/* ===================================================
   1. 全局设置 (Variables, Globals, Typography)
   =================================================== */

/* --- 变量 --- */
:root {
  /* 色彩系统 */
  --primary: #6A39C6; /* 主紫色 */
  --primary-light: #9C4C88; /* 浅紫色 */
  --accent: #FFC8DD; /* 辅助粉色 */
  --bg-light: #faf8fd;
  --text-dark: #000000;
  --title-dark-purple: #000000;
  --text-muted-light: #555555;

  /* Color Palette */
  --thistle: #cdb4dbff;
  --fairy-tale: rgb(247, 198, 217);
  --carnation-pink: rgb(250, 184, 208);
  --uranian-blue: rgb(192, 224, 252);
  --light-sky-blue: rgba(172, 211, 247, 0.829);
  --energy-yellow: #fffec7;

  /* Gradient Accents */
  --accent-a: var(--thistle);
  --accent-b: var(--fairy-tale);
  --accent-c: var(--carnation-pink);
  --accent-d: var(--uranian-blue);
  --accent-e: var(--light-sky-blue);
  --accent-spark: var(--energy-yellow);
  
  /* 间距系统 */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-xxl: 6rem;
  
  /* 样式基础 */
  --radius: 16px;
  --shadow-sm: 0 4px 20px rgba(0,0,0,.06);
  --shadow-md: 0 8px 32px rgba(0,0,0,.10);
  --shadow-lg: 0 20px 50px rgba(0,0,0,.14);
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --header-height: 80px;
}

/* --- 背景动画 --- */
@keyframes auroraFloat {
  0%   { transform: rotate(0deg) scale(1.1) translate(0,0); }
  50%  { transform: rotate(180deg) scale(1.25) translate(3%, -3%); }
  100% { transform: rotate(360deg) scale(1.1) translate(0,0); }
}

body::before {
  content: '';
  position: fixed; inset: -25%;
  z-index: -2;
  background-image:
    radial-gradient(1200px 900px at 12% 20%, var(--accent-b) 0%, transparent 55%),
    radial-gradient(1200px 900px at 84% 18%, var(--accent-a) 0%, transparent 55%),
    radial-gradient(1400px 1000px at 25% 85%, var(--accent-c) 0%, transparent 55%),
    radial-gradient(1200px 900px at 75% 88%, var(--accent-d) 0%, transparent 55%),
    radial-gradient(1200px 900px at 50% 50%, var(--accent-e) 0%, transparent 55%),
    radial-gradient(900px 700px  at 40% 30%, var(--accent-spark) 0%, transparent 60%);
  filter: blur(140px) saturate(1.04);
  opacity: .55;
  animation: auroraFloat 26s ease-in-out infinite alternate;
}

body::after {
  content: '';
  position: fixed; inset: -30%;
  z-index: -3;
  background-image:
    radial-gradient(1400px 1000px at 20% 75%, var(--accent-a) 0%, transparent 58%),
    radial-gradient(1200px 900px  at 80% 70%, var(--accent-c) 0%, transparent 58%),
    radial-gradient(1200px 900px  at 50% 30%, var(--accent-b) 0%, transparent 58%);
  filter: blur(170px) saturate(1.08);
  opacity: .40;
  animation: auroraFloat 38s linear infinite alternate-reverse;
}

html::after {
  content: '';
  position: fixed; inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='120' height='120' viewBox='0 0 120 120'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='2' stitchTiles='stitch'/><feColorMatrix type='saturate' values='0'/><feComponentTransfer><feFuncA type='table' tableValues='0 0 0 0 0 0.02 0'/></feComponentTransfer></filter><rect width='120' height='120' filter='url(%23n)' opacity='0.3'/></svg>");
  opacity: .06;
}

/* --- 全局重置与基础 --- */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: transparent;
  color: var(--text-dark);
  font-family: var(--font-main);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
section { 
  padding: var(--spacing-xxl) 0; 
  overflow: hidden;
  scroll-margin-top: var(--header-height);
}

/* --- 排版 --- */
h1 { font-size: clamp(2.5rem, 5vw, 3.5rem); line-height: 1.3; font-weight: 700; color: var(--title-dark-purple); margin: .5rem 0 1rem; }
h2, h3 { 
  font-weight: 700;
  color: var(--title-dark-purple);
  letter-spacing: 0.02em;
}
h2 { font-size: clamp(2rem, 4vw, 2.5rem); line-height: 1.3; text-align: center; margin: 0 auto var(--spacing-xl); position: relative; }
h3 { font-size: clamp(1.3rem, 3vw, 1.6rem); line-height: 1.3; margin-bottom: var(--spacing-md); }
h4 { font-size: 1.1rem; font-weight: 600; }
p { font-size: 1.06rem; color: var(--text-muted-light); max-width: 70ch; line-height: 1.7; margin-bottom: var(--spacing-md); }
a { color: var(--primary); text-decoration: none; transition: color .25s; }
a:hover { color: var(--primary-light); text-decoration: underline; }

