:root {
  --primary-50: #eff6ff;
  --primary-100: #dbeafe;
  --primary-200: #bfdbfe;
  --primary-300: #93c5fd;
  --primary-400: #60a5fa;
  --primary-500: #3b82f6;
  --primary-600: #2563eb;
  --primary-700: #1d4ed8;
  --primary-800: #1e40af;
  --primary-900: #1e3a8a;

  --secondary-50: #f0fdfa;
  --secondary-100: #ccfbf1;
  --secondary-200: #99f6e4;
  --secondary-300: #5eead4;
  --secondary-400: #2dd4bf;
  --secondary-500: #14b8a6;
  --secondary-600: #0d9488;
  --secondary-700: #0f766e;
  --secondary-800: #115e59;
  --secondary-900: #134e4a;

  --accent-purple: #8b5cf6;
  --accent-pink: #ec4899;
  --accent-orange: #f97316;

  --success-500: #10b981;
  --success-600: #059669;
  --danger-500: #ef4444;
  --danger-600: #dc2626;

  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --bg-elevated: #ffffff;
  --bg-overlay: rgba(15, 23, 42, 0.6);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #64748b;
  --text-inverse: #ffffff;

  --border-light: #e2e8f0;
  --border-medium: #cbd5e1;
  --border-dark: #94a3b8;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);

  --glow-primary: 0 0 20px rgba(59, 130, 246, 0.4);
  --glow-secondary: 0 0 20px rgba(20, 184, 166, 0.4);

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  --font-sans: 'Cairo', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;
  --font-weight-black: 900;

  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --bg-elevated: #1e293b;
  --bg-overlay: rgba(0, 0, 0, 0.7);

  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-tertiary: #94a3b8;
  --text-inverse: #0f172a;

  --border-light: #334155;
  --border-medium: #475569;
  --border-dark: #64748b;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-secondary);
  color: var(--text-primary);
  line-height: 1.8;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition-base), color var(--transition-base);
  position: relative;
  overflow-x: hidden;
  user-select: none;
  -webkit-user-select: none;
  -ms-user-select: none;
}

body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 500px;
  background: radial-gradient(circle at 20% 10%, rgba(59, 130, 246, 0.08) 0%, transparent 50%),
              radial-gradient(circle at 80% 20%, rgba(20, 184, 166, 0.08) 0%, transparent 50%);
  z-index: 0;
  pointer-events: none;
}

[data-theme="dark"] body::before {
  background: radial-gradient(circle at 20% 10%, rgba(59, 130, 246, 0.12) 0%, transparent 50%),
              radial-gradient(circle at 80% 20%, rgba(20, 184, 166, 0.12) 0%, transparent 50%);
}

img { pointer-events: none; }

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 var(--space-6);
  width: 100%;
  position: relative;
  z-index: 1;
}

.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  padding: var(--space-4) 0;
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

[data-theme="dark"] .header {
  background: rgba(15, 23, 42, 0.7);
  border-bottom-color: var(--border-light);
}

.header.scrolled {
  padding: var(--space-3) 0;
  box-shadow: var(--shadow-lg);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-8);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  margin-right: auto;
  margin-left: var(--space-8);
}

.nav-menu a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: var(--font-weight-semibold);
  font-size: 0.9375rem;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  position: relative;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: 80%;
  height: 2px;
  background: linear-gradient(90deg, var(--primary-500), var(--secondary-500));
  transition: transform var(--transition-base);
}

.nav-menu a:hover {
  color: var(--primary-600);
  background: rgba(59, 130, 246, 0.05);
}

[data-theme="dark"] .nav-menu a:hover {
  color: var(--primary-400);
  background: rgba(59, 130, 246, 0.1);
}

.nav-menu a:hover::after { transform: translateX(-50%) scaleX(1); }

.nav-menu a.active {
  color: var(--primary-600);
  background: rgba(59, 130, 246, 0.1);
}

[data-theme="dark"] .nav-menu a.active { color: var(--primary-400); }

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  width: 44px;
  height: 44px;
  cursor: pointer;
  color: var(--text-primary);
  transition: all var(--transition-base);
}

