/* ===================================================================
   SeeleCloud 希儿云 - 官方落地页专用原生核心样式库
   技术规范：纯原生 CSS3，零外部依赖，极速秒开，GPU 硬件加速渲染
   配色主调：希儿量子蓝紫（#00f2fe -> #38bdf8 -> #818cf8 -> #c084fc）
   =================================================================== */

:root {
  --bg-primary: #070a13;
  --bg-secondary: #0d1322;
  --bg-card: rgba(17, 24, 39, 0.75);
  --bg-card-hover: rgba(24, 34, 56, 0.85);
  --bg-glass: rgba(15, 23, 42, 0.65);
  
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(56, 189, 248, 0.4);
  --border-glow: rgba(168, 85, 247, 0.35);

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --accent-cyan: #00f2fe;
  --accent-blue: #38bdf8;
  --accent-purple: #818cf8;
  --accent-violet: #a855f7;
  --accent-fuchsia: #c084fc;
  --accent-green: #10b981;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;

  --gradient-brand: linear-gradient(135deg, #00f2fe 0%, #38bdf8 35%, #818cf8 70%, #c084fc 100%);
  --gradient-glow: linear-gradient(135deg, rgba(0, 242, 254, 0.15) 0%, rgba(168, 85, 247, 0.15) 100%);
  --gradient-btn: linear-gradient(135deg, #00d2fe 0%, #3b82f6 50%, #9333ea 100%);
  --gradient-btn-hover: linear-gradient(135deg, #38bdf8 0%, #60a5fa 50%, #a855f7 100%);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px -4px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 16px 40px -8px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 35px -5px rgba(56, 189, 248, 0.3);
  --shadow-glow-purple: 0 0 35px -5px rgba(168, 85, 247, 0.35);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --container-width: 1240px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --transition-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-normal: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

/* 基础重置与排版规范 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.65;
  letter-spacing: -0.01em;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  position: relative;
  overflow-x: hidden;
  background-color: var(--bg-primary);
  min-height: 100vh;
}

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

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

button, input {
  font-family: inherit;
  font-size: inherit;
}

/* 容器规范 */
.container {
  width: 100%;
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* 动态背景画布与粒子层 (Dynamic Background) */
#dynamic-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1; /* 保证在页面底色之上，内容文字之后，清晰可见 */
  pointer-events: none;
  opacity: 0.95;
}

.ambient-glow {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0; /* 在 body 背景上方，但在动态蝴蝶下方 */
  pointer-events: none;
  overflow: hidden;
}

.ambient-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.22;
  animation: floatAmbient 18s ease-in-out infinite alternate;
}

.ambient-blob-1 {
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, #00f2fe, #38bdf8);
  top: -150px;
  left: 10%;
  animation-duration: 22s;
}

.ambient-blob-2 {
  width: 650px;
  height: 650px;
  background: radial-gradient(circle, #8b5cf6, #c084fc);
  top: 35%;
  right: -100px;
  animation-duration: 26s;
  animation-delay: -5s;
}

.ambient-blob-3 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, #06b6d4, #6366f1);
  bottom: 5%;
  left: 5%;
  animation-duration: 20s;
  animation-delay: -10s;
}

@keyframes floatAmbient {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(60px, 40px) scale(1.08); }
  100% { transform: translate(-40px, 60px) scale(0.95); }
}

/* 网格科技底纹 */
.cyber-grid {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
  background-image: 
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 50px 50px;
  mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.85) 0%, transparent 80%);
}
  background-size: 50px 50px;
  mask-image: radial-gradient(ellipse at center, rgba(0,0,0,0.85) 0%, transparent 80%);
}

/* 顶部导航栏 (Navbar) */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7, 10, 19, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  transition: all var(--transition-normal);
}

.navbar.scrolled {
  background: rgba(7, 10, 19, 0.95);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 74px;
}

/* 品牌 Logo 规范 */
.brand-logo-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.brand-logo-img {
  height: 42px;
  width: auto;
  transition: transform var(--transition-fast);
}

.brand-logo-wrap:hover .brand-logo-img {
  transform: scale(1.02);
}

/* 导航链接 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-item-link {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-muted);
  position: relative;
  padding: 6px 0;
}

.nav-item-link:hover,
.nav-item-link.active {
  color: #ffffff;
}

.nav-item-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-brand);
  transition: width var(--transition-fast);
  border-radius: 2px;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 移动端菜单开关 */
.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-main);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

