/* ==========================================================================
   TNT云 (tntcloud) - 量子科技 + 叠加爆炸风格样式表
   【配色标准】
   主背景：#0A0E27 深蓝黑
   主色：#8B5CF6 量子紫
   次色：#EF4444 爆炸红
   CTA 按钮：紫到红渐变，圆角 12px，带 30px 紫色辉光
   ========================================================================== */

:root {
  --bg-primary: #0A0E27;
  --bg-secondary: #10163b;
  --bg-card: rgba(16, 22, 59, 0.78);
  --bg-card-hover: rgba(28, 38, 92, 0.9);
  
  --border-color: rgba(139, 92, 246, 0.22);
  --border-highlight: rgba(239, 68, 68, 0.5);
  
  --text-main: #f3f4f8;
  --text-muted: #a3a9c2;
  --text-dim: #949ab8; /* WCAG AA 4.5:1 对比度达标 */
  
  /* 品牌色系统：量子炸弹 + 叠加爆炸 + 量子科技 */
  --primary: #8B5CF6;         /* 量子紫 */
  --secondary: #EF4444;       /* 爆炸红 */
  --accent-cyan: #06b6d4;
  
  --primary-gradient: linear-gradient(135deg, #8B5CF6 0%, #EF4444 100%);
  --quantum-gradient: linear-gradient(135deg, #c084fc 0%, #8B5CF6 50%, #EF4444 100%);
  --cta-gradient: linear-gradient(135deg, #8B5CF6 0%, #EF4444 100%);
  --cta-hover-gradient: linear-gradient(135deg, #a78bfa 0%, #f87171 100%);
  
  --gold: #f59e0b;
  --success: #10b981;
  
  --radius-sm: 8px;
  --radius-btn: 12px;         /* 严格设定 12px 圆角 */
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-glow-purple: 0 0 30px rgba(139, 92, 246, 0.6); /* 30px 紫色辉光 */
  --shadow-glow-red: 0 0 30px rgba(239, 68, 68, 0.5);
  --shadow-card: 0 10px 30px -8px rgba(0, 0, 0, 0.6);
  
  --container-width: 1200px;
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* CSS 重置与基础设置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.6;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(circle at 15% 15%, rgba(139, 92, 246, 0.18) 0%, transparent 45%),
    radial-gradient(circle at 85% 25%, rgba(239, 68, 68, 0.15) 0%, transparent 40%),
    radial-gradient(circle at 50% 80%, rgba(139, 92, 246, 0.12) 0%, transparent 50%);
  position: relative;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition);
}

img, svg {
  display: block;
  max-width: 100%;
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* ==========================================================================
   背景动效：紫/红粒子从底部持续上升
   ========================================================================== */
.quantum-particles {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.particle {
  position: absolute;
  bottom: -25px;
  border-radius: 50%;
  opacity: 0;
  animation: particleRise linear infinite;
}

@keyframes particleRise {
  0% {
    transform: translateY(0) scale(0.6);
    opacity: 0;
  }
  20% {
    opacity: 0.85;
  }
  80% {
    opacity: 0.85;
  }
  100% {
    transform: translateY(-105vh) scale(1.3);
    opacity: 0;
  }
}

/* 紫色量子粒子 */
.particle.purple {
  background: var(--primary);
  box-shadow: 0 0 12px var(--primary), 0 0 24px rgba(139, 92, 246, 0.7);
}

/* 红色爆炸粒子 */
.particle.red {
  background: var(--secondary);
  box-shadow: 0 0 12px var(--secondary), 0 0 24px rgba(239, 68, 68, 0.7);
}

