/* ==========================================================================
   CyberGuard 机场 (cyberguardvpn.sbs) - 纯原生现代高质感 CSS 样式系统
   100% 原生 CSS3 · 零外部重型 JS 框架 · 秒开极速加载 · GPU 动态赛博背景
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  /* 品牌核心配色：赛博深邃暗夜蓝、量子青光、电光蓝、能量紫 */
  --bg-deep: #030712;
  --bg-card: rgba(10, 19, 42, 0.75);
  --bg-card-hover: rgba(16, 29, 64, 0.9);
  --bg-glass: rgba(6, 12, 30, 0.85);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(0, 242, 254, 0.35);

  --cyan-primary: #00f2fe;
  --blue-primary: #38bdf8;
  --indigo-primary: #6366f1;
  --purple-primary: #818cf8;
  --emerald-accent: #10b981;
  --amber-accent: #f59e0b;
  --rose-accent: #f43f5e;

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --shadow-card: 0 14px 40px -10px rgba(0, 0, 0, 0.7);
  --shadow-glow: 0 0 32px rgba(0, 242, 254, 0.3);
  --shadow-btn: 0 8px 24px -4px rgba(0, 242, 254, 0.45);

  --container-max: 1240px;
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-family: var(--font-sans);
  background-color: #030712;
  color: var(--text-main);
  line-height: 1.65;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  position: relative;
  min-height: 100vh;
  overflow-x: hidden;
  background-color: transparent !important;
}

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

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* 容器与版心 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
  position: relative;
  z-index: 2;
}

/* ==========================================================================
   动态原生 CSS 赛博星云与流光矩阵背景
   100% 纯原生 CSS · GPU 加速 · 60fps 丝滑秒开 · 零 JS 负担
   ========================================================================== */
.dynamic-background {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  background: radial-gradient(ellipse 95% 70% at 50% 10%, #061536 0%, #03081a 50%, #02040b 100%);
  pointer-events: none;
}

/* 极光能量护盾光晕 */
.dynamic-background::before {
  content: "";
  position: absolute;
  top: -15vh;
  left: 5vw;
  width: 90vw;
  height: 85vh;
  background: radial-gradient(ellipse 75% 60% at 50% 20%, rgba(0, 242, 254, 0.16) 0%, rgba(56, 189, 248, 0.14) 40%, rgba(99, 102, 241, 0.08) 75%, transparent 100%);
  filter: blur(70px);
  animation: cyberPulse 10s ease-in-out infinite alternate;
  will-change: opacity, transform;
}

/* 第一层：高密度微型闪烁星尘 */
.stars-field-1 {
  position: absolute;
  inset: 0;
  background-image: 
    radial-gradient(circle, #ffffff 1.5px, transparent 1.6px),
    radial-gradient(circle, #00f2fe 2px, transparent 2.2px),
    radial-gradient(circle, #38bdf8 1.8px, transparent 2px),
    radial-gradient(circle, #ffffff 1.2px, transparent 1.5px),
    radial-gradient(circle, #818cf8 2px, transparent 2.2px),
    radial-gradient(circle, #00f2fe 1.6px, transparent 1.8px),
    radial-gradient(circle, #ffffff 2.2px, transparent 2.5px),
    radial-gradient(circle, #38bdf8 1.8px, transparent 2px);
  background-position: 
    40px 50px, 140px 190px, 270px 90px, 400px 310px, 
    530px 150px, 660px 390px, 810px 70px, 940px 260px;
  background-size: 1100px 480px;
  background-repeat: repeat;
  animation: starTwinkle1 4s ease-in-out infinite alternate;
  opacity: 0.85;
}

