/* ============ Reset & Base ============ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #f8fafc;
    color: #1e293b;
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

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

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

/* ============ Navbar ============ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255,255,255,0.08);
    transition: background 0.3s, box-shadow 0.3s;
}

.navbar.scrolled {
    background: rgba(15, 23, 42, 0.95);
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.navbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: #f8fafc;
    display: flex;
    align-items: center;
    gap: 8px;
    letter-spacing: -0.5px;
}

.logo i {
    color: #fe2c55;
    font-size: 1.8rem;
}

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

.nav-links a {
    color: rgba(248, 250, 252, 0.7);
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.3s, transform 0.2s;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #fe2c55, #ff6b6b);
    transition: width 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: #f8fafc;
}

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

.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
    gap: 5px;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: #f8fafc;
    border-radius: 2px;
    transition: all 0.3s;
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ============ Hero ============ */
.hero {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: 100px 0 60px;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -30%;
    left: -20%;
    width: 70%;
    height: 80%;
    background: radial-gradient(circle, rgba(254,44,85,0.15) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
    position: relative;
    z-index: 2;
}

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

.hero-text h1 {
    font-size: 3.8rem;
    font-weight: 900;
    background: linear-gradient(135deg, #f8fafc 0%, #cbd5e1 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
    margin-bottom: 16px;
    letter-spacing: -1px;
}

.subtitle {
    font-size: 1.15rem;
    color: #94a3b8;
    margin-bottom: 32px;
    max-width: 480px;
}

.download-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: 28px;
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 32px;
    border-radius: 60px;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: none;
    cursor: pointer;
    text-decoration: none;
}

.btn-download.ios {
    background: #f8fafc;
    color: #0f172a;
    box-shadow: 0 4px 15px rgba(248,250,252,0.3);
}

.btn-download.ios:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 8px 30px rgba(248,250,252,0.4);
}

.btn-download.android {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: #fff;
    box-shadow: 0 4px 15px rgba(59,130,246,0.4);
}

.btn-download.android:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 8px 30px rgba(59,130,246,0.5);
}

.btn-download.small {
    padding: 10px 24px;
    font-size: 0.9rem;
}

.qr-code {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
}

.qr-img {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    background: #f8fafc;
    padding: 4px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.qr-code span {
    color: #94a3b8;
    font-size: 0.9rem;
}

.version-tag {
    font-size: 0.85rem;
    color: #64748b;
    background: rgba(255,255,255,0.05);
    padding: 6px 16px;
    border-radius: 30px;
    display: inline-block;
    border: 1px solid rgba(255,255,255,0.08);
}

/* Hero 右侧手机模型 */
.hero-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.phone-mockup {
    width: 260px;
    height: 520px;
    background: linear-gradient(145deg, #1e293b, #0f172a);
    border-radius: 40px;
    padding: 12px;
    box-shadow: 0 30px 60px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.1);
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.phone-icon {
    font-size: 2rem;
    color: #fe2c55;
    margin: 12px 0 8px;
}

.phone-screen {
    flex: 1;
    width: 100%;
    background: #1e293b;
    border-radius: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.video-placeholder {
    text-align: center;
    color: #475569;
}

.video-placeholder i {
    font-size: 3.5rem;
    color: #fe2c55;
    margin-bottom: 10px;
    opacity: 0.7;
}

.video-placeholder p {
    font-size: 0.9rem;
    color: #64748b;
}

/* 波浪分割 */
.wave-divider {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    line-height: 0;
}

.wave-divider svg {
    width: 100%;
    height: 60px;
}

/* ============ Sections ============ */
.section-title {
    text-align: center;
    font-size: 2.2rem;
    font-weight: 800;
    margin-bottom: 48px;
    color: #0f172a;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, #fe2c55, #ff6b6b);
    margin: 12px auto 0;
    border-radius: 4px;
}

/* ============ Features ============ */
.features {
    padding: 100px 0;
    background: #f8fafc;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 28px;
}

.feature-card {
    background: #fff;
    border-radius: 20px;
    padding: 32px 24px;
    text-align: center;
    box-shadow: 0 4px 20px rgba(0,0,0,0.04);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid rgba(0,0,0,0.02);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 16px 40px rgba(0,0,0,0.08);
    border-color: #fe2c55;
}

.feature-card i {
    font-size: 2.8rem;
    color: #fe2c55;
    margin-bottom: 16px;
    background: linear-gradient(135deg, #fee2e2, #fff1f2);
    width: 70px;
    height: 70px;
    line-height: 70px;
    border-radius: 50%;
    display: inline-block;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: #0f172a;
}

.feature-card p {
    color: #475569;
    font-size: 0.95rem;
}

/* ============ Versions ============ */
.versions {
    padding: 100px 0;
    background: #fff;
}

