/* CSS Reset & Variables */
:root {
    --primary-color: #FF7A00;
    --primary-hover: #E66D00;
    --primary-light: #FFF4EC;
    --gradient-primary: linear-gradient(135deg, #FF7A00 0%, #FF9E43 100%);
    --text-dark: #1E293B;
    --text-body: #475569;
    --text-gray: #64748B;
    --bg-body: #F8FAFC;
    --bg-white: #FFFFFF;
    --bg-gray: #F1F5F9;
    --border-color: #E2E8F0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.05), 0 4px 6px -2px rgba(0,0,0,0.02);
    --shadow-orange: 0 10px 25px -5px rgba(255, 122, 0, 0.3);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --radius-lg: 16px;
    --radius-xl: 24px;
}

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

html {
    scroll-behavior: smooth;
    overscroll-behavior: none;        /* 禁用页面级弹簧回弹 */
    -webkit-overflow-scrolling: auto; /* 关闭 iOS 惯性滚动的过度弹跳 */
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    background-color: var(--bg-body);
    color: var(--text-body);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overscroll-behavior: none;
}

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

ul {
    list-style: none;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--text-dark);
}

/* Utility Classes */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.text-highlight {
    color: var(--primary-color);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
    text-align: center;
}

.btn-primary {
    background: var(--gradient-primary);
    color: var(--bg-white);
    box-shadow: var(--shadow-orange);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 30px -5px rgba(255, 122, 0, 0.4);
    filter: brightness(1.05);
}

.btn-outline {
    background-color: var(--bg-white);
    color: var(--primary-color);
    border-color: var(--border-color);
    box-shadow: var(--shadow-sm);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.section-padding {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.section-tag {
    color: var(--primary-color);
    font-size: 14px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 16px;
    display: block;
}

.section-title {
    font-size: 36px;
    margin-bottom: 24px;
    letter-spacing: -0.5px;
}

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

/* Navbar */
.navbar {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
    z-index: 1000;
    transition: var(--transition);
    /* Safari/WebKit 合成层 fix：防止 backdrop-filter + filter 子元素渲染冲突 */
    -webkit-transform: translateZ(0);
    transform: translateZ(0);
    isolation: isolate;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
    overflow: visible;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 26px;
    font-weight: 800;
    color: var(--text-dark);
    letter-spacing: -0.5px;
}

.nav-logo img {
    width: 36px;
    height: 36px;
    object-fit: contain;
}

.nav-logo i {
    font-size: 30px;
}

.nav-links {
    display: flex;
    gap: 28px;
    align-items: center;
}

.nav-links a {
    font-weight: 600;
    color: var(--text-body);
    font-size: 15px;
    transition: var(--transition);
}

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
    position: relative;
    z-index: 1001;
}

.lang-switch {
    position: relative;
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-gray);
    cursor: pointer;
    font-size: 14px;
    padding: 8px 16px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-white);
    transition: var(--transition);
    user-select: none;
}

.lang-switch:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background-color: var(--primary-light);
}

.lang-switch__arrow {
    font-size: 10px;
    transition: transform 0.2s ease;
}
.lang-switch__arrow--open {
    transform: rotate(180deg);
}

/* Dropdown */
.lang-dropdown {
    display: none;
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    min-width: 160px;
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    box-shadow: var(--shadow-lg);
    padding: 6px;
    z-index: 2000;
    list-style: none;
}
.lang-dropdown--open { display: block; }

.lang-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 9px 12px;
    border-radius: 8px;
    font-size: 14px;
    color: var(--text-body);
    cursor: pointer;
    transition: var(--transition);
}
.lang-option:hover { background: var(--bg-gray); color: var(--text-dark); }
.lang-option--active {
    background: var(--primary-light);
    color: var(--primary-color);
    font-weight: 600;
}
.lang-option__flag { font-size: 18px; line-height: 1; }

.mobile-menu-btn {
    display: none;
    width: 40px;
    height: 40px;
    flex-shrink: 0;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    color: var(--text-dark);
    cursor: pointer;
    background: none;
    border: none;
    border-radius: 8px;
    transition: background var(--transition);
}
.mobile-menu-btn:hover { background: var(--bg-gray); }

/* Hero Section */
.hero {
    padding: 180px 0 120px;
    background: radial-gradient(circle at top right, var(--primary-light), var(--bg-body) 60%);
    position: relative;
    overflow: hidden;
}

/* Decorative background shapes */
.hero::before {
    content: '';
    position: absolute;
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    background: var(--primary-color);
    opacity: 0.05;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(249,115,22,0.08) 0%, transparent 70%);
    /* filter: blur removed - Safari backdrop-filter conflict fix */
}

.hero-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    position: relative;
    z-index: 2;
}

.hero-tag {
    background-color: var(--bg-white);
    color: var(--primary-color);
    padding: 8px 20px;
    border-radius: 100px;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 32px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--primary-light);
}

.hero h1 {
    font-size: 64px;
    letter-spacing: -1.5px;
    margin-bottom: 24px;
    max-width: 900px;
    line-height: 1.15;
}

