/* ==========================================================================
   耶耶云 (YeYe Cloud) - 温暖亲和生活化科技设计系统 (Lifestyle Tech UI)
   色调：蔚蓝天空 (#0284C7) | 纯净清风蓝 (#E0F2FE) | 云朵纯白 (#FFFFFF) | 暖阳金菊黄 (#F59E0B)
   设计语言：人体工学柔和圆角 (rounded-3xl) | 微笑弧线 (Smile Curves) | 有机弹性微动效
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. 设计变量与主题色盘
   -------------------------------------------------------------------------- */
:root {
  /* 品牌核心主色 - 蔚蓝晴空 */
  --sky-primary: #0284c7;
  --sky-hover: #0369a1;
  --sky-deep: #075985;
  --sky-light: #e0f2fe;
  --sky-ultralight: #f0f9ff;
  --sky-glow: rgba(2, 132, 199, 0.18);

  /* 暖阳金菊黄 (活跃状态、网络信号与高亮) */
  --marigold: #f59e0b;
  --marigold-hover: #d97706;
  --marigold-light: #fef3c7;
  --marigold-glow: rgba(245, 158, 11, 0.25);

  /* 状态色 */
  --status-green: #10b981;
  --status-green-glow: rgba(16, 185, 129, 0.28);

  /* 白天模式 (默认) */
  --bg-body: #f8fafc;
  --bg-surface: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f0f9ff;
  --bg-alt: #f0f9ff;
  --bg-header: rgba(255, 255, 255, 0.88);

  --text-main: #0f172a;
  --text-sub: #334155;
  --text-muted: #64748b;
  --text-inverse: #ffffff;

  --border-color: #e2e8f0;
  --border-light: #f1f5f9;
  --border-sky: #bae6fd;

  --accent-gradient: linear-gradient(135deg, #0284c7 0%, #38bdf8 100%);
  --warm-gradient: linear-gradient(135deg, #f59e0b 0%, #fbbf24 100%);
  --card-gradient: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);

  /* 人体工学柔和圆角 */
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 22px;
  --radius-2xl: 28px;
  --radius-3xl: 36px;
  --radius-full: 9999px;

  /* 柔和阴影系统 */
  --shadow-sm: 0 2px 4px rgba(2, 132, 199, 0.04);
  --shadow-md: 0 8px 20px -4px rgba(2, 132, 199, 0.08), 0 4px 6px -2px rgba(15, 23, 42, 0.03);
  --shadow-lg: 0 16px 32px -8px rgba(2, 132, 199, 0.12), 0 6px 12px -4px rgba(15, 23, 42, 0.04);
  --shadow-xl: 0 24px 48px -12px rgba(2, 132, 199, 0.16), 0 12px 20px -6px rgba(15, 23, 42, 0.05);

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --transition-smooth: all 0.28s cubic-bezier(0.34, 1.56, 0.64, 1);
  --theme-transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

/* 暗黑模式 (沉稳星空夜蓝) */
[data-theme="dark"] {
  --bg-body: #070d1e;
  --bg-surface: #0c152e;
  --bg-card: #0f1c3d;
  --bg-card-hover: #14244d;
  --bg-alt: #0a1126;
  --bg-header: rgba(7, 13, 30, 0.88);

  --text-main: #f8fafc;
  --text-sub: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #070d1e;

  --border-color: #1e2e54;
  --border-light: #162445;
  --border-sky: #0369a1;

  --sky-light: rgba(2, 132, 199, 0.18);
  --sky-ultralight: rgba(2, 132, 199, 0.08);
  --marigold-light: rgba(245, 158, 11, 0.18);

  --card-gradient: linear-gradient(180deg, #0f1c3d 0%, #0a1329 100%);
  --shadow-sm: 0 2px 6px rgba(0, 0, 0, 0.35);
  --shadow-md: 0 10px 24px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 18px 36px rgba(0, 0, 0, 0.55);
  --shadow-xl: 0 28px 56px rgba(0, 0, 0, 0.65);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 86px;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-body);
  color: var(--text-main);
  line-height: 1.65;
  transition: var(--theme-transition);
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  transition: var(--transition-smooth);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 90px 0;
  position: relative;
}

