:root {
    /* 核心配色：亮色模式备选，但我们默认聚焦奢华暗黑质感 */
    --bg-color: #f4f4f6; 
    --bg-alt-color: #ffffff;
    --text-main: #111111;
    --text-muted: #555555;
    
    /* 铬金属 / 液态金属 渐变质感 - 亮色模式加深 */
    --chrome-gradient: linear-gradient(135deg, #222222 0%, #555555 40%, #111111 50%, #444444 60%, #000000 100%);
    --chrome-border: rgba(0, 0, 0, 0.15);
    
    --card-bg: rgba(255, 255, 255, 0.6);
    --nav-bg: rgba(255, 255, 255, 0.8);
    --primary-color: #111;
    --primary-hover: #333;
    
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 10px 20px -5px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 40px -5px rgba(0, 0, 0, 0.15);
}

/* 核心深色液态金属主题 (Dark Chrome Luxury) - 默认倾向 */
[data-theme="dark"] {
    --bg-color: #070709;
    --bg-alt-color: #0a0a0c;
    --text-main: #f0f0f2;
    --text-muted: #8e8f96;
    
    --chrome-gradient: linear-gradient(135deg, #ffffff 0%, #888890 25%, #cccccc 50%, #333333 75%, #ffffff 100%);
    --chrome-border: rgba(255, 255, 255, 0.15);
    
    --card-bg: rgba(15, 15, 18, 0.6);
    --nav-bg: rgba(7, 7, 9, 0.75);
    --primary-color: #e2e2e5;
    --primary-hover: #ffffff;
    
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
    --shadow-md: 0 10px 20px -5px rgba(0, 0, 0, 0.8);
    --shadow-lg: 0 20px 40px -5px rgba(0, 0, 0, 0.9);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 100px; /* 为悬浮导航栏留出空间 */
}

body {
    font-family: 'Space Grotesk', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    transition: background-color 0.4s ease, color 0.4s ease;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a {
    color: var(--text-main);
    text-decoration: none;
    transition: all 0.3s ease;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
    z-index: 2;
}

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

/* 铬金属文字特效 */
.chrome-text {
    background: var(--chrome-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: transparent;
    background-size: 200% auto;
    animation: chromeShine 6s linear infinite;
    display: inline-block;
}

@keyframes chromeShine {
    to { background-position: 200% center; }
}

/* 按钮样式 (金属流体感) */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-decoration: none !important;
    border-radius: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.25, 1, 0.5, 1);
    position: relative;
    overflow: hidden;
    will-change: transform;
}

.btn-primary {
    background: var(--chrome-gradient);
    background-size: 200% auto;
    color: #000 !important;
    border: none;
    text-shadow: 0 1px 1px rgba(255,255,255,0.3);
}

.btn-primary:hover {
    background-position: right center;
    box-shadow: 0 0 20px rgba(255,255,255,0.2);
}

.btn-outline {
    background: transparent;
    color: var(--text-main) !important;
    border: 1px solid var(--chrome-border);
    backdrop-filter: blur(5px);
}

.btn-outline:hover {
    background: var(--text-main);
    color: var(--bg-color) !important;
    border-color: var(--text-main);
}

.btn-large { padding: 16px 36px; font-size: 1.1rem; }
.btn-block { display: flex; width: 100%; padding: 14px 0; margin-top: 24px; }

/* 磁性按钮逻辑辅助类 */
.btn-magnetic {
    display: inline-block; /* block for transform origin centered properly */
}

/* 悬浮导航栏 */
header {
    position: fixed;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    width: 92%;
    max-width: 1100px;
    background: var(--nav-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--chrome-border);
    border-radius: 50px;
    z-index: 1000;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
    transition: background 0.4s ease;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
    padding: 0 30px;
}

.logo {
    font-size: 1.3rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

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

.nav-links a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-muted);
}

.nav-links a:hover {
    color: var(--text-main);
}

.nav-links .highlight-link {
    color: var(--text-main);
    position: relative;
}
.nav-links .highlight-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 1px;
    background: var(--chrome-gradient);
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 20px;
}

