/* ================================================
   SwapXNews - Modern Blog Design System
   ================================================ */

/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

/* ================================================
   CSS Custom Properties (Design Tokens)
   ================================================ */
:root {
  /* Color Palette - Dark Theme with Vibrant Accents */
  --bg-primary: hsl(220, 26%, 16%);
  --bg-secondary: hsl(220, 26%, 20%);
  --bg-tertiary: hsl(220, 26%, 24%);

  --text-primary: hsl(0, 0%, 95%);
  --text-secondary: hsl(0, 0%, 70%);
  --text-muted: hsl(0, 0%, 50%);

  --accent-primary: hsl(271, 76%, 53%);
  --accent-secondary: hsl(192, 82%, 51%);
  --accent-gradient: linear-gradient(135deg, hsl(271, 76%, 53%), hsl(192, 82%, 51%));

  --category-tech: hsl(271, 76%, 53%);
  --category-business: hsl(45, 93%, 58%);
  --category-sports: hsl(142, 71%, 45%);
  --category-lifestyle: hsl(340, 82%, 52%);
  --category-politics: hsl(18, 90%, 56%);

  /* Glassmorphism */
  --glass-bg: hsla(220, 26%, 24%, 0.7);
  --glass-border: hsla(0, 0%, 100%, 0.1);
  --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-3xl: 3rem;

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;

  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px hsla(271, 76%, 53%, 0.3);
}

/* ================================================
   Reset & Base Styles
   ================================================ */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* ================================================
   Header & Navigation
   ================================================ */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--glass-border);
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--space-md) var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

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

.logo {
  font-size: var(--font-size-2xl);
  font-weight: 900;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
  transition: transform var(--transition-base);
}

.logo:hover {
  transform: scale(1.05);
}

.search-bar {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  background: var(--bg-tertiary);
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-full);
  border: 1px solid var(--glass-border);
  transition: all var(--transition-base);
}

.search-bar:focus-within {
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.search-bar input {
  background: none;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: var(--font-size-base);
  width: 300px;
}

.search-bar input::placeholder {
  color: var(--text-muted);
}

.search-icon {
  color: var(--text-muted);
  font-size: 1.2rem;
}

/* Category Navigation */
.category-nav {
  display: flex;
  gap: var(--space-sm);
  overflow-x: auto;
  padding-bottom: var(--space-xs);
}

.category-nav::-webkit-scrollbar {
  height: 4px;
}

.category-nav::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

.category-nav::-webkit-scrollbar-thumb {
  background: var(--accent-primary);
  border-radius: var(--radius-full);
}

.category-btn {
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-full);
  font-size: var(--font-size-sm);
  font-weight: 600;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 2px solid transparent;
  transition: all var(--transition-base);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.category-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--accent-gradient);
  transition: left var(--transition-base);
  z-index: -1;
}

.category-btn:hover::before,
.category-btn.active::before {
  left: 0;
}

.category-btn:hover,
.category-btn.active {
  color: var(--text-primary);
  border-color: var(--accent-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

/* ================================================
   Hero Section
   ================================================ */
.hero {
  position: relative;
  padding: var(--space-2xl) var(--space-lg);
  background: linear-gradient(135deg, hsl(220, 26%, 12%), hsl(220, 26%, 16%));
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, hsla(271, 76%, 53%, 0.15), transparent);
  border-radius: 50%;
  animation: pulse 8s ease-in-out infinite;
}

@keyframes pulse {

  0%,
  100% {
    transform: scale(1);
    opacity: 0.3;
  }

  50% {
    transform: scale(1.2);
    opacity: 0.5;
  }
}

.hero-content {
  max-width: 1400px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: clamp(2rem, 5vw, var(--font-size-3xl));
  font-weight: 900;
  margin-bottom: var(--space-md);
  line-height: 1.2;
}

.hero-gradient {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  max-width: 600px;
}

/* ================================================
   Main Content
   ================================================ */
.main-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg);
}

.section-title {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  margin-bottom: var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.section-title::before {
  content: '';
  width: 4px;
  height: 2rem;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
}