.section-alt {
  background-color: var(--bg-alt);
}

/* 微笑弧线装饰分隔线 (Smile Curve Divider) */
.smile-curve-divider {
  width: 100%;
  overflow: hidden;
  line-height: 0;
  transform: translateZ(0);
}

.smile-curve-divider svg {
  display: block;
  width: 100%;
  height: 48px;
}

.smile-curve-divider path {
  fill: var(--bg-alt);
  transition: fill 0.3s ease;
}

.smile-curve-divider.reverse path {
  fill: var(--bg-body);
}

/* 标题徽章与头部 */
.section-header {
  text-align: center;
  max-width: 740px;
  margin: 0 auto 56px;
}

.badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 18px;
  font-size: 0.88rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  background: var(--sky-light);
  color: var(--sky-primary);
  border: 1px solid var(--border-sky);
  margin-bottom: 18px;
  letter-spacing: 0.3px;
}

.badge-pill .pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--marigold);
  box-shadow: 0 0 0 0 rgba(245, 158, 11, 0.6);
  animation: marigoldPulse 2s infinite;
}

@keyframes marigoldPulse {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(245, 158, 11, 0.7); }
  70% { transform: scale(1.1); box-shadow: 0 0 0 8px rgba(245, 158, 11, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(245, 158, 11, 0); }
}

.section-title {
  font-size: 2.45rem;
  font-weight: 850;
  line-height: 1.25;
  color: var(--text-main);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.section-title .gradient-text {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-desc {
  font-size: 1.12rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* --------------------------------------------------------------------------
   3. 导航栏 (Navbar) - 严格防止文字折行与挤压错位
   -------------------------------------------------------------------------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-header);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--theme-transition);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
  gap: 16px;
  max-width: 1320px;
}

/* 品牌 Logo - 绝对不换行 */
.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 850;
  color: var(--text-main);
  white-space: nowrap;
  flex-shrink: 0;
}

.brand-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 4px 14px var(--sky-glow);
  flex-shrink: 0;
}

.brand-icon svg {
  width: 24px;
  height: 24px;
}

/* 导航链接目录 - 绝对不换行，紧凑舒适排版 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: nowrap;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-sub);
  position: relative;
  padding: 6px 10px;
  border-radius: var(--radius-full);
  white-space: nowrap;
  flex-shrink: 0;
}

.nav-link:hover {
  color: var(--sky-primary);
  background-color: var(--sky-light);
}

.nav-link.active {
  color: var(--sky-primary);
  font-weight: 700;
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 18px;
  height: 3px;
  background: var(--marigold);
  border-radius: var(--radius-full);
}

/* 推荐资讯特别高亮徽章 */
.nav-badge-new {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: var(--radius-full);
  background: var(--marigold);
  color: #ffffff;
  margin-left: 4px;
  vertical-align: middle;
}

/* 桌面端严禁显示移动端抽屉 CTA (彻底解决两个‘立即开通’重复显示的问题) */
.mobile-cta {
  display: none !important;
}

/* 导航操作区 - 绝对不换行与挤压 */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  white-space: nowrap;
}

/* 昼夜模式切换按钮 - 半透明毛玻璃质感，自然过渡，无粗糙Emoji */
.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: var(--transition-smooth);
  flex-shrink: 0;
}

.theme-toggle-btn:hover {
  background: var(--sky-light);
  border-color: var(--sky-primary);
  transform: scale(1.06);
}

.theme-icon-sun, .theme-icon-moon {
  width: 20px;
  height: 20px;
  position: absolute;
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.3s ease;
}

.theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: var(--marigold);
}

.theme-icon-moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.2);
  color: var(--sky-primary);
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.2);
}

[data-theme="dark"] .theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.mobile-menu-btn {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--text-main);
  background: var(--sky-light);
  border: 1px solid var(--border-sky);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   4. 按钮规范 & 弹性互动微动效 (Spring-scale bounce)
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 26px;
  font-size: 0.98rem;
  font-weight: 650;
  border-radius: var(--radius-2xl);
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.35s ease, background-color 0.2s ease;
  text-align: center;
  white-space: nowrap;
  min-height: 46px;
  position: relative;
}