/* 第二层：中号色彩群星 */
.stars-field-2 {
  position: absolute;
  inset: 0;
  background-image: 
    radial-gradient(circle, #00f2fe 2.2px, transparent 2.6px),
    radial-gradient(circle, #818cf8 2.5px, transparent 2.8px),
    radial-gradient(circle, #ffffff 2px, transparent 2.3px),
    radial-gradient(circle, #38bdf8 2.6px, transparent 3px),
    radial-gradient(circle, #34d399 1.8px, transparent 2.2px);
  background-position: 
    90px 130px, 290px 320px, 490px 110px, 720px 250px, 930px 420px;
  background-size: 1000px 500px;
  background-repeat: repeat;
  animation: starTwinkle2 6s ease-in-out infinite alternate-reverse;
  opacity: 0.75;
}

/* 第三层：十字闪光量子大星 */
.stars-cross {
  position: absolute;
  inset: 0;
  background-image: 
    radial-gradient(circle, #ffffff 3px, transparent 3.5px),
    radial-gradient(circle, #00f2fe 3.2px, transparent 3.8px),
    radial-gradient(circle, #38bdf8 3px, transparent 3.5px);
  background-position: 180px 220px, 580px 80px, 880px 340px;
  background-size: 1200px 600px;
  background-repeat: repeat;
  animation: starPulseCross 5s ease-in-out infinite alternate;
  opacity: 0.9;
}

/* 动态赛博流光激光线 */
.cyber-beam-1 {
  position: absolute;
  top: 15%;
  left: -20%;
  width: 140%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0, 242, 254, 0.4), rgba(56, 189, 248, 0.8), transparent);
  transform: rotate(-12deg);
  animation: beamSlide1 14s linear infinite;
  opacity: 0.6;
}

.cyber-beam-2 {
  position: absolute;
  top: 60%;
  left: -20%;
  width: 140%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.4), rgba(0, 242, 254, 0.8), transparent);
  transform: rotate(8deg);
  animation: beamSlide2 18s linear infinite;
  opacity: 0.5;
}

/* 赛博网格透视底板 */
.bg-grid-overlay {
  position: absolute;
  inset: 0;
  background-image: 
    linear-gradient(to right, rgba(0, 242, 254, 0.035) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(56, 189, 248, 0.035) 1px, transparent 1px);
  background-size: 50px 50px;
  mask-image: radial-gradient(ellipse 90% 70% at 50% 30%, #000 35%, transparent 85%);
  -webkit-mask-image: radial-gradient(ellipse 90% 70% at 50% 30%, #000 35%, transparent 85%);
}

/* 浮动光晕球 */
.ambient-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  pointer-events: none;
  opacity: 0.35;
}

.orb-1 {
  width: 480px;
  height: 480px;
  background: rgba(0, 242, 254, 0.2);
  top: 10%;
  left: -100px;
  animation: floatOrb1 16s ease-in-out infinite alternate;
}

.orb-2 {
  width: 520px;
  height: 520px;
  background: rgba(99, 102, 241, 0.22);
  top: 40%;
  right: -120px;
  animation: floatOrb2 20s ease-in-out infinite alternate;
}

/* 关键帧动画定义 */
@keyframes cyberPulse {
  0% { transform: scale(0.98); opacity: 0.75; }
  100% { transform: scale(1.04); opacity: 1; }
}

@keyframes starTwinkle1 {
  0% { opacity: 0.45; transform: translateY(0); }
  50% { opacity: 0.95; }
  100% { opacity: 0.45; transform: translateY(-4px); }
}

@keyframes starTwinkle2 {
  0% { opacity: 0.5; transform: translateY(0); }
  50% { opacity: 0.9; }
  100% { opacity: 0.5; transform: translateY(5px); }
}

@keyframes starPulseCross {
  0% { opacity: 0.5; filter: drop-shadow(0 0 1px #fff); }
  100% { opacity: 1; filter: drop-shadow(0 0 8px #00f2fe); }
}

@keyframes beamSlide1 {
  0% { transform: rotate(-12deg) translateY(-80px); }
  50% { transform: rotate(-12deg) translateY(80px); }
  100% { transform: rotate(-12deg) translateY(-80px); }
}

