/* 
   Tecdao 官网原型全局样式表
   基于 网站设计规划.md 实施的深色高科技感 UI 规范
*/

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;600&display=swap');

:root {
  /* 品牌色彩系统 */
  --brand-primary: #6366f1; /* Indigo-500 */
  --brand-primary-dark: #4f46e5; /* Indigo-600 */
  --brand-primary-glow: rgba(99, 102, 241, 0.15);
  --brand-accent: #10b981; /* Emerald-500 */
  --brand-accent-dark: #059669; /* Emerald-600 */
  --brand-accent-glow: rgba(16, 185, 129, 0.15);
  
  /* 背景层次系统 */
  --bg-primary: #0f172a; /* Slate-900 */
  --bg-secondary: #1e293b; /* Slate-800 */
  --bg-card: #1e293b; /* Slate-800 */
  --bg-card-hover: rgba(30, 41, 59, 0.8);
  --bg-sub-card: #334155; /* Slate-700 */
  
  /* 文字与边框 */
  --text-primary: #f8fafc; /* Slate-50 */
  --text-secondary-correct: #94a3b8; /* Slate-400 */
  --text-muted: #64748b; /* Slate-500 */
  --border: #1e293b; /* Slate-800 */
  --border-light: rgba(51, 65, 85, 0.5); /* Slate-700 柔和版 */

  /* 字体系统 */
  --font-heading: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-body: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* 间距 Scale (8px base) */
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-5: 40px;
  --space-6: 48px;
  --space-7: 56px;
  --space-8: 64px;
  --space-10: 80px;
  --space-12: 96px;
  --space-16: 128px;
  
  /* 过渡效果 */
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);

  /* 容器宽度 */
  --container-max-width: 1280px;
}

/* 全局重置与基础样式 */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

body {
  font-family: var(--font-body);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

/* 页面主体渐变背景和网格装饰 */
.site-wrapper {
  position: relative;
  min-height: 100vh;
  background-image: 
    radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.05) 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, rgba(16, 185, 129, 0.04) 0%, transparent 40%);
}

/* 导航栏样式 */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  background-color: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(30, 41, 59, 0.5);
  height: 80px;
  display: flex;
  align-items: center;
}

.navbar-container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-3);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, #fff 0%, var(--brand-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo svg { flex-shrink: 0; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

/* 导航下拉 */
.nav-item-dropdown {
  position: relative;
}

.nav-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary-correct);
  position: relative;
  padding: 24px 0;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 12px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--brand-primary) 0%, var(--brand-accent) 100%);
  transition: var(--transition-normal);
}

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

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(10px);
  background-color: rgba(30, 41, 59, 0.95);
  backdrop-filter: blur(25px);
  -webkit-backdrop-filter: blur(25px);
  border: 1px solid var(--border-light);
  border-radius: 16px;
  padding: var(--space-2);
  min-width: 250px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast), transform var(--transition-fast), visibility var(--transition-fast);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

/* JS 控制的 open 状态替代 :hover */
.dropdown-menu.open {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.dropdown-item {
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 13.5px;
  color: var(--text-secondary-correct);
  display: flex;
  align-items: center;
  gap: 10px;
  transition: var(--transition-fast);
  cursor: pointer;
}

.dropdown-item:hover {
  background-color: rgba(99, 102, 241, 0.1);
  color: var(--text-primary);
  padding-left: 18px;
}

.dropdown-item-desc {
  font-size: 11px;
  color: var(--text-muted);
  display: block;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* 按钮组件 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 24px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-normal);
  border: none;
  outline: none;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--brand-primary);
  color: #fff;
  box-shadow: 0 4px 20px var(--brand-primary-glow);
}

.btn-primary:hover {
  background-color: var(--brand-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(99, 102, 241, 0.3);
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-light);
}

.btn-secondary:hover {
  border-color: var(--brand-primary);
  color: #fff;
  background-color: rgba(99, 102, 241, 0.05);
  transform: translateY(-2px);
}

.btn-accent {
  background-color: var(--brand-accent);
  color: var(--bg-primary);
  box-shadow: 0 4px 20px var(--brand-accent-glow);
}

.btn-accent:hover {
  background-color: var(--brand-accent-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(16, 185, 129, 0.3);
}

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

/* 汉堡菜单按钮 (移动端) */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 24px;
  height: 18px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 110;
}

.menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--text-primary);
  transition: var(--transition-normal);
}

/* 移动端导航抽屉 */
.mobile-nav {
  position: fixed;
  top: 0;
  right: -100%;
  width: 80%;
  max-width: 320px;
  height: 100vh;
  background-color: rgba(15, 23, 42, 0.98);
  border-left: 1px solid var(--border);
  z-index: 105;
  display: flex;
  flex-direction: column;
  padding: 100px 40px 40px;
  gap: var(--space-3);
  transition: var(--transition-normal);
  overflow-y: auto;
}

.mobile-nav.open {
  right: 0;
}

.mobile-nav-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: rgba(0, 0, 0, 0.6);
  z-index: 104;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition-normal);
}

.mobile-nav-overlay.show {
  opacity: 1;
  visibility: visible;
}

.mobile-dropdown-header {
  font-size: 12px;
  font-weight: 700;
  color: var(--brand-primary);
  text-transform: uppercase;
  margin-top: 12px;
  border-bottom: 1px solid var(--border-light);
  padding-bottom: 4px;
}

/* 排版层级 */
h1, h2, h3, h4, h5 {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.15;
}

h1 { font-size: 3.5rem; letter-spacing: -1.5px; }
h2 { font-size: 2.5rem; letter-spacing: -0.75px; }
h3 { font-size: 1.5rem; letter-spacing: -0.25px; }
h4 { font-size: 1rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px; }