/* --- 辅助类 (Helpers) --- */
.container { max-width: 1100px; margin: 0 auto; padding: 0 calc(var(--spacing-md) * 0.6); }

.gradient-text {
  background: linear-gradient(90deg, var(--primary), var(--primary-light)) !important;
  -webkit-background-clip: text !important;
  background-clip: text !important;
  color: transparent !important;
  display: inline-block;
}

.grid-2, .grid-3 { display: grid; gap: var(--spacing-lg); margin-top: var(--spacing-xl); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

.section-subtitle { text-align: center; margin: calc(-1 * var(--spacing-md)) auto var(--spacing-xl); color: var(--text-muted-light); max-width: 600px; }
.mobile-only { display: none; }
.desktop-only { display: block; } /* 默认为 block，将在 820px 隐藏 */


/* ===================================================
   2. 可重用组件 (Components)
   =================================================== */

/* --- 按钮 --- */
.cta-button { display: inline-block; padding: .9rem 1.6rem; border-radius: 999px; border: none; font-weight: 700; color: #fff !important; background: linear-gradient(90deg, var(--primary), var(--primary-light)); box-shadow: 0 8px 30px rgba(75, 36, 144, .25); transition: transform .2s ease, box-shadow .2s ease; cursor: pointer; text-align: center; }
.cta-button:hover { transform: translateY(-2px); box-shadow: 0 12px 36px rgba(75, 36, 144, .35); color: white; text-decoration: none; }
.cta-button:active { transform: translateY(0); }
.cta-button.cta-secondary { background: transparent; border: 2px solid #4b2490; color: #000 !important; }
.cta-button.cta-secondary:hover { background: #4b2490; color: #fff !important; }
.nav a.cta-button, .mobile-menu a.cta-button { color: #fff !important; }

/* --- 通用卡片 --- */
.base-card { background: rgba(255, 255, 255, 0.4); backdrop-filter: blur(15px); border: 1px solid rgba(255, 255, 255, 0.2); border-radius: var(--radius); padding: var(--spacing-lg); transition: all 0.3s ease; }
.base-card.shadow-sm { box-shadow: var(--shadow-sm); }
.base-card.shadow-md { box-shadow: var(--shadow-md); }
.base-card.shadow-lg { box-shadow: var(--shadow-lg); }
.base-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }

/* --- 滚动显示动画 --- */
.reveal { opacity: 0; transform: translateY(20px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.in { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) { 
  * { animation: none !important; transition: none !important; } 
  body::before, body::after { display: none; } 
  .reveal { opacity: 1 !important; transform: translateY(0) !important; } 
}

/* --- 翻转卡片 (用于 Use Cases & Team) --- */
.case-card, .team-card { perspective: 1000px; cursor: pointer; }
.case-card-inner, .team-card-inner { position: relative; width: 100%; height: 100%; transition: transform 0.6s ease; transform-style: preserve-3d; }
.case-card-inner.is-flipped, .team-card-inner.is-flipped { transform: rotateY(180deg); }
.case-card-front, .case-card-back, .team-card-front, .team-card-back { 
  position: absolute; 
  width: 100%; 
  height: 100%; 
  -webkit-backface-visibility: hidden; 
  backface-visibility: hidden; 
  border-radius: var(--radius); 
  border: 1px solid rgba(255, 255, 255, 0.2); 
  box-shadow: var(--shadow-sm); 
  background: rgba(255, 255, 255, 0.4); 
  backdrop-filter: blur(10px); 
  display: flex; 
  flex-direction: column; 
  justify-content: center; 
  padding: 1.5rem; 
}
.case-card-back, .team-card-back { transform: rotateY(180deg); }

/* --- FAQ --- */
.faq-list { max-width: 900px; margin: 2rem auto 0; display: grid; gap: 1rem; }
.faq-item { border-radius: 12px; border: 1px solid rgba(0,0,0,.08); padding: 1rem 1.2rem; background: rgba(255, 255, 255, 0.65); backdrop-filter: blur(15px); }
.faq-item > summary { cursor: pointer; font-weight: 700; color: var(--title-dark-purple); display: flex; align-items: center; list-style: none; }
.faq-item > summary::-webkit-details-marker { display: none; }
.faq-icon { margin-right: 1rem; transition: transform 0.3s ease-in-out; flex-shrink: 0; display: flex; align-items: center; }
details[open] > summary .faq-icon { transform: rotate(45deg); }
.faq-item p { margin-top: .6rem; padding-left: 2.7rem; padding-right: 1.2rem; margin: 0.6rem 0 0 0; }


