/* ==========================================================================
   云梯指南 (nodehub168.com) - Core Design System & Stylesheet
   Theme: Cyberpunk Tech Dark Mode
   ========================================================================== */

/* Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  /* Color Palette */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --card-bg: rgba(241, 245, 249, 0.6);
  --card-hover-border: rgba(0, 242, 254, 0.4);
  
  --accent-cyan: #00f2fe;
  --accent-purple: #9b51e0;
  --accent-cyan-rgb: 0, 242, 254;
  --accent-purple-rgb: 155, 81, 224;
  
  --text-main: #000000;
  --text-muted: #1e3a8a;
  --text-inverse: #ffffff;
  
  --border-color: rgba(15, 23, 42, 0.08);
  --border-glow: rgba(0, 242, 254, 0.15);
  
  /* Gradients */
  --grad-primary: linear-gradient(135deg, var(--accent-cyan) 0%, var(--accent-purple) 100%);
  --grad-dark: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
  
  /* Layout & Shadows */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow-neon: 0 0 20px rgba(0, 242, 254, 0.2);
  --shadow-neon-hover: 0 0 35px rgba(155, 81, 224, 0.35);
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(at 0% 0%, rgba(0, 242, 254, 0.05) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(155, 81, 224, 0.08) 0px, transparent 50%);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  border: 2px solid var(--bg-primary);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-cyan);
}

/* Typography elements */
h1, h2, h3, h4, h5, h6 {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--text-main);
}

a {
  color: #1e3a8a;
  text-decoration: none;
  transition: var(--transition-smooth);
}
a:hover {
  color: #2563eb;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Section Header */
.section-title {
  text-align: center;
  margin-bottom: 48px;
  position: relative;
}
.section-title h2 {
  font-size: 2.25rem;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
  margin-bottom: 12px;
}
.section-title p {
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
  font-size: 1.1rem;
}

/* Button Component */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1rem;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: var(--transition-smooth);
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.btn-primary {
  background: var(--grad-primary);
  color: var(--text-inverse);
  box-shadow: 0 4px 15px rgba(0, 242, 254, 0.3);
}
.btn-primary:hover {
  box-shadow: 0 6px 20px rgba(155, 81, 224, 0.5);
  transform: translateY(-2px);
}
.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--accent-purple) 0%, var(--accent-cyan) 100%);
  opacity: 0;
  z-index: -1;
  transition: var(--transition-smooth);
}
.btn-primary:hover::before {
  opacity: 1;
}

.btn-outline {
  background: transparent;
  color: var(--text-main);
  border: 1px solid rgba(0, 0, 0, 0.15);
}
.btn-outline:hover {
  border-color: var(--accent-cyan);
  color: #1e3a8a;
  box-shadow: var(--shadow-neon);
  transform: translateY(-2px);
}

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition-smooth);
}
.site-header.scrolled {
  border-bottom-color: rgba(0, 242, 254, 0.25);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}
.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}
.logo-area {
  display: flex;
  align-items: center;
  gap: 12px;
}
.logo-icon {
  width: 42px;
  height: 42px;
}
.logo-text {
  font-family: 'Outfit', sans-serif;
  font-size: 1.5rem;
  font-weight: 800;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: 1px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}
.nav-link {
  color: var(--text-main);
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  padding: 8px 0;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--grad-primary);
  transition: var(--transition-smooth);
}
.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}
.nav-link:hover {
  color: #1e3a8a;
}

.nav-cta {
  display: flex;
}

/* Hamburger menu button */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 30px;
  height: 20px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 1001;
}
.menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--text-main);
  transition: var(--transition-smooth);
  border-radius: 2px;
}