/* 呼吁性按钮规范 (CTA Buttons) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  border: 1px solid transparent;
  transition: all var(--transition-normal);
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background: var(--gradient-btn);
  color: #ffffff;
  box-shadow: 0 4px 15px rgba(56, 189, 248, 0.25);
}

.btn-primary:hover {
  background: var(--gradient-btn-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(56, 189, 248, 0.45);
  color: #ffffff;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: #ffffff;
  border-color: var(--border-subtle);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--accent-blue);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

.btn-glow {
  position: relative;
  overflow: hidden;
}

.btn-glow::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(60deg, transparent, rgba(255, 255, 255, 0.25), transparent);
  transform: rotate(30deg);
  animation: btnShine 4.5s infinite;
}

@keyframes btnShine {
  0% { transform: translateX(-100%) rotate(30deg); }
  25%, 100% { transform: translateX(100%) rotate(30deg); }
}

.btn-lg {
  padding: 14px 32px;
  font-size: 16px;
  border-radius: var(--radius-md);
}

.btn-block {
  width: 100%;
}

/* 渐变高亮文字 */
.gradient-text {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

/* 章节通用样式 */
.section-padding {
  position: relative;
  z-index: 2;
  padding: 90px 0;
}

.section-header {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 56px;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 14px;
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-blue);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.section-title {
  font-size: 38px;
  font-weight: 800;
  line-height: 1.25;
  color: #ffffff;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* 1. Hero 英雄区 */
.hero-section {
  position: relative;
  z-index: 2;
  padding: 80px 0 100px;
  text-align: center;
  overflow: hidden;
}

.hero-content {
  max-width: 920px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  background: rgba(129, 140, 248, 0.12);
  border: 1px solid rgba(129, 140, 248, 0.3);
  border-radius: var(--radius-full);
  font-size: 14px;
  font-weight: 500;
  color: #cbd5e1;
  margin-bottom: 24px;
}

.hero-badge .ping-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-cyan);
  box-shadow: 0 0 10px var(--accent-cyan);
  display: inline-block;
  animation: pulseDot 2s infinite;
}

@keyframes pulseDot {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.4); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

.hero-title {
  font-size: 52px;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  color: #ffffff;
}

.hero-subtitle {
  font-size: 18px;
  line-height: 1.75;
  color: var(--text-muted);
  margin-bottom: 38px;
  max-width: 820px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.hero-features-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  margin-top: 32px;
}

.hero-feat-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px 16px;
  text-align: center;
  transition: all var(--transition-normal);
}

.hero-feat-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

.hero-feat-val {
  font-size: 28px;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 4px;
}

.hero-feat-lbl {
  font-size: 13px;
  color: var(--text-muted);
}

/* 2. 特性优势区 (Features Section) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  position: relative;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.feature-card:hover {
  border-color: var(--border-glow);
  background: var(--bg-card-hover);
  transform: translateY(-6px);
  box-shadow: var(--shadow-glow-purple);
}

.feat-icon-box {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  color: var(--accent-cyan);
  margin-bottom: 22px;
}

.feature-card:nth-child(2) .feat-icon-box {
  background: rgba(168, 85, 247, 0.1);
  border-color: rgba(168, 85, 247, 0.25);
  color: var(--accent-fuchsia);
}

.feature-card:nth-child(3) .feat-icon-box {
  background: rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.25);
  color: var(--accent-green);
}

.feature-card:nth-child(4) .feat-icon-box {
  background: rgba(245, 158, 11, 0.1);
  border-color: rgba(245, 158, 11, 0.25);
  color: var(--accent-amber);
}

.feature-card:nth-child(5) .feat-icon-box {
  background: rgba(99, 102, 241, 0.1);
  border-color: rgba(99, 102, 241, 0.25);
  color: var(--accent-purple);
}

.feature-card:nth-child(6) .feat-icon-box {
  background: rgba(244, 63, 94, 0.1);
  border-color: rgba(244, 63, 94, 0.25);
  color: var(--accent-rose);
}

.feature-title {
  font-size: 20px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 12px;
}

.feature-text {
  font-size: 14.5px;
  color: var(--text-muted);
  line-height: 1.68;
}

/* 3. 价格专区：所有价格严格同排 (All Prices in Same Row) */
.pricing-section {
  background: linear-gradient(180deg, transparent 0%, rgba(13, 19, 34, 0.7) 50%, transparent 100%);
  position: relative;
}

.pricing-grid-same-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  align-items: stretch; /* 保证所有价格卡片在同排且高度 100% 一致 */
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: all var(--transition-normal);
  backdrop-filter: blur(14px);
}

