:root {
    --primary-color: #05C160;
    /* 微信风格的绿色，极简且专业 */
    --primary-hover: #04ad54;
    --dark-bg: #FFFFFF;
    /* 全白背景，极致简约 */
    --card-bg: #FFFFFF;
    /* 卡片也是白色，靠阴影区分 */
    --text-white: #1A1A1A;
    /* 接近纯黑的深灰，保证阅读舒适 */
    --text-gray: #666666;
    /* 经典灰 */
    --glass-border: rgba(0, 0, 0, 0.04);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--dark-bg);
    color: var(--text-white);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

ul {
    list-style: none;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {
    0% {
        transform: translateY(0px);
    }

    50% {
        transform: translateY(-10px);
    }

    100% {
        transform: translateY(0px);
    }
}

/* Helper Classes */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 1rem;
    font-weight: 700;
    background: linear-gradient(135deg, #fff 0%, var(--primary-color) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-subtitle {
    text-align: center;
    color: var(--text-gray);
    margin-bottom: 4rem;
    font-size: 0.9rem;
    letter-spacing: 2px;
    text-transform: uppercase;
}

/* Reveal Animation Class */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Header */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 1.5rem 0;
    transition: var(--transition);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    padding: 1rem 0;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}

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

.logo-img {
    height: 48px;
    width: auto;
}

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

.nav-link {
    color: var(--text-white);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    cursor: pointer;
}

.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -5px;
    left: 0;
    background-color: var(--primary-color);
    transition: var(--transition);
}

.nav-link:hover::after {
    width: 100%;
}

.nav-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.6rem 1.5rem;
    border-radius: 50px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.btn-primary {
    background: var(--primary-color);
    color: #000;
    border: none;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 230, 118, 0.3);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--glass-border);
    color: var(--text-white);
}

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

/* Mobile Menu Toggle */
.hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: #333;
    transition: var(--transition);
}

/* Hero Section */
.hero {
    height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

.hero-video-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: -1;
    filter: brightness(0.85);
    /* 调亮背景视频 */
}

.hero-content {
    max-width: 800px;
    padding: 0 20px;
    z-index: 1;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 800;
    letter-spacing: -2px;
    margin-bottom: 1.5rem;
    line-height: 1.1;
    color: #fff;
    /* 视频上的文字保持白色 */
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    animation: fadeInUp 1s ease-out;
}

.hero-title span {
    color: var(--primary-color);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    /* 视频上的副标题保持白色 */
    margin-bottom: 2.5rem;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    font-weight: 500;
    animation: fadeInUp 1s ease-out 0.2s backwards;
}

.hero-btns {
    animation: fadeInUp 1s ease-out 0.4s backwards;
}

/* App Download Section */
.download-section {
    padding: 8rem 0;
    background: #FAFAFA;
}

.download-wrapper {
    display: flex;
    align-items: center;
    background: #fff;
    box-shadow: var(--shadow-md);
    border: none;
    border-radius: 24px;
    padding: 4rem;
    gap: 4rem;
    max-width: 1000px;
    margin: 0 auto;
}

.qrcode-box {
    flex: 1;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.qrcode-img {
    width: 180px;
    height: 180px;
    border-radius: 12px;
    border: none;
    box-shadow: var(--shadow-sm);
    margin: 1.5rem 0;
}

.download-text h3 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

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

/* Features Grid */
.features {
    padding: 6rem 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: #fff;
    border: 1px solid #f0f0f0;
    border-radius: 20px;
    padding: 3rem 2rem;
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: visible;
    box-shadow: var(--shadow-sm);
}

.feature-card:hover {
    transform: translateY(-10px);
    border-color: var(--primary-color);
    box-shadow: 0 20px 40px rgba(5, 193, 96, 0.15);
    /* 绿色阴影 */
}

.feature-card img {
    height: 80px;
    margin-bottom: 1.5rem;
}

.feature-card h4 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--text-white);
}