.hero p {
    font-size: 20px;
    color: var(--text-body);
    margin-bottom: 48px;
    max-width: 700px;
}

.hero-actions {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.hero-platforms {
    margin-top: 48px;
    display: flex;
    align-items: center;
    gap: 20px;
    background: var(--bg-white);
    padding: 16px 32px;
    border-radius: 100px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.hero-platforms span {
    color: var(--text-gray);
    font-size: 14px;
    font-weight: 600;
}

.hero-platforms .platform-icons {
    display: flex;
    gap: 24px;
    align-items: center;
}

.hero-platforms i {
    font-size: 24px;
    color: var(--text-dark);
    opacity: 0.6;
    transition: var(--transition);
}

.hero-platforms i:hover {
    opacity: 1;
    color: var(--primary-color);
    transform: translateY(-3px) scale(1.1);
}

/* About / SEO Text Section */
.about-section {
    background-color: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.about-content h2 {
    font-size: 32px;
    margin-bottom: 24px;
}

.about-content p {
    margin-bottom: 16px;
    font-size: 16px;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    background: var(--bg-gray);
    padding: 40px;
    border-radius: var(--radius-xl);
    position: relative;
}

.stat-item h4 {
    font-size: 40px;
    color: var(--primary-color);
    margin-bottom: 8px;
    line-height: 1;
}

.stat-item p {
    color: var(--text-dark);
    font-weight: 600;
    font-size: 16px;
}

.stat-item span {
    display: block;
    font-size: 13px;
    color: var(--text-gray);
    margin-top: 4px;
    font-weight: 400;
}

/* Features Section */
.features {
    background-color: var(--bg-body);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
    max-width: 1000px;
    margin: 0 auto;
}

.feature-card {
    background: var(--bg-white);
    padding: 48px 40px;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
    z-index: 1;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0;
    z-index: -1;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-card:hover::before {
    opacity: 1;
}

.feature-icon {
    width: 64px;
    height: 64px;
    background-color: var(--primary-light);
    color: var(--primary-color);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    margin-bottom: 32px;
    transition: var(--transition);
}

.feature-card:hover .feature-icon {
    background-color: rgba(255, 255, 255, 0.2);
    color: var(--bg-white);
}

.feature-card h3 {
    font-size: 22px;
    margin-bottom: 16px;
    transition: var(--transition);
}

.feature-card p {
    color: var(--text-body);
    font-size: 15px;
    transition: var(--transition);
}

.feature-card:hover h3,
.feature-card:hover p {
    color: var(--bg-white);
}

/* Download Section */
.download {
    background-color: var(--bg-white);
}

.platforms-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 24px;
}

.platform-card {
    flex: 1 1 200px;
    max-width: 220px;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 40px 24px;
    border-radius: var(--radius-lg);
    border: 2px solid var(--bg-gray);
    transition: var(--transition);
    background-color: var(--bg-white);
    text-align: center;
}

.platform-card:hover {
    border-color: var(--primary-color);
    background-color: var(--primary-light);
    transform: translateY(-4px);
}

.platform-icon {
    font-size: 56px;
    color: var(--text-dark);
    margin-bottom: 24px;
    transition: var(--transition);
}

.platform-card:hover .platform-icon {
    color: var(--primary-color);
}

.platform-name {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 8px;
}

.platform-desc {
    font-size: 13px;
    color: var(--text-gray);
    margin-bottom: 24px;
}

.platform-link {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 15px;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--bg-white);
    padding: 8px 20px;
    border-radius: 100px;
    border: 1px solid var(--primary-color);
    transition: var(--transition);
}

.platform-card:hover .platform-link {
    background: var(--primary-color);
    color: var(--bg-white);
}

.platform-link i {
    transition: transform 0.3s;
}

.platform-card:hover .platform-link i {
    transform: translateX(4px);
}

/* FAQ Section for SEO */
.faq {
    background-color: var(--bg-gray);
}

.faq-grid {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 24px 32px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

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

.faq-question {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.faq-question i {
    color: var(--primary-color);
}

.faq-answer {
    color: var(--text-body);
    font-size: 15px;
    line-height: 1.8;
}

/* Footer */
.footer {
    background-color: #0F172A;
    color: #94A3B8;
    padding: 100px 0 40px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 64px;
    margin-bottom: 64px;
}

.footer-brand .nav-logo {
    color: var(--bg-white);
    margin-bottom: 24px;
}

.footer-brand p {
    margin-bottom: 24px;
    max-width: 320px;
    font-size: 15px;
    line-height: 1.8;
}

.footer-col h4 {
    color: var(--bg-white);
    font-size: 16px;
    margin-bottom: 24px;
    font-weight: 600;
}

.footer-col ul {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.footer-col a {
    transition: var(--transition);
    font-size: 15px;
}

.footer-col a:hover {
    color: var(--primary-color);
    padding-left: 4px;
}

.footer-bottom {
    padding-top: 32px;
    border-top: 1px solid rgba(255,255,255,0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 14px;
}

.footer-lang {
    background-color: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    color: #94A3B8;
}

.footer-lang:hover {
    background-color: rgba(255,255,255,0.1);
    color: var(--bg-white);
    border-color: rgba(255,255,255,0.2);
}

