/* 全局样式设置 */
body {
    margin: 0;
    padding: 0;
    font-family: 'Roboto', sans-serif; /* 使用现代无衬线字体 */
    background-color: #1E90FF; /* 主色调科技蓝 */
    color: #333;
    line-height: 1.6;
}

/* 响应式布局 */
.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* 顶部导航栏 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(30, 144, 255, 0.9);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 50px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    z-index: 1000;
}

.navbar a {
    color: #fff;
    text-decoration: none;
    margin: 0 15px;
    position: relative;
    transition: color 0.3s;
}

.navbar a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    background: #32CD32;
    left: 0;
    bottom: -5px;
    transition: width 0.3s;
}

.navbar a:hover::after {
    width: 100%;
}

.hero {
    height: 100vh;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat center center/cover;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    color: #fff;
    text-align: center;
}

.hero::before {
    content: '';
    position: absolute;
    top:0;
    left:0;
    width: 100%;
    height: 100%;
    background: rgba(30, 144, 255, 0.6);
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 3em;
    margin-bottom: 20px;
    background: linear-gradient(90deg, #1E90FF, #32CD32);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: gradientAnimation 5s infinite;
}

@keyframes gradientAnimation {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* 章节导航 */
.section-nav {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 165, 0, 0.8);
    padding: 10px;
    border-radius: 8px;
}

.section-nav a {
    display: block;
    color: #fff;
    text-decoration: none;
    margin: 10px 0;
    transition: transform 0.3s;
}

.section-nav a:hover {
    transform: scale(1.1);
}

/* 卡片样式 */
.card {
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    padding: 20px;
    margin: 20px 0;
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 8px 12px rgba(0,0,0,0.2);
}

/* 图片样式 */
.card img {
    width: 100%;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.card img:hover {
    transform: scale(1.05);
}

/* 按钮样式 */
.btn {
    display: inline-block;
    background: #FFA500;
    color: #fff;
    padding: 10px 20px;
    border-radius: 5px;
    text-decoration: none;
    transition: background 0.3s, transform 0.3s;
}

.btn:hover {
    background: #FF8C00;
    transform: scale(1.05);
}

/* 响应式调整 */
@media (max-width: 768px) {
    .navbar {
        padding: 10px 20px;
    }
    .hero h1 {
        font-size: 2em;
    }
    .section-nav {
        display: none;
    }
}