.net-status {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-main);
}

.net-status .dot {
    width: 8px;
    height: 8px;
    background-color: #10b981;
    border-radius: 50%;
    box-shadow: 0 0 10px #10b981;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.5); opacity: 0.5; }
    100% { transform: scale(1); opacity: 1; }
}

.theme-toggle {
    background: transparent;
    border: none;
    color: var(--text-main);
    cursor: pointer;
    display: flex;
    align-items: center;
    transition: transform 0.3s;
}
.theme-toggle:hover {
    transform: rotate(15deg);
}

/* 主视觉区 (Hero) */
.hero {
    position: relative;
    padding: 180px 0 120px;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

/* WebGL液态金属模拟动画 */
.liquid-ring {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 50vw;
    height: 50vw;
    max-width: 600px;
    max-height: 600px;
    border: 2px solid transparent;
    border-radius: 40% 60% 70% 30% / 40% 50% 60% 50%;
    background: linear-gradient(var(--bg-color), var(--bg-color)) padding-box, var(--chrome-gradient) border-box;
    animation: morph 12s linear infinite;
    opacity: 0.4;
    z-index: 0;
    pointer-events: none;
    filter: blur(8px);
}
.ring-delayed {
    width: 40vw; height: 40vw;
    max-width: 500px; max-height: 500px;
    animation: morph 18s linear infinite reverse;
    opacity: 0.2;
}

@keyframes morph {
    0% { border-radius: 40% 60% 70% 30% / 40% 50% 60% 50%; transform: translate(-50%, -50%) rotate(0deg); }
    34% { border-radius: 70% 30% 50% 50% / 30% 30% 70% 70%; }
    67% { border-radius: 100% 60% 60% 100% / 100% 100% 60% 60%; transform: translate(-50%, -50%) rotate(360deg); }
    100% { border-radius: 40% 60% 70% 30% / 40% 50% 60% 50%; transform: translate(-50%, -50%) rotate(720deg); }
}

.hero-badge {
    display: inline-block;
    padding: 6px 16px;
    border-radius: 30px;
    border: 1px solid var(--chrome-border);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 2px;
    margin-bottom: 24px;
    backdrop-filter: blur(4px);
}

.hero-title {
    font-size: 4rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -1px;
}

.hero .subtitle {
    font-size: 1.15rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto 48px;
    line-height: 1.7;
}

/* 交互带宽滑块 */
.throughput-widget {
    max-width: 500px;
    margin: 0 auto 48px;
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--chrome-border);
    padding: 24px;
    border-radius: 16px;
    backdrop-filter: blur(10px);
}

.widget-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    font-weight: 600;
}

.chrome-slider {
    -webkit-appearance: none;
    width: 100%;
    height: 4px;
    background: var(--chrome-border);
    border-radius: 4px;
    outline: none;
}
.chrome-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--text-main);
    cursor: pointer;
    box-shadow: 0 0 10px rgba(255,255,255,0.5);
    transition: transform 0.1s;
}
.chrome-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.widget-footer {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 12px;
}

/* 布局区块 */
section { padding: 100px 0; }
.bg-alt { background-color: var(--bg-alt-color); }
.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 64px;
    letter-spacing: -0.5px;
}

/* 网格系统 */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px; }

/* 高级反光卡片系统 */
.card {
    background-color: var(--card-bg);
    border: 1px solid var(--chrome-border);
    border-radius: 20px;
    padding: 40px 32px;
    box-shadow: var(--shadow-sm);
    transition: transform 0.4s ease, border-color 0.4s ease;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(8px);
}

/* 液态反光效果 (JS控制) */
.card::before {
    content: "";
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: radial-gradient(600px circle at var(--mouse-x, 0) var(--mouse-y, 0), rgba(255,255,255,0.08), transparent 40%);
    opacity: 0;
    transition: opacity 0.4s;
    pointer-events: none;
    z-index: 1;
}

