body {
    max-width: 800px;
    margin: 1em auto;
}

h4 {
    margin-bottom: 0;
}

.pure-img {
    width: 80%;
    margin: 0 auto;
}

h1 {
    text-align: center;
    font-weight: normal;
    margin-bottom: 0;
    font-size: 4.5vw;
}

.hash {
    font-family: monospace;
}

.pure-g > div {
    box-sizing: border-box;
}
.l-box {
    padding: 1em;
}

.btn-first, .btn-second {
    text-align: center;
}

.pure-button {
    margin: 5px;
}

.url {
    overflow-wrap: break-word;
    word-wrap: break-word;
    -ms-word-break: break-all;
    word-break: break-all;
}

.ieee {
    margin: 0;
    padding: 0;
    list-style-type: none;
}
.ieee li {
    display: block;
    counter-increment: step-counter;
    margin-left: 30px;
}

.ieee li::before {
    display: inline-block;
    width: 30px;
    content: "["counter(step-counter)"]:";
    margin-left: -30px;
}

.credits {
    margin: 0 0 0 30px;
    padding: 0;
    list-style: none;
}

.credits li:before {
    content: '-';
    display: inline-block;
    width: 30px;
    margin-left: -30px;
}

@media screen and (min-width: 35.5em) {
    body {
        margin: 2em auto;
    }

    .btn-first {
        text-align: right;
    }

    .btn-second {
        text-align: left;
    }

    .pure-button {
        margin: 1em;
    }

    .pure-img {
        width: 100%;
    }

    h1 {
        font-size: 2em;
    }
}