/* ===================================================
   3. 页面布局 (Layout Sections - Desktop First)
   =================================================== */

/* --- 头部 (Header) --- */
.header { position: sticky; top: 0; z-index: 1000; padding: 1rem 0; background: transparent !important; transition: background-color .35s ease, box-shadow .35s ease, backdrop-filter .35s ease; }
.header.scrolled { background: rgba(255,255,255,.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); border-bottom: 1px solid rgba(0,0,0,.06); box-shadow: 0 2px 10px rgba(0,0,0,.05); }
.header-inner { display: flex; justify-content: space-between; align-items: center; width: 100%; }
.logo { font-size: 1.7rem; font-weight: 800; color: var(--title-dark-purple); height: 40px; display: flex; align-items: center; margin-right: auto; }
.logo > span { display: none; } /* 默认隐藏，移动端显示 */
.nav { display: block; } /* 默认显示，移动端隐藏 */
.nav ul { display: flex; list-style: none; gap: 1.5rem; align-items: center; }
.nav a { font-size: 1rem; font-weight: 500; color: var(--text-muted-light); }
.nav a:hover { color: var(--title-dark-purple); text-decoration: none; }
.hamburger { display: none; } /* 默认隐藏，移动端显示 */
.mobile-menu { display: none; } /* 默认隐藏，移动端显示 */

/* --- 价值主张 (Hero Section) --- */
#value.value-prop-section { padding: 0; display: flex; align-items: center; min-height: calc(100vh - var(--header-height)); text-align: center;}
.value-prop { 
  display: grid; 
  grid-template-columns: 1fr 1fr; 
  align-items: center; 
  gap: clamp(16px, 3.6vw, 32px); 
  width: 100%; 
  max-width: 1400px; 
  margin: 0 auto;
}
.vp-text { z-index: 10; text-align: center; padding-left: calc(var(--spacing-xl) * 2); padding-right: var(--spacing-xl); }
.vp-text h2 { margin: 0 auto var(--spacing-md); }
.vp-text p { margin: 0 auto var(--spacing-lg); max-width: 60ch; }
.vp-actions { display: flex; justify-content: center; gap: var(--spacing-md); }
.vp-video { width: 100%; max-width: 550px; margin: 0; padding: 0; display: flex; justify-content: center; align-items: center; }
.vp-video .vp-player-container { width: auto; height: auto; background: transparent; position: relative; }
.vp-video .vp-player {
  display: block; height: 70vh; width: 100%; object-fit: cover; max-width: 100%;
  background: transparent;
  border-radius: var(--radius);
  box-shadow: 0 0 30px rgba(255, 255, 255, 0.8), 0 0 40px rgba(255, 255, 255, 0.6), 0 0 50px rgba(255, 255, 255, 0.4);
  position: relative;
  overflow: hidden;
}
.video-loader {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  border-radius: var(--radius);
  z-index: 20;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}
.loading-spinner {
  width: 60px;
  height: 60px;
  border: 4px solid rgba(106, 57, 198, 0.2);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: 1rem;
}
@keyframes spin { to { transform: rotate(360deg); } }
.video-loader p { color: var(--text-dark); font-size: 1.1rem; font-weight: 500; margin: 0; }
.video-loader.hidden { opacity: 0; visibility: hidden; }

/* --- 不可能三角 (Trilemma Section) --- */
@keyframes moveLogoUp { to { transform: translate(-50%, -150%); } }
@keyframes moveNodeToBottomCenter { to { transform: translate(-50%, 5px) scale(0.9); } }
@keyframes moveNodeToBottomLeft { to { transform: translate(-155%, 5px) scale(0.9); } }
@keyframes moveNodeToBottomRight { to { transform: translate(55%, 5px) scale(0.9); } }
@keyframes fadeInGlow { to { opacity: 1; } }