.mobile-menu-toggle:hover { color: var(--primary-500); }

.mobile-nav {
  display: none;
  position: fixed;
  top: 73px;
  left: 0;
  right: 0;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border-light);
  box-shadow: var(--shadow-xl);
  padding: var(--space-6);
  z-index: var(--z-dropdown);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out, padding 0.3s ease-out;
}

.mobile-nav.active {
  display: block;
  max-height: 500px;
  animation: slideDown 0.3s ease-out;
}

.mobile-nav a {
  display: block;
  padding: var(--space-4);
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: var(--font-weight-semibold);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
  margin-bottom: var(--space-2);
}

.mobile-nav a:hover {
  background: rgba(59, 130, 246, 0.1);
  color: var(--primary-600);
  transform: translateX(-4px);
}

[data-theme="dark"] .mobile-nav a:hover { color: var(--primary-400); }

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--text-primary);
  font-weight: var(--font-weight-extrabold);
  font-size: 1.375rem;
  transition: transform var(--transition-base);
}

.logo:hover { transform: scale(1.02); }

.logo-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--primary-500), var(--secondary-500));
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: var(--font-weight-bold);
  font-size: 1.125rem;
  box-shadow: var(--shadow-md), var(--glow-primary);
  transition: all var(--transition-bounce);
  position: relative;
  overflow: hidden;
}

.logo-icon::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transform: rotate(45deg);
  transition: all var(--transition-slow);
}

.logo:hover .logo-icon {
  transform: rotate(-5deg) scale(1.05);
  box-shadow: var(--shadow-xl), var(--glow-primary);
}

.logo:hover .logo-icon::before { left: 100%; }

.theme-toggle {
  background: var(--bg-elevated);
  border: 1px solid var(--border-light);
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-primary);
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.theme-toggle::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--primary-500), var(--secondary-500));
  opacity: 0;
  transition: opacity var(--transition-base);
}

.theme-toggle:hover {
  transform: scale(1.1) rotate(10deg);
  border-color: var(--primary-500);
  box-shadow: var(--shadow-md), var(--glow-primary);
}

.theme-toggle:hover::before { opacity: 0.1; }
.theme-toggle:active { transform: scale(0.95); }

.theme-toggle svg {
  position: relative;
  z-index: 1;
  transition: transform var(--transition-bounce);
}

.theme-toggle:hover svg { transform: rotate(20deg); }

.article-hero {
  text-align: center;
  padding: var(--space-20) 0 var(--space-12);
  position: relative;
}

.article-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(20, 184, 166, 0.1));
  border: 1px solid var(--primary-200);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: var(--font-weight-semibold);
  color: var(--primary-600);
  margin-bottom: var(--space-6);
  animation: float 3s ease-in-out infinite;
}

[data-theme="dark"] .article-badge {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.15), rgba(20, 184, 166, 0.15));
  border-color: var(--primary-700);
  color: var(--primary-400);
}

.article-badge svg { color: var(--primary-500); }

.article-hero h1 {
  font-size: clamp(1.75rem, 5vw, 2.75rem);
  font-weight: var(--font-weight-black);
  margin-bottom: var(--space-6);
  line-height: 1.3;
  color: var(--text-primary);
}

.article-meta {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-4);
  color: var(--text-tertiary);
  font-size: 0.875rem;
  margin-bottom: var(--space-10);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid var(--border-light);
}

.article-meta span {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.content-body {
  font-size: 1.125rem;
  line-height: 1.9;
  margin-bottom: var(--space-20);
}

.content-body h2 {
  font-size: clamp(1.5rem, 3vw, 1.875rem);
  font-weight: var(--font-weight-extrabold);
  margin: var(--space-12) 0 var(--space-5);
  color: var(--primary-600);
  position: relative;
  padding-right: var(--space-5);
}

[data-theme="dark"] .content-body h2 { color: var(--primary-400); }

.content-body h2::before {
  content: '';
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 70%;
  background: linear-gradient(180deg, var(--primary-500), var(--secondary-500));
  border-radius: var(--radius-full);
}

.content-body h3 {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  font-weight: var(--font-weight-bold);
  margin: var(--space-8) 0 var(--space-4);
  color: var(--text-primary);
}

