/* 
主题颜色变量定义
--primary-color: 主色调，用于整体氛围，传递专业与科技感
--secondary-color: 辅助色，用于增强层次感，突出重点区域
--accent-color: 点缀色，用于吸引视线，制造视觉焦点
*/
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --background-gradient: linear-gradient(135deg, #2980b9, #6dd5fa);
    --font-family: 'Roboto', sans-serif;
}

/* 全局样式设置 */
body {
    margin: 0;
    padding: 0;
    font-family: var(--font-family);
    background: var(--background-gradient);
    color: #fff;
    line-height: 1.6;
}

/* 导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(44, 62, 80, 0.8);
    backdrop-filter: blur(10px);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    z-index: 1000;
}

.navbar a {
    color: #ecf0f1;
    text-decoration: none;
    margin: 0 15px;
    font-weight: 500;
    transition: color 0.3s ease;
}

.navbar a:hover {
    color: var(--accent-color);
}

/* 主体内容样式 */
.container {
    max-width: 1200px;
    margin: 100px auto 50px;
    padding: 20px;
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}

/* 章节导航样式 */
.sidebar {
    background: rgba(44, 62, 80, 0.6);
    padding: 20px;
    border-radius: 10px;
    backdrop-filter: blur(5px);
}

.sidebar a {
    display: block;
    color: #ecf0f1;
    text-decoration: none;
    margin: 10px 0;
    transition: color 0.3s ease;
}

.sidebar a:hover {
    color: var(--accent-color);
}

/* 文章内容样式 */
article h2 {
    font-size: 2rem;
    margin-bottom: 15px;
    color: var(--secondary-color);
}

article h3 {
    font-size: 1.75rem;
    margin-bottom: 10px;
    color: var(--accent-color);
}

article p {
    font-size: 1rem;
    margin-bottom: 15px;
    color: #bdc3c7;
}

article table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 20px;
}

article table, article th, article td {
    border: 1px solid #7f8c8d;
}

article th, article td {
    padding: 10px;
    text-align: left;
}

article pre {
    background: rgba(44, 62, 80, 0.9);
    padding: 15px;
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: 20px;
}

article pre code {
    color: #ecf0f1;
    font-family: 'Courier New', Courier, monospace;
}

/* 按钮样式 */
.button {
    padding: 12px 24px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.button-primary {
    background-color: var(--accent-color);
    color: #ffffff;
}

.button-primary:hover {
    background-color: #c0392b;
    transform: translateY(-2px);
}

.button-secondary {
    background-color: transparent;
    border: 2px solid var(--secondary-color);
    color: var(--secondary-color);
}

.button-secondary:hover {
    background-color: var(--secondary-color);
    color: #ffffff;
    transform: translateY(-2px);
}

/* 图片装饰样式 */
.decorative-image {
    width: 100%;
    max-width: 320px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.decorative-image:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 16px rgba(0,0,0,0.3);
}

/* 响应式布局 */
@media (min-width: 768px) {
    .container {
        grid-template-columns: 3fr 1fr;
    }
}

@media (min-width: 1200px) {
    .container {
        grid-template-columns: 4fr 1fr;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 1s ease forwards;
}

/* 提示信息样式 */
.reference-note {
    background: rgba(236, 240, 241, 0.2);
    padding: 15px;
    border-left: 5px solid var(--accent-color);
    margin-bottom: 20px;
    border-radius: 5px;
}

.reference-note p {
    margin: 0;
    color: #ecf0f1;
}

/* 折叠区域样式 */
.collapsible {
    background: rgba(44, 62, 80, 0.6);
    color: #ecf0f1;
    cursor: pointer;
    padding: 10px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 1rem;
    transition: background 0.3s ease;
    border-radius: 5px;
}

.collapsible:hover {
    background: rgba(44, 62, 80, 0.8);
}

.content {
    padding: 0 15px;
    display: none;
    overflow: hidden;
    background: rgba(44, 62, 80, 0.4);
    border-radius: 5px;
}

.content p {
    margin: 10px 0;
    color: #bdc3c7;
}

/* 代码示例样式 */
.code-example {
    background: rgba(44, 62, 80, 0.9);
    padding: 15px;
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: 20px;
}

.code-example code {
    color: #ecf0f1;
    font-family: 'Courier New', Courier, monospace;
    display: block;
    white-space: pre;
    font-size: 0.9rem;
}