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

:root {
    --primary-black: #000000;
    --text-black: #1a1a1a;
    --text-gray: #666666;
    --text-light: #999999;
    --bg-white: #ffffff;
    --bg-light: #f8f8f8;
    --border-color: #e0e0e0;
    --shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 4px 30px rgba(0, 0, 0, 0.12);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-black);
    background: var(--bg-white);
    line-height: 1.6;
    overflow-x: hidden;
}

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

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 20px 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: baseline;
    gap: 10px;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-black);
    letter-spacing: -0.5px;
}

.tagline {
    font-size: 14px;
    color: var(--text-light);
    font-weight: 400;
}

.nav-links {
    display: flex;
    gap: 40px;
}

.nav-links a {
    color: var(--text-black);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-black);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    color: var(--primary-black);
}

.nav-links a:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    padding: 160px 0 100px;
    text-align: center;
    background: linear-gradient(180deg, var(--bg-light) 0%, var(--bg-white) 100%);
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    color: var(--primary-black);
    margin-bottom: 20px;
    letter-spacing: -2px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 20px;
    color: var(--text-gray);
    margin-bottom: 40px;
    font-weight: 400;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-bottom: 80px;
}

.btn {
    padding: 16px 40px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 12px;
    text-decoration: none;
    transition: all 0.3s ease;
    display: inline-block;
    border: 2px solid var(--primary-black);
}

.btn-primary {
    background: var(--primary-black);
    color: var(--bg-white);
}

.btn-primary:hover {
    background: var(--text-black);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.btn-secondary {
    background: transparent;
    color: var(--primary-black);
}

.btn-secondary:hover {
    background: var(--primary-black);
    color: var(--bg-white);
    transform: translateY(-2px);
}

/* 手机模型 */
.hero-image {
    display: flex;
    justify-content: center;
    margin-top: 60px;
}

.phone-mockup {
    width: 300px;
    height: 600px;
    border: 12px solid var(--primary-black);
    border-radius: 40px;
    background: var(--bg-white);
    box-shadow: var(--shadow-hover);
    position: relative;
    overflow: hidden;
}

.phone-mockup::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 150px;
    height: 30px;
    background: var(--primary-black);
    border-radius: 0 0 20px 20px;
    z-index: 10;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: var(--bg-light);
}

.app-preview {
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.preview-header {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 60px;
}

.preview-icon {
    font-size: 80px;
    margin-bottom: 30px;
}

.preview-text {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-black);
}

/* 功能特点 */
.features {
    padding: 100px 0;
    background: var(--bg-white);
}

.section-title {
    font-size: 42px;
    font-weight: 800;
    text-align: center;
    color: var(--primary-black);
    margin-bottom: 60px;
    letter-spacing: -1px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.feature-card {
    padding: 40px;
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    transition: all 0.3s ease;
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-black);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 22px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 15px;
}

.feature-card p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.6;
}

/* 使用方法 */
.how-it-works {
    padding: 100px 0;
    background: var(--bg-light);
}

.steps {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
    margin-top: 60px;
}

.step {
    flex: 1;
    min-width: 200px;
    max-width: 250px;
    text-align: center;
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--primary-black);
    color: var(--bg-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
    margin: 0 auto 20px;
}

.step-content h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 10px;
}

.step-content p {
    font-size: 14px;
    color: var(--text-gray);
    line-height: 1.5;
}

.step-arrow {
    font-size: 24px;
    color: var(--text-light);
    flex-shrink: 0;
}

/* 应用场景 */
.use-cases {
    padding: 100px 0;
    background: var(--bg-white);
}

.use-case-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.use-case {
    text-align: center;
    padding: 30px;
}

.use-case-emoji {
    font-size: 64px;
    margin-bottom: 20px;
}

.use-case h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 15px;
}

.use-case p {
    font-size: 15px;
    color: var(--text-gray);
}

/* 技术特点 */
.tech-specs {
    padding: 100px 0;
    background: var(--bg-light);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.tech-item {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 30px;
    background: var(--bg-white);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.tech-item strong {
    font-size: 16px;
    font-weight: 700;
    color: var(--primary-black);
}

.tech-item span {
    font-size: 15px;
    color: var(--text-gray);
}

/* 下载 */
.download {
    padding: 100px 0;
    background: var(--bg-white);
    text-align: center;
}

.download-desc {
    font-size: 18px;
    color: var(--text-gray);
    margin-bottom: 40px;
}

.download-buttons {
    display: flex;
    justify-content: center;
    margin-bottom: 50px;
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 16px 32px;
    background: var(--primary-black);
    color: var(--bg-white);
    border-radius: 12px;
    text-decoration: none;
    transition: all 0.3s ease;
    border: none;
}

.btn-download:hover {
    background: var(--text-black);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.download-icon {
    display: flex;
    align-items: center;
}

.download-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 2px;
}

.download-text small {
    font-size: 12px;
    font-weight: 400;
    opacity: 0.8;
}

.download-text strong {
    font-size: 18px;
    font-weight: 600;
}

.qr-code {
    margin-top: 40px;
}

.qr-placeholder {
    width: 200px;
    height: 200px;
    margin: 0 auto 20px;
    border: 2px solid var(--primary-black);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-light);
}

.qr-inner {
    font-size: 14px;
    color: var(--text-light);
}

.qr-hint {
    font-size: 14px;
    color: var(--text-gray);
}

/* 隐私与安全 */
.privacy {
    padding: 100px 0;
    background: var(--bg-light);
}

.privacy-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

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

.privacy-item h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 15px;
}

.privacy-item p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.6;
}

/* 常见问题 */
.faq {
    padding: 100px 0;
    background: var(--bg-white);
}

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

.faq-item {
    padding: 30px;
    margin-bottom: 20px;
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    transition: all 0.3s ease;
}

.faq-item:hover {
    border-color: var(--primary-black);
    box-shadow: var(--shadow);
}

.faq-item h3 {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 12px;
}

.faq-item p {
    font-size: 15px;
    color: var(--text-gray);
    line-height: 1.6;
}

/* 联系我们 */
.contact {
    padding: 100px 0;
    background: var(--bg-light);
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-top: 60px;
}

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

.contact-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.contact-item h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-black);
    margin-bottom: 12px;
}

.contact-item p {
    font-size: 15px;
    color: var(--text-gray);
}

.contact-item a {
    color: var(--primary-black);
    text-decoration: none;
    font-weight: 600;
    border-bottom: 2px solid var(--primary-black);
    transition: opacity 0.3s ease;
}

.contact-item a:hover {
    opacity: 0.7;
}

/* 页脚 */
.footer {
    background: var(--primary-black);
    color: var(--bg-white);
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 3fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 12px;
}

.footer-brand p {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

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

.footer-column h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--bg-white);
}

.footer-column a {
    display: block;
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 14px;
    margin-bottom: 10px;
    transition: color 0.3s ease;
}

.footer-column a:hover {
    color: var(--bg-white);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 30px;
    text-align: center;
}

.footer-bottom p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.6);
    margin-bottom: 5px;
}

.footer-icp {
    font-size: 12px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 300px;
    }

    .phone-mockup {
        width: 250px;
        height: 500px;
    }

    .section-title {
        font-size: 32px;
    }

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

    .steps {
        flex-direction: column;
    }

    .step-arrow {
        transform: rotate(90deg);
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

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

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}

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

.feature-card,
.step,
.use-case,
.faq-item {
    animation: fadeIn 0.6s ease-out;
}