/* ==========================================================================
   Strong VPN - 原生极简高效样式表 (Pure Native CSS)
   特性：无外部依赖、秒开级渲染、现代暗黑科技风、全设备响应式适配
   ========================================================================== */

:root {
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.75);
  --bg-card-hover: rgba(30, 41, 59, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(56, 189, 248, 0.4);
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --primary: #0284c7;
  --primary-hover: #0369a1;
  --accent-cyan: #38bdf8;
  --accent-purple: #818cf8;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  
  --gradient-brand: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #c084fc 100%);
  --gradient-btn: linear-gradient(135deg, #0284c7 0%, #6366f1 100%);
  --gradient-btn-hover: linear-gradient(135deg, #0369a1 0%, #4f46e5 100%);
  --gradient-card: linear-gradient(180deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.01) 100%);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.45);
  --shadow-glow: 0 0 35px rgba(56, 189, 248, 0.25);
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --max-width: 1200px;
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  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;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background: radial-gradient(ellipse 80% 50% at 50% -10%, rgba(56, 189, 248, 0.3) 0%, rgba(99, 102, 241, 0.18) 35%, rgba(168, 85, 247, 0.05) 60%, transparent 75%),
              radial-gradient(circle at 85% 30%, rgba(129, 140, 248, 0.08) 0%, transparent 40%),
              var(--bg-primary);
  background-attachment: fixed;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  display: block;
}

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

/* 导航栏 */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background-color: rgba(10, 14, 23, 0.82);
  border-bottom: 1px solid var(--border-color);
  height: 72px;
  display: flex;
  align-items: center;
}

.navbar .container {
  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: var(--text-main);
}

.logo-badge {
  width: 38px;
  height: 38px;
  background: var(--gradient-btn);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.4);
}

.logo-text-gradient {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

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

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

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

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

/* 按钮通用规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: var(--transition);
  cursor: pointer;
  text-align: center;
  white-space: nowrap;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--gradient-btn);
  color: #ffffff;
  box-shadow: 0 4px 18px rgba(2, 132, 199, 0.38);
}

.btn-primary:hover {
  background: var(--gradient-btn-hover);
  box-shadow: 0 6px 24px rgba(2, 132, 199, 0.55);
  transform: translateY(-2px);
}

.btn-outline {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border-color: var(--border-color);
}

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

.btn-lg {
  padding: 15px 34px;
  font-size: 1.08rem;
}

.btn-block {
  width: 100%;
}

/* 徽章 / 标签 */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-glow {
  background: rgba(56, 189, 248, 0.12);
  color: var(--accent-cyan);
  border: 1px solid rgba(56, 189, 248, 0.3);
  box-shadow: 0 0 16px rgba(56, 189, 248, 0.2);
}

.badge-success {
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-warning {
  background: rgba(245, 158, 11, 0.15);
  color: var(--accent-amber);
  border: 1px solid rgba(245, 158, 11, 0.3);
}

/* 通用区块排版 */
.section {
  padding: 85px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 52px;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-top: 14px;
  margin-bottom: 14px;
  line-height: 1.25;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
}

/* 主视觉区 (Hero Section) 与大聚光灯 (Spotlight) 强光投射系统 */
.hero {
  padding: 105px 0 75px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero-content {
  max-width: 860px;
  margin: 0 auto;
  position: relative;
  z-index: 2;
}

/* 强力聚光灯 (Spotlight) 视觉结构系统 */
.spotlight-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
  overflow: hidden;
}

/* 聚光灯顶部超亮发射光源条 */
.spotlight-emitter {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 760px;
  max-width: 90vw;
  height: 3px;
  background: linear-gradient(90deg, 
    transparent 0%, 
    rgba(56, 189, 248, 0.4) 15%, 
    rgba(56, 189, 248, 1) 35%, 
    #ffffff 50%, 
    rgba(56, 189, 248, 1) 65%, 
    rgba(56, 189, 248, 0.4) 85%, 
    transparent 100%);
  box-shadow: 
    0 0 25px 5px rgba(255, 255, 255, 0.95),
    0 0 55px 18px rgba(56, 189, 248, 0.9),
    0 0 110px 35px rgba(99, 102, 241, 0.7);
  border-radius: 9999px;
}