/* 随机粒子位置、大小与动画时长 */
.p1 { left: 5%; width: 5px; height: 5px; animation-duration: 9s; animation-delay: 0s; }
.p2 { left: 14%; width: 7px; height: 7px; animation-duration: 11s; animation-delay: 2s; }
.p3 { left: 23%; width: 4px; height: 4px; animation-duration: 8s; animation-delay: 4.5s; }
.p4 { left: 32%; width: 8px; height: 8px; animation-duration: 13s; animation-delay: 1.2s; }
.p5 { left: 42%; width: 5px; height: 5px; animation-duration: 10s; animation-delay: 3.4s; }
.p6 { left: 51%; width: 6px; height: 6px; animation-duration: 12s; animation-delay: 0.5s; }
.p7 { left: 60%; width: 4px; height: 4px; animation-duration: 7.5s; animation-delay: 5s; }
.p8 { left: 71%; width: 7px; height: 7px; animation-duration: 11.5s; animation-delay: 2.8s; }
.p9 { left: 80%; width: 5px; height: 5px; animation-duration: 9.5s; animation-delay: 4s; }
.p10 { left: 89%; width: 8px; height: 8px; animation-duration: 14s; animation-delay: 1.8s; }
.p11 { left: 95%; width: 4px; height: 4px; animation-duration: 8.5s; animation-delay: 3s; }
.p12 { left: 28%; width: 6px; height: 6px; animation-duration: 10.5s; animation-delay: 6s; }
.p13 { left: 66%; width: 5px; height: 5px; animation-duration: 9s; animation-delay: 1s; }

/* 顶部导航栏 */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 14, 39, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: #fff;
}

.logo-badge {
  background: var(--primary-gradient);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 900;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  box-shadow: 0 0 10px rgba(139, 92, 246, 0.5);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

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

.nav-links a:hover {
  color: var(--primary);
  text-shadow: 0 0 12px rgba(139, 92, 246, 0.6);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* ==========================================================================
   按钮规范：紫到红的渐变按钮，圆角 12px，带 30px 紫色辉光
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  min-height: 44px; /* 触控靶心规范不低于 44px */
  padding: 12px 24px;
  border-radius: var(--radius-btn); /* 严格 12px 圆角 */
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition);
  white-space: nowrap;
  text-align: center;
}

.btn-primary {
  background: var(--cta-gradient);
  color: #ffffff;
  border-radius: var(--radius-btn); /* 严格 12px 圆角 */
  box-shadow: var(--shadow-glow-purple); /* 严格 30px 紫色辉光 */
  border: none;
  position: relative;
  overflow: hidden;
}

.btn-primary::after {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.25), transparent);
  transition: 0.5s;
}

.btn-primary:hover {
  background: var(--cta-hover-gradient);
  box-shadow: 0 0 35px rgba(239, 68, 68, 0.7), 0 0 45px rgba(139, 92, 246, 0.85);
  transform: translateY(-2px);
}

.btn-primary:hover::after {
  left: 100%;
}

.btn-secondary {
  background: rgba(139, 92, 246, 0.1);
  color: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-btn);
}

.btn-secondary:hover {
  background: rgba(139, 92, 246, 0.2);
  border-color: rgba(239, 68, 68, 0.5);
  transform: translateY(-2px);
  box-shadow: 0 0 18px rgba(139, 92, 246, 0.35);
}

.btn-lg {
  padding: 15px 36px;
  font-size: 1.1rem;
}

.btn-block {
  width: 100%;
}

/* ==========================================================================
   主视觉区 (Hero) 与 3D Bloch 球右侧量子科技动画
   ========================================================================== */
.hero {
  padding: 70px 0 60px;
  position: relative;
  overflow: visible;
}

.hero-layout {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
}

.hero-main {
  flex: 1;
  max-width: 680px;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(139, 92, 246, 0.12);
  border: 1px solid rgba(139, 92, 246, 0.4);
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  color: var(--primary);
  margin-bottom: 22px;
  font-weight: 600;
  box-shadow: 0 0 15px rgba(139, 92, 246, 0.25);
}

.hero h1 {
  font-size: 3.2rem;
  line-height: 1.18;
  font-weight: 900;
  letter-spacing: -1px;
  margin-bottom: 20px;
}

.text-gradient {
  background: var(--quantum-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 25px rgba(239, 68, 68, 0.35));
}

.hero-desc {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 22px;
  line-height: 1.65;
}

.hero-intro {
  background: rgba(16, 22, 59, 0.65);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--secondary);
  border-radius: var(--radius-md);
  padding: 16px 22px;
  margin-bottom: 32px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.35);
}