.card:hover { transform: translateY(-8px); border-color: rgba(255,255,255,0.3); }
.card:hover::before { opacity: 1; }

.card > * { position: relative; z-index: 2; }

/* 核心优势卡片 */
.feature-card { text-align: left; }
.feature-card .icon { margin-bottom: 24px; display: inline-block; color: var(--text-main);}
.feature-card h3 { margin-bottom: 16px; font-size: 1.3rem; }
.feature-card p { color: var(--text-muted); line-height: 1.7; }

/* 场景支持卡片 */
.scenario-card {
    padding: 48px;
    text-align: center;
}
.scenario-bg-blur {
    position: absolute;
    top: 50%; left: 50%; transform: translate(-50%, -50%);
    width: 200px; height: 200px;
    filter: blur(80px);
    z-index: 0; pointer-events: none;
}
.scenario-card h3 { margin-bottom: 20px; font-size: 1.5rem; }
.scenario-card p { color: var(--text-muted); margin-bottom: 32px; }

/* 价格卡片 */
.pricing-card { display: flex; flex-direction: column; text-align: left;}
.pricing-card.popular { border: 1px solid var(--text-main); transform: scale(1.02); }
.pricing-card.popular:hover { transform: scale(1.02) translateY(-8px); }
.pricing-card .badge {
    position: absolute; top: 0; right: 0;
    background: var(--chrome-gradient); color: #000;
    padding: 6px 16px; border-bottom-left-radius: 16px;
    font-size: 0.8rem; font-weight: 700;
}
.pricing-card h3 { font-size: 1.2rem; color: var(--text-muted); margin-bottom: 16px;}
.pricing-card .price { font-size: 3.5rem; font-weight: 700; margin-bottom: 32px; letter-spacing: -2px;}
.pricing-card .price span { font-size: 1.2rem; font-weight: 500; letter-spacing: 0; color: var(--text-muted);}
.pricing-features { list-style: none; margin-bottom: 32px; flex-grow: 1; }
.pricing-features li { margin-bottom: 16px; color: var(--text-main); position: relative; padding-left: 28px; font-size: 0.95rem;}
.pricing-features li::before {
    content: "✦"; position: absolute; left: 0; color: var(--text-muted);
}

/* 评价与FAQ */
.testimonial-card { padding: 32px; }
.quote-mark { font-size: 4rem; line-height: 1; color: var(--chrome-border); margin-bottom: -20px; font-family: serif;}
.testimonial-card .review { font-size: 1.05rem; margin-bottom: 24px; font-style: italic; }
.user-info .user-name { font-weight: 700; }
.user-info .user-title { font-size: 0.85rem; color: var(--text-muted); }

.faq-list { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 20px;}
.faq-item { padding: 24px 32px; margin-bottom: 0; border: 1px solid var(--chrome-border);}
.faq-item h4 { margin-bottom: 12px; font-size: 1.15rem; }

/* 页脚 */
footer {
    padding: 64px 0 40px;
    text-align: center;
    border-top: 1px solid var(--chrome-border);
}
.footer-links {
    display: flex; justify-content: center; gap: 32px; margin-bottom: 32px; flex-wrap: wrap;
}
.footer-links a { color: var(--text-muted); font-weight: 500; }
.footer-links a:hover { color: var(--text-main); }
.copyright { color: var(--text-muted); font-size: 0.9rem; }

/* 响应式适配 */
@media (max-width: 992px) {
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    .pricing-card.popular { transform: none; }
    .pricing-card.popular:hover { transform: translateY(-8px); }
    .hero-title { font-size: 3.2rem; }
    .nav-links { display: none; } /* 移动端精简导航 */
}

@media (max-width: 768px) {
    .grid-3, .grid-2 { grid-template-columns: 1fr; }
    header { width: 95%; top: 10px; }
    .hero { padding: 140px 0 80px; }
    .hero-title { font-size: 2.5rem; }
    .card { padding: 32px 24px; }
    .pricing-card .price { font-size: 2.8rem; }
}