient(45deg, rgba(0, 0, 0, 0.1) 25%, transparent 25%), linear-gradient(-45deg, rgba(0, 0, 0, 0.1) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, rgba(0, 0, 0, 0.1) 75%), linear-gradient(-45deg, transparent 75%, rgba(0, 0, 0, 0.1) 75%);
    background-size: 64px 64px;
    background-position: 0 0, 0 32px, 32px -32px, -32px 0px;
}

.with-grid:after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
    width: 100%;
    height: 100%;
    background-color: transparent;
    background-image: linear-gradient(0deg, transparent 24%, rgba(255, 0, 255, 0.3) 25%, rgba(255, 0, 255, 0.3) 26%,
    transparent 27%, transparent 74%, rgba(255, 0, 255, 0.3) 75%, rgba(255, 0, 255, 0.3) 76%, transparent 77%, transparent),
    linear-gradient(90deg, transparent 24%, rgba(255, 0, 255, 0.3) 25%, rgba(255, 0, 255, 0.3) 26%, transparent 27%,
            transparent 74%, rgba(255, 0, 255, 0.3) 75%, rgba(255, 0, 255, 0.3) 76%, transparent 77%, transparent);
    background-size: 128px 128px;
    background-position: center;
}

.flex {
    display: flex;
    align-items: stretch;
    align-content: center;
}

.flex > * {
    /*background: #699ce8;*/
    vertical-align: middle;
}

.flex > figure {
    background: #4f5667;
    /*border: 1px dashed #CCCED3;*/
    padding: 2rem;
    /*border-radius: 1rem;*/
    box-shadow: 5px 5px 0 #191D27;
}

figure picture {
    display: inline-block;
    margin: 30px 0;
    border: 1px inset #000;
    min-height: 160px;
    overflow: hidden;
}

figure picture img,
figure picture canvas {
    margin: 0;
    display: inline-block;
}

#uploader-img {
    min-height: 96px;
    max-width: 240px;
}

#uploader-pic {
    cursor: pointer;
}

#composer-img-canvas {
    width: 352px;
}

input, button {
    background: #262C3B;
    color: #CCCED3;
    padding: 6px 9px;
    border: 1px solid #111;
    min-height: 32px;
    text-align: center;
    vertical-align: center;
}

input {
    user-select: auto;
}

input:focus, button:focus {
    border-color: #CCCED3;
    outline: none;
}

input:active, button:active {
    border-color: #fcc751;
}

button:disabled, button:active:disabled {
    color: #4f5667;
    border: 1px solid #111;
}

button {
    cursor: pointer;
}

input[type=file] {
    display: block;
    width: 100%;
    margin-right: 10px;
    padding: 5px 9px;
}