/* 
 * CRDX Theme Styles - Mobile-First Responsive Design
 * Cloud Research & Development Center Website
 */

/* CSS Variables for consistent theming */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary: #0891b2;
  --accent: #f59e0b;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --dark: #111827;
  --gray-900: #111827;
  --gray-800: #1f2937;
  --gray-700: #374151;
  --gray-600: #4b5563;
  --gray-500: #6b7280;
  --gray-400: #9ca3af;
  --gray-300: #d1d5db;
  --gray-200: #e5e7eb;
  --gray-100: #f3f4f6;
  --gray-50: #f9fafb;
  --white: #ffffff;
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --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;
  
  /* Borders */
  --radius: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  /* Transitions */
  --transition: all 0.2s ease-in-out;
  --transition-slow: all 0.3s ease-in-out;
}

/* Reset and base styles */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  line-height: 1.15;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--gray-900);
  background-color: var(--white);
  overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--space-4);
  color: var(--gray-900);
}

h1 { font-size: 2.25rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
  margin-bottom: var(--space-4);
  color: var(--gray-700);
}

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

a:hover {
  color: var(--primary-dark);
}

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

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.section {
  padding: var(--space-16) 0;
}

.section-sm {
  padding: var(--space-12) 0;
}

.section-lg {
  padding: var(--space-24) 0;
}

/* Grid System */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid-2 {
  grid-template-columns: 1fr;
}

.grid-3 {
  grid-template-columns: 1fr;
}

.flex {
  display: flex;
  gap: var(--space-4);
}

.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.text-center { text-align: center; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-6);
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1;
  text-decoration: none;
  border: 0;
  border-radius: var(--radius);
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--primary);
  color: var(--white);
}

.btn-primary:hover {
  background-color: var(--primary-dark);
  color: var(--white);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background-color: var(--white);
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-secondary:hover {
  background-color: var(--primary);
  color: var(--white);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: 1rem;
}

/* Header/Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: var(--white);
  border-bottom: 1px solid var(--gray-200);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) 0;
}

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

.navbar-logo img {
  height: 40px;
  width: auto;
}

.navbar-menu {
  display: none;
}

.navbar-toggle {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
}

.navbar-toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--gray-700);
  transition: var(--transition);
}

.navbar-toggle.active span:first-child {
  transform: rotate(45deg) translate(5px, 5px);
}

.navbar-toggle.active span:nth-child(2) {
  opacity: 0;
}

.navbar-toggle.active span:last-child {
  transform: rotate(-45deg) translate(7px, -6px);
}

/* Mobile Navigation */
.mobile-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: var(--white);
  z-index: 40;
  transform: translateX(-100%);
  transition: var(--transition-slow);
}

.mobile-nav.active {
  transform: translateX(0);
}

.mobile-nav-content {
  padding: var(--space-20) var(--space-6) var(--space-6);
}

.mobile-nav-item {
  display: block;
  padding: var(--space-4) 0;
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--gray-900);
  border-bottom: 1px solid var(--gray-200);
}

/* Hero Section */
.hero {
  padding: var(--space-16) 0;
  background: linear-gradient(135deg, var(--gray-50) 0%, var(--white) 100%);
  position: relative;
  overflow: hidden;
}

.hero-content {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: var(--space-6);
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--gray-600);
  margin-bottom: var(--space-8);
}

.hero-cta {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  align-items: center;
}

.hero-image {
  margin-top: var(--space-12);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.client-logos {
  margin-top: var(--space-16);
  text-align: center;
}

.client-logos-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--gray-500);
  margin-bottom: var(--space-6);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.client-logo-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
  align-items: center;
  opacity: 0.7;
}

.client-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3);
  border-radius: var(--radius);
  transition: var(--transition);
}

.client-logo:hover {
  opacity: 1;
  transform: translateY(-2px);
}

.client-logo img {
  height: 32px;
  width: auto;
  filter: grayscale(100%);
  transition: var(--transition);
}

.client-logo:hover img {
  filter: grayscale(0%);
}

/* Features Section */
.features {
  padding: var(--space-20) 0;
  background-color: var(--white);
}

.features-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

.feature-card {
  background-color: var(--white);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  text-align: center;
  border: 1px solid var(--gray-200);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}

.feature-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--space-6);
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  border-radius: var(--radius-lg);
}

