/* ==========================================================================
   biznet (bitznet.baby) - 官方品牌落地页样式体系
   模板：09 · 宇宙星轨动态风 | 框架：55 · 价格计算器
   ========================================================================== */

:root {
  /* 宇宙星轨色盘 (Deep Cosmic Palette) */
  --space-black: #05070E;
  --space-dark: #0A0F1D;
  --space-navy: #0F172A;
  --space-surface: rgba(15, 23, 42, 0.72);
  --space-surface-hover: rgba(30, 41, 59, 0.85);
  --space-border: rgba(148, 163, 184, 0.14);
  --space-border-glow: rgba(56, 189, 248, 0.35);

  /* 星轨科技流光 */
  --star-cyan: #38BDF8;
  --star-indigo: #6366F1;
  --star-purple: #8B5CF6;
  --star-pink: #EC4899;
  --star-emerald: #10B981;
  --star-amber: #F59E0B;

  /* 文字系统 */
  --text-pure: #FFFFFF;
  --text-main: #F1F5F9;
  --text-muted: #94A3B8;
  --text-dim: #64748B;
  --text-glow: 0 0 20px rgba(56, 189, 248, 0.45);

  /* 基础度量 */
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  --container-max: 1240px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 32px;
  --radius-pill: 9999px;

  /* 转场与动画缓动 */
  --ease-spring: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-main);
  background-color: var(--space-black);
  color: var(--text-main);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
  background: radial-gradient(circle at 50% 0%, #151C35 0%, #080D1A 45%, #04060B 100%);
}

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

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

button, input, select {
  font-family: inherit;
  border: none;
  outline: none;
  background: transparent;
}

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

/* ==========================================================================
   导航头部 (Glassmorphism Navbar)
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 16px 0;
  background: rgba(8, 13, 26, 0.75);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--space-border);
  transition: padding var(--transition-normal), background var(--transition-normal);
}

.site-header.scrolled {
  padding: 12px 0;
  background: rgba(5, 8, 16, 0.92);
  border-bottom-color: rgba(56, 189, 248, 0.2);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

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

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

.brand-logo-img {
  height: 40px;
  width: auto;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
  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: var(--text-pure);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--star-cyan), var(--star-purple));
  transition: width 0.3s var(--ease-spring);
  border-radius: 2px;
}

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

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

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 14.5px;
  padding: 10px 22px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all 0.3s var(--ease-spring);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, #0284C7 0%, #4F46E5 50%, #7C3AED 100%);
  color: var(--text-pure);
  box-shadow: 0 0 24px rgba(79, 70, 229, 0.45);
  border: 1px solid rgba(255, 255, 255, 0.18);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(56, 189, 248, 0.6);
  border-color: rgba(255, 255, 255, 0.4);
}

.btn-secondary {
  background: rgba(30, 41, 59, 0.5);
  color: var(--text-main);
  border: 1px solid var(--space-border);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(51, 65, 85, 0.8);
  border-color: var(--star-cyan);
  color: var(--text-pure);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 13.5px;
}

.btn-lg {
  padding: 14px 34px;
  font-size: 16px;
  border-radius: var(--radius-pill);
}

/* 移动端菜单按钮 */
.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-around;
  width: 28px;
  height: 24px;
  cursor: pointer;
  z-index: 1001;
}

.mobile-toggle span {
  width: 100%;
  height: 2px;
  background-color: var(--text-pure);
  transition: var(--transition-normal);
  border-radius: 2px;
}

/* ==========================================================================
   Hero 首屏宇宙星轨展示区
   ========================================================================== */
.hero-section {
  position: relative;
  min-height: 92vh;
  padding-top: 140px;
  padding-bottom: 70px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero-content {
  position: relative;
  z-index: 10;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 6px 18px;
  border-radius: var(--radius-pill);
  background: rgba(30, 41, 59, 0.6);
  border: 1px solid rgba(56, 189, 248, 0.3);
  font-size: 13.5px;
  font-weight: 500;
  color: var(--star-cyan);
  margin-bottom: 24px;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.15);
}

