body {
    margin: 0px;
    background-color: #777;
}
img {
    max-width: 100%;
}

.container {
    height: 97vh;
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-template-rows: 80px minmax(300px, max-content) 50px;
}

/*header中的样式*/
header {
    height: 70px;
    background-color: lightblue;
    position: relative;
}

header>a {
    position: absolute;
    right: 100px;
    top: 46px;
    text-decoration: none;
    color: black;
}

header>a:hover {
    text-decoration: underline !important;
    text-decoration-color: #CCC;
}

/*main中的样式*/
main {
    background-color: #777;
    position: relative;
    min-height: calc(99vh - 144px);
}

section p {
    word-break: break-all;
}

.parent {
    box-shadow: 0px -1px 2px #eee, 0px 1px 2px #222;
    /*    transition: height 1s ease;*/
    margin-top: 6px;
}

.parent[open]>summary {
    list-style-image: url("../images/open.png");
}

.parent>summary {
    color: white;
    padding: 0.5rem 1rem;
    font-size: 1.5rem;
    font-weight: 700;
    list-style-image: url('../images/close.png');
    height: 30px;
}

.parent>summary:hover,
.child>summary:hover {
    background-color: #999;
}

.parent>div {
    background-color: white;
    padding: 20px 0px;
    box-shadow: 0px 2px 2px black inset;
    transition: max-height 2s ease;
}

.child>summary {
    background-color: #333333;
    padding: 6px 1rem;
    color: #EEEEEE;
    margin-bottom: 1px;
    font-size: 1.2rem;
    font-weight: 600;
    list-style-type: none;
}

.child>div {
    border-left: 1px dotted #DDD;
    border-right: 1px dotted #DDD;
    background-color: #FDFDFD;
    padding: 1rem;
}

.child>summary::before {
    content: '\2795 ';
}

.child[open]>summary::before {
    content: "\2796 ";
}

.help {
    line-height: 1.7rem;
    text-indent: 2em;
    word-wrap: break-word;

}

footer {
    background-color: #DDD;
    display: flex;
    justify-content: space-between;
    padding: 10px 20px;
}

.footer-column {
    padding: 0 15px;
}

.footer-column h3,
.footer-column p,
.footer-column ul {
    margin: 0px;
    color: #444444;
}

.footer-column p,
.footer-column ul {
    font-size: 0.8rem;
    line-height: 1.1rem;
}

.footer-column a {
    text-decoration: none;
    color: rgba(0, 0, 255, 0.8);
}

section {
    padding: 20px;
    /*    line-height: 2.3rem;*/
}

.good {
    margin: 30px;
}

.resources {
    margin: 20px;
    padding: 20px;
    box-shadow: 0px 3px 5px 0px rgba(0, 0, 0, 0.2);
    background-color: white;
}

.good ul {
    /*    color: gold;*/
    font-size: 1rem;
}

p {
    text-indent: 2em;
    font-size: 1.2rem;
    color: #333333;
    line-height: 2rem;
    text-align: justify;
}

pre {
    padding: 10px 40px;
    font-size: 16px;
    border: 1px solid #999;
}

#small_btc_qr {
    height: 16px;
    position: absolute;
    margin-left: 10px;
    cursor: pointer;
}

#large_btc_qr,
#large_eth_qr {
    width: 200px;
    position: absolute;
    top: -204px;
    right: 0px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 1s;
}

#small_btc_qr:hover+#large_btc_qr,
#small_eth_qr:hover+#large_eth_qr {
    opacity: 1;
}

#small_eth_qr {
    height: 16px;
    position: absolute;
    cursor: pointer;
}

.comments {
    float: right;
    color: gray;
}

section>img {
    margin-left: 2em;
}