/* ==========================================================================
   夜煞云 (Night Fury Cloud) - 全局品牌视觉样式表
   配色哲学：暗夜深空底色 (#0B0F19) + 夜煞电光紫/青极速渐变 (#7C3AED / #06B6D4)
   ========================================================================== */

:root {
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: #1f293d;
  --bg-card-hover: #28354e;
  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --text-dim: #6b7280;

  --accent-purple: #7c3aed;
  --accent-cyan: #06b6d4;
  --accent-pink: #ec4899;
  --accent-green: #10b981;
  --accent-amber: #f59e0b;

  --gradient-brand: linear-gradient(135deg, #7c3aed 0%, #06b6d4 100%);
  --gradient-brand-glow: linear-gradient(135deg, rgba(124, 58, 237, 0.4) 0%, rgba(6, 182, 212, 0.4) 100%);
  --gradient-card: linear-gradient(180deg, rgba(31, 41, 61, 0.8) 0%, rgba(17, 24, 39, 0.9) 100%);

  --border-light: rgba(255, 255, 255, 0.08);
  --border-accent: rgba(124, 58, 237, 0.3);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "Fira Code", Consolas, Monaco, "Courier New", monospace;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --shadow-glow: 0 0 25px rgba(124, 58, 237, 0.25);
  --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.5);

  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s 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-size: 16px;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
  color: #38bdf8;
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* 容器居中 */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

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

/* 按钮基础 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.8rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: center;
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-brand);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(124, 58, 237, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 28px rgba(6, 182, 212, 0.6);
  color: #ffffff;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border: 1px solid var(--border-light);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--accent-purple);
  color: #ffffff;
}

.btn-lg {
  padding: 1.1rem 2.4rem;
  font-size: 1.1rem;
}

.btn-sm {
  padding: 0.5rem 1.2rem;
  font-size: 0.875rem;
}

/* 头部导航栏 */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(11, 15, 25, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-light);
  transition: all var(--transition-fast);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.4rem;
  font-weight: 700;
  color: #ffffff;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--gradient-brand);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-glow);
}

.logo-icon svg {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: #ffffff;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 2rem;
}

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

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

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-main);
  cursor: pointer;
}

/* Hero 首屏区 */
.hero {
  padding-top: 170px;
  padding-bottom: 100px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(124, 58, 237, 0.25) 0%, rgba(6, 182, 212, 0.1) 50%, rgba(11, 15, 25, 0) 70%);
  z-index: 0;
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background: rgba(124, 58, 237, 0.15);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  color: var(--accent-cyan);
  margin-bottom: 1.5rem;
}

.hero-badge span {
  width: 8px;
  height: 8px;
  background: var(--accent-cyan);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-cyan);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(1.3); }
  100% { opacity: 1; transform: scale(1); }
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1.5rem;
  letter-spacing: -0.02em;
}

.hero-desc {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  line-height: 1.8;
  max-width: 780px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.2rem;
  margin-bottom: 3.5rem;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  margin-top: 3rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--border-light);
}

.stat-item {
  text-align: center;
}

.stat-num {
  font-size: 2rem;
  font-weight: 800;
  color: #ffffff;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* 核心优势板块 */
.section {
  padding: 90px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 4rem auto;
}

.section-tag {
  font-size: 0.875rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-cyan);
  letter-spacing: 0.1em;
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

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

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

/* 特性卡片 */
.feature-card {
  background: var(--gradient-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 2.2rem;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

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

.feature-icon {
  width: 54px;
  height: 54px;
  background: rgba(124, 58, 237, 0.1);
  border: 1px solid rgba(124, 58, 237, 0.2);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  color: var(--accent-cyan);
}

.feature-icon svg {
  width: 28px;
  height: 28px;
  stroke: var(--accent-cyan);
  fill: none;
  stroke-width: 2;
}

.feature-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: #ffffff;
}

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

/* 测速与对比展示区 */
.speed-demo-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  margin-top: 2rem;
}

.speed-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1.5rem;
  text-align: left;
}

.speed-table th, .speed-table td {
  padding: 1.1rem 1.5rem;
  border-bottom: 1px solid var(--border-light);
}

.speed-table th {
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-main);
  font-weight: 600;
  font-size: 0.95rem;
}

.speed-table td {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.speed-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
}

.speed-badge.green {
  background: rgba(16, 185, 129, 0.15);
  color: #34d399;
}

.speed-badge.purple {
  background: rgba(124, 58, 237, 0.15);
  color: #c084fc;
}

/* 套餐价格板块 */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  align-items: stretch;
}

.price-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-normal);
}

.price-card.popular {
  background: linear-gradient(180deg, rgba(31, 41, 61, 0.95) 0%, rgba(17, 24, 39, 0.98) 100%);
  border: 2px solid var(--accent-purple);
  box-shadow: 0 0 35px rgba(124, 58, 237, 0.3);
  transform: scale(1.03);
}

.popular-badge {
  position: absolute;
  top: -15px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-brand);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.3rem 1.2rem;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
}