/* ================================================
   Blog Grid
   ================================================ */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

/* Blog Card */
.blog-card {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-lg);
  border: 1px solid var(--glass-border);
  overflow: hidden;
  transition: all var(--transition-base);
  cursor: pointer;
  position: relative;
}

.blog-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--accent-gradient);
  opacity: 0;
  transition: opacity var(--transition-base);
  z-index: 0;
}

.blog-card:hover::before {
  opacity: 0.05;
}

.blog-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: var(--accent-primary);
}

.blog-card-image {
  width: 100%;
  height: 220px;
  object-fit: cover;
  background: linear-gradient(135deg, var(--bg-secondary), var(--bg-tertiary));
  position: relative;
  z-index: 1;
}

.blog-card-content {
  padding: var(--space-md);
  position: relative;
  z-index: 1;
}

.blog-card-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
  flex-wrap: wrap;
}

.category-badge {
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.category-badge.tech {
  background: hsla(271, 76%, 53%, 0.2);
  color: var(--category-tech);
  border: 1px solid var(--category-tech);
}

.category-badge.business {
  background: hsla(45, 93%, 58%, 0.2);
  color: var(--category-business);
  border: 1px solid var(--category-business);
}

.category-badge.sports {
  background: hsla(142, 71%, 45%, 0.2);
  color: var(--category-sports);
  border: 1px solid var(--category-sports);
}

.category-badge.lifestyle {
  background: hsla(340, 82%, 52%, 0.2);
  color: var(--category-lifestyle);
  border: 1px solid var(--category-lifestyle);
}

.category-badge.politics {
  background: hsla(18, 90%, 56%, 0.2);
  color: var(--category-politics);
  border: 1px solid var(--category-politics);
}

.blog-card-date {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.blog-card-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  margin-bottom: var(--space-sm);
  line-height: 1.3;
  transition: color var(--transition-base);
}

.blog-card:hover .blog-card-title {
  color: var(--accent-secondary);
}

.blog-card-excerpt {
  color: var(--text-secondary);
  font-size: var(--font-size-base);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.blog-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-sm);
  border-top: 1px solid var(--glass-border);
}

.blog-card-author {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  font-weight: 500;
}

.read-more {
  color: var(--accent-primary);
  font-weight: 600;
  font-size: var(--font-size-sm);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: gap var(--transition-base);
}

.blog-card:hover .read-more {
  gap: 0.75rem;
}

/* ================================================
   Footer
   ================================================ */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--glass-border);
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
}

.footer-content {
  max-width: 1400px;
  margin: 0 auto;
}

.footer-logo {
  font-size: var(--font-size-xl);
  font-weight: 900;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-sm);
}

.footer-text {
  color: var(--text-muted);
  font-size: var(--font-size-sm);
}

/* ================================================
   Utility Classes
   ================================================ */
.hidden {
  display: none !important;
}

/* ================================================
   Responsive Design
   ================================================ */
@media (max-width: 768px) {
  .nav-container {
    padding: var(--space-sm);
  }

  .nav-top {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .search-bar input {
    width: 200px;
  }

  .hero {
    padding: var(--space-xl) var(--space-md);
  }

  .main-content {
    padding: var(--space-xl) var(--space-md);
  }

  .blog-grid {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }
}

@media (max-width: 480px) {
  .search-bar {
    width: 100%;
  }

  .search-bar input {
    width: 100%;
  }

  .category-nav {
    gap: var(--space-xs);
  }

  .category-btn {
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
  }
}

/* ================================================
   Animations
   ================================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.blog-card {
  animation: fadeInUp var(--transition-slow) ease-out;
}

.blog-card:nth-child(1) {
  animation-delay: 0ms;
}

.blog-card:nth-child(2) {
  animation-delay: 100ms;
}

.blog-card:nth-child(3) {
  animation-delay: 200ms;
}

.blog-card:nth-child(4) {
  animation-delay: 300ms;
}

.blog-card:nth-child(5) {
  animation-delay: 400ms;
}

.blog-card:nth-child(6) {
  animation-delay: 500ms;
}