/* 主 CTA 悬浮弹性跳跃 + 微笑曲线高亮 */
.btn-primary {
  background: var(--accent-gradient);
  color: #ffffff !important;
  box-shadow: 0 6px 18px var(--sky-glow);
}

.btn-primary::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 20%;
  width: 60%;
  height: 3px;
  background: var(--marigold);
  border-radius: var(--radius-full);
  opacity: 0;
  transform: translateY(4px) scaleX(0.5);
  transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.btn-primary:hover {
  transform: scale(1.05) translateY(-3px);
  box-shadow: 0 12px 28px rgba(2, 132, 199, 0.35);
}

.btn-primary:hover::after {
  opacity: 1;
  transform: translateY(0) scaleX(1);
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-main);
  border: 1.5px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  background: var(--sky-light);
  border-color: var(--sky-primary);
  color: var(--sky-primary);
  transform: translateY(-2px);
}

.btn-marigold {
  background: var(--warm-gradient);
  color: #ffffff !important;
  box-shadow: 0 6px 18px var(--marigold-glow);
}

.btn-marigold:hover {
  transform: scale(1.04) translateY(-2px);
  box-shadow: 0 10px 24px rgba(245, 158, 11, 0.4);
}

.btn-lg {
  padding: 15px 34px;
  font-size: 1.08rem;
  border-radius: var(--radius-3xl);
  min-height: 52px;
}

.btn-block {
  width: 100%;
}

/* --------------------------------------------------------------------------
   5. 主视觉 Hero 区域 (含品牌大标题、平台卡片堆叠与微笑弧线)
   -------------------------------------------------------------------------- */
.hero-section {
  padding: 80px 0 60px;
  position: relative;
  overflow: hidden;
  background: radial-gradient(circle at 50% 20%, var(--sky-light) 0%, transparent 70%);
}

.hero-content {
  text-align: center;
  max-width: 880px;
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

.hero-title {
  font-size: 3.4rem;
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-main);
  margin-bottom: 22px;
}

.hero-subtitle {
  font-size: 1.26rem;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 38px;
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  margin-bottom: 50px;
  flex-wrap: wrap;
}

/* 多平台堆叠卡片 (Mac, Windows, iOS, Android) */
.platform-stack-card {
  background: var(--bg-surface);
  border: 1.5px solid var(--border-sky);
  border-radius: var(--radius-3xl);
  padding: 30px 36px;
  box-shadow: var(--shadow-xl);
  max-width: 960px;
  margin: 0 auto;
  animation: breathingPulse 5s ease-in-out infinite alternate;
}

@keyframes breathingPulse {
  0% { transform: translateY(0); box-shadow: 0 16px 32px -8px rgba(2, 132, 199, 0.12); }
  100% { transform: translateY(-6px); box-shadow: 0 24px 48px -12px rgba(2, 132, 199, 0.22); }
}

.platform-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 22px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  flex-wrap: wrap;
  gap: 12px;
}

.platform-status-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  font-weight: 650;
  color: var(--text-sub);
}

.live-twinkle-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--status-green);
  box-shadow: 0 0 10px var(--status-green);
  animation: twinkleLive 1.8s infinite;
}

@keyframes twinkleLive {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.8); }
}

.platform-chips-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.platform-chip {
  background: var(--sky-ultralight);
  border: 1px solid var(--border-sky);
  border-radius: var(--radius-2xl);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  transition: var(--transition-smooth);
}

.platform-chip:hover {
  background: var(--sky-light);
  transform: translateY(-4px) scale(1.02);
  border-color: var(--sky-primary);
}

.platform-chip-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: #ffffff;
  color: var(--sky-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
  box-shadow: var(--shadow-sm);
}

[data-theme="dark"] .platform-chip-icon {
  background: #0f1c3d;
}

.platform-chip-name {
  font-size: 0.96rem;
  font-weight: 750;
  color: var(--text-main);
  margin-bottom: 2px;
}