/* Hero Section */
.hero-section {
  position: relative;
  padding: 100px 0 120px;
  background: radial-gradient(circle at 50% 30%, rgba(155, 81, 224, 0.15) 0%, transparent 70%);
  border-bottom: 1px solid var(--border-color);
  overflow: hidden;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  align-items: center;
  gap: 48px;
}
.hero-content h1 {
  font-size: 3.5rem;
  line-height: 1.15;
  margin-bottom: 24px;
  background: linear-gradient(135deg, var(--text-main) 30%, #312e81 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-content h1 span {
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin-bottom: 40px;
  max-width: 600px;
}
.hero-actions {
  display: flex;
  gap: 16px;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(0, 242, 254, 0.08);
  border: 1px solid rgba(0, 242, 254, 0.2);
  border-radius: 50px;
  padding: 6px 16px;
  font-size: 0.85rem;
  color: #1e3a8a;
  font-weight: 600;
  margin-bottom: 24px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}
.visual-glow-sphere {
  position: absolute;
  width: 250px;
  height: 250px;
  border-radius: 50%;
  background: var(--grad-primary);
  filter: blur(80px);
  opacity: 0.25;
  animation: float-slow 8s infinite alternate;
}
.visual-box {
  width: 100%;
  max-width: 320px;
  aspect-ratio: 1;
  background: rgba(255, 255, 255, 0.8);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
  position: relative;
  z-index: 2;
  overflow: hidden;
  backdrop-filter: blur(10px);
}
.visual-box::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: conic-gradient(from 0deg, transparent 20%, var(--accent-cyan) 50%, transparent 80%);
  animation: rotate-border 10s linear infinite;
  z-index: -1;
  opacity: 0.4;
}
.visual-box-inner {
  width: 100%;
  height: 100%;
  background: var(--bg-secondary);
  border-radius: calc(var(--radius-lg) - 4px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 16px;
  border: 1px solid rgba(15, 23, 42, 0.05);
}
.visual-box-logo {
  width: 100px;
  height: 100px;
  animation: pulse-slow 4s infinite ease-in-out;
}

/* Intro Section */
.intro-section {
  padding: 100px 0;
  position: relative;
}
.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.intro-graphic {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
.graphic-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: var(--transition-smooth);
}
.graphic-card:hover {
  transform: translateY(-5px);
  border-color: rgba(0, 242, 254, 0.2);
  background: rgba(241, 245, 249, 0.8);
}
.graphic-card .icon {
  font-size: 2rem;
  margin-bottom: 16px;
  display: inline-block;
}
.graphic-card h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}
.graphic-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
}
.intro-text h2 {
  font-size: 2.25rem;
  margin-bottom: 20px;
}
.intro-text p {
  color: var(--text-muted);
  margin-bottom: 24px;
  font-size: 1.1rem;
}
.intro-feature-list {
  list-style: none;
}
.intro-feature-item {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  color: var(--text-main);
  font-weight: 500;
}
.intro-feature-item::before {
  content: '✓';
  display: flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  background: rgba(0, 242, 254, 0.15);
  border-radius: 50%;
  color: #1e3a8a;
  font-size: 0.8rem;
  font-weight: bold;
}

/* Category grid and cards */
.categories-section {
  padding: 100px 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  position: relative;
}
.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 32px;
}
.category-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px;
  transition: var(--transition-bounce);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  height: 100%;
}
.category-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--grad-primary);
  opacity: 0;
  transition: var(--transition-smooth);
}
.category-card:hover {
  transform: translateY(-8px);
  border-color: var(--card-hover-border);
  box-shadow: var(--shadow-neon);
}
.category-card:hover::before {
  opacity: 1;
}
.category-icon {
  width: 50px;
  height: 50px;
  background: rgba(155, 81, 224, 0.1);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  font-size: 1.5rem;
  color: #1e3a8a;
  transition: var(--transition-smooth);
}
.category-card:hover .category-icon {
  background: var(--grad-primary);
  color: var(--text-inverse);
  box-shadow: 0 0 15px rgba(0, 242, 254, 0.4);
}
.category-card h3 {
  font-size: 1.4rem;
  margin-bottom: 12px;
}
.category-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 24px;
  flex-grow: 1;
}
.category-link {
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 8px;
  color: #1e3a8a;
}
.category-link svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
  transition: var(--transition-smooth);
}
.category-card:hover .category-link svg {
  transform: translateX(4px);
}

