/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部导航 */
.header {
    background: #fff;
    border-bottom: 1px solid #e5e5e5;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-brand h1 {
    font-size: 24px;
    font-weight: bold;
    color: #007acc;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-menu a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-menu a:hover {
    color: #007acc;
}

.download-btn {
    background: #007acc;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: 500;
    transition: background 0.3s;
}

.download-btn:hover {
    background: #005999;
}

/* 英雄区域 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 120px 0 80px;
    margin-top: 70px;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-content h1 {
    font-size: 48px;
    font-weight: bold;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-content p {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-actions {
    display: flex;
    gap: 15px;
    margin-bottom: 40px;
}

.primary-btn {
    background: #ff6b6b;
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.primary-btn:hover {
    background: #ff5252;
    transform: translateY(-2px);
}

.secondary-btn {
    background: transparent;
    color: white;
    border: 2px solid white;
    padding: 15px 30px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.secondary-btn:hover {
    background: white;
    color: #667eea;
}

.hero-stats {
    display: flex;
    gap: 40px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 24px;
    font-weight: bold;
    margin-bottom: 5px;
}

.stat-label {
    font-size: 14px;
    opacity: 0.8;
}

.hero-image {
    text-align: center;
}

.app-screenshot {
    background: rgba(255,255,255,0.1);
    border-radius: 15px;
    padding: 20px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
}

.platform-info {
    margin-top: 20px;
    font-size: 14px;
    opacity: 0.8;
}

/* 关于部分 */
.about {
    padding: 80px 0;
    background: #f8f9fa;
}

.about h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.about > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 60px;
    color: #666;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.about-features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-top: 60px;
}

.about-feature {
    text-align: center;
    padding: 30px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.about-feature:hover {
    transform: translateY(-5px);
}

.about-feature h3 {
    font-size: 24px;
    margin-bottom: 15px;
    color: #333;
}

.about-feature p {
    color: #666;
    line-height: 1.6;
}

/* 功能特性 */
.features {
    padding: 80px 0;
}

.features h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.features > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 60px;
    color: #666;
}

.feature-section {
    margin-bottom: 80px;
}

.feature-section h3 {
    font-size: 28px;
    margin-bottom: 20px;
    color: #333;
}

.feature-section > p {
    font-size: 16px;
    margin-bottom: 30px;
    color: #666;
}

.feature-section ul {
    margin-bottom: 40px;
    padding-left: 20px;
}

.feature-section li {
    margin-bottom: 10px;
    color: #555;
}

.annotation-tools {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 15px;
    margin-bottom: 40px;
}

.tool-item {
    background: #f0f0f0;
    padding: 10px 15px;
    border-radius: 5px;
    text-align: center;
    font-weight: 500;
    color: #555;
}

/* 新增：更好的两栏布局用于展示说明与图片（多种截图方式区块） */
.feature-grid {
    display: flex;
    gap: 40px;
    align-items: flex-start;
    justify-content: space-between;
}

.feature-grid .feature-text {
    flex: 1 1 420px;
    max-width: 640px;
}

.feature-grid .feature-text ul {
    padding-left: 20px;
    margin-top: 10px;
}

.feature-grid .feature-text li {
    margin-bottom: 14px;
    line-height: 1.8;
    color: #444;
    font-size: 16px;
}

.feature-grid .feature-image {
    flex: 1 1 420px;
    max-width: 520px;
}

.feature-grid .feature-image img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 12px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.04);
}

/* 在较窄屏幕上保持良好表现（仍以桌面为主，但改进中间断点） */
@media (max-width: 980px) {
    .feature-grid {
        flex-direction: column;
        gap: 24px;
    }
    .feature-grid .feature-image,
    .feature-grid .feature-text {
        max-width: 100%;
    }
}

/* 核心优势 */
.advantages {
    padding: 80px 0;
    background: #f8f9fa;
}

.advantages h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.advantages > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 60px;
    color: #666;
}

.advantage-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.advantage-item {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.advantage-item:hover {
    transform: translateY(-5px);
}

.advantage-item h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: #333;
}

.advantage-item p {
    color: #666;
    line-height: 1.6;
}

/* 使用流程 */
.process {
    padding: 80px 0;
}

.process h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.process > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 60px;
    color: #666;
}

.process-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 80px;
}

.step {
    text-align: center;
    position: relative;
}

.step-number {
    width: 60px;
    height: 60px;
    background: #007acc;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: bold;
    margin: 0 auto 20px;
}

.step h3 {
    font-size: 24px;
    margin-bottom: 15px;
    color: #333;
}

.step p {
    color: #666;
    line-height: 1.6;
    margin-bottom: 30px;
}

.step-image {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 20px;
    margin-top: 20px;
}

.login-process {
    background: #f8f9fa;
    padding: 60px;
    border-radius: 15px;
    margin-top: 60px;
}

