:root {
    --primary-color: #2C5282;
    --secondary-color: #4299E1;
    --accent-color: #E53E3E;
    --text-color: #2D3748;
    --light-text: #718096;
    --background: #F7FAFC;
    --white: #FFFFFF;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans SC', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: var(--background);
}

/* 导航栏样式优化 */
nav {
    background: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 1rem 5%;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo img {
    height: 40px;
    width: auto;
    transition: transform 0.3s ease;
}

.logo img:hover {
    transform: scale(1.05);
}

.logo-text-cn {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--primary-color);
}

.logo-text-en {
    font-size: 0.8rem;
    color: var(--light-text);
}

nav ul {
    display: flex;
    gap: 2rem;
    align-items: center;
    list-style: none;
}

nav ul a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s, transform 0.2s;
    position: relative;
}

nav ul a:hover {
    color: var(--secondary-color);
    transform: translateY(-2px);
}

nav ul a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--secondary-color);
    transition: width 0.3s ease;
}

nav ul a:hover::after {
    width: 100%;
}

.nav-button {
    background: var(--primary-color);
    color: var(--white) !important;
    padding: 0.5rem 1.5rem;
    border-radius: 6px;
    transition: background-color 0.3s, transform 0.3s;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.nav-button:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.nav-button::after {
    display: none;
}

/* 主要内容样式优化 */
main {
    margin-top: 80px;
}

.section-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

/* 关于部分样式优化 */
.about-section, .products-section, .download-section {
    padding: 4rem 2rem;
    border-bottom: 1px solid #e7e7e7;
    background: #f9f9f9;
}

.about-section {
    background-color: #fff;
}

/* 视频预览样式优化 */
.video-preview {
    max-width: 550px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.video-thumbnail {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--white);
    text-decoration: none;
    padding: 1rem 1.5rem;
    position: relative;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    width: 100%;
}

.video-thumbnail:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.video-thumbnail img {
    height: 70px;
    width: auto;
    object-fit: contain;
    display: block;
    transition: none;
    filter: none;
}

.video-thumbnail:hover img {
    filter: none;
}

.play-button {
    position: static;
    transform: none;
    background: transparent;
    padding: 0;
    border-radius: 0;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
    box-shadow: none;
}

.play-icon {
    font-size: 1.2rem;
    color: var(--secondary-color);
    transition: color 0.3s ease;
}

.button-text {
    font-size: 1rem;
    color: var(--secondary-color);
    transition: color 0.3s ease;
}

.video-thumbnail:hover .play-icon,
.video-thumbnail:hover .button-text {
    color: var(--primary-color);
}

/* 产品展示部分 */
.products-section {
    background: linear-gradient(135deg, #EBF4FF 0%, #F7FAFC 100%);
}

.product-showcase {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    justify-content: center;
}

.product-info h3 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.product-info p {
    color: var(--light-text);
    font-size: 1.1rem;
    line-height: 1.8;
}

/* 下载部分样式 */
.download-section {
    background: var(--white);
}

.download-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 4rem;
}

.download-info {
    text-align: center;
}

.download-info h3 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.download-button {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    padding: 1rem 2rem;
    border-radius: 8px;
    margin-top: 1.5rem;
    transition: background 0.3s;
}

.download-button:hover {
    background: var(--secondary-color);
}

.qr-code {
    text-align: center;
}

.qr-code-img {
    width: 120px;
    height: 120px;
    padding: 8px;
    background: var(--white);
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s ease; /* 添加过渡效果 */
}
    
.qr-code-img:hover {
    transform: scale(1.3); /* 鼠标悬停时放大1.2倍 */
}
.qr-code p {
    margin-top: 0.5rem;
    color: var(--light-text);
}

/* 页脚样式 */
footer {
    background: var(--primary-color);
    color: var(--white);
    padding: 2rem 0;
    text-align: center;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .product-showcase {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .download-container {
        flex-direction: column;
        gap: 2rem;
    }

    .featured-title {
        font-size: 1.5rem;
    }

    .video-preview {
        flex-direction: column;
    }
    
    .video-thumbnail {
        margin-bottom: 20px;
    }
}

/* --- Core Features Section --- */
.features-section {
    padding: 4rem 0;
    background: linear-gradient(135deg, #f0f7ff 0%, #ffffff 100%);
    position: relative;
    overflow: hidden;
}

.features-section::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 200px;
    height: 200px;
    background: radial-gradient(circle, rgba(66, 153, 225, 0.1) 0%, rgba(255, 255, 255, 0) 70%);
    border-radius: 50%;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title h2 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
    position: relative;
    display: inline-block;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 2px;
    background: var(--secondary-color);
    border-radius: 2px;
}

.section-title p {
    color: var(--light-text);
    font-size: 1rem;
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.8rem;
}

.feature-item {
    text-align: center;
    padding: 1.8rem 1.2rem;
    background: var(--white);
    border-radius: 10px;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    position: relative;
    z-index: 1;
    overflow: hidden;
}

.feature-item::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--secondary-color);
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.4s ease;
    z-index: -1;
}

.feature-item:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

.feature-item:hover::before {
    transform: scaleX(1);
    transform-origin: left;
}

.feature-item i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1.2rem;
    transition: transform 0.3s ease, color 0.3s ease;
    display: inline-block;
}

.feature-item:hover i {
    transform: scale(1.15) rotate(5deg);
    color: var(--secondary-color);
}

.feature-item h3 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 0.8rem;
    font-weight: 600;
    transition: color 0.3s ease;
}

.feature-item:hover h3 {
    color: var(--secondary-color);
}

.feature-item p {
    color: var(--light-text);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .features-grid {
        grid-template-columns: 1fr;
        max-width: 400px;
        margin: 0 auto;
    }
    
    .section-title h2 {
        font-size: 1.6rem;
    }
    
    .feature-item {
        padding: 1.5rem 1.2rem;
    }
}

/* --- 全新的视频卡片样式 --- */
.video-card {
    display: flex;
    align-items: center;
    background-color: #ffffff;
    border-radius: 12px;
    padding: 20px 24px;
    margin: 2rem auto;
    max-width: 800px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease-in-out;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.video-card__logo {
    flex-shrink: 0;
    margin-right: 24px;
}

.video-card__logo img {
    height: 60px;
    width: auto;
    border-radius: 8px;
}

/* 针对Pro+的logo进行微调 */
.video-card--pro .video-card__logo img {
    background-color: transparent;
    padding: 0;
}

.video-card__info {
    flex-grow: 1;
    text-align: left;
}

.video-card__title {
    font-size: 1.2rem;
    font-weight: 500;
    color: #333;
    margin: 0;
}

.video-card__button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    border-radius: 8px;
    background-color: #007bff;
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.2s ease, transform 0.2s ease;
    flex-shrink: 0;
}

.video-card__button:hover {
    background-color: #0056b3;
    transform: scale(1.05);
}

.video-card__button .play-icon {
    margin-right: 8px;
    font-size: 0.9em;
}

/* --- 卡片定制 --- */
/* 央视视频卡片按钮颜色 */
.video-card--cctv .video-card__button {
    background-color: #c0392b; /* 红色系，更匹配央视风格 */
}

.video-card--cctv .video-card__button:hover {
    background-color: #a93226;
}

/* 针对原产品介绍部分容器的微调 */
.product-showcase {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.product-info {
    flex: 1;
}

.product-showcase .video-card {
    flex: 1;
    margin: 0; /* 移除外边距，因为它已在flex容器中 */
}

.section-title h2 {
    text-align: center;
    font-size: 2rem;
}