.trilemma-wrapper { position: relative; height: 650px; max-width: 1000px; margin: 0 auto; }
.trilemma-node {
  width: 260px;
  height: 260px;
  border-radius: 50%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background: rgba(255, 255, 255, 0.4);
  border: 2px solid rgba(106, 57, 198, 0.3);
  box-shadow: var(--shadow-md);
  padding: 1.5rem;
  position: absolute;
  text-align: center;
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
  opacity: 0;
  transform: scale(0.8);
  top: 50%; left: 50%;
}
.trilemma-node h3 { margin-bottom: 0.5rem; font-size: 1.2rem; }
.trilemma-node p { font-size: 0.95rem; line-height: 1.5; }
.node-realism { transform: translate(-50%, -80%) scale(0.8); }
.node-cost { transform: translate(-95%, 10%) scale(0.8); }
.node-latency { transform: translate(-5%, 10%) scale(0.8); }
.trilemma-center { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%) scale(0.7); text-align: center; z-index: 3; opacity: 0; transition: opacity 0.7s ease-out, transform 0.7s ease-out; width: 320px; }
.trilemma-center h3 { font-size: 2.8rem; font-weight: 800; margin: 0; background: linear-gradient(90deg, var(--primary), var(--primary-light)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; text-shadow: 0 0 25px rgba(106, 57, 198, 0.8); text-align: center; }
.trilemma-center p { font-size: 1.2rem; color: var(--text-muted-light); margin-top: 0.5rem; text-shadow: none; text-align: center; }
.trilemma-center .glow-text { font-size: 1.3rem; font-weight: 700; margin-top: 0.8rem; background: linear-gradient(90deg, var(--primary), var(--primary-light)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; text-shadow: 0 0 15px rgba(106, 57, 198, 0.8); text-align: center; opacity: 0; }
.trilemma-wrapper.reveal.in .node-realism { opacity: 1; transform: translate(-50%, -110%) scale(1); transition-delay: 0.2s; }
.trilemma-wrapper.reveal.in .node-cost { opacity: 1; transform: translate(-115%, 10%) scale(1); transition-delay: 0.4s; }
.trilemma-wrapper.reveal.in .node-latency { opacity: 1; transform: translate(15%, 10%) scale(1); transition-delay: 0.6s; }
.trilemma-wrapper.reveal.in .trilemma-center { opacity: 1; transform: translate(-50%, -50%) scale(1); transition-delay: 1.0s; }
.trilemma-wrapper.animate-complete .trilemma-center { animation: moveLogoUp 0.8s ease-in-out forwards; animation-delay: 0.2s; }
.trilemma-wrapper.animate-complete .node-realism { animation: moveNodeToBottomCenter 0.8s ease-in-out forwards; animation-delay: 0.2s; }
.trilemma-wrapper.animate-complete .node-cost { animation: moveNodeToBottomLeft 0.8s ease-in-out forwards; animation-delay: 0.2s; }
.trilemma-wrapper.animate-complete .node-latency { animation: moveNodeToBottomRight 0.8s ease-in-out forwards; animation-delay: 0.2s; }
.trilemma-wrapper.animate-complete .trilemma-center .glow-text { animation: fadeInGlow 0.8s ease-out 1.0s forwards; }

/* --- 技术特性 (Tech Features) --- */
.tech-features-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 2rem; max-width: 800px; margin: 3rem auto 0; }
.feature-card { background: rgba(255, 255, 255, 0.7); backdrop-filter: blur(10px); padding: var(--spacing-lg); border-radius: var(--radius); border: 1px solid rgba(255, 255, 255, 0.2); box-shadow: var(--shadow-sm); transition: transform .25s ease, box-shadow .25s ease, opacity .5s ease, transform .5s ease; }
.feature-card:hover { transform: translateY(-5px) scale(1.02); }
.feature-card h3 { font-size: 1.1rem; margin-bottom: 0.5rem; text-align: center; }
.feature-card p { font-size: 0.95rem; line-height: 1.6; }

/* --- 技术展示 (Tech Demo) --- */
.tech-tilt-row { display: flex; justify-content: center; gap: clamp(140px, 18vw, 220px); width: 100%; }
.tilt-card { width: clamp(220px, 20vw, 280px); border: 2px solid transparent; transition: transform 0.35s ease, box-shadow 0.35s ease, background-color 0.35s ease; }
.tilt-media { width: 100%; aspect-ratio: 9 / 16; border-radius: 8px; overflow: hidden; background: transparent; margin-bottom: 1rem; }
.tilt-media video { width: 100%; height: 100%; object-fit: cover; }
.tilt-text h3 { text-align: center; margin-bottom: 0.8rem; }

/* --- 产品 (Product) --- */
.product-card { text-align: center; background: rgba(255, 255, 255, 0.7); backdrop-filter: blur(10px); padding: var(--spacing-lg); border-radius: var(--radius); border: 1px solid rgba(255, 255, 255, 0.2); box-shadow: var(--shadow-sm); }
.card-icon-wrapper { height: 48px; margin: 0 auto var(--spacing-md); display: flex; justify-content: center; align-items: center; }
.card-icon-wrapper > * { max-height: 100%; max-width: 100%; }
#lottie-rocket-icon { transform: scale(1.3); transform-origin: center; }