.hero-summary {
  font-size: 0.96rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.hero-summary strong {
  color: var(--primary);
  font-weight: 700;
}

.hero-cta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 38px;
}

.hero-trust {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 24px;
  padding-top: 22px;
  border-top: 1px solid rgba(139, 92, 246, 0.16);
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.trust-item svg {
  color: var(--secondary);
  filter: drop-shadow(0 0 8px rgba(239, 68, 68, 0.6));
}

/* ==========================================================================
   【右侧动画】Bloch 球与量子态节点规范
   - 200px Bloch 球（半透明紫色径向渐变 + 紫色边框）
   - 3 个椭圆轨道（紫/红/紫，rotateX 70° 倾斜）
   - 3 个量子态节点（白色|0⟩ + 紫色|+⟩ + 红色|-⟩）沿椭圆轨道运行 4 秒一周期
   - 整体 Y 轴 3D 旋转 20 秒一周期
   - 2 层虚线圆轨道反向旋转
   ========================================================================== */
.bloch-stage {
  width: 360px;
  height: 360px;
  perspective: 1200px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  flex-shrink: 0;
  user-select: none;
}

/* 2层虚线圆轨道反向旋转 */
.dashed-orbit {
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
}

.dashed-orbit-1 {
  width: 320px;
  height: 320px;
  border: 1.5px dashed rgba(139, 92, 246, 0.45);
  animation: rotateDashedCW 15s linear infinite;
  box-shadow: 0 0 15px rgba(139, 92, 246, 0.2);
}

.dashed-orbit-2 {
  width: 350px;
  height: 350px;
  border: 1.5px dashed rgba(239, 68, 68, 0.45);
  animation: rotateDashedCCW 15s linear infinite;
  box-shadow: 0 0 15px rgba(239, 68, 68, 0.2);
}

@keyframes rotateDashedCW {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes rotateDashedCCW {
  0% { transform: rotate(360deg); }
  100% { transform: rotate(0deg); }
}

/* 整体 Y 轴 3D 旋转 20 秒一周期 */
.bloch-assembly {
  width: 200px;
  height: 200px;
  position: relative;
  transform-style: preserve-3d;
  animation: blochRotateY 20s linear infinite;
  display: flex;
  align-items: center;
  justify-content: center;
}

@keyframes blochRotateY {
  0% { transform: rotateY(0deg); }
  100% { transform: rotateY(360deg); }
}

/* 200px Bloch 球（半透明紫色径向渐变 + 紫色边框） */
.bloch-sphere {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, rgba(139, 92, 246, 0.5) 0%, rgba(139, 92, 246, 0.18) 55%, rgba(10, 14, 39, 0.85) 100%);
  border: 2px solid var(--primary);
  box-shadow: 0 0 35px rgba(139, 92, 246, 0.6), inset 0 0 25px rgba(139, 92, 246, 0.35);
  position: absolute;
  top: 0;
  left: 0;
}

/* 赤道与本初子午线经纬线修饰 */
.bloch-sphere::before {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  height: 1px;
  background: rgba(139, 92, 246, 0.45);
  transform: translateY(-50%);
}

.bloch-sphere::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background: rgba(139, 92, 246, 0.45);
  transform: translateX(-50%);
}

/* 3 个椭圆轨道（紫/红/紫，rotateX 70° 倾斜） */
.orbit-ellipse {
  position: absolute;
  width: 260px;
  height: 260px;
  border-radius: 50%;
  transform-style: preserve-3d;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 轨道 1：紫色 */
.orbit-1 {
  border: 1.8px solid var(--primary);
  transform: rotateX(70deg) rotateZ(0deg);
  box-shadow: 0 0 15px rgba(139, 92, 246, 0.5);
}

/* 轨道 2：红色 */
.orbit-2 {
  border: 1.8px solid var(--secondary);
  transform: rotateX(70deg) rotateZ(60deg);
  box-shadow: 0 0 15px rgba(239, 68, 68, 0.5);
}

/* 轨道 3：紫色 */
.orbit-3 {
  border: 1.8px solid var(--primary);
  transform: rotateX(70deg) rotateZ(120deg);
  box-shadow: 0 0 15px rgba(139, 92, 246, 0.5);
}