@keyframes beamSlide2 {
  0% { transform: rotate(8deg) translateY(60px); }
  50% { transform: rotate(8deg) translateY(-60px); }
  100% { transform: rotate(8deg) translateY(60px); }
}

@keyframes floatOrb1 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(80px, 60px) scale(1.15); }
}

@keyframes floatOrb2 {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(-70px, -50px) scale(1.1); }
}

@keyframes pulseGlow {
  0% { box-shadow: 0 0 0 0 rgba(0, 242, 254, 0.7); }
  70% { box-shadow: 0 0 0 10px rgba(0, 242, 254, 0); }
  100% { box-shadow: 0 0 0 0 rgba(0, 242, 254, 0); }
}

/* ==========================================================================
   顶部导航栏 (Navbar)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background-color: var(--bg-glass);
  border-bottom: 1px solid var(--border-subtle);
  transition: all var(--transition-fast);
}

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

.brand-logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo-link img {
  height: 48px;
  width: auto;
}

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

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

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

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan-primary), var(--blue-primary));
  transition: width var(--transition-fast);
}

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

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

/* 按钮规范与呼吁按钮 (CTA) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 700;
  border-radius: var(--radius-md);
  padding: 12px 24px;
  font-size: 15px;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, #00f2fe 0%, #38bdf8 50%, #6366f1 100%);
  color: #020617;
  font-weight: 800;
  box-shadow: 0 4px 18px rgba(0, 242, 254, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0, 242, 254, 0.6);
  filter: brightness(1.08);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-main);
  border: 1px solid var(--border-subtle);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--border-highlight);
  color: #ffffff;
  transform: translateY(-2px);
}

.btn-lg {
  padding: 15px 32px;
  font-size: 17px;
  border-radius: var(--radius-md);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 13px;
  border-radius: var(--radius-sm);
}

/* ==========================================================================
   Hero 头部首屏区域
   ========================================================================== */
.hero-section {
  padding: 70px 0 50px;
  text-align: center;
  position: relative;
}

.status-badge-wrap {
  display: inline-flex;
  margin-bottom: 24px;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 7px 18px;
  border-radius: var(--radius-full);
  background: rgba(0, 242, 254, 0.08);
  border: 1px solid rgba(0, 242, 254, 0.3);
  font-size: 13.5px;
  font-weight: 600;
  color: #38bdf8;
  backdrop-filter: blur(10px);
}

.status-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background-color: #10b981;
  box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7);
  animation: pulseGlow 2s infinite;
}

.hero-title {
  font-size: clamp(34px, 5.2vw, 56px);
  font-weight: 900;
  line-height: 1.18;
  margin-bottom: 22px;
  letter-spacing: -0.02em;
}

.text-gradient {
  background: linear-gradient(135deg, #00f2fe 10%, #38bdf8 50%, #818cf8 90%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  max-width: 820px;
  margin: 0 auto 32px;
  font-size: clamp(16px, 2vw, 19px);
  color: var(--text-muted);
  line-height: 1.7;
}

.hero-keywords {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  max-width: 900px;
  margin: 0 auto 36px;
}

.keyword-pill {
  padding: 4px 12px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 12.5px;
  color: #cbd5e1;
  transition: all var(--transition-fast);
}

.keyword-pill:hover {
  background: rgba(0, 242, 254, 0.12);
  border-color: rgba(0, 242, 254, 0.4);
  color: #00f2fe;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 18px;
  margin-bottom: 28px;
}

.hero-trust-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
  font-size: 13.5px;
  color: var(--text-dim);
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 6px;
  color: #94a3b8;
}

.trust-item svg {
  color: #10b981;
}

/* ==========================================================================
   实时性能指标看板 (Live Stats Bar)
   ========================================================================== */
.stats-bar-section {
  padding: 20px 0 50px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(12px);
}

.stat-item {
  text-align: center;
  padding: 10px;
  position: relative;
}

.stat-item:not(:last-child)::after {
  content: "";
  position: absolute;
  right: 0;
  top: 15%;
  height: 70%;
  width: 1px;
  background: var(--border-subtle);
}