.platform-chip-ping {
  font-size: 0.82rem;
  color: var(--status-green);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 4px;
}

.meter-bars {
  display: inline-flex;
  align-items: flex-end;
  gap: 2px;
  height: 12px;
}

.meter-bar {
  width: 3px;
  background: var(--status-green);
  border-radius: 1px;
}

/* 信任指标栏 (Trust Indicators) */
.trust-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 40px;
}

.trust-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 18px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-sm);
}

.trust-number {
  font-size: 1.8rem;
  font-weight: 850;
  color: var(--sky-primary);
  line-height: 1.1;
  margin-bottom: 4px;
}

.trust-label {
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 550;
}

/* --------------------------------------------------------------------------
   6. 产品核心优势 (3个图文卡片 - 人体工学大圆角 rounded-3xl)
   -------------------------------------------------------------------------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.feature-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-3xl);
  padding: 40px 32px;
  transition: var(--transition-smooth);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.feature-card:hover {
  transform: translateY(-8px);
  border-color: var(--sky-primary);
  box-shadow: var(--shadow-xl);
}

.feature-icon-wrapper {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-2xl);
  background: var(--sky-light);
  color: var(--sky-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  transition: var(--transition-smooth);
}

.feature-card:hover .feature-icon-wrapper {
  transform: scale(1.1) rotate(-3deg);
  background: var(--accent-gradient);
  color: #ffffff;
}

.feature-icon-wrapper svg {
  width: 32px;
  height: 32px;
}

.feature-title {
  font-size: 1.38rem;
  font-weight: 800;
  margin-bottom: 14px;
  color: var(--text-main);
}

.feature-desc {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.75;
  flex-grow: 1;
}

.feature-meter-row {
  margin-top: 24px;
  padding-top: 18px;
  border-top: 1px dashed var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.meter-label {
  font-size: 0.84rem;
  color: var(--text-sub);
  font-weight: 600;
}

.meter-value-tag {
  font-size: 0.84rem;
  font-weight: 750;
  color: var(--marigold);
  background: var(--marigold-light);
  padding: 4px 10px;
  border-radius: var(--radius-full);
}

/* --------------------------------------------------------------------------
   7. 专项能力图卡 (流媒体图卡 & AI支持图卡)
   -------------------------------------------------------------------------- */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.showcase-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-3xl);
  padding: 42px 36px;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
}

.showcase-card:hover {
  transform: translateY(-6px);
  border-color: var(--sky-primary);
  box-shadow: var(--shadow-xl);
}

.showcase-header {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-bottom: 20px;
}

.showcase-icon-badge {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-2xl);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  flex-shrink: 0;
}

.icon-streaming {
  background: linear-gradient(135deg, #0284c7 0%, #06b6d4 100%);
  box-shadow: 0 4px 16px rgba(2, 132, 199, 0.3);
}

.icon-ai {
  background: linear-gradient(135deg, #0284c7 0%, #10b981 100%);
  box-shadow: 0 4px 16px rgba(16, 185, 129, 0.3);
}

.showcase-icon-badge svg {
  width: 28px;
  height: 28px;
}

.showcase-card-title {
  font-size: 1.55rem;
  font-weight: 800;
  color: var(--text-main);
}

.showcase-desc {
  font-size: 1.02rem;
  color: var(--text-muted);
  line-height: 1.75;
  margin-bottom: 26px;
}

.app-chips-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 28px;
}

.app-chip {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 14px;
  background: var(--sky-ultralight);
  border: 1px solid var(--border-sky);
  border-radius: var(--radius-xl);
  font-size: 0.9rem;
  font-weight: 650;
  color: var(--text-main);
  transition: var(--transition-smooth);
}

.app-chip:hover {
  background: var(--sky-light);
  transform: translateY(-2px);
  border-color: var(--sky-primary);
}

.chip-status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--marigold);
  box-shadow: 0 0 6px var(--marigold);
}

.showcase-features-list {
  margin-top: auto;
  border-top: 1px dashed var(--border-color);
  padding-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.showcase-features-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.94rem;
  color: var(--text-sub);
}