.content-body p {
  margin-bottom: var(--space-6);
  color: var(--text-secondary);
  line-height: 1.9;
}

.content-body strong {
  color: var(--text-primary);
  font-weight: var(--font-weight-bold);
}

.content-body ul {
  margin-bottom: var(--space-6);
  padding-right: var(--space-8);
  list-style: none;
}

.content-body li {
  margin-bottom: var(--space-4);
  position: relative;
  padding-right: var(--space-6);
  color: var(--text-secondary);
}

.content-body li::before {
  content: '•';
  position: absolute;
  right: 0;
  color: var(--primary-500);
  font-size: 1.5rem;
  line-height: 1;
  top: 0;
}

.featured-box {
  background: linear-gradient(135deg, var(--primary-500), var(--secondary-500));
  color: white;
  padding: var(--space-10);
  border-radius: var(--radius-2xl);
  margin: var(--space-10) 0;
  box-shadow: var(--shadow-2xl), var(--glow-primary);
  position: relative;
  overflow: hidden;
}

.featured-box::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.1), transparent 70%);
  pointer-events: none;
}

.featured-box h3 {
  font-size: 1.5rem;
  font-weight: var(--font-weight-extrabold);
  margin-bottom: var(--space-4);
  position: relative;
  z-index: 1;
}

.featured-box p {
  font-size: 1.0625rem;
  line-height: 1.8;
  margin-bottom: 0;
  position: relative;
  z-index: 1;
  opacity: 0.95;
}

.toast-container {
  position: fixed;
  top: var(--space-6);
  left: 50%;
  transform: translateX(-50%);
  z-index: var(--z-tooltip);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  pointer-events: none;
}

.toast {
  background: var(--bg-elevated);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-xl);
  padding: var(--space-4) var(--space-6);
  box-shadow: var(--shadow-xl);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-width: 320px;
  pointer-events: auto;
  backdrop-filter: blur(20px);
  animation: toastIn 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.toast.toast-out { animation: toastOut 0.3s ease-out forwards; }

.toast-icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
}

.toast.success .toast-icon { background: var(--success-500); color: white; }
.toast.error .toast-icon { background: var(--danger-500); color: white; }

.toast-message {
  flex: 1;
  font-size: 0.9375rem;
  font-weight: var(--font-weight-medium);
  color: var(--text-primary);
}

.footer {
  margin-top: auto;
  padding: var(--space-12) 0 var(--space-8);
  border-top: 1px solid var(--border-light);
  background: var(--bg-primary);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-8);
  margin-bottom: var(--space-8);
}

.footer-section h3 {
  font-size: 1.125rem;
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-4);
  color: var(--text-primary);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: var(--font-weight-medium);
  font-size: 0.9375rem;
  transition: all var(--transition-base);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.footer-links a:hover {
  color: var(--primary-500);
  transform: translateX(-4px);
}

.footer-links a span.icon-wrapper {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 20px;
  height: 20px;
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-6);
  border-top: 1px solid var(--border-light);
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

.footer-bottom p {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-10px); }
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(-20px) scale(0.95); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes toastOut {
  to { opacity: 0; transform: translateY(-20px) scale(0.95); }
}

.fade-in {
  animation: slideUp 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
  opacity: 0;
}

@media (max-width: 768px) {
  .article-hero { padding: var(--space-16) 0 var(--space-10); }
  .content-body { font-size: 1rem; }
  .content-body h2 { margin: var(--space-10) 0 var(--space-4); }
  .featured-box { padding: var(--space-8); }
  .footer-content { grid-template-columns: 1fr; gap: var(--space-6); }
  .toast { min-width: 280px; margin: 0 var(--space-4); }
  .nav-menu { display: none; }
  .mobile-menu-toggle { display: flex; align-items: center; justify-content: center; }
  .article-meta { flex-direction: column; gap: var(--space-2); }
}

@media (max-width: 480px) {
  .container { padding: 0 var(--space-4); }
  .content-body h2::before { display: none; }
  .content-body h2 { padding-right: 0; }
}

.hidden { display: none !important; }
.loading { pointer-events: none; opacity: 0.6; }