/* ============================================
   AI News Feed - Design System & Styles
   ============================================ */

/* ============================================
   CSS Custom Properties (Design Tokens)
   ============================================ */
:root {
  /* Color Palette - Dark Theme with Vibrant Accents */
  --color-bg-primary: #0a0a0f;
  --color-bg-secondary: #13131a;
  --color-bg-tertiary: #1a1a24;
  --color-surface: rgba(255, 255, 255, 0.05);
  --color-surface-hover: rgba(255, 255, 255, 0.08);

  /* Gradient Colors */
  --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --gradient-bg: linear-gradient(135deg, #0a0a0f 0%, #1a1a24 50%, #0f0a1a 100%);

  /* Text Colors */
  --color-text-primary: #ffffff;
  --color-text-secondary: #a0a0b8;
  --color-text-tertiary: #6b6b85;

  /* Accent Colors */
  --color-accent-purple: #667eea;
  --color-accent-pink: #f093fb;
  --color-accent-cyan: #00f2fe;
  --color-accent-blue: #4facfe;

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

  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3rem;

  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;

  /* 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 40px rgba(102, 126, 234, 0.3);

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

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

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

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text-primary);
  background: var(--gradient-bg);
  background-attachment: fixed;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Animated Background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(circle at 20% 30%, rgba(102, 126, 234, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(240, 147, 251, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 50% 50%, rgba(0, 242, 254, 0.05) 0%, transparent 50%);
  animation: backgroundPulse 15s ease-in-out infinite;
  pointer-events: none;
  z-index: 0;
}

@keyframes backgroundPulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.7;
  }
}

/* ============================================
   Typography
   ============================================ */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-sm);
}

h1 {
  font-size: var(--font-size-5xl);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: var(--font-size-3xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

p {
  margin-bottom: var(--spacing-sm);
}

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

a:hover {
  color: var(--color-accent-blue);
}

/* ============================================
   Layout
   ============================================ */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
  position: relative;
  z-index: 1;
}

/* ============================================
   Header / Hero Section
   ============================================ */
.header {
  text-align: center;
  padding: var(--spacing-2xl) 0 var(--spacing-xl);
  position: relative;
}

.header__title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  margin-bottom: var(--spacing-md);
  animation: fadeInUp 0.8s ease-out;
}

.header__subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-text-secondary);
  font-weight: 400;
  max-width: 600px;
  margin: 0 auto var(--spacing-lg);
  animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

.header__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-md);
  background: var(--color-surface);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-xl);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  backdrop-filter: blur(10px);
  animation: fadeInUp 0.8s ease-out 0.4s backwards;
}

.header__badge::before {
  content: '📰';
  font-size: var(--font-size-lg);
}


/* ============================================
   Filter Controls
   ============================================ */
.filters {
  padding: var(--spacing-lg) 0;
  margin-bottom: var(--spacing-lg);
  animation: fadeInUp 0.8s ease-out 0.6s backwards;
}

.filters__container {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  background: var(--color-surface);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  backdrop-filter: blur(20px);
}

.filters__group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.filters__label {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.filters__buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-surface-hover);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-family-primary);
}

.filter-btn:hover {
  background: var(--color-surface-hover);
  border-color: rgba(102, 126, 234, 0.5);
  color: var(--color-text-primary);
  transform: translateY(-2px);
}

.filter-btn.active {
  background: var(--gradient-primary);
  border-color: transparent;
  color: white;
  box-shadow: var(--shadow-md);
}

.filters__select {
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-surface-hover);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-family-primary);
  outline: none;
}

.filters__select:hover {
  border-color: rgba(102, 126, 234, 0.5);
}

.filters__select:focus {
  border-color: var(--color-accent-purple);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
}

.filters__select option {
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  padding: var(--spacing-sm);
}

.filters__active {
  margin-top: var(--spacing-md);
  padding: var(--spacing-sm) var(--spacing-md);
  background: rgba(102, 126, 234, 0.1);
  border: 1px solid rgba(102, 126, 234, 0.3);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  color: var(--color-accent-purple);
  text-align: center;
}

.filters__clear {
  margin-top: var(--spacing-md);
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--color-surface-hover);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-family-primary);
  align-self: center;
}

.filters__clear:hover {
  background: var(--gradient-secondary);
  border-color: transparent;
  color: white;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* Search Container */
.search-container {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  padding-right: 3rem;
  background: var(--color-surface-hover);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-base);
  font-weight: 500;
  color: var(--color-text-primary);
  font-family: var(--font-family-primary);
  outline: none;
  transition: all var(--transition-fast);
}

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

.search-input:hover {
  border-color: rgba(102, 126, 234, 0.5);
}

.search-input:focus {
  border-color: var(--color-accent-purple);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
  background: var(--color-surface);
}

.search-icon {
  position: absolute;
  right: var(--spacing-md);
  font-size: var(--font-size-lg);
  pointer-events: none;
  opacity: 0.5;
  transition: opacity var(--transition-fast);
}

.search-input:focus+.search-icon {
  opacity: 0.8;
}


/* ============================================
   Loading State
   ============================================ */

.loading {
  text-align: center;
  padding: var(--spacing-2xl) 0;
}

.loading__spinner {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--spacing-md);
  border: 4px solid var(--color-surface);
  border-top-color: var(--color-accent-purple);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