.showcase-features-list li svg {
  width: 18px;
  height: 18px;
  color: var(--status-green);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   8. 互动特色功能：智能带宽与使用场景拱桥滑动测算器 (Bandwidth Arch Slider)
   -------------------------------------------------------------------------- */
.calculator-card {
  background: var(--bg-surface);
  border: 1.5px solid var(--border-sky);
  border-radius: var(--radius-3xl);
  padding: 48px 40px;
  box-shadow: var(--shadow-xl);
  max-width: 900px;
  margin: 0 auto;
}

.slider-container {
  margin: 36px 0;
  position: relative;
}

.slider-arch-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 20px;
}

.slider-tier-name {
  font-size: 1.7rem;
  font-weight: 850;
  color: var(--sky-primary);
}

.slider-speed-badge {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--marigold);
  background: var(--marigold-light);
  padding: 6px 18px;
  border-radius: var(--radius-full);
}

/* 原生定制柔和滑杆 */
.arch-range-slider {
  -webkit-appearance: none;
  width: 100%;
  height: 14px;
  border-radius: var(--radius-full);
  background: var(--sky-light);
  outline: none;
  transition: background 0.3s ease;
  cursor: pointer;
}

.arch-range-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: #ffffff;
  border: 4px solid var(--sky-primary);
  box-shadow: 0 4px 12px var(--sky-glow);
  cursor: pointer;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.arch-range-slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
  border-color: var(--marigold);
}

.arch-range-slider::-moz-range-thumb {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: #ffffff;
  border: 4px solid var(--sky-primary);
  box-shadow: 0 4px 12px var(--sky-glow);
  cursor: pointer;
}

.slider-tiers-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 14px;
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 600;
}

.calculator-result-box {
  background: var(--sky-ultralight);
  border: 1px solid var(--border-sky);
  border-radius: var(--radius-2xl);
  padding: 24px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.result-desc-text {
  font-size: 1rem;
  color: var(--text-sub);
  line-height: 1.6;
  max-width: 520px;
}

/* --------------------------------------------------------------------------
   9. 套餐价格对比表 (参考网上真实套餐价格)
   -------------------------------------------------------------------------- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-3xl);
  padding: 42px 32px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-md);
}

.pricing-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
}

.pricing-card.featured {
  border: 2.5px solid var(--sky-primary);
  background: var(--bg-surface);
  box-shadow: 0 16px 36px var(--sky-glow);
  transform: scale(1.02);
}

.pricing-card.featured:hover {
  transform: scale(1.02) translateY(-8px);
}

.featured-ribbon {
  position: absolute;
  top: -15px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--warm-gradient);
  color: #ffffff;
  font-size: 0.82rem;
  font-weight: 750;
  padding: 5px 20px;
  border-radius: var(--radius-full);
  letter-spacing: 0.5px;
  box-shadow: 0 4px 12px var(--marigold-glow);
}

.pricing-header {
  text-align: center;
  margin-bottom: 22px;
}

.plan-name {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 8px;
}

.plan-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.price-box {
  display: flex;
  align-items: baseline;
  justify-content: center;
  margin: 18px 0;
}

.currency {
  font-size: 1.5rem;
  font-weight: 750;
  color: var(--sky-primary);
  margin-right: 2px;
}

.price-amount {
  font-size: 3.3rem;
  font-weight: 900;
  color: var(--text-main);
  line-height: 1;
}

.price-cycle {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-left: 6px;
}

.price-market-hint {
  font-size: 0.82rem;
  color: var(--marigold);
  font-weight: 600;
  background: var(--marigold-light);
  display: inline-block;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  margin-top: 6px;
}

.pricing-divider {
  height: 1px;
  background: var(--border-color);
  margin: 16px 0 24px;
}

.pricing-features {
  flex-grow: 1;
  margin-bottom: 32px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.pricing-feature-item {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.95rem;
  color: var(--text-sub);
}

.pricing-feature-item svg {
  width: 18px;
  height: 18px;
  color: var(--status-green);
  flex-shrink: 0;
}

.pricing-feature-item.disabled {
  color: var(--text-muted);
  text-decoration: line-through;
  opacity: 0.55;
}

