@font-face {
    font-family: "sweet_tea";
    src: url("fonts/SweetTeaCheess.TTF");
}
@font-face {
    font-family: "dfpc";
    src: url("fonts/DFPCraftDou-W3.TTF");
}
@font-face {
    font-family: "slidefu";
    src: url("fonts/Slidefu-Regular-2.ttf");
}
@font-face {
    font-family: "hanyixixing";
    src: url("fonts/HanyiXixing.ttf");
}
@font-face {
    font-family: "cat_gnaw";
    src: url("fonts/cat.ttf");
    font-weight: 100!important;
}
@font-face {
    font-family: "hongleizhuoshu";
    src: url("fonts/鸿雷拙书简体.ttf");
}
@font-face {
    font-family: "jiangchengyuanti";
    src: url("fonts/江城圆体 500W.ttf");
}
@font-face {
    font-family: "mengyuansongtiw27";
    src: url("fonts/梦源宋体 CN W27.ttf");
}
@font-face {
    font-family: "mengyuansongtiw14";
    src: url("fonts/梦源宋体 CN W14.ttf");
}
@font-face {
    font-family: "mengyuansongtiw";
    src: url("fonts/梦源宋体 CN W15.ttf");
}
@font-face {
    font-family: "pinganchangfangti";
    src: url("fonts/平安长方体.ttf");
}
@font-face {
    font-family: "pingfangqiaomuti";
    src: url("fonts/平方乔木体.ttf");
}
@font-face {
    font-family: "pingfangqingchunti";
    src: url("fonts/平方青春体.ttf");
}
@font-face {
    font-family: "pingfangsatuoti";
    src: url("fonts/平方洒脱体.ttf");
}
@font-face {
    font-family: "pingfangsanshengti";
    src: url("fonts/平方三生体.ttf");
}
@font-face {
    font-family: "siyuansongti";
    src: url("fonts/思源宋体旧字形 Medium.ttf");
}
@font-face {
    font-family: "xiangcuichaoxisongw40";
    src: url("fonts/香萃潮汐宋 W40.ttf");
}
@font-face {
    font-family: "xiangcuichaoxisongw15";
    src: url("fonts/香萃潮汐宋W15.ttf");
}
@font-face {
    font-family: "xiangcuidazijiti";
    src: url("fonts/香萃打字机体 W40.ttf");
}
.font_sweet_tea{
    font-family: "sweet_tea";
}
.font_dfpc{
    font-family: "dfpc";
}
.font_slidefu{
    font-family: "slidefu";
}
.font_hanyixixing{
    font-family:"hanyixixing";
}
.font_cat_gnaw{
    font-family:"cat_gnaw";
}
.font_hongleizhuoshu{
    font-family:"hongleizhuoshu";
}
.font_jiangchengyuanti{
    font-family:"jiangchengyuanti";
}
.font_mengyuansongtiw14{
    font-family:"mengyuansongtiw14";
}
.font_mengyuansongtiw15{
    font-family:"mengyuansongtiw15";
}
.font_mengyuansongtiw27{
    font-family:"mengyuansongtiw27";
}
.font_pingfangqiaomuti{
    font-family:"pingfangqiaomuti";
}
.font_pinganchangfangti{
    font-family:"pinganchangfangti";
}
.font_pingfangsanshengti{
    font-family:"pingfangsanshengti";
}
.font_pingfangqingchunti{
    font-family:"pingfangqingchunti";
}
.font_pingfangsatuoti{
    font-family:"pingfangsatuoti";
}
.font_siyuansongti{
    font-family:"siyuansongti";
}
.font_xiangcuichaoxisongw15{
    font-family:"xiangcuichaoxisongw15";
}
.font_xiangcuichaoxisongw40{
    font-family:"xiangcuichaoxisongw40";
}
.font_xiangcuidazijiti{
    font-family:"xiangcuidazijiti";
}
.definition{
    font-family:"cat_gnaw";
    letter-spacing: 0em;
    font-size:16pt;
    font-weight: 500;
    margin-top: 20px;
}
.theorem{
    font-family:"cat_gnaw";
    letter-spacing: 0em;
    font-size:16pt;
    font-weight: 500;
    margin-top: 20px;
}
.theorem_single{
    font-family:"cat_gnaw";
    letter-spacing: 0em;
    font-size:16pt;
    font-weight: 500;
    margin-top: 20px;
}
.main_content{
    font-family:"cat_gnaw";
    letter-spacing: 0em;
    font-size:16pt;
    font-weight: 500!important;
    margin-bottom: 20px;
}
span[class="definition denation theorem"]{
    display: inline-block;
}
a{
    font-weight:600;
}
.main_content a{
    font-weight:200;
}
.theorem>a{
    font-weight:400;
}
.theorem_single>a{
    font-weight:400;
}
.notation{
    font-family:"cat_gnaw";
    letter-spacing: 0em;
    font-size:16pt;
    font-weight: 500;
    margin-top: 20px;
}
.example{
    font-family:"cat_gnaw";
    color: #ec6157;
    font-size:15pt;
    font-weight: 400;
}
.exercise{
    font-family:"cat_gnaw";
    color: #47c981;
    font-size:15pt;
    font-weight: 400;
}
.body{
    counter-reset: chapter_count; /* 创建并重置计数器 */
}
.chapter{
    counter-reset: section_count;
    counter-increment: chapter_count ;
}
.section{
    counter-reset: example_count definition_count theorem_count notation_count exercise_count;
    counter-increment: section_count ;
}
.hidden{
    display:none;
}
.definition::before {
    counter-increment: definition_count ; 
    content: "定义" counter(chapter_count) "." counter(section_count) "." counter(definition_count)"："; 
    color: #579185;
}
.theorem::before {
    counter-increment: theorem_count ; 
    content: "定理" counter(chapter_count) "." counter(section_count) "." counter(theorem_count)"："; 
    color: #714e8e;
}
.theorem_single::before {
    counter-increment: theorem_count ; 
    content: "定理" counter(theorem_count)"："; 
    color: #714e8e;
}
.terminology{
    font-weight: 700;
    color:#f58355;
}
.terminology:hover {
    border-bottom: 1px solid #f58355; /* 设置下划线的样式和颜色 */
    padding-bottom: 1px; /* 留出空间让下划线浮现出来 */
}
div.main_content .terminology{
    font-weight: 400;
}
.main_content .terminology{
    font-weight: 400;
}
.theorem .terminology{
    font-weight: 400;
}
.definition .terminology{
    font-weight: 400;
}
.theorem_single .terminology{
    font-weight: 400;
}
.definition .terminology{
    font-weight: 400;
}
.example::before {
    counter-increment: example_count ; 
    content: "例"counter(example_count)". "; 
    color: #ec6157;
    font-size:15pt;
    font-weight: 400;
}
.exercise::before {
    counter-increment: exercise_count ; 
    content: "Exercise"counter(chapter_count) "." counter(section_count) "."counter(exercise_count)". "; 
    color: #47c981;
    font-size:15pt;
    font-weight: 400;
}
.notation::before{
    counter-increment: notation_count ; 
    content: "规定"counter(notation_count)". ";
    color: #3e45a5;
}
.proof_head::before{
    content:"证明：";
    font-family: "sweet_tea";
    font-size:18pt;
}
.proof_tail::after{
    content:"";
    float: right;
    width: 40px;  /* 设置图片的宽度 */
    height: 40px;  /* 设置图片的高度 */
    background-image: url('/img/emoji/qed.jpg');  /* 图片路径 */
    background-size: cover;  /* 图片覆盖整个区域 */
    background-position: right bottom;  /* 图片居中 */
    position: relative;
    top: -40px;  
}
.proof_tail{
    margin-bottom: 100pt;
}