.stat-number {
  font-size: clamp(26px, 3.5vw, 36px);
  font-weight: 900;
  font-family: var(--font-mono);
  color: #ffffff;
  margin-bottom: 4px;
}

.stat-number span {
  color: var(--cyan-primary);
  font-size: 0.65em;
  margin-left: 2px;
}

.stat-label {
  font-size: 13.5px;
  color: var(--text-muted);
  font-weight: 500;
}

/* ==========================================================================
   核心卖点网格 (Core Features)
   ========================================================================== */
.features-section {
  padding: 60px 0;
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 48px;
}

.section-tag {
  display: inline-block;
  padding: 4px 14px;
  border-radius: var(--radius-full);
  background: rgba(0, 242, 254, 0.1);
  border: 1px solid rgba(0, 242, 254, 0.3);
  font-size: 13px;
  font-weight: 700;
  color: var(--cyan-primary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(26px, 3.6vw, 38px);
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.65;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 30px;
  transition: all var(--transition-fast);
  backdrop-filter: blur(12px);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--cyan-primary), transparent);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  background: var(--bg-card-hover);
  box-shadow: 0 16px 36px rgba(0, 242, 254, 0.12);
}

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

.feature-icon-wrap {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: rgba(0, 242, 254, 0.1);
  border: 1px solid rgba(0, 242, 254, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--cyan-primary);
  margin-bottom: 20px;
}

.feature-title {
  font-size: 19px;
  font-weight: 700;
  margin-bottom: 10px;
  color: #ffffff;
}

.feature-text {
  font-size: 14.5px;
  color: var(--text-muted);
  line-height: 1.65;
}

/* ==========================================================================
   价格套餐区域 (Pricing) - 核心要求：所有价格同排 (Same Row Grid)
   ========================================================================== */
.pricing-section {
  padding: 70px 0;
  position: relative;
}

.pricing-row-container {
  display: grid;
  /* 严格所有价格同排：桌面端 4 列并列展示 */
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 30px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: all var(--transition-fast);
  backdrop-filter: blur(12px);
}

.pricing-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-highlight);
  background: var(--bg-card-hover);
  box-shadow: 0 18px 42px rgba(0, 242, 254, 0.18);
}

.pricing-card.popular {
  border-color: rgba(0, 242, 254, 0.6);
  background: linear-gradient(180deg, rgba(14, 28, 64, 0.9) 0%, rgba(8, 17, 38, 0.9) 100%);
  box-shadow: 0 12px 36px rgba(0, 242, 254, 0.22);
}

.pricing-card.popular::before {
  content: "🔥 畅销爆款 · 极力推荐";
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(90deg, #00f2fe, #38bdf8);
  color: #020617;
  font-size: 12px;
  font-weight: 800;
  padding: 3px 14px;
  border-radius: var(--radius-full);
  box-shadow: 0 4px 12px rgba(0, 242, 254, 0.4);
  white-space: nowrap;
}

.card-top {
  margin-bottom: 24px;
}

.plan-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.plan-name {
  font-size: 20px;
  font-weight: 800;
  color: #ffffff;
}

.plan-badge {
  font-size: 11.5px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.08);
  color: #cbd5e1;
}

.popular .plan-badge {
  background: rgba(0, 242, 254, 0.2);
  color: #00f2fe;
}

.plan-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  min-height: 42px;
  line-height: 1.5;
  margin-bottom: 18px;
}

.price-box {
  display: flex;
  align-items: baseline;
  gap: 4px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 20px;
}

.price-currency {
  font-size: 22px;
  font-weight: 700;
  color: var(--cyan-primary);
}

.price-amount {
  font-size: 42px;
  font-weight: 900;
  font-family: var(--font-mono);
  color: #ffffff;
  line-height: 1;
}

.price-period {
  font-size: 13.5px;
  color: var(--text-dim);
}

.features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 26px;
}

.features-list li {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  font-size: 13.5px;
  color: #cbd5e1;
  line-height: 1.5;
}

