:root {
    --primary-blue: #00A0DC;
    --secondary-blue: #0081B4;
    --accent-orange: #FF7A00;
    --dark: #1A1A1A;
    --light: #FFFFFF;
}

/* 基础重置样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    background-color: var(--dark);
    color: var(--light);
}

/* Header 样式 */
.site-header {
    background-color: rgba(0, 0, 0, 0.9);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo-image {
    height: 40px;
    width: auto;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-blue);
    letter-spacing: 2px;
}

/* Hero 样式更新 */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    background: linear-gradient(to bottom, var(--dark), var(--secondary-blue));
    overflow: hidden;
    padding: 80px 2rem 2rem;
}

.hero-content {
    text-align: center;
    z-index: 2;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 900;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, var(--primary-blue), var(--light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-transform: uppercase;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--light);
    margin-bottom: 2rem;
}

.read-now-btn {
    padding: 1rem 3rem;
    font-size: 1.2rem;
    font-weight: bold;
    background: var(--accent-orange);
    color: var(--light);
    border: none;
    border-radius: 50px;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.read-now-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(255, 122, 0, 0.3);
}

.hero-images {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    pointer-events: none;
}

.hero-image {
    position: absolute;
    height: 90%;
    width: auto;
    object-fit: contain;
}

.hero-image-left {
    left: -5%;
    bottom: 0;
    opacity: 0.7;
}

.hero-image-right {
    right: -5%;
    bottom: 0;
    opacity: 0.7;
}

/* 响应式设计更新 */
@media (max-width: 768px) {
    .hero {
        padding-top: 60px;
        justify-content: flex-start;
    }

    .hero-title {
        font-size: 2.5rem;
        margin-top: 1rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
        margin-bottom: 1.5rem;
    }

    .hero-images {
        position: relative;
        height: auto;
        margin-top: 2rem;
    }

    .hero-image {
        position: static;
        height: auto;
        width: 100%;
        max-height: 50vh;
        opacity: 1;
        object-fit: cover;
    }
}

@media (max-width: 480px) {
    .hero {
        padding-top: 50px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-images {
        display: block;
    }
}

/* 章节导航样式 */
.chapter-navigation {
    padding: 4rem 2rem;
    background-color: var(--dark);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--light);
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--accent-orange);
}

.chapters-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.chapter-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 8px;
    text-decoration: none;
    color: var(--light);
    transition: all 0.3s ease;
}

.chapter-item:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateX(10px);
}

.chapter-check {
    color: var(--primary-blue);
    font-size: 1.2rem;
}

.chapter-title {
    font-size: 1.1rem;
    color: var(--light);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .chapter-navigation {
        padding: 2rem 1rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .chapter-item {
        padding: 0.8rem;
    }

    .chapter-title {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .section-title {
        font-size: 1.8rem;
    }

    .chapter-item:hover {
        transform: none;
    }
}

/* SEO Content 样式 */
.seo-content {
    padding: 4rem 2rem;
    background-color: var(--dark);
    color: var(--light);
}

.seo-content article {
    max-width: 1200px;
    margin: 0 auto;
    font-size: 1.1rem;
    line-height: 1.8;
}

/* 标题样式 */
.seo-content h2 {
    font-size: 2.5rem;
    color: var(--primary-blue);
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 3px solid var(--accent-orange);
}

.seo-content h3 {
    font-size: 2rem;
    color: var(--light);
    margin: 2.5rem 0 1.5rem;
    position: relative;
    padding-left: 1rem;
}

.seo-content h3::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 4px;
    background-color: var(--primary-blue);
    border-radius: 2px;
}

.seo-content h4 {
    font-size: 1.5rem;
    color: var(--secondary-blue);
    margin: 2rem 0 1rem;
}

/* 段落样式 */
.seo-content p {
    margin-bottom: 1.5rem;
    color: rgba(255, 255, 255, 0.9);
}

/* 列表样式 */
.seo-content ul {
    margin: 1.5rem 0;
    padding-left: 2rem;
}

.seo-content ul li {
    margin-bottom: 0.8rem;
    position: relative;
    padding-left: 1.5rem;
    list-style: none;
}

.seo-content ul li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--accent-orange);
    font-size: 1.2em;
}

/* 强调文本 */
.seo-content strong {
    color: var(--primary-blue);
    font-weight: 600;
}

/* 链接样式 */
.seo-content a {
    color: var(--primary-blue);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.3s ease;
}

.seo-content a:hover {
    border-bottom-color: var(--primary-blue);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .seo-content {
        padding: 3rem 1.5rem;
    }

    .seo-content article {
        font-size: 1rem;
    }

    .seo-content h2 {
        font-size: 2rem;
    }

    .seo-content h3 {
        font-size: 1.75rem;
        padding-left: 0.8rem;
    }

    .seo-content h4 {
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    .seo-content {
        padding: 2rem 1rem;
    }

    .seo-content h2 {
        font-size: 1.75rem;
    }

    .seo-content h3 {
        font-size: 1.5rem;
        margin: 2rem 0 1rem;
    }

    .seo-content h4 {
        font-size: 1.2rem;
    }

    .seo-content ul {
        padding-left: 1rem;
    }
}

/* 打印样式 */
@media print {
    .seo-content {
        background-color: white;
        color: black;
    }

    .seo-content h2,
    .seo-content h3,
    .seo-content h4 {
        color: black;
    }
}
/* 视频部分样式 */
.video-section {
    padding: 4rem 2rem;
    background-color: var(--dark);
}

.video-section .container {
    max-width: 1200px;
    margin: 0 auto;
}

.video-section .section-title {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--light);
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

.video-section .section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: var(--accent-orange);
}

.video-container {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin-top: 2rem;
}

.video-wrapper {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 宽高比 */
    height: 0;
    overflow: hidden;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.video-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .video-section {
        padding: 3rem 1rem;
    }

    .video-container {
        grid-template-columns: 1fr; /* 手机端改为单列 */
        gap: 1.5rem;
    }

    .video-section .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .video-section {
        padding: 2rem 1rem;
    }

    .video-section .section-title {
        font-size: 1.8rem;
    }

    .video-wrapper {
        margin-bottom: 1rem;
    }
}