.gradient-text {
  background: linear-gradient(135deg, #fff 20%, var(--brand-primary) 60%, var(--brand-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.gradient-accent-text {
  background: linear-gradient(135deg, var(--brand-accent) 0%, #fff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* 区块与布局组件 */
section {
  padding: var(--space-12) var(--space-3);
}

.section-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto var(--space-8);
}

.section-header h2 {
  margin-bottom: var(--space-2);
}

.section-header p {
  font-size: 1.125rem;
  color: var(--text-secondary-correct);
}

/* 卡片基础设计 */
.card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: 16px;
  padding: var(--space-4);
  transition: var(--transition-normal);
}

.card:hover {
  border-color: rgba(99, 102, 241, 0.3);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.5);
}

/* 常用徽章与标签 */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  border-radius: 100px;
  font-size: 12px;
  font-weight: 600;
  background-color: rgba(99, 102, 241, 0.1);
  color: var(--brand-primary);
  border: 1px solid rgba(99, 102, 241, 0.2);
  margin-bottom: var(--space-2);
}

.badge-accent {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--brand-accent);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

/* 推荐信样式 (替代 border-left 模式) */
.testimonial-card {
  position: relative;
  padding: var(--space-5) var(--space-4);
  background: linear-gradient(135deg, rgba(30, 41, 59, 0.6) 0%, rgba(15, 23, 42, 0.6) 100%);
  border: 1px solid var(--border-light);
  border-radius: 16px;
}

.testimonial-card::before {
  content: '"';
  position: absolute;
  top: 8px;
  left: var(--space-3);
  font-size: 64px;
  line-height: 1;
  font-family: Georgia, serif;
  color: var(--brand-primary);
  opacity: 0.3;
  pointer-events: none;
}

.testimonial-stars {
  color: var(--brand-accent);
  font-size: 18px;
  letter-spacing: 2px;
  margin-bottom: var(--space-2);
}

.testimonial-text {
  font-style: italic;
  font-size: 16px;
  line-height: 1.7;
  margin-bottom: var(--space-3);
  color: var(--text-secondary-correct);
}

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

.testimonial-author strong {
  color: var(--text-primary);
  font-size: 14px;
}

.testimonial-author span {
  color: var(--text-muted);
  font-size: 13px;
}

/* Pricing Overview Section */
.pricing-overview-card {
  background: linear-gradient(135deg, rgba(30, 41, 59, 0.9) 0%, rgba(15, 23, 42, 0.9) 100%);
  border: 1px solid var(--border-light);
  border-radius: 24px;
  padding: var(--space-6);
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
  box-shadow: 0 15px 35px rgba(0,0,0,0.3);
  position: relative;
  overflow: hidden;
}

.pricing-overview-card::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.05) 0%, transparent 60%);
  pointer-events: none;
}

/* 页脚 */
.footer {
  background-color: #0b0f19;
  border-top: 1px solid var(--border);
  padding: var(--space-10) var(--space-3) var(--space-5);
  color: var(--text-secondary-correct);
}

.footer-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-7);
}

.footer-brand p {
  margin-top: var(--space-2);
  font-size: 14px;
  max-width: 280px;
}

.footer-links h4 {
  font-size: 13px;
  margin-bottom: var(--space-3);
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: 12px;
}

.footer-links a {
  font-size: 14px;
}

.footer-links a:hover {
  color: var(--brand-primary);
  padding-left: 4px;
}

.footer-bottom {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding-top: var(--space-5);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--text-muted);
}

.footer-socials {
  display: flex;
  gap: 20px;
}

.footer-socials a:hover {
  color: var(--text-primary);
}

/* 通用无障碍焦点环 */
*:focus-visible {
  outline: 2px solid var(--brand-primary);
  outline-offset: 4px;
}

/* 无障碍: 尊重用户的动效偏好 */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* 入场动效 (Intersection Observer 驱动) */
.anim-fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.anim-fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

.anim-stagger > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

.anim-stagger.visible > *:nth-child(1) { transition-delay: 0ms; }
.anim-stagger.visible > *:nth-child(2) { transition-delay: 100ms; }
.anim-stagger.visible > *:nth-child(3) { transition-delay: 200ms; }
.anim-stagger.visible > *:nth-child(4) { transition-delay: 300ms; }
.anim-stagger.visible > *:nth-child(5) { transition-delay: 400ms; }
.anim-stagger.visible > * {
  opacity: 1;
  transform: translateY(0);
}

/* SVG 图标基础 */
.icon-svg {
  width: 1em;
  height: 1em;
  display: inline-block;
  vertical-align: -0.125em;
  flex-shrink: 0;
}

/* 响应式样式适配 */
@media (max-width: 1024px) {
  h1 { font-size: 2.75rem; }
  h2 { font-size: 2rem; }
  section {
    padding: var(--space-10) var(--space-3);
  }
  .footer-container {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-5);
  }
  .footer-brand {
    grid-column: span 2;
  }
}

@media (max-width: 900px) {
  h1 { font-size: 2.25rem; letter-spacing: -0.75px; }
  h2 { font-size: 1.75rem; letter-spacing: -0.25px; }
  h3 { font-size: 1.25rem; }
  section {
    padding: var(--space-8) 20px;
  }
  .section-header {
    margin-bottom: var(--space-6);
  }
  .nav-links, .nav-actions {
    display: none;
  }
  .menu-toggle {
    display: flex;
  }
  
  /* 汉堡菜单激活状态 */
  .menu-toggle.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }
  .menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  .menu-toggle.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }
  
  .footer-container {
    grid-template-columns: 1fr;
    gap: var(--space-5);
  }
  .footer-brand {
    grid-column: span 1;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 20px;
    text-align: center;
  }
}