/* 聚光灯向下强烈投射的大光锥 (Conical Beam) */
.spotlight-cone {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 1250px;
  max-width: 100vw;
  height: 850px;
  clip-path: polygon(42% 0%, 58% 0%, 100% 100%, 0% 100%);
  background: linear-gradient(180deg, 
    rgba(255, 255, 255, 0.65) 0%, 
    rgba(56, 189, 248, 0.48) 14%, 
    rgba(99, 102, 241, 0.3) 45%, 
    rgba(147, 51, 234, 0.12) 75%, 
    transparent 100%);
  filter: blur(34px);
  opacity: 0.9;
  animation: spotlight-pulse 8s ease-in-out infinite alternate;
}

/* 顶部中心超亮光斑核心 */
.spotlight-bloom {
  position: absolute;
  top: -80px;
  left: 50%;
  transform: translateX(-50%);
  width: 780px;
  height: 520px;
  background: radial-gradient(ellipse 65% 55% at 50% 15%, 
    rgba(255, 255, 255, 0.85) 0%, 
    rgba(56, 189, 248, 0.75) 22%, 
    rgba(99, 102, 241, 0.45) 48%, 
    transparent 78%);
  filter: blur(42px);
  opacity: 0.88;
}

/* 广域向下漫反射环境光罩 */
.spotlight-ambient {
  position: absolute;
  top: -40px;
  left: 50%;
  transform: translateX(-50%);
  width: 1600px;
  height: 980px;
  background: radial-gradient(ellipse 80% 65% at 50% 10%, 
    rgba(56, 189, 248, 0.32) 0%, 
    rgba(99, 102, 241, 0.2) 42%, 
    rgba(168, 85, 247, 0.08) 72%, 
    transparent 90%);
  filter: blur(65px);
  opacity: 0.85;
}

/* 聚光灯照耀下的高科技透视网格微光 */
.spotlight-grid {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: 1300px;
  height: 750px;
  background-image: 
    linear-gradient(to right, rgba(255, 255, 255, 0.07) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.07) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(ellipse 65% 55% at 50% 15%, black 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 65% 55% at 50% 15%, black 20%, transparent 75%);
  opacity: 0.7;
}

@keyframes spotlight-pulse {
  0% {
    opacity: 0.82;
    transform: translateX(-50%) scale(0.98);
  }
  50% {
    opacity: 1;
    transform: translateX(-50%) scale(1.02);
  }
  100% {
    opacity: 0.82;
    transform: translateX(-50%) scale(0.98);
  }
}

.hero-title {
  font-size: clamp(2.3rem, 5vw, 3.6rem);
  font-weight: 900;
  letter-spacing: -1px;
  line-height: 1.15;
  margin-top: 20px;
  margin-bottom: 22px;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
  color: var(--text-muted);
  max-width: 740px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

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

.hero-trust {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
  padding: 20px 28px;
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  max-width: 820px;
  margin: 0 auto;
  flex-wrap: wrap;
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.92rem;
  color: var(--text-main);
  font-weight: 500;
}

.trust-item svg {
  color: var(--accent-cyan);
  flex-shrink: 0;
}

/* 核心优势卡片网格 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card {
  background: var(--bg-card);
  background-image: var(--gradient-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 30px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

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

.card-icon {
  width: 52px;
  height: 52px;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--accent-cyan);
}

.card-title {
  font-size: 1.22rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.card-desc {
  font-size: 0.94rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* 流媒体与 AI 支持专区 */
.services-section {
  background: linear-gradient(180deg, rgba(17, 24, 39, 0.4) 0%, rgba(10, 14, 23, 0.8) 100%);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.service-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 34px;
  position: relative;
}

.service-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
}

.service-tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 22px 0;
}

.service-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  color: var(--text-main);
  font-weight: 500;
}

.service-tag .status-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-emerald);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--accent-emerald);
}

/* 价格对比表 */
.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: 38px 30px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition);
}

.pricing-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-glow);
}

.pricing-card.popular {
  border-color: var(--accent-cyan);
  background: linear-gradient(180deg, rgba(2, 132, 199, 0.12) 0%, rgba(17, 24, 39, 0.9) 100%);
  box-shadow: 0 0 30px rgba(56, 189, 248, 0.2);
  transform: scale(1.02);
}

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

.pricing-ribbon {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-btn);
  color: #ffffff;
  padding: 4px 18px;
  font-size: 0.8rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  box-shadow: 0 4px 12px rgba(2, 132, 199, 0.4);
  white-space: nowrap;
}

.pricing-plan-name {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.pricing-plan-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  min-height: 44px;
}

.pricing-price-wrap {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin-bottom: 26px;
}

.pricing-currency {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--accent-cyan);
}