/* --- 对比 (Comparison) --- */
.comparison-table { width: 100%; margin-top: 2.2rem; border-collapse: collapse; text-align: left; border-radius: 12px; overflow: hidden; box-shadow: var(--shadow-md); border: 1px solid rgba(0,0,0,.08); table-layout: fixed; }
.comparison-table th, .comparison-table td { padding: 1.2rem; border-bottom: 1px solid rgba(0,0,0,.08); }
.comparison-table th { background: rgba(255, 255, 255, .6); font-weight: 600; }
.comparison-table tr { background: rgba(255, 255, 255, .35); }
.comparison-table tr:hover { background: rgba(255, 255, 255, .65); }
.comparison-table td:first-child { font-weight: 600; color: var(--title-dark-purple); }
.comparison-table th:first-child,
.comparison-table td:first-child {
  border-left: 3px solid transparent;
  border-right-style: none;
  transition: border-left-color 0.8s ease-out;
  transition-delay: 0.6s;
  width: 34%;
}
.comparison-table.reveal.in th:first-child,
.comparison-table.reveal.in td:first-child {
  border-image: linear-gradient(165deg, var(--accent-a), var(--accent-b), var(--accent-c), var(--accent-d)) 1;
  border-image-slice: 1;
  border-left-color: var(--primary);
}
.comparison-table th:first-child { border-top-left-radius: 12px; }
.comparison-table tr:last-child td:first-child { border-bottom-left-radius: 12px; }

/* --- 客户赋能 (Use Cases) --- */
#use-cases { background: transparent; }
.case-card { height: 320px; }
.case-card-inner { background: transparent; border: none; box-shadow: none; }
.case-card-front, .case-card-back { padding: 2rem; }
.case-card-front h3 { text-align: center; margin-bottom: 1.5rem; }
.case-card-front .case-content { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1rem; justify-content: center; }
.case-card-front h4 { font-size: 1.05rem; margin: .25rem 0; text-align: center; }
.case-card-back h3 { color: var(--primary); text-align: center; margin-bottom: 1.5rem; }
.case-card-icon { display: none; } /* Icon seems unused in HTML */
#use-cases .grid-3 > div { text-align: center; }

/* --- 团队 (Team) --- */
.team-section { background: transparent; }
.team-container-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 4rem; align-items: start; max-width: 1100px; margin: 3rem auto 0; }
.team-members-list { display: grid; gap: 1.5rem; }
.team-card { min-height: 90px; }
.team-card-front, .team-card-back { padding: 1.5rem; }
.team-card-back { align-items: flex-start; text-align: left; }
.team-card-front h3 { margin-bottom: 0.25rem; font-size: 1.25rem; }
.team-card-front p { color: var(--text-muted-light); margin: 0; font-size: 1rem; }
.team-card-back p { font-size: 0.95rem; color: var(--text-muted-light); margin: 0; }
.team-achievements h3 { font-size: 1.75rem; color: var(--title-dark-purple); margin-bottom: 1rem; text-align: left; }
.team-achievements p { color: var(--text-muted-light); margin-bottom: 2.5rem; text-align: left; max-width: 100%; }
.achievements-grid { display: grid; gap: 2rem; }
.achievement-item h4 { font-size: 1rem; color: var(--text-muted-light); font-weight: 500; margin-bottom: 1rem; text-transform: uppercase; letter-spacing: 0.05em; text-align: left; }
.logo-group { display: flex; flex-wrap: wrap; gap: 1.5rem; align-items: center; }
.logo-text { font-size: 1.5rem; font-weight: 600; color: var(--title-dark-purple); opacity: 0.8; }
.logo-svg { height: 28px; opacity: 0.7; transition: all 0.3s ease; }
.logo-svg:hover { opacity: 1; transform: translateY(-2px); }

/* --- 最终CTA (Final CTA) --- */
.final-cta { background: linear-gradient(135deg, var(--primary), var(--primary-light)); color: #fff; border-radius: var(--radius); margin: 0 2rem; }
.final-cta .container { display: flex; flex-direction: column; align-items: center; text-align: center; }
.final-cta h2, .final-cta p { color: #fff; text-align: center; }
.final-cta p { max-width: 720px; }
.final-cta .cta-button { margin-top: 2rem; }

/* --- 联系我们 (Contact) --- */
.contact-strip { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 2rem; margin-top: 2rem; align-items: center; }
.contact-col { text-align: left; }
.contact-points { list-style: none; padding: 0; margin-top: 1rem; }