.features-list li svg {
  width: 17px;
  height: 17px;
  flex-shrink: 0;
  color: #10b981;
  margin-top: 2px;
}

.features-list li.highlight-item {
  color: #ffffff;
  font-weight: 600;
}

.features-list li.highlight-item svg {
  color: var(--cyan-primary);
}

.card-action {
  margin-top: auto;
}

.card-action .btn {
  width: 100%;
}

.pricing-guarantee-note {
  margin-top: 36px;
  text-align: center;
  font-size: 14px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.pricing-guarantee-note span {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: #cbd5e1;
}

/* ==========================================================================
   全平台客户端支持 (Clients Compatibility)
   ========================================================================== */
.clients-section {
  padding: 60px 0;
}

.clients-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

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

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

.client-os-icon {
  width: 44px;
  height: 44px;
  margin: 0 auto 14px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--cyan-primary);
}

.client-name {
  font-size: 17px;
  font-weight: 700;
  margin-bottom: 6px;
  color: #ffffff;
}

.client-apps {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ==========================================================================
   文章与知识库区域 (Articles Knowledge Base)
   ========================================================================== */
.articles-section {
  padding: 70px 0;
}

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

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 22px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-fast);
  backdrop-filter: blur(10px);
}

.article-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  background: var(--bg-card-hover);
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.5);
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  font-size: 12px;
  color: var(--text-dim);
}

.article-category {
  padding: 2px 8px;
  border-radius: 4px;
  background: rgba(0, 242, 254, 0.1);
  color: var(--cyan-primary);
  font-weight: 600;
}

.article-title {
  font-size: 16.5px;
  font-weight: 700;
  line-height: 1.45;
  color: #ffffff;
  margin-bottom: 10px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

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

.article-excerpt {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 12px;
  border-top: 1px solid var(--border-subtle);
  font-size: 12.5px;
  color: var(--blue-primary);
  font-weight: 600;
}

.article-footer span {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* ==========================================================================
   用户口碑评价 (User Reviews)
   ========================================================================== */
.reviews-section {
  padding: 70px 0;
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 26px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  backdrop-filter: blur(12px);
  transition: all var(--transition-fast);
}

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

.review-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.reviewer-info {
  display: flex;
  align-items: center;
  gap: 12px;
}

.reviewer-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #00f2fe, #6366f1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: #020617;
  font-size: 16px;
}

.reviewer-name {
  font-size: 15px;
  font-weight: 700;
  color: #ffffff;
}

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

.review-stars {
  color: #f59e0b;
  font-size: 14px;
  letter-spacing: 2px;
}

.review-body {
  font-size: 14px;
  color: #cbd5e1;
  line-height: 1.65;
  margin-bottom: 16px;
}

.review-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-dim);
  border-top: 1px solid var(--border-subtle);
  padding-top: 12px;
}

.verified-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: #10b981;
  font-weight: 600;
}

/* ==========================================================================
   常见问题 FAQ (Accordion Cards)
   ========================================================================== */
.faq-section {
  padding: 70px 0;
}

.faq-list {
  max-width: 920px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 22px 26px;
  transition: all var(--transition-fast);
}

.faq-item:hover {
  border-color: var(--border-highlight);
  background: var(--bg-card-hover);
}

.faq-question {
  font-size: 17px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.faq-question svg {
  color: var(--cyan-primary);
  flex-shrink: 0;
}

.faq-answer {
  font-size: 14.5px;
  color: var(--text-muted);
  line-height: 1.7;
  padding-left: 28px;
}

/* ==========================================================================
   权威外链生态区 (Outbound Resources)
   ========================================================================== */
.ecosystem-section {
  padding: 50px 0;
}

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

.ecosystem-link-card {
  display: flex;
  align-items: center;
  gap: 12px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  transition: all var(--transition-fast);
}

.ecosystem-link-card:hover {
  background: rgba(0, 242, 254, 0.08);
  border-color: rgba(0, 242, 254, 0.3);
  transform: translateY(-2px);
}