/* 3 个量子态节点（白色|0⟩ + 紫色|+⟩ + 红色|-⟩）沿椭圆轨道运行 4 秒一周期 */
.quantum-node-track {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  animation: orbitTrackRun 4s linear infinite;
  transform-style: preserve-3d;
}

@keyframes orbitTrackRun {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.node-quantum {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  font-size: 0.74rem;
  font-weight: 900;
  letter-spacing: 0.5px;
  white-space: nowrap;
  line-height: 1;
}

/* 节点 1：白色 |0⟩ */
.node-state-0 {
  background: #ffffff;
  color: #0A0E27;
  box-shadow: 0 0 15px #ffffff, 0 0 25px rgba(255, 255, 255, 0.8);
}

/* 节点 2：紫色 |+⟩ */
.node-state-plus {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 0 15px var(--primary), 0 0 25px rgba(139, 92, 246, 0.8);
}

/* 节点 3：红色 |-⟩ */
.node-state-minus {
  background: var(--secondary);
  color: #ffffff;
  box-shadow: 0 0 15px var(--secondary), 0 0 25px rgba(239, 68, 68, 0.85);
}

/* ==========================================================================
   通用板块与原有栅格布局（严格保持现有结构、栅格与组件位置）
   ========================================================================== */
.section {
  padding: 70px 0;
  position: relative;
  z-index: 1;
}

.section-title {
  text-align: center;
  margin-bottom: 50px;
}

.section-title span.badge {
  color: var(--secondary);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  display: block;
  margin-bottom: 8px;
  text-shadow: 0 0 10px rgba(239, 68, 68, 0.5);
}

.section-title h2 {
  font-size: 2.3rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-bottom: 12px;
}

.section-title p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 600px;
  margin: 0 auto;
}

/* 核心优势板块 (3个核心图文卡片) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.feature-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--primary-gradient);
  opacity: 0;
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-card), 0 0 20px rgba(139, 92, 246, 0.25);
  background: var(--bg-card-hover);
}

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

.feature-icon-box {
  width: 58px;
  height: 58px;
  background: rgba(139, 92, 246, 0.15);
  border: 1px solid rgba(139, 92, 246, 0.35);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  margin-bottom: 24px;
  box-shadow: 0 0 15px rgba(139, 92, 246, 0.2);
}

.feature-card h3 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 14px;
  color: #fff;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
  margin-bottom: 20px;
  flex-grow: 1;
}

.feature-highlights {
  list-style: none;
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.feature-highlights li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.88rem;
  color: var(--text-main);
}

.feature-highlights li svg {
  color: var(--secondary);
  flex-shrink: 0;
}

/* 流媒体与 AI 支持图卡 (4列栅格) */
.services-section {
  background: rgba(16, 22, 59, 0.45);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.service-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: var(--transition);
}

.service-card:hover {
  border-color: rgba(239, 68, 68, 0.5);
  transform: translateY(-3px);
  background: var(--bg-card-hover);
  box-shadow: 0 0 20px rgba(239, 68, 68, 0.2);
}

.service-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.service-badge {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  background: rgba(239, 68, 68, 0.15);
  color: var(--secondary);
  border: 1px solid rgba(239, 68, 68, 0.35);
}

.service-card h4 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: #fff;
}

.service-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.service-tag {
  background: rgba(139, 92, 246, 0.08);
  border: 1px solid var(--border-color);
  font-size: 0.78rem;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
}

/* 价格对比表 (3列栅格) */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition);
}

.pricing-card:hover {
  border-color: rgba(139, 92, 246, 0.5);
  transform: translateY(-4px);
  box-shadow: 0 0 25px rgba(139, 92, 246, 0.25);
}

.pricing-card.featured {
  background: linear-gradient(180deg, rgba(32, 28, 77, 0.95) 0%, rgba(16, 22, 59, 0.98) 100%);
  border: 2px solid var(--secondary);
  box-shadow: 0 0 35px rgba(239, 68, 68, 0.35);
  transform: scale(1.03);
  z-index: 2;
}