/* --- 页脚 (Footer) --- */
.footer { background: #fff; padding: 4rem 0 2rem; text-align: center; border-top: 1px solid rgba(0,0,0,.08); }
.footer .container { display: flex; flex-direction: column; align-items: center; gap: 1.4rem; }
.footer .logo { margin: 0 auto var(--spacing-md); }
.footer .logo span { display: inline-block; }
.footer .links { display: flex; gap: 1.2rem; list-style: none; flex-wrap: wrap; justify-content: center; }
.footer .copyright { color: var(--text-muted-light); font-size: .92rem; }


/* ===================================================
   4. 响应式媒体查询 (Responsive Media Queries)
   =================================================== */

/* --- 992px (大平板 / 汉堡菜单) --- */
@media (max-width: 992px) {
  .nav { display: none; }
  .hamburger { display: block; position: relative; width: 40px; height: 40px; border: none; background: transparent; cursor: pointer; }
  .hamburger span { position: absolute; left: 9px; right: 9px; height: 2px; background: #333; border-radius: 2px; transition: transform .25s, top .25s, opacity .25s, background .35s ease; }
  .hamburger span:nth-child(1) { top: 12px; }
  .hamburger span:nth-child(2) { top: 19px; }
  .hamburger span:nth-child(3) { top: 26px; }
  .hamburger.open span:nth-child(1) { top: 19px; transform: rotate(45deg); }
  .hamburger.open span:nth-child(2) { opacity: 0; }
  .hamburger.open span:nth-child(3) { top: 19px; transform: rotate(-45deg); }
  .mobile-menu { position: fixed; inset: var(--header-height) 0 auto 0; background: rgba(255, 255, 255, .95); backdrop-filter: blur(10px); transform: translateY(-16px); opacity: 0; pointer-events: none; display: flex; flex-direction: column; padding: 1.5rem 1.25rem; border-bottom: 1px solid rgba(0,0,0,.08); transition: opacity .25s ease, transform .25s ease; z-index: 999; }
  .mobile-menu ul { list-style: none; width: 100%; }
  .mobile-menu li { margin-bottom: 0.25rem; }
  .mobile-menu a { display: block; padding: 1rem 1.25rem; border-radius: 12px; background: rgba(255, 255, 255, .8); box-shadow: var(--shadow-sm); color: #333; font-weight: 500; font-size: 1.1rem; transition: all 0.2s ease; }
  .mobile-menu a:hover { background: white; text-decoration: none; transform: translateX(4px); }
  .mobile-menu.open { opacity: 1; transform: translateY(0); pointer-events: auto; }
  .no-scroll { overflow: hidden; }

  /* Team Layout */
  .team-container-grid { grid-template-columns: 1fr; gap: 3rem; }
}

/* --- 960px (小平板 / Hero 堆叠) --- */
@media (max-width: 960px) {
  /* Hero Section */
  #value.value-prop-section { min-height: auto; padding: var(--spacing-xxl) 0; }
  .value-prop { grid-template-columns: 1fr; gap: var(--spacing-lg); }
  .vp-text { padding: 0 var(--spacing-md); }
  .vp-video { margin: 0 auto; } /* 居中视频 */
  .vp-video .vp-player { height: 65vh; }
  
  /* Tech Demo Section */
  .tech-tilt-row { flex-direction: column; align-items: center; } 
  .tilt-card { width: min(80vw, 320px); }
}

/* --- 820px (手机) --- */
@media (max-width: 820px) {

  .desktop-only { display: none; }
  .mobile-only { display: block; }
  
  :root {
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.25rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 2.5rem;
    --text-dark: #3a2e5c;
    --title-dark-purple: #3a2e5c;
    --text-muted-light: #5c5378;
  }

  h1 { font-size: 1.6rem; }
  h2, h3 { letter-spacing: 0.02em; }
  h2 { font-size: 1.3rem; }
  h3 { font-size: 1.1rem; }
  p { font-size: 0.85rem; }
  td { font-size: 0.8rem; }
  section { padding: var(--spacing-xl) 0; }
  .container { padding: 0 var(--spacing-sm); }
  
  /* 手机端背景 */
  body::before {
    display: block !important;
    opacity: 0.4;
    animation-duration: 20s;
    background-attachment: scroll;
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
    background-image:
      radial-gradient(1000px 800px at 15% 20%, var(--accent-d) 0%, transparent 60%),
      radial-gradient(1000px 800px at 80% 25%, var(--accent-e) 0%, transparent 60%),
      radial-gradient(1200px 900px at 20% 90%, var(--accent-c) 0%, transparent 65%),
      radial-gradient(1200px 900px at 80% 95%, var(--accent-a) 0%, transparent 65%),
      radial-gradient(1000px 800px at 50% 50%, var(--accent-spark) 0%, transparent 60%);
  }
  body::after {
      display: block !important;
      opacity: 0.25;
      background-attachment: scroll;
  }