.version-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.version-card {
    background: #f8fafc;
    border-radius: 24px;
    padding: 36px 28px;
    text-align: center;
    box-shadow: 0 4px 20px rgba(0,0,0,0.04);
    transition: all 0.4s;
    border: 1px solid rgba(0,0,0,0.02);
}

.version-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 40px rgba(0,0,0,0.08);
}

.version-card i:first-child {
    font-size: 3rem;
    margin-bottom: 12px;
}

.version-card.ios i:first-child {
    color: #1d1d1f;
}

.version-card.android i:first-child {
    color: #3ddc84;
}

.version-card.lite i:first-child {
    color: #f59e0b;
}

.version-card h3 {
    font-size: 1.4rem;
    margin-bottom: 6px;
}

.version-card p {
    color: #64748b;
    margin-bottom: 20px;
}

.version-card ul {
    text-align: left;
    margin-bottom: 24px;
    padding: 0;
}

.version-card ul li {
    padding: 6px 0;
    color: #334155;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.version-card ul li i {
    color: #10b981;
    font-size: 1rem;
}

.btn-download.small {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: #0f172a;
    color: #f8fafc;
    padding: 12px 28px;
    border-radius: 60px;
    font-weight: 600;
    transition: all 0.3s;
}

.btn-download.small:hover {
    background: #fe2c55;
    transform: scale(1.05);
}

/* ============ FAQ ============ */
.faq {
    padding: 100px 0;
    background: #f1f5f9;
}

.faq-list {
    max-width: 720px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.04);
    overflow: hidden;
    transition: box-shadow 0.3s;
}

.faq-item:hover {
    box-shadow: 0 4px 20px rgba(0,0,0,0.06);
}

.faq-question {
    width: 100%;
    background: transparent;
    border: none;
    padding: 20px 24px;
    font-size: 1rem;
    font-weight: 600;
    color: #0f172a;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: background 0.3s;
}

.faq-question:hover {
    background: #f8fafc;
}

.faq-question i {
    transition: transform 0.3s;
    color: #94a3b8;
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
    color: #fe2c55;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    padding: 0 24px;
    background: #fafafa;
}

.faq-item.active .faq-answer {
    max-height: 200px;
    padding: 16px 24px 24px;
}

.faq-answer p {
    color: #475569;
    font-size: 0.95rem;
}

/* ============ Footer ============ */
.footer {
    background: #0f172a;
    color: #cbd5e1;
    padding: 60px 0 0;
}

.footer-inner {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.06);
}

.footer-col h4 {
    color: #f8fafc;
    font-size: 1.05rem;
    margin-bottom: 16px;
}

.footer-col p {
    font-size: 0.9rem;
    color: #94a3b8;
}

.footer-col ul li {
    margin-bottom: 8px;
}

.footer-col ul li a {
    color: #94a3b8;
    font-size: 0.9rem;
    transition: color 0.3s;
}

.footer-col ul li a:hover {
    color: #fe2c55;
}

.social-icons {
    display: flex;
    gap: 16px;
    font-size: 1.3rem;
}

.social-icons a {
    color: #94a3b8;
    transition: color 0.3s, transform 0.3s;
}

.social-icons a:hover {
    color: #fe2c55;
    transform: scale(1.2);
}

.footer-bottom {
    text-align: center;
    padding: 24px 20px;
    font-size: 0.85rem;
    color: #64748b;
}

/* ============ Back to Top ============ */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: #fe2c55;
    color: #fff;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(254,44,85,0.4);
    transition: all 0.3s;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: #e01e4a;
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(254,44,85,0.5);
}

/* ============ Responsive ============ */
@media (max-width: 768px) {
    .navbar-inner {
        height: 56px;
    }

    .nav-links {
        position: fixed;
        top: 56px;
        left: 0;
        right: 0;
        background: rgba(15, 23, 42, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        padding: 20px 0;
        gap: 20px;
        transform: translateY(-120%);
        transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
        border-bottom: 1px solid rgba(255,255,255,0.05);
    }

    .nav-links.open {
        transform: translateY(0);
    }

    .hamburger {
        display: flex;
    }

    .hero-content {
        flex-direction: column;
        text-align: center;
        gap: 40px;
    }

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

    .subtitle {
        margin-left: auto;
        margin-right: auto;
    }

    .download-buttons {
        justify-content: center;
    }

    .qr-code {
        justify-content: center;
    }

    .hero-visual {
        display: none; /* 手机端隐藏模型 */
    }

    .section-title {
        font-size: 1.8rem;
    }

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

    .footer-inner {
        grid-template-columns: 1fr 1fr;
        text-align: center;
    }

    .social-icons {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-text h1 {
        font-size: 2rem;
    }

    .btn-download {
        width: 100%;
        justify-content: center;
    }

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