/* Footer styling */
.site-footer {
  background: var(--bg-secondary);
  padding: 80px 0 30px;
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr 0.8fr 1.2fr;
  gap: 48px;
  margin-bottom: 60px;
}
.footer-brand p {
  margin-top: 16px;
  color: var(--text-muted);
  font-size: 0.95rem;
}
.footer-col h4 {
  font-size: 1.1rem;
  margin-bottom: 24px;
  position: relative;
  padding-bottom: 8px;
}
.footer-col h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 30px;
  height: 2px;
  background: var(--grad-primary);
}
.footer-links {
  list-style: none;
}
.footer-links li {
  margin-bottom: 12px;
}
.footer-links a {
  color: var(--text-muted);
  font-size: 0.95rem;
}
.footer-links a:hover {
  color: #2563eb;
  padding-left: 4px;
}
.footer-disclaimer p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 30px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 20px;
}
.copyright {
  font-size: 0.85rem;
  color: var(--text-muted);
}
.footer-legal-links {
  display: flex;
  gap: 24px;
}
.footer-legal-links a {
  font-size: 0.85rem;
  color: var(--text-muted);
}
.footer-legal-links a:hover {
  color: #2563eb;
}

/* 404 Page Design */
.error-page-body {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: var(--bg-primary);
  text-align: center;
}
.error-container {
  max-width: 600px;
  padding: 40px 24px;
}
.error-code {
  font-size: 8rem;
  font-weight: 800;
  background: var(--grad-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
  margin-bottom: 10px;
  letter-spacing: -0.05em;
  filter: drop-shadow(0 0 20px rgba(0, 242, 254, 0.3));
  font-family: 'Outfit', sans-serif;
}
.error-title {
  font-size: 2rem;
  margin-bottom: 16px;
  color: var(--text-main);
}
.error-desc {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 40px;
}
.error-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
}

/* Keyframes animations */
@keyframes float-slow {
  0% { transform: translateY(0px) scale(1); }
  100% { transform: translateY(-20px) scale(1.05); }
}
@keyframes pulse-slow {
  0%, 100% { opacity: 0.8; transform: scale(1); filter: drop-shadow(0 0 5px rgba(0, 242, 254, 0.4)); }
  50% { opacity: 1; transform: scale(1.05); filter: drop-shadow(0 0 20px rgba(155, 81, 224, 0.8)); }
}
@keyframes rotate-border {
  100% { transform: rotate(360deg); }
}

/* Media Queries (Responsive Mobile Design) */
@media (max-width: 1024px) {
  .hero-content h1 {
    font-size: 3rem;
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 768px) {
  body {
    overflow-x: hidden;
  }
  .menu-toggle {
    display: flex;
  }
  .main-nav {
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    bottom: 0;
    height: calc(100vh - 80px);
    background: var(--bg-primary);
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding: 60px 24px;
    gap: 32px;
    transform: translateX(100%);
    transition: var(--transition-smooth);
    z-index: 999;
  }
  .main-nav.active {
    transform: translateX(0);
  }
  /* Animation for menu toggle */
  .menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
  }
  .menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  .menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -7px);
  }
  
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
  .hero-content {
    order: 2;
  }
  .hero-visual {
    order: 1;
    margin-bottom: 24px;
  }
  .hero-subtitle {
    margin-left: auto;
    margin-right: auto;
  }
  .hero-actions {
    justify-content: center;
  }
  .intro-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
}

@media (max-width: 480px) {
  .hero-content h1 {
    font-size: 2.25rem;
  }
  .hero-actions {
    flex-direction: column;
    gap: 12px;
    width: 100%;
  }
  .btn {
    width: 100%;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .intro-graphic {
    grid-template-columns: 1fr;
  }
}

/* Deep Blue Text Overrides for Inline Styling & Explicit Accent Colors */
a[style*="color: var(--accent-cyan)"],
a[style*="color: var(--accent-purple)"],
span[style*="color: var(--accent-cyan)"],
span[style*="color: var(--accent-purple)"],
p[style*="color: var(--accent-cyan)"],
p[style*="color: var(--accent-purple)"] {
  color: #1e3a8a !important;
}