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

:root {
    --primary-color: #007AFF;
    --secondary-color: #5856D6;
    --text-primary: #1C1C1E;
    --text-secondary: #8E8E93;
    --background: #FFFFFF;
    --background-secondary: #F2F2F7;
    --border-color: #E5E5EA;
    --gradient-start: #007AFF;
    --gradient-end: #5856D6;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--text-primary);
    background: var(--background);
    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;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 16px 0;
}

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

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

.logo-icon {
    width: 32px;
    height: 32px;
    border-radius: 7.2px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1),
                0 1px 3px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.logo:hover .logo-icon {
    transform: scale(1.05);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15),
                0 2px 4px rgba(0, 0, 0, 0.1);
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

.nav-links .lang-switch {
    margin-left: 20px;
    padding: 6px 12px;
    background: var(--background-secondary);
    border-radius: 20px;
    font-size: 14px;
    transition: all 0.3s ease;
}

.nav-links .lang-switch:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

/* Hero Section */
.hero {
    padding: 100px 0 60px;
    background: linear-gradient(135deg, #F5F7FA 0%, #E9ECEF 100%);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

.hero-title {
    font-size: 56px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
}

.gradient-text {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: 32px;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.btn {
    padding: 14px 28px;
    border-radius: 12px;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 122, 255, 0.4);
}

.btn-secondary {
    background: white;
    color: var(--primary-color);
    border: 2px solid var(--border-color);
}

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

.apple-icon {
    width: 20px;
    height: 20px;
}

.hero-stats {
    display: flex;
    gap: 48px;
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 32px;
    font-weight: 700;
    color: var(--primary-color);
}

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

.phone-mockup {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.phone-mockup img {
    width: 100%;
    max-width: 320px;
    max-height: 500px;
    height: auto;
    object-fit: contain;
    filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.1));
}

/* Features Section */
.features {
    padding: 80px 0;
    background: white;
}

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

.section-title {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 16px;
}

.section-description {
    font-size: 18px;
    color: var(--text-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 32px;
}

.feature-card {
    padding: 32px;
    background: var(--background-secondary);
    border-radius: 20px;
    transition: all 0.3s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
}

.feature-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.feature-icon svg {
    width: 24px;
    height: 24px;
    color: white;
}

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

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Sizes Section */
.sizes {
    padding: 80px 0;
    background: var(--background-secondary);
}

.sizes-tabs {
    max-width: 800px;
    margin: 0 auto;
}

.tab-buttons {
    display: flex;
    gap: 8px;
    margin-bottom: 32px;
    justify-content: center;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 12px 24px;
    background: white;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.tab-btn.active {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    border-color: transparent;
}

.tab-pane {
    display: none;
}

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

.size-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 16px;
}

.size-item {
    padding: 20px;
    background: white;
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    transition: all 0.3s;
}

.size-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.size-name {
    font-weight: 600;
    color: var(--text-primary);
}

.size-spec {
    font-size: 14px;
    color: var(--primary-color);
    font-weight: 500;
}

/* Download Section */
.download {
    padding: 100px 0;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: white;
    text-align: center;
}

.download-title {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 16px;
}

.download-description {
    font-size: 18px;
    opacity: 0.9;
    margin-bottom: 32px;
}

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

.download-btn img {
    height: 50px;
}

.download-note {
    font-size: 14px;
    opacity: 0.8;
}

/* Footer */
.footer {
    padding: 40px 0;
    background: var(--text-primary);
    color: white;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 32px;
}

.footer-brand .logo-text {
    color: white;
}

.footer-brand p {
    margin-top: 8px;
    opacity: 0.7;
    font-size: 14px;
}

.footer-links {
    display: flex;
    gap: 24px;
}

.footer-links a {
    color: white;
    text-decoration: none;
    opacity: 0.7;
    transition: opacity 0.3s;
}

.footer-links a:hover {
    opacity: 1;
}

.footer-copyright {
    font-size: 14px;
    opacity: 0.7;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    .hero {
        padding: 80px 0 40px;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 30px;
    }
    
    .hero-title {
        font-size: 32px;
    }
    
    .hero-description {
        font-size: 16px;
        padding: 0 20px;
    }
    
    .hero-buttons {
        flex-direction: column;
        justify-content: center;
        align-items: center;
        width: 100%;
        padding: 0 20px;
    }
    
    .hero-buttons .btn {
        width: 100%;
        justify-content: center;
    }
    
    .hero-stats {
        justify-content: center;
        gap: 24px;
    }
    
    .stat-number {
        font-size: 24px;
    }
    
    .phone-mockup img {
        max-width: 280px;
        max-height: 400px;
    }
    
    .features {
        padding: 60px 0;
    }
    
    .section-title {
        font-size: 32px;
    }
    
    .section-description {
        font-size: 16px;
        padding: 0 20px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 20px;
        padding: 0 16px;
    }
    
    .feature-card {
        padding: 24px;
    }
    
    .sizes {
        padding: 60px 0;
    }
    
    .tab-buttons {
        padding: 0 16px;
    }
    
    .tab-btn {
        padding: 10px 16px;
        font-size: 14px;
    }
    
    .size-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        padding: 0 16px;
    }
    
    .download {
        padding: 60px 20px;
    }
    
    .download-title {
        font-size: 32px;
        padding: 0 20px;
    }
    
    .download-description {
        font-size: 16px;
        padding: 0 20px;
    }
    
    .nav-links {
        display: none;
    }
    
    .footer {
        padding: 30px 0;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
        gap: 24px;
    }
    
    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 16px;
    }
}

/* 小屏幕手机 */
@media (max-width: 375px) {
    .hero-title {
        font-size: 28px;
    }
    
    .stat {
        min-width: 80px;
    }
    
    .stat-number {
        font-size: 20px;
    }
    
    .stat-label {
        font-size: 12px;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .feature-card h3 {
        font-size: 18px;
    }
    
    .size-grid {
        grid-template-columns: 1fr;
    }
    
    .download-title {
        font-size: 28px;
    }
}

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

.hero-content > * {
    animation: fadeInUp 0.6s ease-out;
}

.feature-card {
    animation: fadeInUp 0.6s ease-out;
    animation-fill-mode: both;
}

.feature-card:nth-child(1) { animation-delay: 0.1s; }
.feature-card:nth-child(2) { animation-delay: 0.2s; }
.feature-card:nth-child(3) { animation-delay: 0.3s; }
.feature-card:nth-child(4) { animation-delay: 0.4s; }
.feature-card:nth-child(5) { animation-delay: 0.5s; }
.feature-card:nth-child(6) { animation-delay: 0.6s; }