  /* 手机端头部 (固定, 透明) */
  .header {
    position: fixed;
    background: transparent !important;
    border-bottom: none;
    box-shadow: none;
    left: 0;
    right: 0;
    width: 100%;
  }
  .header .container {
    padding-left: var(--spacing-sm);
    padding-right: var(--spacing-sm);
  }
  .header:not(.scrolled) .logo span {
    color: white;
  }
  .header:not(.scrolled) .hamburger span {
    background: white;
  }
  .header.scrolled .logo span {
    color: var(--title-dark-purple);
  }
  .header.scrolled .hamburger span {
    background: var(--title-dark-purple);
  }

  .logo canvas { margin-left: -3rem; }
  .logo > span { 
    display: block; 
    font-size: 1.7rem; 
    font-weight: 800;
    transition: color 0.35s ease;
  }
  
  /* --- 价值主张区域 (Hero Section) [恢复为原始设计] --- */
  #value.value-prop-section {
    padding: 0;
    text-align: center;
    min-height: 100vh;
    height: 100vh;
  }
  
  .value-prop {
    grid-template-columns: 1fr;
    gap: 0;
    position: relative;
    width: 100%;
    height: 100vh;
  }
  
  .vp-text {
    order: 2;
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-md) var(--spacing-md) 2rem;
    z-index: 10;
    background: linear-gradient(to top, white 20%, rgba(255, 255, 255, 0.95) 60%, transparent 100%);
    border-top-left-radius: 30px;
    border-top-right-radius: 30px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s ease-out 0.5s forwards;
  }
  
  @keyframes fadeInUp {
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  .vp-video {
    order: 1;
    width: 100%;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
    margin: 0;
  }
  
  .vp-video .vp-player-container {
    width: 100%;
    height: 100%;
    margin: 0;
  }
  
  .vp-player {
    height: 100vh !important;
    width: 100%;
    object-fit: cover;
    position: absolute;
    top: 0;
    left: 0;
    border-radius: 0 !important;
    box-shadow: none !important;
    margin: 0;
  }
  
  .vp-actions {
    justify-content: center;
    display: flex;
    gap: 1rem;
    margin-top: var(--spacing-md);
  }
  
  .vp-actions .cta-button {
    box-shadow: 0 6px 15px rgba(75, 36, 144, .20);
  }
  
  .vp-text h2 {
    color: var(--text-dark) !important;
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    margin-top: 0;
  }
   .vp-text p {
    color: var(--text-dark) !important;
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
  }
  /* --- [Hero 结束] --- */

  /* --- 不可能三角 (Trilemma) [手机端轮播] --- */
  #trilemma {
    background: linear-gradient(to bottom, white 0%, white 30%, rgba(255, 255, 255, 0) 100%);
    padding-top: var(--spacing-xxl);
    margin-top: 0;
  }
  #trilemma > .container {
      display: flex;
      flex-direction: column;
      align-items: center;
  }
  .trilemma-wrapper {
    height: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0;
    position: relative;
    width: 100%;
  }
  .trilemma-center {
    position: relative;
    top: auto;
    left: auto;
    transform: none !important;
    width: 100%;
    order: -1;
    margin-bottom: 0 !important;
    z-index: 20;
    display: flex;
    flex-direction: column;
    align-items: center;
    & h3, & p { display: none; }
  }
  .trilemma-center .glow-text {
    font-size: 1.1rem !important;
    margin-top: 0 !important;
    opacity: 1 !important;
    animation: none !important;
  }
  .trilemma-carousel {
    position: relative;
    width: 100%;
    height: 320px;
    display: flex;
    align-items: center;
    justify-content: center;
    order: 2;
    overflow: hidden;
  }
  .trilemma-nodes-container {
    display: flex;
    align-items: center;
    height: 100%;
    position: absolute;
    left: 0;
    transition: transform 0.5s ease-in-out;
  }
  .trilemma-node {
    width: 240px !important;
    height: 240px !important;
    flex-shrink: 0;
    text-align: center !important;
    padding: 1.5rem !important;
    margin: 0 1rem !important;
    position: relative !important;
    transform: scale(0.8) !important;
    top: auto !important;
    left: auto !important;
    opacity: 0.6 !important;
    transition: transform 0.5s ease-in-out, opacity 0.5s ease-in-out;
  }
  .trilemma-node.active {
      transform: scale(1) !important;
      opacity: 1 !important;
  }
  .trilemma-node h4 { font-size: 1.1rem !important; }
  .trilemma-node p { font-size: 0.9rem !important; line-height: 1.5; }
  .carousel-arrow {
    display: flex;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 30;
    transition: all 0.3s ease;
  }
  .carousel-arrow:hover { background: rgba(255, 255, 255, 0.5); }
  .carousel-arrow-left { left: 1rem; }
  .carousel-arrow-right { right: 1rem; }
  .carousel-arrow::before {
    content: '';
    width: 10px;
    height: 10px;
    border-style: solid;
    border-color: var(--text-dark);
    border-width: 0 2px 2px 0;
  }
  .carousel-arrow-left::before { transform: rotate(135deg); }
  .carousel-arrow-right::before { transform: rotate(-45deg); }
  .trilemma-wrapper.animate-complete .trilemma-center,
  .trilemma-wrapper.animate-complete .trilemma-node { animation: none; }
  .trilemma-wrapper.reveal.in .trilemma-center,  
  .trilemma-wrapper.reveal.in .trilemma-node { opacity: 1; transition-delay: 0s !important; }
  