.pricing-card.featured:hover {
  transform: scale(1.04) translateY(-4px);
}

.popular-ribbon {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--cta-gradient);
  color: #ffffff;
  font-size: 0.76rem;
  font-weight: 800;
  padding: 4px 18px;
  border-radius: var(--radius-btn);
  letter-spacing: 1px;
  text-transform: uppercase;
  box-shadow: 0 4px 14px rgba(239, 68, 68, 0.5);
}

.plan-name {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 6px;
  color: #fff;
}

.plan-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 22px;
  min-height: 42px;
}

.plan-price {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.plan-price .currency {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--secondary);
}

.plan-price .amount {
  font-size: 3rem;
  font-weight: 900;
  line-height: 1;
  color: #fff;
}

.plan-price .period {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-left: 4px;
}

.plan-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 32px;
  flex-grow: 1;
}

.plan-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.92rem;
  color: var(--text-main);
}

.plan-features li svg {
  color: var(--primary);
  flex-shrink: 0;
}

.pricing-note {
  text-align: center;
  margin-top: 36px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* 用户评价 (3列栅格) */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: var(--gold);
  margin-bottom: 14px;
  font-size: 0.95rem;
  letter-spacing: 2px;
}

.review-text {
  font-size: 0.93rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 20px;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 12px;
  border-top: 1px solid var(--border-color);
  padding-top: 14px;
}

.avatar {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background: var(--primary-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: #fff;
  font-size: 0.9rem;
  box-shadow: 0 0 10px rgba(139, 92, 246, 0.4);
}

.user-info h5 {
  font-size: 0.92rem;
  color: #fff;
  font-weight: 600;
}

.user-info span {
  font-size: 0.78rem;
  color: var(--text-dim);
}

/* 常见问题 (FAQ 6项纯CSS折叠卡片) */
.faq-container {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.faq-item[open] {
  border-color: rgba(239, 68, 68, 0.5);
  background: var(--bg-card-hover);
  box-shadow: 0 0 18px rgba(139, 92, 246, 0.2);
}

.faq-question {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 600;
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  list-style: none;
}

.faq-question::-webkit-details-marker {
  display: none;
}

.faq-icon {
  width: 20px;
  height: 20px;
  color: var(--secondary);
  transition: transform 0.25s ease;
  flex-shrink: 0;
}

.faq-item[open] .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 24px 22px 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* CTA 横幅区 */
.cta-banner {
  background: linear-gradient(135deg, rgba(139, 92, 246, 0.18) 0%, rgba(239, 68, 68, 0.22) 100%);
  border: 1px solid var(--border-highlight);
  border-radius: var(--radius-lg);
  padding: 56px 40px;
  text-align: center;
  margin: 40px 0 80px;
  box-shadow: 0 0 35px rgba(139, 92, 246, 0.25);
}

.cta-banner h2 {
  font-size: 2.2rem;
  margin-bottom: 14px;
  font-weight: 800;
}

.cta-banner p {
  color: var(--text-muted);
  font-size: 1.08rem;
  max-width: 640px;
  margin: 0 auto 30px;
}

/* 页脚 Footer - 严格保留四个规定标题，打开新页面展示 */
.footer {
  background: #060918;
  border-top: 1px solid var(--border-color);
  padding: 50px 0 35px;
  margin-top: auto;
  position: relative;
  z-index: 1;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.footer-link {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 500;
  padding: 6px 14px;
  border-radius: var(--radius-btn);
  transition: var(--transition);
}

.footer-link:hover {
  color: #fff;
  background: rgba(139, 92, 246, 0.15);
  box-shadow: 0 0 15px rgba(139, 92, 246, 0.35);
}

.footer-bottom {
  text-align: center;
  border-top: 1px solid rgba(139, 92, 246, 0.12);
  padding-top: 24px;
  font-size: 0.85rem;
  color: var(--text-dim);
}

/* 子页面文章样式 */
.page-hero {
  padding: 60px 0 40px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
  background: rgba(16, 22, 59, 0.4);
}

.page-hero h1 {
  font-size: 2.6rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.page-hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 640px;
  margin: 0 auto;
}