.pricing-feature-item.disabled svg {
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   10. 用户评价 (Testimonials)
   -------------------------------------------------------------------------- */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.testimonial-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-3xl);
  padding: 34px 30px;
  display: flex;
  flex-direction: column;
  transition: var(--transition-smooth);
  box-shadow: var(--shadow-sm);
}

.testimonial-card:hover {
  transform: translateY(-6px);
  border-color: var(--sky-primary);
  box-shadow: var(--shadow-lg);
}

.star-rating {
  display: flex;
  gap: 5px;
  color: var(--marigold);
  margin-bottom: 16px;
}

.star-rating svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

.testimonial-quote {
  font-size: 1rem;
  color: var(--text-sub);
  line-height: 1.75;
  font-style: normal;
  margin-bottom: 24px;
  flex-grow: 1;
}

.user-profile {
  display: flex;
  align-items: center;
  gap: 14px;
  border-top: 1px solid var(--border-color);
  padding-top: 18px;
}

.user-avatar {
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--accent-gradient);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 750;
  font-size: 1.15rem;
  flex-shrink: 0;
}

.user-meta {
  display: flex;
  flex-direction: column;
}

.user-name {
  font-weight: 750;
  font-size: 0.98rem;
  color: var(--text-main);
}

.user-tagline {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   11. 常见问题解答 (FAQ) - 有机弹性曲线展开 (Organic Spring Curves)
   -------------------------------------------------------------------------- */
.faq-container {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.faq-item {
  background: var(--bg-card);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-2xl);
  overflow: hidden;
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

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

.faq-item.active {
  border-color: var(--sky-primary);
  box-shadow: 0 8px 24px var(--sky-glow);
}

.faq-question {
  width: 100%;
  text-align: left;
  padding: 22px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  font-size: 1.08rem;
  font-weight: 650;
  color: var(--text-main);
  background: none;
  cursor: pointer;
}

.faq-toggle-icon {
  width: 24px;
  height: 24px;
  color: var(--sky-primary);
  transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
  flex-shrink: 0;
}

.faq-item.active .faq-toggle-icon {
  transform: rotate(180deg);
  color: var(--marigold);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.45s cubic-bezier(0.34, 1.56, 0.64, 1), padding 0.3s ease;
  padding: 0 28px;
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.85;
}

.faq-item.active .faq-answer {
  max-height: 400px;
  padding: 0 28px 24px;
}

/* --------------------------------------------------------------------------
   12. 终极行动横幅 (CTA Banner)
   -------------------------------------------------------------------------- */
.cta-banner {
  background: var(--accent-gradient);
  border-radius: var(--radius-3xl);
  padding: 64px 44px;
  text-align: center;
  color: #ffffff;
  position: relative;
  overflow: hidden;
  box-shadow: 0 24px 48px var(--sky-glow);
}

.cta-banner-title {
  font-size: 2.35rem;
  font-weight: 850;
  margin-bottom: 16px;
}

.cta-banner-desc {
  font-size: 1.15rem;
  opacity: 0.95;
  max-width: 640px;
  margin: 0 auto 34px;
}

.cta-banner .btn-cta-white {
  background: #ffffff;
  color: var(--sky-primary) !important;
  font-weight: 750;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.12);
}

.cta-banner .btn-cta-white:hover {
  transform: scale(1.05) translateY(-3px);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.2);
}

/* --------------------------------------------------------------------------
   13. 页脚 (Footer) - 严格遵循“只保留四个标题”规范
   -------------------------------------------------------------------------- */
.footer {
  margin-top: auto;
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 50px 0 38px;
  transition: var(--theme-transition);
}

.footer-nav {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 52px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.footer-nav-link {
  font-size: 1.05rem;
  font-weight: 650;
  color: var(--text-sub);
  position: relative;
  padding: 8px 12px;
  border-radius: var(--radius-full);
}

.footer-nav-link:hover {
  color: var(--sky-primary);
  background-color: var(--sky-light);
}

.footer-copyright {
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 24px;
}

