:root {
    --primary-mint: #A8FF78;
    --primary-mint-dark: #8BD463;
    --brand-blue: #1A3E5E;
    --text-dark: #0F1D19;
    --text-muted: #4A5D58;
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.5);
    --font-main: 'Outfit', 'Inter', -apple-system, sans-serif;
    --aspect-ratio: 16 / 9;
}

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

body {
    background-color: #f1f4f2;
    font-family: var(--font-main);
    color: var(--text-dark);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
}

/* 响应式背景全幅容器 */
.app-viewport {
    width: 100vw;
    height: 100vh;
    position: relative;
    /* 让 background.png 横向撑满 */
    background: linear-gradient(rgba(245, 250, 247, 0.88), rgba(245, 250, 247, 0.88)),
        url('background.png');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    /* 增强沉浸感，背景不随由于滚动变动过多 */
    overflow: hidden;
    border: none;
}

/* 内部内容流 */
.content-scroller {
    width: 100%;
    height: 100%;
    overflow-y: auto;
    scroll-behavior: smooth;
    padding: 0;
}

.content-scroller::-webkit-scrollbar {
    width: 5px;
}

.content-scroller::-webkit-scrollbar-thumb {
    background: var(--primary-mint-dark);
    border-radius: 10px;
}

/* 导航系统 - 优化为居中压缩版 */
.v2-nav {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 1400px;
    padding: 2.5rem 4rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    /* 弱化背景，保持干净 */
    background: rgba(245, 250, 247, 0.7);
    backdrop-filter: blur(8px);
}

.brand-id {
    display: flex;
    align-items: center;
}

.brand-name {
    font-size: 2.4rem;
    font-weight: 900;
    color: #26498F;
    /* 精准吸取 LOGO 深蓝色 */
    letter-spacing: -0.04em;
    text-transform: uppercase;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    line-height: 1;
}

.brand-icon {
    height: 1.15em;
    /* 根据 LOGO 烧杯形状微调，确保视觉均衡 */
    width: auto;
    display: block;
}

.brand-tag {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.2em;
    color: var(--text-muted);
}

/* Hero Carousel System (Synced with V4) */
.hero-viewport {
    position: relative;
    width: 100%;
    min-height: 520px;
}

.hero-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 5rem;
    align-items: center;
    opacity: 0;
    visibility: hidden;
    transition: all 1.2s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: none;
}

.hero-slide.active {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.carousel-indicators {
    position: absolute;
    bottom: 2rem;
    left: 0;
    display: flex;
    gap: 0.8rem;
    z-index: 10;
}

.dot {
    width: 25px;
    height: 3px;
    background: rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: 0.3s;
}

.dot.active {
    background: #26498F;
    width: 50px;
}

.hero-promo {
    width: 100%;
    border-radius: 30px;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.06);
}

/* 模块化排版 */
section {
    padding: 8rem 4rem;
    max-width: 1400px;
    margin: 0 auto;
}

.section-hero {
    min-height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.big-title {
    font-size: 4rem;
    line-height: 1.1;
    font-weight: 900;
    margin-bottom: 2rem;
}

.lead-text {
    font-size: 1.4rem;
    color: var(--text-muted);
    line-height: 1.7;
    max-width: 800px;
    margin-bottom: 3rem;
}

/* 全量文案卡片系统 */
.feature-block {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 3rem;
    margin-top: 4rem;
}

.glass-module {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 30px;
    padding: 3.5rem;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.04);
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.glass-module:hover {
    transform: translateY(-5px);
    border-color: var(--primary-mint);
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.08);
}

.module-tag {
    color: var(--primary-mint-dark);
    font-weight: 800;
    font-size: 0.8rem;
    margin-bottom: 1.5rem;
    display: block;
}

.module-title {
    font-size: 2.2rem;
    margin-bottom: 1.5rem;
    font-weight: 800;
}

.module-desc {
    line-height: 1.8;
    color: var(--text-muted);
    font-size: 1.05rem;
}

/* 按钮 */
.btn-action {
    background: var(--text-dark);
    color: white;
    padding: 1rem 2.5rem;
    border-radius: 60px;
    text-decoration: none;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.btn-action:hover {
    background: var(--primary-mint);
    color: var(--text-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(168, 255, 120, 0.2);
}

/* --- 响应式适配 (Mobile & Tablet) --- */
.main-nav {
    display: flex;
    gap: 2.5rem;
    font-weight: 700;
}

.main-nav a {
    text-decoration: none;
    color: var(--text-dark);
    transition: color 0.3s;
}

.main-nav a:hover {
    color: var(--primary-mint-dark);
}

/* --- Mobile Menu Toggle --- */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: space-around;
    width: 30px;
    height: 22px;
    background: transparent;
    border: none;
    cursor: pointer;
    z-index: 1001;
    padding: 0;
}

.mobile-menu-btn span {
    width: 100%;
    height: 3px;
    background: var(--text-dark);
    border-radius: 10px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: 1px;
}

.mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(45deg);
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg);
}

@media (max-width: 1024px) {
    .big-title {
        font-size: 3rem;
    }

    section {
        padding: 6rem 3rem;
    }

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

    .v2-nav {
        padding: 1.5rem 3rem;
    }

    .brand-name {
        font-size: 2rem;
    }

    .main-nav {
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .big-title {
        font-size: 2.2rem;
    }

    section {
        padding: 4rem 1.5rem;
    }

    .v2-nav {
        padding: 1.2rem 1.5rem;
        flex-direction: row;
        align-items: center;
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(12px);
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    }

    .brand-name {
        font-size: 1.6rem;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .main-nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        height: 100vh;
        background: rgba(250, 252, 251, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 3rem;
        transition: right 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
        box-shadow: -10px 0 40px rgba(0, 0, 0, 0.08);
        z-index: 1000;
        padding: 0;
    }

    .main-nav.active {
        right: 0;
    }

    .main-nav a {
        font-size: 1.4rem;
        padding: 1rem;
        width: 100%;
        text-align: center;
    }

    .hero-viewport {
        min-height: 950px;
    }

    .hero-slide {
        grid-template-columns: 1fr;
        text-align: center;
        padding-top: 6rem;
        /* 留出顶部导航空间 */
    }

    .hero-slide>div:first-child {
        display: flex;
        flex-direction: column;
        align-items: center;
    }

    .lead-text {
        font-size: 1.1rem;
        text-align: center;
    }

    .feature-block {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        margin-top: 2rem;
    }

    .glass-module {
        padding: 2rem;
    }

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

    .carousel-indicators {
        justify-content: center;
        width: 100%;
        bottom: -2rem;
    }

    .btn-action {
        padding: 0.8rem 2rem;
        font-size: 0.95rem;
    }

    .content-scroller {
        padding-top: 80px;
    }

    /* 防止导航栏遮挡内容 */
}