.article-content {
  max-width: 860px;
  margin: 50px auto 80px;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 40px;
  margin-bottom: 30px;
  box-shadow: var(--shadow-card);
}

.article-card h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: #fff;
  display: flex;
  align-items: center;
  gap: 12px;
}

.article-card h2 svg {
  color: var(--secondary);
}

.article-card p {
  color: var(--text-muted);
  line-height: 1.75;
  font-size: 0.98rem;
  margin-bottom: 16px;
}

.article-card p:last-child {
  margin-bottom: 0;
}

.article-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 16px 0;
}

.article-list li {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
  padding-left: 20px;
  position: relative;
}

.article-list li::before {
  content: "•";
  position: absolute;
  left: 6px;
  color: var(--secondary);
  font-weight: bold;
}

.node-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 16px;
}

.node-item {
  background: rgba(139, 92, 246, 0.06);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 14px;
}

.node-item strong {
  color: #fff;
  display: block;
  font-size: 0.95rem;
  margin-bottom: 4px;
}

.node-item span {
  font-size: 0.8rem;
  color: var(--text-dim);
}

.sitemap-group {
  margin-bottom: 30px;
}

.sitemap-group h3 {
  font-size: 1.2rem;
  color: var(--primary);
  margin-bottom: 14px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
}

.sitemap-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

.sitemap-links a {
  background: rgba(139, 92, 246, 0.05);
  border: 1px solid var(--border-color);
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sitemap-links a:hover {
  border-color: var(--secondary);
  background: rgba(239, 68, 68, 0.08);
}

.sitemap-links a span.title {
  color: #fff;
  font-weight: 600;
  font-size: 0.95rem;
}

.sitemap-links a span.desc {
  color: var(--text-dim);
  font-size: 0.82rem;
}

/* ==========================================================================
   响应式媒体查询 (@media) - 保证手机端单栏优雅显示
   ========================================================================== */

@media (max-width: 1024px) {
  .hero-layout {
    flex-direction: column;
    text-align: center;
  }
  
  .hero-main {
    max-width: 100%;
  }
  
  .hero-cta {
    justify-content: center;
  }
  
  .hero-trust {
    justify-content: center;
  }
  
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 520px;
    margin: 0 auto;
  }
  
  .pricing-card.featured {
    transform: none;
  }
  
  .pricing-card.featured:hover {
    transform: translateY(-4px);
  }
  
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .header {
    padding: 10px 0;
  }
  
  .nav {
    flex-wrap: wrap;
    gap: 8px;
  }
  
  .nav-links {
    display: flex;
    order: 3;
    width: 100%;
    overflow-x: auto;
    white-space: nowrap;
    padding: 6px 0 2px;
    gap: 12px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  
  .nav-links::-webkit-scrollbar {
    display: none;
  }
  
  .nav-links a {
    font-size: 0.86rem;
    padding: 5px 12px;
    background: rgba(139, 92, 246, 0.1);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-btn);
  }
  
  .hero {
    padding: 40px 0 30px;
  }
  
  .hero h1 {
    font-size: 2.15rem;
    letter-spacing: -0.5px;
  }
  
  .hero-desc {
    font-size: 1rem;
  }
  
  .hero-cta {
    flex-direction: column;
    width: 100%;
    gap: 12px;
  }
  
  .hero-cta .btn {
    width: 100%;
    padding: 16px 20px; /* 大拇指触控高友好区 */
    font-size: 1.05rem;
  }
  
  .bloch-stage {
    width: 280px;
    height: 280px;
    transform: scale(0.82);
  }
  
  .features-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }
  
  .feature-card {
    padding: 26px 20px;
  }
  
  .services-grid {
    grid-template-columns: 1fr;
    gap: 14px;
  }
  
  .reviews-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  
  .cta-banner {
    padding: 36px 20px;
    margin: 30px 0 60px;
  }
  
  .cta-banner h2 {
    font-size: 1.65rem;
  }
  
  .cta-banner .btn {
    width: 100%;
    padding: 16px 20px;
  }
  
  .footer-nav {
    flex-direction: column;
    gap: 14px;
  }
  
  .footer-link {
    width: 100%;
    text-align: center;
    padding: 12px 16px;
    background: rgba(139, 92, 246, 0.08);
    border: 1px solid var(--border-color);
  }
  
