@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=SF+Pro+Display:wght@400;500;600;700;800;900&display=swap');

:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f7;
    --bg-tertiary: #fafafa;
    --text-primary: #1d1d1f;
    --text-secondary: #6e6e73;
    --text-tertiary: #86868b;
    --accent-blue: #007AFF;
    --accent-blue-hover: #0051d5;
    --border-light: rgba(0, 0, 0, 0.08);
    --border-lighter: rgba(0, 0, 0, 0.05);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Inter', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        radial-gradient(circle at 20% 30%, rgba(0, 122, 255, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(0, 122, 255, 0.02) 0%, transparent 50%),
        repeating-linear-gradient(0deg, transparent, transparent 2px, rgba(0, 0, 0, 0.01) 2px, rgba(0, 0, 0, 0.01) 4px),
        repeating-linear-gradient(90deg, transparent, transparent 2px, rgba(0, 0, 0, 0.01) 2px, rgba(0, 0, 0, 0.01) 4px);
    pointer-events: none;
    z-index: 0;
}

body > * {
    position: relative;
    z-index: 1;
}

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

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-lighter);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s ease;
}

.nav.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.logo {
    height: 36px;
    width: auto;
    transition: opacity 0.3s ease;
}

.logo:hover {
    opacity: 0.8;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-links a:not(.cta-button):hover {
    color: var(--text-primary);
}

.cta-button {
    background: var(--accent-blue);
    color: white !important;
    padding: 0.5rem 1.2rem;
    border-radius: 20px;
    font-weight: 600;
}

.cta-button:hover {
    background: var(--accent-blue-hover);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 8rem 2rem 4rem;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content {
    animation: fadeInUp 1s ease-out;
}

.label {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text-tertiary);
    margin-bottom: 1.5rem;
}

.hero h1 {
    font-size: clamp(2.5rem, 5vw, 5rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    letter-spacing: -0.03em;
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeIn 1.2s ease-out;
}

.hero-phone {
    max-width: 300px;
    width: 100%;
    height: auto;
    border-radius: 20px;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.15);
    animation: float 6s ease-in-out infinite;
}

.scroll-hint {
    position: absolute;
    bottom: 3rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    color: var(--text-tertiary);
    font-size: 0.75rem;
    letter-spacing: 2px;
    text-transform: uppercase;
}

.scroll-line {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, var(--text-tertiary), transparent);
    animation: scrollDown 2s ease-in-out infinite;
}

/* Features Section */
.features-section {
    padding: 8rem 0;
}

.section-title {
    margin-bottom: 4rem;
}

.section-title.center {
    text-align: center;
}

.section-tag {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text-tertiary);
    margin-bottom: 1rem;
}

.section-title h2 {
    font-size: clamp(2.5rem, 4vw, 4rem);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

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

.feature-item {
    background: var(--bg-primary);
    border-radius: 24px;
    overflow: hidden;
    border: 1px solid var(--border-light);
    transition: all 0.4s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.feature-item.large {
    grid-column: span 2;
    display: grid;
    grid-template-columns: 1fr 1fr;
}

.feature-item:hover {
    border-color: var(--border-light);
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.feature-visual {
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 3rem;
    min-height: 400px;
}

.feature-visual img {
    max-width: 250px;
    width: 100%;
    height: auto;
    border-radius: 16px;
}

.feature-info {
    padding: 3rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.feature-info h3 {
    font-size: 1.8rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

.feature-info p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.6;
}

/* Modes Section */
.modes-section {
    padding: 8rem 0;
    background: var(--bg-secondary);
}

.modes-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.mode-item {
    background: var(--bg-primary);
    border-radius: 20px;
    padding: 1.5rem;
    border: 1px solid var(--border-light);
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.mode-item:hover {
    border-color: var(--border-light);
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
}

.mode-item.featured {
    background: var(--bg-tertiary);
    border-color: var(--accent-blue);
}

.mode-img {
    position: relative;
    margin-bottom: 1.5rem;
    border-radius: 16px;
    overflow: hidden;
    background: var(--bg-tertiary);
}

.mode-img img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 16px;
}

.mode-tag {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    padding: 0.4rem 0.8rem;
    border-radius: 12px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-primary);
    border: 1px solid var(--border-lighter);
}

.mode-tag.highlight {
    background: var(--accent-blue);
    color: white;
    border-color: var(--accent-blue);
}

.mode-item h4 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.mode-item p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
}

/* CTA Section */
.cta-section {
    padding: 8rem 2rem;
    text-align: center;
}

.cta-container {
    max-width: 800px;
    margin: 0 auto;
}

.cta-container h2 {
    font-size: clamp(2.5rem, 4vw, 4rem);
    font-weight: 800;
    margin-bottom: 1rem;
}

.cta-container p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
    background: var(--accent-blue);
    color: white;
    padding: 1rem 2.5rem;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 700;
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.3);
}

.download-btn:hover {
    background: var(--accent-blue-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 122, 255, 0.4);
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-lighter);
    padding: 4rem 2rem 2rem;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2fr 3fr;
    gap: 4rem;
    margin-bottom: 3rem;
}

.footer-brand img {
    height: 36px;
    margin-bottom: 1rem;
}

.footer-brand p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.link-group h5 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.link-group a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    margin-bottom: 0.8rem;
    transition: color 0.3s ease;
}

.link-group a:hover {
    color: var(--text-primary);
}

.footer-bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding-top: 2rem;
    border-top: 1px solid var(--border-lighter);
    text-align: center;
}

.footer-bottom p {
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.beian {
    margin-top: 1rem;
}

.beian a {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-tertiary);
    text-decoration: none;
    font-size: 0.85rem;
    transition: color 0.3s ease;
}

.beian a:hover {
    color: var(--text-secondary);
}

.beian img {
    height: 16px;
    width: auto;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-15px);
    }
}

@keyframes scrollDown {
    0% {
        opacity: 0;
        height: 0;
    }
    50% {
        opacity: 1;
    }
    100% {
        opacity: 0;
        height: 40px;
    }
}

/* Responsive */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-visual {
        order: -1;
    }

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

    .feature-item.large {
        grid-column: span 1;
        grid-template-columns: 1fr;
    }

    .modes-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .stats-grid {
        gap: 2rem;
    }

    .footer-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-links a:not(.cta-button) {
        display: none;
    }

    .hero {
        padding: 6rem 1.5rem 3rem;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .stats-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

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

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

    .container {
        padding: 0 1.5rem;
    }
}

/* Scroll Animations */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}