/* 全局样式设置 */
body {
    margin: 0;
    padding: 0;
    background: linear-gradient(135deg, #121212, #1e1e1e); /* 使用深色渐变作为背景 */
    color: #ffffff;
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    overflow-x: hidden; /* 防止出现横向滚动条 */
}

/* 导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(18, 18, 18, 0.9);
    padding: 15px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    transition: background 0.3s ease;
}

.navbar.scrolled {
    background: #121212;
}

.navbar a {
    color: #03A9F4;
    text-decoration: none;
    margin: 0 15px;
    font-weight: bold;
    transition: color 0.3s ease;
}

.navbar a:hover {
    color: #32CD32;
}

/* 主标题样式 */
.header {
    width: 100%;
    height: 100vh;
    background: url('https://images.gptkong.com/demo/sample1.png') no-repeat center center/cover;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(18, 18, 18, 0.7);
}

.header .title {
    position: relative;
    color: #ffffff;
    font-size: 3em;
    text-shadow: 0 0 10px #03A9F4, 0 0 20px #03A9F4;
    z-index: 1;
    animation: fadeIn 2s ease-in-out;
}

/* 导航菜单样式 */
.nav-menu {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    padding: 60px 20px 20px 20px;
}

.nav-menu a {
    background: linear-gradient(45deg, #32CD32, #FFA500);
    padding: 10px 20px;
    margin: 10px;
    border-radius: 4px;
    color: #ffffff;
    text-decoration: none;
    transition: transform 0.3s ease, background 0.3s ease;
}

.nav-menu a:hover {
    transform: scale(1.05);
    background: linear-gradient(45deg, #FFA500, #32CD32);
}

/* 章节内容样式 */
section {
    padding: 60px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

section h2, section h3, section h4 {
    color: #03A9F4;
    margin-bottom: 20px;
}

section p {
    font-size: 16px;
    margin-bottom: 20px;
}

/* 图片样式 */
img.decorative {
    width: 320px;
    height: 320px;
    border-radius: 15px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.5);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

img.decorative:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.7);
}

/* 代码块样式 */
pre code {
    display: block;
    padding: 20px;
    background: #1e1e1e;
    border-radius: 8px;
    overflow-x: auto;
    font-family: 'Courier New', Courier, monospace;
    color: #03A9F4;
    margin-bottom: 20px;
}

/* 底部样式 */
.footer {
    background: #1e1e1e;
    padding: 40px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #ffffff;
}

.footer .community, .footer .support {
    display: flex;
    align-items: center;
}

.footer .community img, .footer .support img {
    width: 24px;
    height: 24px;
    margin-right: 10px;
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        padding: 10px 20px;
    }

    .nav-menu {
        flex-direction: column;
    }

    img.decorative {
        width: 100%;
        height: auto;
    }

    .footer {
        flex-direction: column;
        text-align: center;
    }

    .footer .community, .footer .support {
        margin: 10px 0;
    }
}

@media (max-width: 480px) {
    .header .title {
        font-size: 2em;
    }

    section p {
        font-size: 14px;
    }

    .footer {
        padding: 20px 10px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* 滚动指引箭头样式 */
.scroll-arrow {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%) rotate(-45deg);
    width: 30px;
    height: 30px;
    border-left: 3px solid #03A9F4;
    border-bottom: 3px solid #03A9F4;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) rotate(-45deg) translateY(0); }
    40% { transform: translateX(-50%) rotate(-45deg) translateY(-10px); }
    60% { transform: translateX(-50%) rotate(-45deg) translateY(-5px); }
}

/* 折叠区域样式 */
.collapsible {
    background-color: #2c2c2c;
    color: #ffffff;
    cursor: pointer;
    padding: 18px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 16px;
    transition: background 0.3s ease;
    margin-bottom: 10px;
}

.collapsible:hover {
    background-color: #3a3a3a;
}

.collapsible:after {
    content: '\002B';
    float: right;
    margin-left: 5px;
}

.collapsible.active:after {
    content: "\2212";
}

.content {
    padding: 0 18px;
    background-color: #1e1e1e;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.2s ease-out;
}

/* 内部链接样式 */
a.internal-link {
    color: #03A9F4;
    text-decoration: none;
    position: relative;
}

a.internal-link::after {
    content: '';
    position: absolute;
    width: 100%;
    transform: scaleX(0);
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: #32CD32;
    transform-origin: bottom right;
    transition: transform 0.3s ease;
}

a.internal-link:hover::after {
    transform: scaleX(1);
    transform-origin: bottom left;
}