.pricing-card:hover {
  transform: translateY(-8px);
  border-color: var(--border-focus);
  box-shadow: var(--shadow-lg);
}

/* 高光推荐热门套餐卡片 */
.pricing-card.featured {
  background: linear-gradient(180deg, rgba(30, 27, 75, 0.6) 0%, rgba(15, 23, 42, 0.95) 100%);
  border: 2px solid var(--accent-blue);
  box-shadow: 0 0 35px -5px rgba(56, 189, 248, 0.35);
  transform: scale(1.02);
}

.pricing-card.featured:hover {
  transform: scale(1.02) translateY(-8px);
  box-shadow: 0 0 45px -2px rgba(56, 189, 248, 0.5);
}

.pricing-badge-popular {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-brand);
  color: #050811;
  font-size: 12px;
  font-weight: 800;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(0, 242, 254, 0.4);
}

.plan-header {
  margin-bottom: 24px;
}

.plan-name {
  font-size: 22px;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 8px;
}

.plan-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  min-height: 42px;
}

.plan-price-wrap {
  margin: 18px 0;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-subtle);
}

.price-currency {
  font-size: 20px;
  font-weight: 700;
  color: var(--accent-cyan);
  vertical-align: super;
}

.price-amount {
  font-size: 44px;
  font-weight: 900;
  letter-spacing: -0.03em;
  color: #ffffff;
}

.price-period {
  font-size: 14px;
  color: var(--text-muted);
  font-weight: 500;
}

.plan-billing-detail {
  font-size: 12.5px;
  color: var(--accent-blue);
  background: rgba(56, 189, 248, 0.08);
  padding: 4px 8px;
  border-radius: 4px;
  display: inline-block;
  margin-top: 6px;
}

.plan-features-list {
  list-style: none;
  margin-bottom: 30px;
  flex-grow: 1;
}

.plan-feature-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 13.5px;
  color: #cbd5e1;
  margin-bottom: 12px;
  line-height: 1.5;
}

.plan-feature-item strong {
  color: #ffffff;
}

.feature-check {
  color: var(--accent-cyan);
  font-weight: bold;
  font-size: 14px;
  flex-shrink: 0;
  margin-top: 1px;
}

.plan-btn-wrap {
  margin-top: auto; /* 保证同排按钮全部在底部基线对齐 */
}

/* 4. 流媒体与 AI 解锁专区 */
.unlock-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.unlock-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
  transition: all var(--transition-normal);
}

.unlock-card:hover {
  border-color: var(--accent-purple);
  transform: translateY(-4px);
}

.unlock-icon {
  font-size: 36px;
  margin-bottom: 14px;
}

.unlock-title {
  font-size: 17px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 8px;
}

.unlock-desc {
  font-size: 13px;
  color: var(--text-muted);
}

/* 5. 客户端支持矩阵 (Clients) */
.client-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
}

.client-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px 16px;
  text-align: center;
  transition: all var(--transition-normal);
}

.client-card:hover {
  border-color: var(--accent-blue);
  background: var(--bg-card-hover);
  transform: translateY(-4px);
}

.client-icon {
  font-size: 32px;
  margin-bottom: 12px;
}

.client-name {
  font-size: 16px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 6px;
}

.client-tags {
  font-size: 12px;
  color: var(--text-muted);
}

/* 6. 文章与知识库列表 (Articles Preview) */
.articles-preview-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.article-preview-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-normal);
  text-decoration: none;
}

.article-preview-card:hover {
  border-color: var(--accent-cyan);
  background: var(--bg-card-hover);
  transform: translateY(-6px);
  box-shadow: var(--shadow-glow);
}

.art-badge-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
}

.art-badge {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent-blue);
  background: rgba(56, 189, 248, 0.1);
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.art-date {
  font-size: 12px;
  color: var(--text-dim);
}

.art-title {
  font-size: 18px;
  font-weight: 700;
  color: #ffffff;
  line-height: 1.45;
  margin-bottom: 12px;
  transition: color var(--transition-fast);
}

.article-preview-card:hover .art-title {
  color: var(--accent-cyan);
}

.art-summary {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

.art-readmore {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent-blue);
}

.art-readmore span {
  transition: transform var(--transition-fast);
}

.article-preview-card:hover .art-readmore span {
  transform: translateX(4px);
}

/* 7. 用户真实评价区 (User Reviews) */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 30px;
  position: relative;
  transition: all var(--transition-normal);
}

