body {
    background: #fff;
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-size: 16px;
    line-height: 1.5;
    margin: 0 auto;
    max-width: 800px;
    padding: 2em 2em 4em;
    background-image: url(back.svg); 
    
    background-repeat: no-repeat;
    background-position: left center;
    background: opacity: 0.5;
    background-size;1200px;
}

h1, h2, h3, h4, h5, h6 {
    color: #222;
    font-weight: 600;
    line-height: 1.3;
}

h2 {
    margin-top: 1.3em;
}

a {
    color: #0083e8;
}

b, strong {
    font-weight: 600;
}

samp {
    display: none;
}

img {
   
    border-radius: 4px;
    display: block;
    margin: 1.3em auto;
    max-width: 95%;
}

@keyframes colorize {
    0% {
        -webkit-filter: grayscale(100%);
        filter: grayscale(100%);
    }
    100% {
        -webkit-filter: grayscale(0%);
        filter: grayscale(0%);
    }
}