  /* --- 技术展示 (Tech Demo) [手机端轮播] --- */
  .tech-demo-section {
    position: relative;
    overflow: hidden;
    padding: var(--spacing-xl) 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    height: auto;
  }
  .tech-demo-section > .container {
      width: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: var(--spacing-lg);
  }
  .tech-demo-section > .container > h2,
  .tech-demo-section > .container > .section-subtitle {
      position: relative;
      z-index: 10;
      width: 90%;
      color: var(--text-dark);
      text-shadow: 0 1px 3px rgba(255,255,255,0.4);
      margin-bottom: 0;
  }
  .tech-demo-section > .container > h2 { margin-top: 0; }
  .tech-demo-section > .container > .section-subtitle {
      color: var(--text-muted-light);
      margin-top: calc(-1 * var(--spacing-md));
  }
  .tech-demo-carousel-wrapper { width: 100%; position: relative; }
  .tech-demo-container-outer { width: 80%; margin: 0 auto; overflow: hidden; border-radius: var(--radius); }
  .tech-demo-container {
    position: relative;
    width: 100%;
    display: flex;
    gap: 2rem;
    transition: transform 0.5s ease-in-out;
    border-radius: var(--radius);
  }
  .tech-demo-slide {
    flex-shrink: 0;
    width: 100%;
    position: relative;
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: none;
    margin: 0;
  }
  .tech-demo-slide video {
    width: 100%;
    height: auto;
    aspect-ratio: 9 / 16;
    object-fit: cover;
    display: block;
  }
  .tech-demo-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-lg) var(--spacing-md);
    background: linear-gradient(to top, rgba(106, 57, 198, 0.85) 0%, rgba(156, 76, 136, 0.7) 60%, transparent 100%);
    color: white;
    text-align: center;
  }
  .tech-demo-caption h3 { color: white; margin-bottom: 0.5rem; }
  .tech-demo-caption p { color: rgba(255,255,255,0.8); margin-bottom: 0; }
  .tech-demo-section .carousel-arrow-left { left: 0; }
  .tech-demo-section .carousel-arrow-right { right: 0; }

  /* --- 其他手机端布局调整 --- */
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .tech-features-grid { grid-template-columns: 1fr; }
  
  .case-card { height: 300px; min-height: auto; }
  .case-card-front,
  .case-card-back { padding: 1.5rem; }

  .team-achievements h3 { font-size: 1.3rem; font-weight: 600; text-align: center !important; }
  .team-achievements { text-align: center; }
  .team-achievements p { text-align: center !important; }
  .achievements-grid { align-items: center; }
  .achievement-item h4 { text-align: center !important; }
  .logo-group { justify-content: center !important; }
  
  #demo.final-cta { margin-top: var(--spacing-xl) !important; }
  .tech-features-grid .feature-card,
  .grid-3 .product-card { text-align: center !important; }
  
  .final-cta { margin: 0 !important; border-radius: 0 !important; }
  
  .team-container-grid { grid-template-columns: 1fr; }
  .contact-strip { grid-template-columns: 1fr; }
  
  #contact h2 { margin-bottom: var(--spacing-sm); }
  #contact .contact-col p { margin-bottom: var(--spacing-sm); }
  #contact .contact-points li { font-size: 0.9rem; }
  
  .footer .logo > span { color: var(--text-dark); }
}