/* 整体布局与响应式设计 */
body {
    margin: 0;
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(135deg, #1A237E 70%, #424242 25%, #03DAC6 5%);
    color: #ffffff;
    overflow-x: hidden;
}

/* 导航条样式 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(66, 66, 66, 0.7);
    backdrop-filter: blur(10px);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 30px;
    z-index: 1000;
}

.navbar a {
    color: #ffffff;
    text-decoration: none;
    margin: 0 15px;
    font-size: 16px;
    transition: color 0.3s ease;
}

.navbar a:hover {
    color: #03DAC6;
}

/* 章节导航系统 */
.chapter-nav {
    position: fixed;
    top: 80px;
    left: 20px;
    background: rgba(66, 66, 66, 0.8);
    padding: 10px;
    border-radius: 8px;
}

.chapter-nav a {
    display: block;
    color: #ffffff;
    text-decoration: none;
    margin: 10px 0;
    font-size: 16px;
    transition: color 0.3s ease;
}

.chapter-nav a:hover {
    color: #03DAC6;
}

/* 主要内容区块样式 */
.section {
    padding: 100px 50px;
    min-height: 100vh;
}

.section:nth-child(even) {
    background: rgba(66, 66, 66, 0.5);
}

.section:nth-child(odd) {
    background: rgba(26, 35, 126, 0.5);
}

.section h2 {
    font-size: 24px;
    margin-bottom: 20px;
    position: relative;
}

.section h2::after {
    content: '';
    width: 50px;
    height: 3px;
    background: #03DAC6;
    position: absolute;
    left: 0;
    bottom: -10px;
}

/* 图文布局 */
.content-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

.content-grid img {
    width: 100%;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

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

.content-grid p {
    font-size: 17px;
    line-height: 1.6;
}

/* 强调文本 */
.highlight {
    color: #03DAC6;
    font-weight: bold;
}

/* CSS3代码块样式 */
.code-block {
    background: rgba(0, 0, 0, 0.7);
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 20px 0;
    font-family: 'Courier New', Courier, monospace;
    font-size: 16px;
}

.code-block code {
    color: #03DAC6;
}

/* 按钮样式 */
.button {
    background: linear-gradient(90deg, #03DAC6, #6200EA);
    border: none;
    color: #ffffff;
    padding: 12px 24px;
    border-radius: 25px;
    cursor: pointer;
    transition: background 0.5s ease;
    font-size: 16px;
}

.button:hover {
    background: linear-gradient(90deg, #6200EA, #03DAC6);
}

/* 卡片样式 */
.card {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    padding: 20px;
    backdrop-filter: blur(5px);
    transition: transform 0.3s ease, background 0.3s ease;
}

.card:hover {
    transform: translateY(-10px);
    background: rgba(255, 255, 255, 0.2);
}

/* 加载动画 */
.loader {
    border: 8px solid rgba(0, 0, 0, 0.1);
    border-top: 8px solid #03DAC6;
    border-radius: 50%;
    width: 60px;
    height: 60px;
    animation: spin 1s linear infinite;
    margin: auto;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* 底部导航样式 */
.footer {
    background: rgba(26, 35, 126, 0.9);
    color: #ffffff;
    padding: 40px 20px;
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
}

.footer a {
    color: #03DAC6;
    text-decoration: none;
    margin: 10px 0;
    transition: color 0.3s ease;
}

.footer a:hover {
    text-decoration: underline;
}

/* 页面提示样式 */
.header-note {
    position: fixed;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    background: #03DAC6;
    color: #000000;
    padding: 10px 20px;
    border-radius: 0 0 8px 8px;
    font-size: 16px;
    z-index: 1001;
}