.pricing-amount {
  font-size: 3rem;
  font-weight: 900;
  line-height: 1;
  color: #ffffff;
}

.pricing-period {
  font-size: 0.92rem;
  color: var(--text-dim);
}

.pricing-features {
  list-style: none;
  margin: 24px 0 32px;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

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

.pricing-feature-item svg {
  color: var(--accent-emerald);
  flex-shrink: 0;
}

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

.testimonial-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;
}

.testimonial-stars {
  display: flex;
  gap: 4px;
  color: var(--accent-amber);
  margin-bottom: 14px;
}

.testimonial-text {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 22px;
}

.testimonial-user {
  display: flex;
  align-items: center;
  gap: 12px;
}

.user-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #ffffff;
  font-size: 1rem;
}

.user-info h4 {
  font-size: 0.96rem;
  font-weight: 600;
}

.user-info p {
  font-size: 0.82rem;
  color: var(--text-dim);
}

/* 常见问题 (FAQ) - 使用原生语义化 details/summary，无需任何 JS 即可原生秒响应 */
.faq-wrap {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.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(56, 189, 248, 0.35);
  background: rgba(30, 41, 59, 0.6);
}

.faq-item summary {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  transition: var(--transition);
}

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

.faq-item summary:hover {
  color: var(--accent-cyan);
}

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

.faq-item[open] .faq-icon-arrow {
  transform: rotate(180deg);
  color: var(--accent-cyan);
}

.faq-answer {
  padding: 0 24px 22px;
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  padding-top: 16px;
}

/* 页脚 (严格遵守要求：只保留四个标题，在新页面打开) */
.footer {
  margin-top: auto;
  background-color: #06090e;
  border-top: 1px solid var(--border-color);
  padding: 45px 0 35px;
}

.footer .container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  flex-wrap: wrap;
}

.footer-nav a {
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: var(--transition);
  position: relative;
  padding: 6px 4px;
}

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

.footer-copyright {
  font-size: 0.85rem;
  color: var(--text-dim);
  text-align: center;
}

/* 子页面专属文章排版规范 (用于关于我们、服务条款、隐私政策、网站地图) */
.page-hero {
  padding: 75px 0 45px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
  background: radial-gradient(ellipse 70% 60% at 50% 0%, rgba(56, 189, 248, 0.35) 0%, rgba(99, 102, 241, 0.18) 40%, transparent 75%),
              var(--bg-primary);
  position: relative;
  overflow: hidden;
}

.page-title {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 14px;
  letter-spacing: -0.5px;
}

.page-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 650px;
  margin: 0 auto;
}

.content-wrapper {
  max-width: 860px;
  margin: 50px auto 80px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 44px;
  box-shadow: var(--shadow-md);
}

.content-wrapper h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: #ffffff;
  margin: 32px 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 10px;
}

.content-wrapper h2:first-of-type {
  margin-top: 0;
}

.content-wrapper h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--accent-cyan);
  margin: 22px 0 10px;
}

.content-wrapper p {
  font-size: 0.98rem;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 16px;
}

.content-wrapper ul {
  list-style: none;
  margin-bottom: 22px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.content-wrapper li {
  font-size: 0.96rem;
  color: var(--text-muted);
  line-height: 1.6;
  position: relative;
  padding-left: 24px;
}

.content-wrapper li::before {
  content: "•";
  position: absolute;
  left: 6px;
  color: var(--accent-cyan);
  font-size: 1.4rem;
  line-height: 1;
}

.highlight-box {
  background: rgba(56, 189, 248, 0.08);
  border-left: 4px solid var(--accent-cyan);
  padding: 18px 22px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 24px 0;
}

.highlight-box p {
  margin: 0;
  color: var(--text-main);
  font-weight: 500;
}

/* 网站地图节点链接树 */
.sitemap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.sitemap-card {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
}

.sitemap-card h3 {
  font-size: 1.15rem;
  color: var(--accent-cyan);
  margin-bottom: 14px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  padding-bottom: 8px;
}

.sitemap-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.sitemap-list a {
  color: var(--text-muted);
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: var(--transition);
}

.sitemap-list a:hover {
  color: var(--accent-cyan);
  padding-left: 4px;
}

/* ==========================================================================
   响应式适配规范 (@media)
   确保在手机端完美单栏显示，按钮适合手指点击（尺寸>=48px）
   ========================================================================== */

@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .services-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .navbar {
    height: auto;
    padding: 14px 0;
  }
  
