/* 全局重置和字体 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #d4edda; /* 仿照图片的淡绿色背景 */
}

/* 容器最大宽度限制 */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- 顶部横幅 --- */
header {
    height: 200px;
    position: relative;
    overflow: hidden;
    margin-bottom: 20px;
}

/* 几何图形背景 */
.banner {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    text-align: center;
    /* 这里使用了CSS来模拟图片中的几何多边形背景 */
    background: linear-gradient(135deg, #66bb6a 25%, transparent 25%) top left,
                linear-gradient(225deg, #42a5f5 25%, transparent 25%) top right,
                linear-gradient(315deg, #26a69a 25%, transparent 25%) bottom right,
                linear-gradient(45deg, #26a69a 25%, transparent 25%) bottom left;
    background-size: 50px 50px;
    background-color: #26a69a; /* 主背景色 */
}

/* 为了更接近图片效果，添加一个半透明的遮罩层样式 */
.banner::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    /* 这是一个半透明的蓝色/青色遮罩，覆盖在几何图形上 */
    background: rgba(76, 175, 80, 0.6);
}

.banner h1, .banner h2 {
    position: relative;
    z-index: 1;
    margin: 5px 0;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

/* --- 导航栏 --- */
nav {
    background-color: #333; /* 深色背景 */
    padding: 10px 0;
    margin-bottom: 40px;
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

nav li {
    margin: 0 15px;
}

nav a {
    color: white;
    text-decoration: none;
    font-size: 1.1em;
    padding: 5px 10px;
    transition: color 0.3s;
}

nav a:hover {
    color: #4caf50; /* 鼠标悬停时变为绿色 */
}

/* --- 主要内容 --- */
main {
    background-color: #e8f5e9; /* 内容区背景色，比整体背景稍浅 */
    padding: 30px 0;
    border-radius: 8px;
}

.content h3 {
    margin-bottom: 20px;
    color: #2c3e50;
}

.note {
    color: #666;
    font-style: italic;
    margin-bottom: 30px;
}

/* 论文列表样式 */
.paper-list {
    list-style-type: disc;
    padding-left: 20px;
}

.paper-list li {
    margin-bottom: 10px;
}

/* 日期样式 */
.date {
    color: #4caf50;
    font-weight: bold;
    font-family: monospace;
}

/* 链接样式 */
.paper-list a {
    color: #2196f3;
    text-decoration: none;
}

.paper-list a:hover {
    text-decoration: underline;
    color: #1976d2;
}