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

:root {
    --primary-color: #2d5cff;
    --primary-dark: #1a3cb8;
    --primary-light: #5a7fff;
    --text-color: #1a1a2e;
    --text-secondary: #4a4a68;
    --text-light: #6b6b8a;
    --bg-color: #ffffff;
    --bg-secondary: #f5f7fb;
    --bg-dark: #0d1b3e;
    --border-color: #e2e8f0;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: all 0.3s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--primary-dark);
}

ul {
    list-style: none;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    font-size: 16px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: #fff;
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
    color: #fff;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: #fff;
}

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
}

.logo-text {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-color);
}

.nav-menu {
    display: flex;
    align-items: center;
}

.nav-list {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    display: block;
    padding: 8px 16px;
    color: var(--text-secondary);
    font-size: 15px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--primary-color);
    background: var(--bg-secondary);
}

.btn-contact {
    padding: 10px 20px;
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.btn-contact:hover {
    background: var(--primary-dark);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    gap: 6px;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-color);
    transition: var(--transition);
}

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 100px 0 60px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1;
}

.hero-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.15;
}

.hero-bg::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.9) 0%, rgba(245,247,251,0.95) 100%);
}

.hero-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
}

.hero-content {
    flex: 1;
    max-width: 600px;
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
    font-size: 14px;
    color: var(--text-light);
}

.breadcrumb a {
    color: var(--text-light);
}

.breadcrumb a:hover {
    color: var(--primary-color);
}

.breadcrumb span {
    color: var(--text-light);
}

.hero h1 {
    font-size: 42px;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 20px;
    color: var(--text-color);
}

.hero-desc {
    font-size: 18px;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-image {
    flex-shrink: 0;
}

.phone-mockup {
    max-width: 300px;
    border-radius: 24px;
    box-shadow: var(--shadow-lg);
}

.download-section {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.download-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.section-desc {
    font-size: 16px;
    color: var(--text-secondary);
    text-align: center;
    max-width: 700px;
    margin: 0 auto 40px;
}

.download-hero {
    max-width: 600px;
    margin: 0 auto 40px;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.download-tabs {
    background: var(--bg-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.tab-buttons {
    display: flex;
    border-bottom: 1px solid var(--border-color);
}

.tab-btn {
    flex: 1;
    padding: 16px 24px;
    font-size: 16px;
    font-weight: 500;
    color: var(--text-secondary);
    background: transparent;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.tab-btn:hover {
    color: var(--primary-color);
    background: var(--bg-secondary);
}

.tab-btn.active {
    color: var(--primary-color);
}

.tab-btn.active::after {
    content: "";
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-color);
}

.tab-content {
    padding: 32px;
}

.tab-pane {
    display: none;
}

.tab-pane.active {
    display: block;
}

.download-card {
    display: flex;
    gap: 40px;
    align-items: flex-start;
}

.download-card-img {
    flex-shrink: 0;
}

.download-card-img img {
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
}

.download-card-info {
    flex: 1;
}

.download-card-info h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 16px;
}

.download-card-info p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.7;
}

.feature-list {
    margin-bottom: 24px;
}

.feature-list li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 10px;
    color: var(--text-secondary);
}

.feature-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 600;
}

.btn-download {
    margin-bottom: 16px;
}

.download-tip {
    font-size: 13px;
    color: var(--text-light);
}

.intro-section {
    padding: 80px 0;
}

.intro-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 48px;
}

.intro-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
}

.intro-img {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    margin-bottom: 24px;
}

.intro-text p {
    color: var(--text-secondary);
    margin-bottom: 16px;
    line-height: 1.8;
}

.intro-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 24px;
    text-align: center;
}

.intro-card img {
    max-width: 200px;
    margin: 0 auto 20px;
    border-radius: var(--radius-md);
}

.intro-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.intro-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.features-section {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.features-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.feature-card {
    background: var(--bg-color);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.feature-img {
    margin-bottom: 20px;
    border-radius: var(--radius-md);
    overflow: hidden;
}

.feature-img img {
    width: 100%;
    aspect-ratio: 1;
    object-fit: cover;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.tutorial-section {
    padding: 80px 0;
}

.tutorial-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.tutorial-steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-bottom: 48px;
}

.step-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 24px;
    text-align: center;
    position: relative;
}

.step-num {
    position: absolute;
    top: 16px;
    left: 16px;
    width: 36px;
    height: 36px;
    background: var(--primary-color);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
}

.step-img {
    margin-bottom: 16px;
}

.step-img img {
    max-width: 160px;
    margin: 0 auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.step-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
}

.step-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.tutorial-extra {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 32px;
}

.tutorial-extra h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 24px;
    text-align: center;
}

.tips-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.tip-item {
    background: var(--bg-color);
    border-radius: var(--radius-md);
    padding: 20px;
}

.tip-item h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.tip-item p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.security-section {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.security-banner {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    margin-bottom: 40px;
}

.security-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.security-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
    margin-bottom: 32px;
}

.security-item {
    background: var(--bg-color);
    border-radius: var(--radius-md);
    padding: 24px;
    margin-bottom: 20px;
}

.security-item h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
}

.security-item p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.security-side img {
    border-radius: var(--radius-md);
    margin-bottom: 20px;
}

.security-tips {
    background: var(--bg-color);
    border-radius: var(--radius-md);
    padding: 20px;
}

.security-tips h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 12px;
}

.security-tips ul {
    padding-left: 0;
}

.security-tips li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    font-size: 14px;
    color: var(--text-secondary);
}

.security-tips li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

.security-warning {
    background: linear-gradient(135deg, #fff5f5, #fff);
    border: 1px solid #fecaca;
    border-radius: var(--radius-md);
    padding: 24px;
}

