/* 全局样式设置 */
body {
    margin: 0;
    padding: 0;
    font-family: 'Roboto', sans-serif;
    color: #333;
    background: linear-gradient(135deg, #1e3c72 70%, #2a5298 25%, #ff6a00 5%);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* 导航栏样式 */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    padding: 1rem 0;
    margin: 0;
}

nav li {
    position: relative;
    margin: 0 1.5rem;
}

nav a {
    text-decoration: none;
    color: #1e3c72;
    font-size: 1.2rem;
    transition: color 0.3s ease;
}

nav a:hover {
    color: #ff6a00;
}

/* 下拉菜单样式 */
nav li:hover ul {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

nav ul ul {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: #fff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    padding: 0.5rem 0;
    border-radius: 4px;
}

nav ul ul li {
    margin: 0;
}

nav ul ul a {
    padding: 0.5rem 1.5rem;
    display: block;
    font-size: 1rem;
    color: #2a5298;
}

nav ul ul a:hover {
    background: #f0f0f0;
    color: #ff6a00;
}

/* 主要内容区域 */
.main-content {
    flex: 1;
    padding: 6rem 2rem 2rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}

/* 标题样式 */
h1 {
    font-size: 2.5rem;
    text-align: center;
    color: #ffffff;
    margin-bottom: 2rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

/* 提示文字样式 */
.highlight-text {
    text-align: center;
    font-size: 1.2rem;
    color: #fff;
    margin-bottom: 3rem;
    padding: 1rem;
    background: rgba(0, 0, 0, 0.5);
    border-radius: 8px;
}

/* 文章内容样式 */
article {
    background: rgba(255, 255, 255, 0.8);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

article h2 {
    font-size: 2rem;
    color: #1e3c72;
    margin-bottom: 1rem;
    border-bottom: 2px solid #ff6a00;
    padding-bottom: 0.5rem;
}

article p {
    font-size: 1.1rem;
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

article pre {
    background: #f5f5f5;
    padding: 1rem;
    border-radius: 8px;
    overflow: auto;
}

article code {
    font-family: 'Courier New', Courier, monospace;
    color: #d14;
    background: #f9f2f4;
    padding: 2px 4px;
    border-radius: 4px;
}

/* 图片样式 */
.image-gallery {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.image-gallery img {
    width: 100%;
    max-width: 320px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.image-gallery img:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 12px rgba(0,0,0,0.2);
}

/* 响应式设计 */
@media (min-width: 768px) {
    .main-content {
        grid-template-columns: 1fr 1fr;
    }
}

@media (min-width: 1024px) {
    .main-content {
        grid-template-columns: 1fr 1fr 1fr;
    }
}

/* 按钮样式 */
.button {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: #2575fc;
    color: #fff;
    border: none;
    border-radius: 25px;
    text-decoration: none;
    font-size: 1rem;
    transition: background 0.3s ease, transform 0.3s ease;
}

.button:hover {
    background: #6a11cb;
    transform: scale(1.05);
}

/* 交互动效 */
@keyframes lightbulb {
    0% { opacity: 0; transform: scale(0.5); }
    50% { opacity: 1; transform: scale(1.2); }
    100% { opacity: 1; transform: scale(1); }
}

.lightbulb {
    animation: lightbulb 1s ease-in-out forwards;
}

/* 代码块标题 */
pre code::before {
    content: "示例代码：";
    display: block;
    font-weight: bold;
    margin-bottom: 0.5rem;
    color: #1e3c72;
}

pre code {
    overflow: visible;
}

/* 折叠区域样式 */
.collapsible {
    background-color: #f1f1f1;
    color: #444;
    cursor: pointer;
    padding: 0.5rem;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 1.1rem;
    border-radius: 8px;
    transition: background-color 0.3s ease;
}

.collapsible:hover {
    background-color: #ddd;
}

.content {
    padding: 0 1rem;
    display: none;
    overflow: hidden;
    background-color: #f9f9f9;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.active + .content {
    display: block;
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* 提示条样式 */
.alert {
    background: #ff6a00;
    color: #fff;
    padding: 1rem;
    text-align: center;
    border-radius: 8px;
    margin-bottom: 2rem;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

/* 页脚样式 */
footer {
    background: rgba(255, 255, 255, 0.9);
    text-align: center;
    padding: 1rem 0;
    box-shadow: 0 -2px 4px rgba(0,0,0,0.1);
}

footer p {
    margin: 0;
    font-size: 1rem;
    color: #2a5298;
}

/* 隐藏图片描述 */
img[alt=""] {
    aria-hidden: true;
}