.login-process h3 {
    font-size: 28px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.login-process > p {
    font-size: 16px;
    text-align: center;
    margin-bottom: 40px;
    color: #666;
}

.login-steps {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
    margin-bottom: 40px;
}

.login-step {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.login-step-number {
    width: 40px;
    height: 40px;
    background: #007acc;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    flex-shrink: 0;
}

.login-step-content h4 {
    font-size: 18px;
    margin-bottom: 8px;
    color: #333;
}

.login-step-content p {
    color: #666;
    line-height: 1.5;
}

.login-demo {
    text-align: center;
    margin-top: 40px;
}

/* 用户评价 */
.reviews {
    padding: 80px 0;
    background: #f8f9fa;
}

.reviews h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.reviews > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 40px;
    color: #666;
}

.reviews-header {
    text-align: center;
    margin-bottom: 60px;
}

.rating {
    display: inline-block;
    text-align: center;
}

.rating-number {
    font-size: 48px;
    font-weight: bold;
    color: #333;
    display: block;
}

.rating-count {
    font-size: 16px;
    color: #666;
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 40px;
}

.review-card {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    position: relative;
}

.review-card p {
    font-size: 16px;
    line-height: 1.6;
    color: #555;
    margin-bottom: 25px;
    font-style: italic;
}

.reviewer {
    display: flex;
    align-items: center;
    gap: 15px;
}

.reviewer-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    flex-shrink: 0;
    object-fit: cover;
}

.reviewer-name {
    font-weight: 600;
    color: #333;
    margin-bottom: 2px;
}

.reviewer-title {
    font-size: 14px;
    color: #666;
}

.view-more {
    text-align: center;
}

.view-more-btn {
    background: #007acc;
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s;
}

.view-more-btn:hover {
    background: #005999;
}

/* 常见问题 */
.faq {
    padding: 80px 0;
}

.faq h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
    color: #333;
}

.faq > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 60px;
    color: #666;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 30px;
    border-bottom: 1px solid #e5e5e5;
    padding-bottom: 30px;
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: #333;
}

.faq-item p {
    color: #666;
    line-height: 1.6;
}

/* 下载区域 */
.download-section {
    padding: 80px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.download-section h2 {
    font-size: 36px;
    text-align: center;
    margin-bottom: 20px;
}

.download-section > .container > p {
    font-size: 18px;
    text-align: center;
    margin-bottom: 60px;
}

.download-options {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 80px;
}

.download-option {
    background: rgba(255,255,255,0.1);
    padding: 40px 30px;
    border-radius: 15px;
    text-align: center;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
    transition: transform 0.3s;
}

.download-option:hover {
    transform: translateY(-5px);
}

.download-option.coming-soon {
    opacity: 0.7;
}

.download-option h3 {
    font-size: 24px;
    margin-bottom: 15px;
}

.download-option p {
    margin-bottom: 20px;
    opacity: 0.9;
}

.version-info {
    font-size: 14px;
    margin-bottom: 25px;
    opacity: 0.8;
}

.download-btn-large {
    background: white;
    color: #667eea;
    border: none;
    padding: 15px 30px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    width: 100%;
}

.download-btn-large:hover:not(.disabled) {
    background: #f0f0f0;
    transform: translateY(-2px);
}

.download-btn-large.disabled {
    background: #ccc;
    color: #666;
    cursor: not-allowed;
    transform: none;
}

.stats-banner {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    text-align: center;
}

.stats-banner .stat-number {
    font-size: 36px;
    font-weight: bold;
    margin-bottom: 10px;
}

.stats-banner .stat-label {
    font-size: 16px;
    opacity: 0.9;
}

/* 页脚 */
.footer {
    background: #2d3748;
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 3fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand h3 {
    font-size: 24px;
    margin-bottom: 15px;
    color: #fff;
}

.footer-brand p {
    color: #a0aec0;
    line-height: 1.6;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
    color: #fff;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: 10px;
}

.footer-section a {
    color: #a0aec0;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: #fff;
}

.footer-bottom {
    border-top: 1px solid #4a5568;
    padding-top: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-bottom p {
    color: #a0aec0;
}

.footer-bottom-links {
    display: flex;
    gap: 20px;
}

.footer-bottom-links a {
    color: #a0aec0;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-bottom-links a:hover {
    color: #fff;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }

    .hero-actions {
        justify-content: center;
        flex-wrap: wrap;
    }

    .hero-stats {
        justify-content: center;
    }

    .about-features {
        grid-template-columns: 1fr;
    }

    .advantage-grid {
        grid-template-columns: 1fr;
    }

    .process-steps {
        grid-template-columns: 1fr;
    }

    .reviews-grid {
        grid-template-columns: 1fr;
    }

    .download-options {
        grid-template-columns: 1fr;
    }

    .stats-banner {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .footer-links {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }

    .login-steps {
        grid-template-columns: 1fr;
    }
}