/* Scroll Animation Classes */
.fade-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

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

/* Responsive Design */
@media (max-width: 1024px) {
    .hero h1 { font-size: 48px; }
    .about-grid { grid-template-columns: 1fr; gap: 40px; }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 40px; }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .platforms-grid { gap: 16px; }
}

@media (max-width: 768px) {
    /* Navbar */
    .nav-links, .nav-actions .btn-outline { display: none; }
    .mobile-menu-btn { display: flex; }
    /* 语言按钮缩为图标，隐藏文字标签 */
    .lang-switch__label { display: none; }
    .lang-switch { padding: 8px 10px; gap: 4px; border-radius: 10px; }
    /* 下拉菜单从右侧展开，不超出屏幕 */
    .lang-dropdown { right: 0; left: auto; min-width: 150px; }

    /* Hero */
    .hero { padding: 96px 0 56px; }
    .hero h1 { font-size: 34px; letter-spacing: -0.5px; }
    .hero p { font-size: 15px; margin-bottom: 32px; }
    .hero-actions { flex-direction: column; width: 100%; max-width: 300px; }
    .hero-actions .btn { width: 100%; justify-content: center; }
    .hero-platforms {
        flex-direction: column;
        gap: 12px;
        padding: 20px 24px;
        border-radius: 20px;
        align-items: flex-start;
    }
    .hero-platforms .platform-icons { gap: 16px; }
    .hero-platforms i { font-size: 20px; }

    /* Section */
    .section-padding { padding: 56px 0; }
    .section-title { font-size: 26px; }
    .section-subtitle { font-size: 15px; }

    /* Features */
    .features-grid { grid-template-columns: 1fr; gap: 16px; }
    .feature-card { padding: 32px 24px; }
    .feature-icon { width: 52px; height: 52px; font-size: 22px; margin-bottom: 20px; }
    .feature-card h3 { font-size: 18px; }

    /* Platform cards */
    .platforms-grid { gap: 12px; }
    .platform-card { flex: 1 1 140px; padding: 28px 16px; }
    .platform-icon { font-size: 42px; margin-bottom: 16px; }
    .platform-name { font-size: 16px; }
    .platform-desc { font-size: 12px; }

    /* About */
    .about-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
        padding: 24px;
    }
    .stat-item h4 { font-size: 26px; }
    .stat-item p  { font-size: 13px; }
    .stat-item span { font-size: 12px; }
    .about-content h2 { font-size: 26px; }

    /* FAQ (首页) */
    .faq-item { padding: 20px 20px; }
    .faq-question { font-size: 15px; }
    .faq-answer { font-size: 14px; }

    /* CTA */
    .cta-section .btn { width: 100%; max-width: 320px; }

    /* Navbar — logo 缩小 */
    .nav-logo { font-size: 20px; gap: 8px; }
    .nav-logo img { width: 28px; height: 28px; }
    .nav-container { height: 64px; }

    /* Footer */
    .footer { padding: 48px 0 28px; }
    .footer-grid { grid-template-columns: 1fr; gap: 28px; margin-bottom: 32px; }
    .footer-brand p { max-width: 100%; font-size: 13px; }
    .footer-col h4 { font-size: 14px; margin-bottom: 16px; }
    .footer-col ul { gap: 12px; }
    .footer-col a { font-size: 13px; }
    .footer-bottom { flex-direction: column; gap: 12px; text-align: center; font-size: 12px; }

    /* Mobile Menu Dropdown */
    .mobile-menu-open .nav-links {
        display: flex;
        flex-direction: column;
        gap: 0;          /* 重置桌面端的 gap: 28px */
        position: absolute;
        top: 64px;
        left: 0;
        width: 100%;
        background-color: var(--bg-white);
        padding: 0;
        box-shadow: var(--shadow-lg);
        border-bottom: 1px solid var(--border-color);
        z-index: 999;
    }
    .mobile-menu-open .nav-links li {
        width: 100%;
    }
    .mobile-menu-open .nav-links a {
        display: block;
        font-size: 15px;
        width: 100%;
        text-align: center;
        padding: 13px 20px;
        border-bottom: 1px solid var(--bg-gray);
        box-sizing: border-box;
    }
    .mobile-menu-open .nav-links li:last-child a { border-bottom: none; }
}

@media (max-width: 480px) {
    .container { padding: 0 16px; }
    .hero h1 { font-size: 28px; }
    .hero p { font-size: 14px; }
    .section-title { font-size: 22px; }
    /* 保持 2 列，进一步缩小字号和内边距 */
    .about-stats { grid-template-columns: repeat(2, 1fr); gap: 10px; padding: 18px; }
    .stat-item h4 { font-size: 22px; }
    .stat-item p  { font-size: 12px; }
    .stat-item span { font-size: 11px; margin-top: 2px; }
    .platform-card { flex: 1 1 calc(50% - 6px); max-width: none; padding: 20px 12px; }
    .platform-icon { font-size: 32px; margin-bottom: 10px; }
    .platform-name { font-size: 14px; }
    .platform-link { font-size: 12px; padding: 6px 12px; }
}