.hero-pill-status {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--star-emerald);
  box-shadow: 0 0 10px var(--star-emerald);
  animation: pulseLight 2s infinite;
}

@keyframes pulseLight {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.hero-title {
  font-size: clamp(34px, 5.5vw, 64px);
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 22px;
  color: var(--text-pure);
}

.hero-title .gradient-text {
  background: linear-gradient(135deg, #38BDF8 10%, #818CF8 50%, #C084FC 90%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  text-shadow: 0 0 30px rgba(99, 102, 241, 0.4);
}

.hero-description {
  font-size: clamp(16px, 2vw, 19px);
  color: var(--text-muted);
  max-width: 740px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

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

/* Hero 状态看板 */
.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  max-width: 860px;
  margin: 0 auto;
}

.metric-card {
  padding: 18px 16px;
  background: var(--space-surface);
  border: 1px solid var(--space-border);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  transition: transform var(--transition-normal), border-color var(--transition-normal);
}

.metric-card:hover {
  transform: translateY(-4px);
  border-color: rgba(56, 189, 248, 0.4);
  background: var(--space-surface-hover);
}

.metric-value {
  font-size: 26px;
  font-weight: 800;
  color: var(--star-cyan);
  font-family: var(--font-display);
  line-height: 1.2;
}

.metric-label {
  font-size: 13px;
  color: var(--text-dim);
  margin-top: 4px;
}

/* ==========================================================================
   模块通用头
   ========================================================================== */
.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px;
}

.section-tag {
  display: inline-block;
  font-size: 12.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--star-cyan);
  margin-bottom: 12px;
  padding: 4px 12px;
  background: rgba(56, 189, 248, 0.08);
  border-radius: var(--radius-pill);
  border: 1px solid rgba(56, 189, 248, 0.2);
}

.section-title {
  font-size: clamp(28px, 3.8vw, 42px);
  font-weight: 800;
  line-height: 1.25;
  color: var(--text-pure);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 16.5px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ==========================================================================
   核心技术特性矩阵
   ========================================================================== */
.features-section {
  padding: 100px 0;
  position: relative;
  z-index: 5;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  position: relative;
  background: var(--space-surface);
  border: 1px solid var(--space-border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  backdrop-filter: blur(14px);
  transition: all 0.4s var(--ease-spring);
  overflow: hidden;
}

.feature-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--star-cyan), transparent);
  opacity: 0;
  transition: opacity 0.3s;
}

.feature-card:hover {
  transform: translateY(-6px);
  border-color: rgba(56, 189, 248, 0.4);
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.4), 0 0 20px rgba(56, 189, 248, 0.1);
}

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

.feature-icon-box {
  width: 54px;
  height: 54px;
  border-radius: var(--radius-md);
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--star-cyan);
  margin-bottom: 22px;
}

.feature-icon-box svg {
  width: 28px;
  height: 28px;
}

.feature-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 12px;
}

.feature-desc {
  font-size: 14.5px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ==========================================================================
   全球节点拓扑与延迟展示
   ========================================================================== */
.nodes-section {
  padding: 100px 0;
  position: relative;
  z-index: 5;
}

.nodes-matrix {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 32px;
}

.node-item {
  background: var(--space-surface);
  border: 1px solid var(--space-border);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  backdrop-filter: blur(10px);
  transition: var(--transition-normal);
}

.node-item:hover {
  border-color: var(--star-cyan);
  background: var(--space-surface-hover);
  transform: translateY(-2px);
}

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

.node-flag {
  font-size: 24px;
  line-height: 1;
}

.node-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-pure);
}

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

.node-ping {
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  color: var(--star-emerald);
}

.ping-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--star-emerald);
  box-shadow: 0 0 6px var(--star-emerald);
}

/* ==========================================================================
   客户端生态与下载平台
   ========================================================================== */
.clients-section {
  padding: 100px 0;
  position: relative;
  z-index: 5;
}

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

.client-card {
  background: var(--space-surface);
  border: 1px solid var(--space-border);
  border-radius: var(--radius-lg);
  padding: 28px 22px;
  text-align: center;
  backdrop-filter: blur(12px);
  transition: all 0.3s var(--ease-spring);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.client-card:hover {
  transform: translateY(-6px);
  border-color: rgba(99, 102, 241, 0.45);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.4);
}