.ecosystem-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--cyan-primary);
  flex-shrink: 0;
}

.ecosystem-title {
  font-size: 14px;
  font-weight: 700;
  color: #ffffff;
}

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

/* ==========================================================================
   页尾 Footer
   ========================================================================== */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  background: #02050f;
  padding: 60px 0 30px;
  font-size: 14px;
  color: var(--text-dim);
  position: relative;
  z-index: 2;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 36px;
  margin-bottom: 48px;
}

.footer-brand p {
  margin-top: 14px;
  font-size: 14px;
  color: var(--text-muted);
  max-width: 340px;
  line-height: 1.6;
}

.footer-col-title {
  font-size: 15px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

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

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-subtle);
  padding-top: 24px;
  font-size: 13px;
}

/* ==========================================================================
   文章详情页专有样式 (Article Detail Page Layout)
   ========================================================================== */
.article-detail-wrap {
  padding: 50px 0 80px;
  max-width: 900px;
  margin: 0 auto;
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13.5px;
  color: var(--text-dim);
  margin-bottom: 24px;
}

.breadcrumb-nav a:hover {
  color: var(--cyan-primary);
}

.article-header {
  margin-bottom: 36px;
}

.article-header h1 {
  font-size: clamp(26px, 3.8vw, 42px);
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 18px;
  color: #ffffff;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  font-size: 13.5px;
  color: var(--text-muted);
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-subtle);
}

.article-toc {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-left: 3px solid var(--cyan-primary);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin-bottom: 36px;
}

.article-toc-title {
  font-size: 16px;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 10px;
}

.article-toc ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.article-toc a {
  font-size: 14px;
  color: var(--text-muted);
}

.article-toc a:hover {
  color: var(--cyan-primary);
  padding-left: 4px;
}

.article-content {
  font-size: 16.5px;
  line-height: 1.85;
  color: #e2e8f0;
}

.article-content h2 {
  font-size: 24px;
  font-weight: 800;
  color: #ffffff;
  margin: 40px 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.article-content h3 {
  font-size: 19px;
  font-weight: 700;
  color: #f1f5f9;
  margin: 28px 0 12px;
}

.article-content p {
  margin-bottom: 20px;
}

.article-content ul, .article-content ol {
  margin: 16px 0 24px 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.article-content li {
  line-height: 1.7;
}

.article-callout {
  background: rgba(0, 242, 254, 0.06);
  border: 1px solid rgba(0, 242, 254, 0.25);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin: 28px 0;
}

.article-callout-title {
  font-weight: 800;
  color: var(--cyan-primary);
  margin-bottom: 8px;
  font-size: 15.5px;
}

.article-cta-box {
  background: linear-gradient(135deg, rgba(14, 30, 70, 0.9) 0%, rgba(6, 14, 36, 0.9) 100%);
  border: 1px solid var(--border-highlight);
  border-radius: var(--radius-lg);
  padding: 36px;
  text-align: center;
  margin: 44px 0;
  box-shadow: 0 12px 36px rgba(0, 242, 254, 0.15);
}

.article-cta-box h3 {
  font-size: 24px;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 10px;
}

.article-cta-box p {
  font-size: 15px;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 22px;
}

.related-articles-section {
  margin-top: 60px;
  padding-top: 36px;
  border-top: 1px solid var(--border-subtle);
}

/* ==========================================================================
   移动端与响应式适配 (@media queries)
   ========================================================================== */
@media (max-width: 1024px) {
  .pricing-row-container {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .clients-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .ecosystem-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-top {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stat-item:nth-child(2)::after {
    display: none;
  }
  .pricing-row-container {
    grid-template-columns: 1fr;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .articles-grid {
    grid-template-columns: 1fr;
  }
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  .clients-grid {
    grid-template-columns: 1fr;
  }
  .ecosystem-grid {
    grid-template-columns: 1fr;
  }
  .footer-top {
    grid-template-columns: 1fr;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
}