.review-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-4px);
}

.review-stars {
  color: #facc15;
  font-size: 16px;
  margin-bottom: 14px;
  letter-spacing: 2px;
}

.review-quote {
  font-size: 14.5px;
  color: #e2e8f0;
  line-height: 1.7;
  margin-bottom: 22px;
  font-style: normal;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 14px;
  border-top: 1px solid var(--border-subtle);
  padding-top: 16px;
}

.author-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-violet));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 700;
  color: #ffffff;
}

.author-info h4 {
  font-size: 15px;
  font-weight: 700;
  color: #ffffff;
}

.author-info p {
  font-size: 12.5px;
  color: var(--text-dim);
}

/* 8. 常见问题 FAQ 手风琴 (FAQ Accordion) */
.faq-wrap {
  max-width: 860px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  margin-bottom: 16px;
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item:hover {
  border-color: var(--border-focus);
}

.faq-question {
  width: 100%;
  text-align: left;
  background: transparent;
  border: none;
  padding: 22px 26px;
  font-size: 17px;
  font-weight: 600;
  color: #ffffff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.faq-icon {
  font-size: 20px;
  color: var(--accent-cyan);
  transition: transform var(--transition-normal);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
  color: var(--accent-violet);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 26px;
  color: var(--text-muted);
  font-size: 15px;
  line-height: 1.75;
}

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 26px 24px;
}

.faq-answer p {
  margin-bottom: 12px;
}

.faq-answer p:last-child {
  margin-bottom: 0;
}

/* 9. 底部行动呼吁横幅 (Bottom Banner) */
.cta-banner {
  background: linear-gradient(135deg, rgba(30, 27, 75, 0.8) 0%, rgba(15, 23, 42, 0.95) 100%);
  border: 1px solid rgba(56, 189, 248, 0.3);
  border-radius: var(--radius-lg);
  padding: 56px 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: 0 0 50px -10px rgba(56, 189, 248, 0.2);
}

.cta-banner::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-brand);
}

.cta-banner h2 {
  font-size: 34px;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 16px;
}

.cta-banner p {
  font-size: 16px;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 32px;
}

/* 10. 页脚与外链规范 (Footer) */
.footer {
  position: relative;
  z-index: 2;
  background: #040711;
  border-top: 1px solid var(--border-subtle);
  padding: 70px 0 35px;
  color: var(--text-muted);
  font-size: 14px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-brand p {
  margin-top: 16px;
  line-height: 1.7;
  max-width: 340px;
  font-size: 13.5px;
}

.footer-col-title {
  font-size: 16px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 20px;
  letter-spacing: 0.02em;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 12px;
}

.footer-links a:hover {
  color: var(--accent-cyan);
}

.footer-external-list {
  list-style: none;
}

.footer-external-list li {
  margin-bottom: 10px;
}

.footer-external-list a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  font-size: 13px;
}

.footer-external-list a:hover {
  color: var(--accent-blue);
}

.footer-bottom {
  border-top: 1px solid var(--border-subtle);
  padding-top: 30px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 13px;
  color: var(--text-dim);
}

/* 回到顶部浮动按钮 */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 46px;
  height: 46px;
  background: rgba(17, 24, 39, 0.85);
  border: 1px solid var(--border-subtle);
  color: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 90;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  backdrop-filter: blur(8px);
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

/* 响应式媒体查询 (Responsive) */
@media (max-width: 1200px) {
  .pricing-grid-same-row {
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
  }
  .pricing-card {
    padding: 24px 18px;
  }
  .price-amount {
    font-size: 38px;
  }
}

@media (max-width: 992px) {
  .hero-title {
    font-size: 40px;
  }
  .hero-features-bar {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  /* 平板端 2x2 保持同排整洁 */
  .pricing-grid-same-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }
  .unlock-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .client-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .articles-preview-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
    position: absolute;
    top: 74px;
    left: 0;
    width: 100%;
    background: rgba(7, 10, 19, 0.98);
    border-bottom: 1px solid var(--border-subtle);
    padding: 24px;
    flex-direction: column;
    gap: 18px;
  }
  .nav-menu.open {
    display: flex;
  }
  .nav-toggle {
    display: block;
  }
  .hero-title {
    font-size: 32px;
  }
  .hero-subtitle {
    font-size: 15px;
  }
  .section-title {
    font-size: 28px;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .pricing-grid-same-row {
    grid-template-columns: 1fr;
  }
  .unlock-grid {
    grid-template-columns: 1fr;
  }
  .client-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .articles-preview-grid {
    grid-template-columns: 1fr;
  }
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}