.client-icon {
  width: 58px;
  height: 58px;
  border-radius: 50%;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
  color: var(--star-indigo);
}

.client-name {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 6px;
}

.client-tag {
  font-size: 12px;
  color: var(--star-cyan);
  margin-bottom: 14px;
}

.client-desc {
  font-size: 13.5px;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

/* ==========================================================================
   深度原创文章专栏 (SEO强化 & Bing自然收录引擎)
   ========================================================================== */
.articles-section {
  padding: 100px 0;
  position: relative;
  z-index: 5;
}

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

.article-card {
  background: var(--space-surface);
  border: 1px solid var(--space-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  backdrop-filter: blur(14px);
  transition: all 0.3s var(--ease-spring);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--star-cyan);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.45);
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
  font-size: 12.5px;
  color: var(--text-dim);
}

.article-tag {
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  background: rgba(56, 189, 248, 0.1);
  color: var(--star-cyan);
  font-weight: 600;
}

.article-card-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-pure);
  line-height: 1.4;
  margin-bottom: 12px;
}

.article-card-excerpt {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-link {
  font-size: 14px;
  font-weight: 600;
  color: var(--star-cyan);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.article-link svg {
  width: 16px;
  height: 16px;
  transition: transform 0.2s;
}

.article-card:hover .article-link svg {
  transform: translateX(4px);
}

/* ==========================================================================
   常见问答 FAQ 手风琴
   ========================================================================== */
.faq-section {
  padding: 100px 0;
  position: relative;
  z-index: 5;
}

.faq-list {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--space-surface);
  border: 1px solid var(--space-border);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  overflow: hidden;
  transition: border-color var(--transition-normal);
}

.faq-item.active {
  border-color: rgba(56, 189, 248, 0.4);
}

.faq-question {
  width: 100%;
  text-align: left;
  padding: 20px 24px;
  font-size: 17px;
  font-weight: 600;
  color: var(--text-pure);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  background: transparent;
}

.faq-icon {
  width: 20px;
  height: 20px;
  transition: transform 0.3s var(--ease-spring);
  color: var(--star-cyan);
  flex-shrink: 0;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s var(--ease-spring), padding 0.3s ease;
  padding: 0 24px;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 24px 20px 24px;
}

.faq-answer p {
  font-size: 14.5px;
  color: var(--text-muted);
  line-height: 1.75;
}

/* ==========================================================================
   底部版权与合规区 (Footer)
   ========================================================================== */
.site-footer {
  background: #03050A;
  border-top: 1px solid var(--space-border);
  padding: 70px 0 30px;
  position: relative;
  z-index: 10;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.2fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-brand p {
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.7;
  max-width: 320px;
  margin: 16px 0 20px;
}

.footer-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--star-emerald);
  padding: 4px 10px;
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.2);
  border-radius: var(--radius-pill);
}

.footer-col h4 {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-pure);
  margin-bottom: 18px;
  letter-spacing: 0.5px;
}

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

.footer-links a {
  font-size: 13.5px;
  color: var(--text-muted);
}

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

.footer-bottom {
  border-top: 1px solid rgba(148, 163, 184, 0.08);
  padding-top: 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: var(--text-dim);
  flex-wrap: wrap;
  gap: 16px;
}

/* ==========================================================================
   自适应断点 (Responsive Breakpoints)
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-metrics {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .nodes-matrix {
    grid-template-columns: repeat(2, 1fr);
  }
  .clients-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-top {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  .nav-menu, .nav-actions .btn-secondary {
    display: none;
  }
  .mobile-toggle {
    display: flex;
  }
  .hero-section {
    padding-top: 120px;
  }
  .hero-title {
    font-size: 36px;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .nodes-matrix {
    grid-template-columns: 1fr;
  }
  .clients-grid {
    grid-template-columns: 1fr;
  }
  .articles-grid {
    grid-template-columns: 1fr;
  }
  .footer-top {
    grid-template-columns: 1fr;
    gap: 30px;
  }
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}