  .node-grid {
    grid-template-columns: 1fr;
  }
  
  .sitemap-links {
    grid-template-columns: 1fr;
  }
  
  .article-card {
    padding: 24px 18px;
  }
}

/* ==========================================================================
   SEO 知识科普专栏文章系统样式
   ========================================================================== */
.seo-toc-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 30px;
  margin-bottom: 36px;
  box-shadow: var(--shadow-card);
}

.seo-toc-title {
  font-size: 1.3rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.seo-toc-title svg {
  color: var(--secondary);
}

.seo-toc-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.seo-toc-link {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  background: rgba(139, 92, 246, 0.06);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.45;
  transition: var(--transition);
}

.seo-toc-link:hover {
  background: rgba(239, 68, 68, 0.1);
  border-color: var(--border-highlight);
  color: #fff;
  transform: translateY(-2px);
}

.seo-toc-num {
  font-weight: 800;
  color: var(--primary);
  font-size: 0.85rem;
  background: rgba(139, 92, 246, 0.2);
  padding: 2px 6px;
  border-radius: 4px;
  flex-shrink: 0;
}

.seo-article {
  scroll-margin-top: 90px;
  position: relative;
}

.seo-article-header {
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.seo-meta-bar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 10px;
  font-size: 0.82rem;
  color: var(--text-dim);
}

.seo-badge-tag {
  background: rgba(139, 92, 246, 0.15);
  color: var(--primary);
  border: 1px solid rgba(139, 92, 246, 0.3);
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 600;
}

.seo-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 16px 0 20px;
}

.seo-kw {
  font-size: 0.76rem;
  padding: 3px 8px;
  border-radius: 4px;
  background: rgba(239, 68, 68, 0.1);
  color: var(--secondary);
  border: 1px solid rgba(239, 68, 68, 0.25);
}

.seo-internal-link {
  color: var(--primary);
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 4px;
  transition: var(--transition);
}

.seo-internal-link:hover {
  color: #ffffff;
  text-shadow: 0 0 10px var(--primary);
}

.seo-cta-inline {
  background: linear-gradient(135deg, rgba(139, 92, 246, 0.15) 0%, rgba(239, 68, 68, 0.15) 100%);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 18px 22px;
  margin-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

@media (max-width: 1024px) {
  .seo-toc-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .seo-toc-grid {
    grid-template-columns: 1fr;
  }
  .seo-cta-inline {
    flex-direction: column;
    align-items: stretch;
    text-align: center;
  }
}

/* ==========================================================================
   无障碍 (Accessibility) 与代码质量增强
   - 键盘焦点清晰指示 (:focus-visible)
   - 快速跳过导航 (Skip to Content)
   - 锚点滚动边距 (scroll-margin-top)
   - 遵循系统减弱动效 (prefers-reduced-motion)
   - 移动端 44x44px 触控靶心规范
   ========================================================================== */

/* 键盘焦点高亮样式 */
:focus-visible {
  outline: 2px solid var(--primary) !important;
  outline-offset: 3px !important;
}

/* 跳过导航快捷入口 */
.skip-link {
  position: absolute;
  top: -60px;
  left: 20px;
  background: var(--primary);
  color: #0A0E27;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.95rem;
  z-index: 9999;
  transition: top 0.2s ease-in-out;
  text-decoration: none;
  box-shadow: 0 4px 15px rgba(139, 92, 246, 0.6);
}

.skip-link:focus {
  top: 15px;
}

/* 固定页眉防遮挡锚点标题 */
[id] {
  scroll-margin-top: 85px;
}

/* 系统减弱动效适配 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  .quantum-particles {
    display: none !important;
  }
  
  .bloch-assembly,
  .dashed-orbit-1,
  .dashed-orbit-2,
  .quantum-node-track {
    animation: none !important;
  }
}

/* 移动端 44x44px 触控靶心规范强化 */
@media (max-width: 768px) {
  .nav-links a {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 8px 14px;
  }
  
  .footer-link {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }
}