.feature-card p {
    color: var(--text-gray);
    font-size: 0.95rem;
}

/* Advantages Section */
.advantages {
    padding: 6rem 0;
    background: #fff;
}

.adv-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.adv-item {
    position: relative;
    border-radius: 16px;
    overflow: hidden;
    height: 300px;
    display: flex;
    align-items: flex-end;
    padding: 2rem;
    background: #F5F7FA;
    transition: var(--transition);
    box-shadow: inset 0 -100px 100px rgba(0, 0, 0, 0.1);
}

.adv-item:hover {
    transform: scale(1.02);
}

.adv-item img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.6;
    transition: var(--transition);
}

.adv-item:hover img {
    opacity: 0.4;
    transform: scale(1.1);
}

.adv-item h4 {
    position: relative;
    z-index: 2;
    font-size: 1.5rem;
    font-weight: bold;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
}

/* About Us Section */
.about {
    padding: 6rem 0;
    display: flex;
    align-items: center;
}

.about-content-wrapper {
    display: flex;
    align-items: center;
    gap: 4rem;
}

.about-img {
    flex: 1;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.about-text {
    flex: 1;
}

.about-text p {
    margin-bottom: 1.5rem;
    color: var(--text-gray);
    font-size: 1.05rem;
}

.highlight-text {
    font-size: 1.2rem;
    color: var(--primary-color);
    font-weight: 600;
    border-left: 4px solid var(--primary-color);
    padding-left: 1rem;
}

/* Topics Grid */
.topics {
    padding: 4rem 0 8rem;
}

.topic-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    justify-content: center;
}

.topic-card {
    background: #FFFFFF;
    box-shadow: var(--shadow-sm);
    border: 1px solid #eee;
    padding: 2.5rem 1.5rem;
    border-radius: 16px;
    width: calc(20% - 1.6rem);
    min-width: 200px;
    text-align: center;
    transition: var(--transition);
}

.topic-card:hover {
    background: #fff;
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.topic-card img {
    height: 60px;
    margin-bottom: 1rem;
}

.topic-card h3 {
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.topic-card p {
    font-size: 0.85rem;
    color: var(--text-gray);
}

/* Footer */
footer {
    background: #000;
    padding: 4rem 0 2rem;
    border-top: 1px solid #222;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 2rem;
    margin-bottom: 3rem;
}

.contact-info h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.footer-downloads {
    display: flex;
    gap: 3rem;
}

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

.download-item img {
    width: 100px;
    height: 100px;
    margin-bottom: 0.5rem;
    border-radius: 8px;
}

.copyright {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #222;
    color: #666;
    font-size: 0.9rem;
}

.copyright a {
    color: #888;
    margin-left: 10px;
}

/* Responsive */
@media (max-width: 968px) {
    .hero-title {
        font-size: 3rem;
    }

    .adv-grid {
        grid-template-columns: 1fr;
        height: auto;
    }

    .adv-item {
        height: 200px;
    }

    .about-content-wrapper {
        flex-direction: column;
    }

    .topic-card {
        width: calc(50% - 1rem);
        /* 2 per row */
    }
}

@media (max-width: 768px) {

    .navbar .nav-menu,
    .navbar .nav-buttons {
        display: none;
    }

    .hamburger {
        display: flex;
    }

    .navbar.active .nav-menu {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: #fff;
        padding: 2rem;
        gap: 1.5rem;
        box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
    }

    .navbar.active .nav-buttons {
        display: flex;
        flex-direction: column;
        width: 100%;
        margin-top: 1rem;
    }

    .navbar.active .btn {
        text-align: center;
    }

    .hero-title {
        font-size: 2.2rem;
    }

    .download-wrapper {
        flex-direction: column;
        padding: 2rem;
        text-align: center;
    }

    .topic-card {
        width: 100%;
        /* 1 per row */
    }

    .footer-content {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .footer-downloads {
        flex-direction: column;
        gap: 2rem;
    }
}