.hide{
    opacity: 0;
    font-size: 0pt;
    height: 20px;

}
body{
    font-size: 14pt;
}
.arrow-right {
    width: 0;
    height: 0;
    border-top: 10px solid transparent;
    border-bottom: 10px solid transparent;
    border-left: 20px solid black;
}

.arrow-down {
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 20px solid black;
}

/* 容器布局，使用 flexbox 实现 2x2 的选项布局 */
.options-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px; /* 选项之间的间距 */
    width: 50vw; /* 容器宽度，可以根据需要调整 */
    margin: 0 auto; /* 居中 */
    margin-bottom: 50pt;
}

  /* 每个选项占据 50% 的宽度，实现 2x2 布局 */
.option {
    width: 45%; /* 确保每个选项占用两列的一半 */
    display: flex;
    align-items: center;
    gap: 10px; /* 输入框和文本之间的间距 */
}
.options {
    width: 90%; /* 确保每个选项占用两列的一半 */
    display: flex;
    align-items: center;
    gap: 10px; /* 输入框和文本之间的间距 */
}

  /* 输入框大小调整 */
.option input[type="radio"] {
    transform: scale(1.2); /* 放大 radio 按钮 */
    background-color: #f0f0f0;
    cursor: pointer;
    border-radius: 5px;
}
.options input[type="checkbox"] {
    transform: scale(1.2); /* 放大 radio 按钮 */
    background-color: #f0f0f0;
    cursor: pointer;
    border-radius: 5px;
}
input[type="text"] {
    background-color: #f9f9f9;
    padding: 5px;
    font-size: 14px;
    border: 2px solid #ccc;
    border-radius: 8px;
    width: 150px;
    transition: all 0.3s ease;
    margin-bottom: 50pt;
}
.answer_block{
    margin-top: 15em;
    margin-bottom: 15em;
}