  .navbar .container {
    flex-direction: column;
    gap: 14px;
  }
  
  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
  }
  
  .hero {
    padding: 60px 0 45px;
  }
  
  .hero-cta {
    flex-direction: column;
    width: 100%;
  }
  
  .hero-cta .btn {
    width: 100%;
    min-height: 48px;
  }
  
  .hero-trust {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
  }
  
  .features-grid,
  .pricing-grid,
  .testimonials-grid,
  .services-grid,
  .sitemap-grid {
    grid-template-columns: 1fr !important;
  }
  
  .pricing-card.popular {
    transform: none !important;
  }
  
  .footer-nav {
    flex-direction: column;
    gap: 16px;
  }
  
  .btn {
    min-height: 48px; /* 适合手机手指触控 */
  }

  .content-wrapper {
    padding: 24px 18px;
    margin: 30px auto 50px;
  }
}

/* ==========================================================================
   高科技网格卡片 (Grid Cards) 与 SEO 文章专属排版
   ========================================================================== */

.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin: 40px 0 60px;
}

.article-card {
  background: var(--bg-card);
  background-image: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 26px;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.article-card:hover {
  border-color: var(--accent-cyan);
  background-color: var(--bg-card-hover);
  transform: translateY(-5px);
  box-shadow: var(--shadow-glow);
}

.article-card-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-cyan);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
  width: fit-content;
}

.article-card-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: #ffffff;
  line-height: 1.45;
  margin-bottom: 12px;
  transition: var(--transition);
}

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

.article-card-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding-top: 16px;
  font-size: 0.84rem;
  color: var(--text-dim);
}

.article-card-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--accent-cyan);
  font-weight: 600;
  font-size: 0.9rem;
  transition: var(--transition);
}

.article-card-btn:hover {
  color: #ffffff;
  transform: translateX(4px);
}

/* 文章详情页专属排版 */
.article-header {
  text-align: center;
  padding: 60px 0 35px;
  border-bottom: 1px solid var(--border-color);
  background: radial-gradient(circle at 50% 0%, rgba(56, 189, 248, 0.12) 0%, transparent 60%);
}

.article-header .article-title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 800;
  line-height: 1.3;
  margin: 18px auto 20px;
  max-width: 920px;
  color: #ffffff;
}

.article-header-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 22px;
  font-size: 0.9rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.article-body {
  max-width: 880px;
  margin: 45px auto 70px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 45px;
  box-shadow: var(--shadow-md);
  font-size: 1.05rem;
  line-height: 1.85;
}

.article-body h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: #ffffff;
  margin: 38px 0 18px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 10px;
}

.article-body h2:first-of-type {
  margin-top: 0;
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--accent-cyan);
  margin: 26px 0 12px;
}

.article-body p {
  color: var(--text-muted);
  margin-bottom: 20px;
}

.article-body strong {
  color: #ffffff;
  font-weight: 600;
}

.article-body a {
  color: var(--accent-cyan);
  text-decoration: underline;
  text-underline-offset: 4px;
  transition: var(--transition);
  font-weight: 600;
}

.article-body a:hover {
  color: #ffffff;
  text-decoration-color: #ffffff;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 26px 0;
  font-size: 0.95rem;
}

.article-body th, .article-body td {
  padding: 14px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

.article-body th {
  background: rgba(255, 255, 255, 0.04);
  color: #ffffff;
  font-weight: 700;
}

.article-body tr:hover td {
  background: rgba(255, 255, 255, 0.02);
}

.article-body ol, .article-body ul {
  margin: 18px 0 24px 24px;
  color: var(--text-muted);
}

.article-body li {
  margin-bottom: 10px;
  line-height: 1.7;
}

/* 返回推荐咨询专属按钮容器（仅建1个） */
.back-advisor-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-color);
  padding-top: 32px;
  margin-top: 45px;
  flex-wrap: wrap;
  gap: 18px;
}

.btn-back-advisor {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 26px;
  font-size: 0.96rem;
  font-weight: 600;
  color: #ffffff;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  transition: var(--transition);
  text-decoration: none !important;
}

.btn-back-advisor:hover {
  background: rgba(56, 189, 248, 0.15);
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  transform: translateX(-4px);
}

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

@media (max-width: 768px) {
  .articles-grid {
    grid-template-columns: 1fr;
  }
  .article-body {
    padding: 26px 18px;
  }
  .back-advisor-container {
    flex-direction: column;
    align-items: stretch;
  }
  .btn-back-advisor {
    justify-content: center;
    width: 100%;
    min-height: 48px;
  }
}