/* --------------------------------------------------------------------------
   14. 子页面与推荐资讯专属排版 (Article & Insights)
   -------------------------------------------------------------------------- */
.page-header {
  padding: 64px 0 44px;
  background: var(--bg-alt);
  border-bottom: 1px solid var(--border-color);
  text-align: center;
}

.page-title {
  font-size: 2.5rem;
  font-weight: 850;
  color: var(--text-main);
  margin-bottom: 12px;
}

.page-subtitle {
  font-size: 1.08rem;
  color: var(--text-muted);
  max-width: 640px;
  margin: 0 auto;
}

.article-content {
  max-width: 880px;
  margin: 50px auto 80px;
  background: var(--bg-card);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-3xl);
  padding: 50px;
  box-shadow: var(--shadow-sm);
}

.article-section {
  margin-bottom: 40px;
}

.article-section-title {
  font-size: 1.45rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  border-bottom: 2px solid var(--sky-light);
  padding-bottom: 10px;
}

.article-text {
  font-size: 1.02rem;
  color: var(--text-sub);
  line-height: 1.85;
  margin-bottom: 16px;
}

.article-list {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 18px;
  color: var(--text-sub);
  line-height: 1.85;
}

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

/* 推荐资讯卡片流 */
.news-cards-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  margin-top: 24px;
}

.news-card-item {
  background: var(--bg-surface);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-2xl);
  padding: 30px;
  transition: var(--transition-smooth);
  display: flex;
  flex-direction: column;
}

.news-card-item:hover {
  transform: translateY(-4px);
  border-color: var(--sky-primary);
  box-shadow: var(--shadow-md);
}

.news-meta-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.news-tag {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--sky-primary);
  background: var(--sky-light);
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.news-date {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.news-card-title {
  font-size: 1.25rem;
  font-weight: 750;
  color: var(--text-main);
  margin-bottom: 10px;
}

.news-card-summary {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.sitemap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 24px;
}

.sitemap-card {
  background: var(--bg-surface);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-2xl);
  padding: 26px;
}

.sitemap-card h3 {
  font-size: 1.18rem;
  font-weight: 750;
  color: var(--text-main);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.sitemap-card ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.sitemap-card a {
  color: var(--sky-primary);
  font-size: 0.96rem;
}

.sitemap-card a:hover {
  text-decoration: underline;
}

/* --------------------------------------------------------------------------
   14.1 深度科普长文专属排版 (TOC, Callout, Breadcrumbs, Related Posts)
   -------------------------------------------------------------------------- */
.article-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.article-breadcrumb a {
  color: var(--sky-primary);
}

.article-breadcrumb a:hover {
  text-decoration: underline;
}

.article-meta-box {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 30px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-color);
}

.article-meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* 目录容器 (Table of Contents) */
.toc-container {
  background: var(--sky-ultralight);
  border: 1.5px solid var(--border-sky);
  border-radius: var(--radius-2xl);
  padding: 24px 28px;
  margin: 32px 0 40px;
}

.toc-title {
  font-size: 1.12rem;
  font-weight: 800;
  color: var(--sky-primary);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 8px;
}

.toc-list li {
  position: relative;
  padding-left: 18px;
}

.toc-list li::before {
  content: "•";
  position: absolute;
  left: 0;
  color: var(--marigold);
  font-weight: bold;
}

.toc-list a {
  color: var(--text-sub);
  font-size: 0.96rem;
  font-weight: 550;
  transition: var(--transition-smooth);
}

.toc-list a:hover {
  color: var(--sky-primary);
  text-decoration: underline;
}

/* 重点提示框 (Callout Box) */
.article-callout {
  background: var(--bg-surface);
  border-left: 4px solid var(--sky-primary);
  border-radius: var(--radius-md);
  padding: 18px 22px;
  margin: 26px 0;
  box-shadow: var(--shadow-sm);
}

.article-callout.tip {
  border-left-color: var(--status-green);
  background: rgba(16, 185, 129, 0.05);
}

.article-callout.warning {
  border-left-color: var(--marigold);
  background: var(--marigold-light);
}

