/* ===== reset ===== */
* {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    color: #3a3a3a;
}

ul,
li {
    list-style: none;
    padding: 0;
    margin: 0;
    text-indent: -1em;
    transform: translateX(0.5em);
}

li:before {
    content: "/";
    margin-right: 0.5em;
    letter-spacing: 0;
}

/* ===== parts ===== */

header {
    display: flex;
    padding: 0.8em;
    line-height: 3em;
    letter-spacing: 3px;
}

header ul {
    display: flex;
    gap: 0 2em;
    flex-wrap: wrap;
}

@media (width < 950px) {
    header ul {
        flex-direction: column;
    }
}

header ul li {
    white-space: nowrap;
}

footer {
    text-align: center;
    padding: 0.8em;
    line-height: 3em;
    letter-spacing: 3px;
}

/* ===== top page ===== */

.top__main {
    height: 100%;
    text-align: center;
    line-height: 3em;
    letter-spacing: 3px;
}

.top__main h1 {
    white-space: nowrap;
}

.top__main .table-of-contents ul {
    text-align: left;
}


/* ===== article ===== */

article,
main {
    max-width: 800px;
    margin: 0 auto;
    padding: 0.8em;
    line-height: 2em;
    letter-spacing: 1px;
}

article pre {
    line-height: 1.5em;
    overflow-x: scroll;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;

    width: 100%;
    height: auto;

    pointer-events: none;
    z-index: -1;
}

.toc {
    border: 1px solid #8d8d8d;
    margin: 3em auto;
    padding: 1em 0;
}

.toc ul {
    display: flex;
    flex-direction: column;
    gap: 1em;
    margin: 0 2em;
}