.content h3 a,
.content h4 a,
.content h5 a,
.content h6 a,
.content #toc a {
    color: #0092fd;
    text-decoration: none;
}

.content #toc {
    display: inline-block;
    border: 1px solid #eee;
    padding: 10px 20px;
    margin: 10px 0 30px 0;
    list-style-type: none;
}

.content #toc li {
    margin: 0;
    list-style-type: none;
}

.content > h3::before,
.content > h4::before,
.content > h5::before,
.content > h6::before {
    content: "▽ ";
    display: inline;
    border-top: none;
}

.content > h3.folded, .content > h3.folded *,
.content > h4.folded, .content > h4.folded *,
.content > h5.folded, .content > h5.folded *,
.content > h6.folded, .content > h6.folded * {
    opacity: 0.5;
}

.content > h3.folded::before,
.content > h4.folded::before,
.content > h5.folded::before,
.content > h6.folded::before {
    content: "▷ ";
}

.content > h3, .content > h4,
.content > h5, .content > h6 {
    padding-bottom: 0.5em;
    border-bottom: #eee 1px solid;
}

details summary:nth-child(1)::after {
    content: " ]";
}

details summary:nth-child(1)::before {
    content: "[ ▶ ";
}

details[open] summary:nth-child(1)::before {
    content: "[ ▼ ";
}

img.icon {
    height: 1.5em;
    vertical-align: middle;
}

div.table {
    width: 100%;
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    align-items: stretch;
    padding: 1em 0px;
}

div.c {
    display: table;
    padding: 8px;
    font-family: 'NanumSquare';
    font-weight: normal;
    border-bottom: #eee 1px solid;
    text-align: center;
    vertical-align: middle;
    box-sizing: border-box;
}

div.c0 {
    flex-grow: 1;
    flex-basis: 96%;
    border-bottom: #eee 1px solid;
    box-sizing: border-box;
}

div.c1 {
    flex-grow: 4;
    flex-basis: 96%;
}

div.c2 {
    flex-grow: 2;
    flex-basis: 46%;
}

div.c3 {
    flex-grow: 1;
    flex-basis: 31%;
}

div.c4, div.c4_1 {
    flex-grow: 1;
    flex-basis: 21%;
}

div.c4_3 {
    flex-grow: 3;
    flex-basis: 71%;
}

div.c6 {
    flex-grow: 1;
    flex-basis: 16%;
}

div.c > span {
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}

@media (max-width: 1000px) {
    div.c4 {
        flex-grow: 2;
        flex-basis: 46%;
    }

    div.c2 {
        flex-grow: 4;
        flex-basis: 96%;
    }

    div.c6 {
        flex-grow: 2;
        flex-basis: 29%;
    }
}

input.invalid {
    border-color: red;
}