.price-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 0.5rem;
}

.price-subtitle {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.price-amount {
  font-size: 3rem;
  font-weight: 800;
  color: #ffffff;
  line-height: 1;
  margin-bottom: 1.5rem;
}

.price-amount span {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 400;
}

.price-features {
  margin-bottom: 2rem;
  flex-grow: 1;
}

.price-features li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.85rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.price-features li svg {
  width: 18px;
  height: 18px;
  stroke: var(--accent-cyan);
  flex-shrink: 0;
}

/* 客户端教程 Tabs */
.tutorial-tabs {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.tab-btn {
  padding: 0.8rem 1.8rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-full);
  color: var(--text-muted);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.tab-btn:hover, .tab-btn.active {
  background: var(--gradient-brand);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 4px 15px rgba(124, 58, 237, 0.3);
}

.tutorial-content {
  display: none;
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
}

.tutorial-content.active {
  display: block;
}

.step-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.step-item {
  display: flex;
  gap: 1.5rem;
}

.step-num {
  width: 40px;
  height: 40px;
  background: rgba(124, 58, 237, 0.15);
  border: 1px solid var(--accent-purple);
  color: var(--accent-cyan);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.step-body h4 {
  font-size: 1.1rem;
  color: #ffffff;
  margin-bottom: 0.5rem;
}

.step-body p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* FAQ 手风琴 */
.faq-grid {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 900px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

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

.faq-question {
  width: 100%;
  padding: 1.4rem 1.8rem;
  background: none;
  border: none;
  text-align: left;
  color: #ffffff;
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.faq-question svg {
  width: 20px;
  height: 20px;
  stroke: var(--accent-cyan);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 1.8rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 400px;
  padding: 0 1.8rem 1.4rem 1.8rem;
}

/* 文章卡片网格 */
.article-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 1.8rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-normal);
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-card);
}

.article-tag {
  font-size: 0.8rem;
  color: var(--accent-cyan);
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.article-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.article-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 1.2rem;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-link {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--accent-cyan);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

/* 文章详情页专用排版 */
.article-header {
  padding-top: 140px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--border-light);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.breadcrumb a {
  color: var(--text-muted);
}

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

.article-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  font-size: 0.875rem;
  color: var(--text-dim);
  margin-top: 1rem;
}

.article-body {
  padding: 50px 0;
  max-width: 860px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.85;
  color: #d1d5db;
}

.article-body h2 {
  font-size: 1.8rem;
  color: #ffffff;
  margin: 2.5rem 0 1.2rem 0;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-light);
}

.article-body h3 {
  font-size: 1.35rem;
  color: #f3f4f6;
  margin: 1.8rem 0 1rem 0;
}

.article-body p {
  margin-bottom: 1.5rem;
}

.article-body ul, .article-body ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-body ul li {
  list-style-type: disc;
  margin-bottom: 0.5rem;
}

.article-body ol li {
  list-style-type: decimal;
  margin-bottom: 0.5rem;
}

.callout-box {
  background: rgba(124, 58, 237, 0.08);
  border-left: 4px solid var(--accent-purple);
  border-radius: var(--radius-sm);
  padding: 1.2rem 1.5rem;
  margin: 1.8rem 0;
}

.callout-box.tip {
  background: rgba(6, 182, 212, 0.08);
  border-left-color: var(--accent-cyan);
}

.cta-box {
  background: linear-gradient(135deg, rgba(124, 58, 237, 0.15) 0%, rgba(6, 182, 212, 0.15) 100%);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  text-align: center;
  margin: 3rem 0;
}

.cta-box h3 {
  font-size: 1.6rem;
  color: #ffffff;
  margin-bottom: 0.8rem;
}

.cta-box p {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

/* 页脚 Footer */
.footer {
  background: #070a12;
  border-top: 1px solid var(--border-light);
  padding: 70px 0 30px 0;
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 3rem;
  margin-bottom: 4rem;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 1rem;
  line-height: 1.7;
}

.footer-col h4 {
  color: #ffffff;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1.2rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: #ffffff;
}

.footer-bottom {
  border-top: 1px solid var(--border-light);
  padding-top: 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--text-dim);
  font-size: 0.85rem;
}

/* 响应式适配 */
@media (max-width: 1024px) {
  .hero-title {
    font-size: 2.8rem;
  }
  .pricing-grid, .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
  .price-card.popular {
    transform: none;
  }
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-light);
    flex-direction: column;
    padding: 2rem;
    gap: 1.5rem;
    transform: translateY(-150%);
    transition: transform var(--transition-normal);
  }
  .nav-menu.open {
    transform: translateY(0);
  }
  .mobile-toggle {
    display: block;
  }
  .hero-title {
    font-size: 2.2rem;
  }
  .hero-desc {
    font-size: 1rem;
  }
  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid, .grid-3, .grid-2, .grid-4 {
    grid-template-columns: 1fr;
  }
  .tutorial-tabs {
    flex-wrap: wrap;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}