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

:root {
  /* Color Palette - YunGui Neon Light Tech */
  --bg-primary: #f4f7fb;
  --bg-secondary: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --accent-primary: #00d2ff; /* Neon blue */
  --accent-secondary: #3a7bd5; /* Deep blue */
  --border-color: #e2e8f0;
  --card-border: #e2e8f0;
  --neon-glow: 0 0 15px rgba(0, 210, 255, 0.4), 0 0 30px rgba(0, 210, 255, 0.2);
  
  /* Layout */
  --container-width: 1200px;
  --header-height: 70px;
  --radius-md: 12px;
  --radius-lg: 16px;
  
  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
}

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

ul {
  list-style: none;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Container */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  display: flex;
  align-items: center;
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

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

.logo-img {
  height: 38px;
  width: auto;
  border-radius: 8px;
}

.logo-text {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.nav-menu {
  display: flex;
  gap: 32px;
}

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

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

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Hero Section - Unique Light Style */
.hero {
  margin-top: var(--header-height);
  padding: 80px 0 60px;
  position: relative;
  background: radial-gradient(circle at 50% 0%, rgba(0, 210, 255, 0.1) 0%, rgba(255, 255, 255, 0) 60%), var(--bg-primary);
  text-align: center;
  border-bottom: 1px solid rgba(0, 210, 255, 0.15);
  overflow: hidden;
}

/* Subtle decorative shapes for hero */
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(255,255,255,0.8) 0%, rgba(255,255,255,0) 70%);
  border-radius: 50%;
  z-index: 1;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  right: -5%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255,255,255,0.6) 0%, rgba(255,255,255,0) 70%);
  border-radius: 50%;
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 10;
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 3.2rem;
  margin-bottom: 1rem;
  letter-spacing: -1px;
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.search-bar {
  display: flex;
  max-width: 500px;
  margin: 0 auto;
  background: white;
  border: 1px solid var(--card-border);
  border-radius: 40px;
  padding: 5px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.03);
}

.search-input {
  flex: 1;
  padding: 12px 20px;
  border: none;
  background: transparent;
  font-size: 1rem;
  outline: none;
  color: var(--text-primary);
}

.search-btn {
  background: var(--text-primary);
  color: white;
  border: none;
  padding: 0 25px;
  font-weight: 500;
  cursor: pointer;
  border-radius: 35px;
  transition: background var(--transition-fast);
}

.search-btn:hover {
  background: var(--accent-primary);
  box-shadow: 0 0 15px rgba(0, 210, 255, 0.5);
}

/* Small Module Cards Layout */
.section-title {
  text-align: center;
  font-size: 1.8rem;
  margin: 60px 0 40px;
}

.kb-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 60px;
}

.kb-card {
  background: #ffffff;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
  position: relative;
}

.kb-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--neon-glow);
  border-color: var(--accent-primary);
}

/* Icon block */
.kb-icon-wrap {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 16px;
}

/* Different icon colors */
.bg-blue { background: #eff6ff; color: #3b82f6; }
.bg-green { background: #f0fdf4; color: #22c55e; }
.bg-purple { background: #faf5ff; color: #a855f7; }
.bg-orange { background: #fff7ed; color: #f97316; }
.bg-red { background: #fef2f2; color: #ef4444; }
.bg-cyan { background: #ecfeff; color: #06b6d4; }
.bg-yellow { background: #fefce8; color: #eab308; }
.bg-indigo { background: #eef2ff; color: #6366f1; }

.kb-card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.kb-card p {
  color: var(--text-secondary);
  font-size: 0.85rem;
  line-height: 1.5;
}

/* Article Page specific */
.article-header {
  margin-top: var(--header-height);
  padding: 60px 0 40px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.article-header h1 {
  font-size: 2.2rem;
  max-width: 900px;
  margin: 0 auto 15px;
  text-align: center;
}

.article-meta {
  display: flex;
  justify-content: center;
  gap: 15px;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

.article-content {
  padding: 40px 0;
  background: var(--bg-primary);
}

.article-body {
  max-width: 800px;
  margin: 0 auto;
}

.article-body p {
  margin-bottom: 1.6rem;
  font-size: 1.05rem;
  color: #334155;
}

.article-body h2 {
  font-size: 1.6rem;
  margin: 2.5rem 0 1rem;
}

.article-body h3 {
  font-size: 1.3rem;
  margin: 1.5rem 0 1rem;
}

.highlight-box {
  background: var(--bg-secondary);
  border-left: 4px solid var(--accent-primary);
  padding: 20px;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: 2rem 0;
}

/* Footer */
.footer {
  border-top: 1px solid var(--card-border);
  padding: 40px 0 20px;
  margin-top: 60px;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

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

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

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

.footer-bottom {
  text-align: center;
  padding-top: 20px;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 1024px) {
  .kb-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .kb-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .nav-menu {
    display: none;
  }
  .mobile-menu-btn {
    display: block;
  }
  .hero h1 {
    font-size: 2.5rem;
  }
}

@media (max-width: 480px) {
  .kb-grid {
    grid-template-columns: 1fr;
  }
}