.about{
    position: relative;
}
.container{
    width: 70%;
    margin: auto;
    padding: 20px;


}
p{
    text-align: left;
    text-indent: 2em;
    line-height: 2;
}
/* 样式表 */
body {
    font-family: Arial, sans-serif;
    font-size: 16px;
    line-height: 1.5;
}
h1 {
    font-size: 24px;
    font-weight: bold;
    margin-top: 30px;
    text-align: center;
}
h2 {
    font-size: 20px;
    font-weight: bold;
    margin-top: 20px;
    text-align: center;
}
h3 {
    font-size: 18px;
    font-weight: bold;
    margin-top: 15px;
    text-align: center;
}
p {
    margin-top: 10px;
    text-indent: 2em;
}
.abstract {
    margin-top: 30px;
    border-top: 1px solid #ccc;
    padding-top: 20px;
}
.abstract h2 {
    margin-top: 0;
}
.bibliography {
    margin-top: 30px;
    border-top: 1px solid #ccc;
    padding-top: 20px;
}
.bibliography h2 {
    margin-top: 0;
}

.container img{
    width: 80%;
    display: block;
    margin:20px auto;
}