.security-warning h3 {
    font-size: 18px;
    font-weight: 600;
    color: #dc2626;
    margin-bottom: 12px;
}

.security-warning p {
    color: var(--text-secondary);
    line-height: 1.7;
}

.faq-section {
    padding: 80px 0;
}

.faq-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.faq-container {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.faq-question {
    padding: 20px 24px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: var(--transition);
}

.faq-question::after {
    content: "+";
    font-size: 24px;
    color: var(--primary-color);
    transition: var(--transition);
}

.faq-item.active .faq-question::after {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding: 0 24px 20px;
    color: var(--text-secondary);
    line-height: 1.7;
}

.faq-image {
    position: sticky;
    top: 100px;
}

.faq-image img {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.faq-more {
    text-align: center;
    margin-top: 40px;
}

.faq-more p {
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.about-section {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.about-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 48px;
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: center;
}

.about-content p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.8;
}

.about-stats {
    display: flex;
    gap: 32px;
    margin-top: 32px;
}

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

.stat-num {
    display: block;
    font-size: 36px;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
}

.about-images {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.about-images img {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.contact-section {
    padding: 80px 0;
}

.contact-section h2 {
    font-size: 32px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.contact-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 32px;
    text-align: center;
    transition: var(--transition);
}

.contact-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 72px;
    height: 72px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
}

.contact-icon svg {
    color: #fff;
}

.contact-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.contact-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.6;
}

.footer {
    position: relative;
    background: var(--bg-dark);
    color: #fff;
    padding: 60px 0 30px;
}

.footer-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 0;
    opacity: 0.1;
    overflow: hidden;
}

.footer-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.footer-inner {
    position: relative;
    z-index: 1;
}

.footer-main {
    text-align: center;
    margin-bottom: 40px;
}

.footer-brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.footer-brand img {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
}

.footer-brand span {
    font-size: 24px;
    font-weight: 700;
}

.footer-desc {
    color: rgba(255,255,255,0.7);
    max-width: 500px;
    margin: 0 auto 24px;
}

.footer-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 16px 32px;
}

.footer-links a {
    color: rgba(255,255,255,0.8);
    font-size: 14px;
    transition: var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 24px;
    text-align: center;
}

.footer-legal {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 16px;
}

.footer-legal a {
    color: rgba(255,255,255,0.6);
    font-size: 13px;
}

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

.copyright {
    color: rgba(255,255,255,0.5);
    font-size: 13px;
}

.back-to-top {
    position: fixed;
    bottom: 100px;
    right: 24px;
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    box-shadow: var(--shadow-md);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-4px);
}

.floating-contact {
    position: fixed;
    bottom: 32px;
    right: 24px;
    z-index: 998;
}

.btn-floating {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 24px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: #fff;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    font-size: 15px;
    font-weight: 500;
}

.btn-floating:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(45,92,255,0.4);
}

.hide-mobile {
    display: block;
}

@media (max-width: 1024px) {
    .hero-inner {
        flex-direction: column;
        text-align: center;
    }
    
    .hero-content {
        max-width: 100%;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .breadcrumb {
        justify-content: center;
    }
    
    .intro-grid {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .tutorial-steps {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .security-grid {
        grid-template-columns: 1fr;
    }
    
    .faq-container {
        grid-template-columns: 1fr;
    }
    
    .faq-image {
        display: none;
    }
    
    .about-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .header-inner {
        height: 60px;
    }
    
    .nav-menu {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background: var(--bg-color);
        padding: 20px;
        box-shadow: var(--shadow-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-list {
        flex-direction: column;
        gap: 0;
    }
    
    .nav-link {
        display: block;
        padding: 12px 16px;
        border-bottom: 1px solid var(--border-color);
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hide-mobile {
        display: none;
    }
    
    .hero {
        min-height: auto;
        padding: 80px 0 40px;
    }
    
    .hero h1 {
        font-size: 28px;
    }
    
    .hero-desc {
        font-size: 16px;
    }
    
    .phone-mockup {
        max-width: 220px;
    }
    
    .download-section h2,
    .intro-section h2,
    .features-section h2,
    .tutorial-section h2,
    .security-section h2,
    .faq-section h2,
    .about-section h2,
    .contact-section h2 {
        font-size: 24px;
    }
    
    .section-desc {
        font-size: 14px;
    }
    
    .tab-buttons {
        flex-direction: column;
    }
    
    .tab-btn {
        border-bottom: 1px solid var(--border-color);
    }
    
    .tab-btn.active::after {
        display: none;
    }
    
    .tab-content {
        padding: 20px;
    }
    
    .download-card {
        flex-direction: column;
        text-align: center;
    }
    
    .download-card-info h3 {
        font-size: 20px;
    }
    
    .feature-list {
        text-align: left;
    }
    
    .tutorial-steps {
        grid-template-columns: 1fr;
    }
    
    .tips-grid {
        grid-template-columns: 1fr;
    }
    
    .about-stats {
        justify-content: center;
    }
    
    .stat-num {
        font-size: 28px;
    }
    
    .footer-links {
        flex-direction: column;
        gap: 12px;
    }
    
    .footer-legal {
        flex-wrap: wrap;
        gap: 12px;
    }
    
    .back-to-top {
        bottom: 90px;
        right: 16px;
        width: 44px;
        height: 44px;
    }
    
    .floating-contact {
        bottom: 24px;
        right: 16px;
    }
    
    .btn-floating span {
        display: none;
    }
    
    .btn-floating {
        width: 56px;
        height: 56px;
        padding: 0;
        border-radius: 50%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }
    
    .hero h1 {
        font-size: 24px;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 14px;
    }
    
    .hero-actions {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-actions .btn {
        width: 100%;
    }
}