.article-callout-title {
  font-weight: 750;
  font-size: 0.98rem;
  margin-bottom: 6px;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 测评对比表格 */
.article-table-wrapper {
  overflow-x: auto;
  margin: 28px 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.article-table th {
  background: var(--sky-light);
  color: var(--sky-primary);
  font-weight: 750;
  padding: 14px 18px;
  border-bottom: 1.5px solid var(--border-color);
  white-space: nowrap;
}

.article-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-sub);
}

.article-table tr:last-child td {
  border-bottom: none;
}

.article-table tr:hover td {
  background: var(--sky-ultralight);
}

/* 文中转化卡片 (In-article CTA) */
.article-cta-box {
  background: var(--accent-gradient);
  color: #ffffff;
  border-radius: var(--radius-2xl);
  padding: 32px 28px;
  margin: 44px 0;
  text-align: center;
  box-shadow: 0 12px 28px var(--sky-glow);
}

.article-cta-box h3 {
  font-size: 1.45rem;
  font-weight: 850;
  margin-bottom: 10px;
}

.article-cta-box p {
  font-size: 0.98rem;
  opacity: 0.92;
  margin-bottom: 20px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* 相关阅读网格 (Related Posts) */
.related-posts-section {
  margin-top: 54px;
  padding-top: 36px;
  border-top: 2px dashed var(--border-color);
}

.related-posts-title {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.related-posts-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.related-post-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 18px 20px;
  transition: var(--transition-smooth);
  display: flex;
  flex-direction: column;
}

.related-post-card:hover {
  transform: translateY(-3px);
  border-color: var(--sky-primary);
  box-shadow: var(--shadow-sm);
}

.related-post-card h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
  line-height: 1.5;
}

.related-post-card:hover h4 {
  color: var(--sky-primary);
}

.related-post-card span {
  font-size: 0.82rem;
  color: var(--text-muted);
}

@media (max-width: 768px) {
  .related-posts-grid {
    grid-template-columns: 1fr;
  }
}

/* --------------------------------------------------------------------------
   15. 响应式与移动端触摸适配 (@media)
   -------------------------------------------------------------------------- */
@media (max-width: 1120px) {
  /* 导航栏自适应：屏幕宽度不足以横排展示8个菜单项时，优雅转为抽屉导航 */
  .mobile-menu-btn {
    display: inline-flex;
  }

  .nav-actions .btn {
    display: none !important;
  }

  .nav-links {
    position: fixed;
    top: 76px;
    left: 0;
    right: 0;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 24px;
    gap: 14px;
    box-shadow: var(--shadow-xl);
    transform: translateY(-130%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.3s ease;
    max-height: calc(100vh - 76px);
    overflow-y: auto;
  }

  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-links .mobile-cta {
    display: inline-flex !important;
    width: 100%;
    margin-top: 10px;
  }

  .features-grid,
  .pricing-grid,
  .testimonials-grid,
  .showcase-grid {
    grid-template-columns: 1fr;
    max-width: 580px;
    margin-left: auto;
    margin-right: auto;
  }

  .platform-chips-row {
    grid-template-columns: repeat(2, 1fr);
  }

  .pricing-card.featured {
    transform: none;
  }
  .pricing-card.featured:hover {
    transform: translateY(-8px);
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 20px;
  }

  .section {
    padding: 64px 0;
  }

  .hero-section {
    padding: 50px 0 36px;
  }

  .hero-title {
    font-size: 2.15rem;
  }

  .hero-subtitle {
    font-size: 1.05rem;
  }

  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }

  .hero-cta-group .btn {
    width: 100%;
  }

  .platform-chips-row {
    grid-template-columns: 1fr;
  }

  .app-chips-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .trust-bar {
    grid-template-columns: 1fr 1fr;
    gap: 14px;
  }

  .calculator-card {
    padding: 30px 20px;
  }

  .calculator-result-box {
    flex-direction: column;
    align-items: flex-start;
  }

  .cta-banner {
    padding: 44px 24px;
  }

  .cta-banner-title {
    font-size: 1.85rem;
  }

  .footer-nav {
    flex-direction: column;
    gap: 20px;
  }

  .article-content {
    padding: 30px 20px;
  }

  .sitemap-grid {
    grid-template-columns: 1fr;
  }
}