/* 动画 - 绿叶飘落 */
@keyframes leafFall {
    0% {
        transform: translateY(-100px) rotate(0deg);
        opacity: 1;
    }
    100% {
        transform: translateY(100vh) rotate(360deg);
        opacity: 0;
    }
}

.leaf {
    position: absolute;
    top: 0;
    width: 15px;
    height: 40px;
    background-color: #4CAF50;
    border-radius: 50%;
    animation: leafFall linear infinite;
    animation-duration: 10s;
    pointer-events: none;
    z-index: -1; /* 让树叶在最底层 */
    opacity: 0.8;
}

/* 随机调整树叶的动画时长 */
.leaf:nth-child(1) {
    animation-duration: 8s;
}

.leaf:nth-child(2) {
    animation-duration: 9s;
}

.leaf:nth-child(3) {
    animation-duration: 7s;
}

.leaf:nth-child(4) {
    animation-duration: 6s;
}

/* 基本样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    color: #333;
    overflow-x: hidden; /* 防止水平滚动条 */
    overflow-y: auto;  /* 允许垂直滚动 */
    height: 100vh;  /* 保证页面高度是100% */
}

header {
    background-color: #2d6a4f;
    color: white;
    padding: 20px;
    text-align: center;
    background-image: url('images/image1.jpg');
    background-size: cover;
    background-position: center;
}

header .logo h1 {
    font-size: 2.5em;
    margin: 0;
}

header nav ul {
    list-style-type: none;
    padding: 0;
    margin-top: 10px;
}

header nav ul li {
    display: inline;
    margin: 0 15px;
}

header nav ul li a {
    color: white;
    text-decoration: none;
    font-size: 1.2em;
}

section {
    padding: 40px 20px;
    margin: 20px auto;
    max-width: 800px;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

section h2 {
    font-size: 2.5em;
    margin-bottom: 20px;
    color: #2d6a4f;
}

.article h3 {
    font-size: 1.8em;
    color: #00796b;
}

.article p {
    font-size: 1.1em;
    line-height: 1.6;
}

.article-image {
    width: 100%;
    margin: 20px 0;
    border-radius: 8px;
}

footer {
    background-color: #00796b;
    color: white;
    text-align: center;
    padding: 10px;
    position: fixed;
    bottom: 0;
    width: 100%;
}