/* Reset */
body, h1, h2, p, ul, li, a {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 通用样式 */
body {
    font-family: 'Poppins', Arial, sans-serif; /* 替换为更现代的字体 */
    line-height: 1.8;
    background-color: #f3f8fd; /* 更柔和的背景色 */
    color: #333;
}

/* Header */
header {
    background-color: rgba(255, 255, 255, 0.9); /* 透明度增强轻盈感 */
    padding: 15px 20px;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.05); /* 更浅的阴影 */
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .logo h1 {
    font-size: 24px;
    color: #0056b3; /* 更深邃的蓝色 */
}

nav .menu {
    display: flex;
    gap: 20px; /* 拉开间距 */
}

nav .menu a {
    text-decoration: none;
    font-weight: 600;
    color: #0056b3;
    font-size: 16px;
    padding: 8px 20px;
    border-radius: 30px;
    transition: all 0.3s ease;
    background-color: #e7f3ff; /* 默认蓝色浅底 */
}

nav .menu a:hover {
    background-color: #0056b3;
    color: #ffffff;
    transform: scale(1.1);
}

/* Main Content */
main {
    max-width: 900px;
    margin: 30px auto;
    padding: 25px;
    background-color: #ffffff;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

main h2 {
    font-size: 1.8em;
    margin-bottom: 15px;
    color: #0056b3;
    border-left: 5px solid #0056b3;
    padding-left: 10px;
}

main p {
    font-size: 1.1em;
    line-height: 1.8;
    margin-bottom: 25px;
    color: #555;
}

/* 列表样式 */
ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

ul li {
    margin-bottom: 15px;
}

ul li a {
    text-decoration: none;
    color: #0056b3;
    font-weight: 600;
    transition: all 0.3s;
}

ul li a:hover {
    text-decoration: underline;
    color: #003580;
}

/* Footer */
footer {
    text-align: center;
    padding: 20px;
    background-color: rgba(255, 255, 255, 0.9);
    box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
    margin-top: 40px;
    font-size: 0.9em;
    color: #555;
}

/* 按钮风格 */
a.btn {
    display: inline-block;
    background-color: #0056b3;
    color: #ffffff;
    padding: 12px 20px;
    text-decoration: none;
    border-radius: 25px;
    font-weight: bold;
    transition: all 0.3s ease;
    text-align: center;
}

a.btn:hover {
    background-color: #003580;
    transform: translateY(-3px);
}

/* 卡片风格 */
.card {
    background-color: #ffffff;
    border-radius: 12px;
    margin-bottom: 30px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.card h2 {
    font-size: 1.6em;
    margin-bottom: 15px;
    color: #0056b3;
}

.card p {
    color: #555;
    line-height: 1.8;
    margin-bottom: 10px;
}

.card .tags {
    margin-top: 10px;
    display: flex;
    gap: 12px;
}

.card .tag {
    background-color: #e0f7ff;
    color: #0056b3;
    padding: 5px 12px;
    font-size: 0.9em;
    border-radius: 20px;
}

/* 背景图 */
body {
    background-image: url('../images/background.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    background-color: #f3f8fd;
}