.loading__text {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ============================================
   Skeleton Loaders
   ============================================ */
.skeleton-card {
  background: var(--color-surface);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  backdrop-filter: blur(20px);
  animation: fadeInUp 0.6s ease-out backwards;
}

.skeleton-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-md);
  gap: var(--spacing-sm);
}

.skeleton-card__category,
.skeleton-card__source,
.skeleton-card__date {
  height: 20px;
  background: var(--color-surface-hover);
  border-radius: var(--radius-sm);
  animation: pulse 1.5s ease-in-out infinite;
}

.skeleton-card__category {
  width: 80px;
}

.skeleton-card__source {
  width: 100px;
}

.skeleton-card__date {
  width: 90px;
}

.skeleton-card__title {
  height: 28px;
  background: var(--color-surface-hover);
  border-radius: var(--radius-sm);
  margin-bottom: var(--spacing-sm);
  animation: pulse 1.5s ease-in-out infinite;
  animation-delay: 0.1s;
}

.skeleton-card__title-line2 {
  height: 28px;
  width: 70%;
  background: var(--color-surface-hover);
  border-radius: var(--radius-sm);
  margin-bottom: var(--spacing-md);
  animation: pulse 1.5s ease-in-out infinite;
  animation-delay: 0.2s;
}

.skeleton-card__description {
  height: 16px;
  background: var(--color-surface-hover);
  border-radius: var(--radius-sm);
  margin-bottom: var(--spacing-xs);
  animation: pulse 1.5s ease-in-out infinite;
  animation-delay: 0.3s;
}

.skeleton-card__description:nth-of-type(2) {
  width: 95%;
}

.skeleton-card__description:nth-of-type(3) {
  width: 85%;
  margin-bottom: var(--spacing-md);
}

.skeleton-card__footer {
  height: 36px;
  width: 120px;
  background: var(--color-surface-hover);
  border-radius: var(--radius-sm);
  animation: pulse 1.5s ease-in-out infinite;
  animation-delay: 0.4s;
}

@keyframes pulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.5;
  }
}


/* ============================================
   News Feed Grid
   ============================================ */
.feed {
  padding: var(--spacing-xl) 0;
}

.no-results {
  text-align: center;
  padding: var(--spacing-2xl);
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  background: var(--color-surface);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(20px);
}


.feed__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-2xl);
}

/* ============================================
   News Card
   ============================================ */
.card {
  background: var(--color-surface);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  backdrop-filter: blur(20px);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
  animation: fadeInUp 0.6s ease-out backwards;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition-base);
  pointer-events: none;
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: rgba(102, 126, 234, 0.3);
}

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

/* Stagger animation for cards */
.card:nth-child(1) {
  animation-delay: 0.1s;
}

.card:nth-child(2) {
  animation-delay: 0.2s;
}

.card:nth-child(3) {
  animation-delay: 0.3s;
}

.card:nth-child(4) {
  animation-delay: 0.4s;
}

.card:nth-child(5) {
  animation-delay: 0.5s;
}

.card:nth-child(6) {
  animation-delay: 0.6s;
}

.card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-md);
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.card__category {
  display: inline-flex;
  align-items: center;
  padding: 4px var(--spacing-sm);
  background: var(--color-surface-hover);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-text-secondary);
}


.card__source {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--gradient-primary);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: white;
}

.card__date {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  white-space: nowrap;
}

.card__title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  line-height: 1.3;
  color: var(--color-text-primary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card__title a {
  color: inherit;
  transition: color var(--transition-fast);
}

.card__title a:hover {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.card__description {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: var(--spacing-md);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

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

.card__link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-surface-hover);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  transition: all var(--transition-fast);
  cursor: pointer;
}

.card__link:hover {
  background: var(--gradient-primary);
  border-color: transparent;
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
}

.card__link::after {
  content: '→';
  font-size: var(--font-size-lg);
  transition: transform var(--transition-fast);
}

.card__link:hover::after {
  transform: translateX(4px);
}

/* ============================================
   Error State
   ============================================ */
.error {
  text-align: center;
  padding: var(--spacing-2xl);
  background: var(--color-surface);
  border: 1px solid rgba(255, 85, 108, 0.3);
  border-radius: var(--radius-lg);
  margin: var(--spacing-xl) 0;
}

.error__icon {
  font-size: var(--font-size-5xl);
  margin-bottom: var(--spacing-md);
}

.error__title {
  font-size: var(--font-size-2xl);
  color: var(--color-accent-pink);
  margin-bottom: var(--spacing-sm);
}

.error__message {
  color: var(--color-text-secondary);
  font-size: var(--font-size-lg);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  text-align: center;
  padding: var(--spacing-xl) 0;
  color: var(--color-text-tertiary);
  font-size: var(--font-size-sm);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer__text {
  margin-bottom: var(--spacing-xs);
}

.footer__link {
  color: var(--color-accent-purple);
  font-weight: 600;
}

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

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

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
  .feed__grid {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-md);
  }
}

@media (max-width: 768px) {
  :root {
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
  }

  .header {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
  }

  .header__title {
    font-size: clamp(2rem, 8vw, 3rem);
  }

  .header__subtitle {
    font-size: var(--font-size-lg);
  }

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

  .card {
    padding: var(--spacing-md);
  }

  .card__title {
    font-size: var(--font-size-lg);
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-sm);
  }

  .card__header {
    flex-direction: column;
    align-items: flex-start;
  }

  .card__date {
    white-space: normal;
  }
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}