.feature-icon img {
  width: 32px;
  height: 32px;
  filter: brightness(0) invert(1);
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  color: var(--gray-900);
}

.feature-text {
  color: var(--gray-600);
  margin-bottom: var(--space-6);
  line-height: 1.6;
}

.feature-button {
  font-weight: 500;
  color: var(--primary);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: var(--transition);
}

.feature-button:hover {
  border-bottom-color: var(--primary);
}

/* Work/Testimonials Section */
.work {
  padding: var(--space-20) 0;
  background-color: var(--gray-50);
}

.work-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.work-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
}

.work-card {
  background-color: var(--white);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.work-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.work-icon {
  width: 80px;
  height: 80px;
  margin-bottom: var(--space-6);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.work-icon img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.work-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-4);
  color: var(--gray-900);
}

.work-description {
  color: var(--gray-600);
  line-height: 1.6;
}

/* Research Papers - Magazine Style Section */
.research-papers {
  padding: var(--space-20) 0;
  background: linear-gradient(135deg, var(--gray-50) 0%, var(--gray-100) 100%);
}

.research-papers-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.research-papers-subtitle {
  font-size: 1.125rem;
  color: var(--gray-600);
  font-style: italic;
  margin-top: var(--space-2);
}

/* Magazine-style Grid Layout */
.magazine-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  max-width: 1400px;
  margin: 0 auto;
}

/* Featured Article (Large) */
.featured-article {
  background: var(--white);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  transition: var(--transition);
  border: 1px solid var(--gray-200);
}

.featured-article:hover {
  transform: translateY(-4px);
  box-shadow: 0 25px 50px -12px rgb(0 0 0 / 0.25);
}

.featured-article-header {
  position: relative;
  height: 200px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  text-align: center;
  padding: var(--space-6);
}

.featured-article-badge {
  position: absolute;
  top: var(--space-4);
  left: var(--space-4);
  background: var(--accent);
  color: var(--white);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.featured-article-icon {
  font-size: 3rem;
  margin-bottom: var(--space-4);
}

.featured-article-content {
  padding: var(--space-8);
}

.featured-article-title {
  font-size: 1.75rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: var(--space-4);
  color: var(--gray-900);
}

.featured-article-excerpt {
  font-size: 1.125rem;
  line-height: 1.7;
  color: var(--gray-600);
  margin-bottom: var(--space-6);
}

.featured-article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--gray-200);
}

.article-date {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.875rem;
  color: var(--gray-500);
  font-weight: 500;
}

.article-read-time {
  font-size: 0.875rem;
  color: var(--gray-500);
  background: var(--gray-100);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius);
}

.read-more-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--primary);
  color: var(--white);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-lg);
  font-weight: 600;
  text-decoration: none;
  transition: var(--transition);
}

.read-more-btn:hover {
  background: var(--primary-dark);
  color: var(--white);
  transform: translateX(4px);
}

.read-more-btn i {
  transition: var(--transition);
}

.read-more-btn:hover i {
  transform: translateX(2px);
}

/* Regular Articles (Smaller cards) */
.regular-articles {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

.article-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid var(--gray-200);
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.article-card-header {
  height: 120px;
  background: linear-gradient(135deg, var(--secondary) 0%, var(--primary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  position: relative;
}

.article-card-icon {
  font-size: 2rem;
}

.article-card-content {
  padding: var(--space-6);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.article-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: var(--space-3);
  color: var(--gray-900);
}

.article-card-excerpt {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--gray-600);
  margin-bottom: var(--space-4);
  flex: 1;
}

.article-card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
  color: var(--gray-500);
  margin-bottom: var(--space-4);
}

.article-card-link {
  align-self: flex-start;
  color: var(--primary);
  font-weight: 600;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  transition: var(--transition);
}

.article-card-link:hover {
  color: var(--primary-dark);
  transform: translateX(2px);
}

/* Research Papers List Page */
.research-list-container {
  max-width: 1000px;
  margin: 0 auto;
  padding: var(--space-8) var(--space-4);
}

.research-list-header {
  text-align: center;
  margin-bottom: var(--space-12);
  padding-bottom: var(--space-8);
  border-bottom: 2px solid var(--gray-200);
}

.research-list-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: var(--space-4);
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.research-list-description {
  font-size: 1.125rem;
  color: var(--gray-600);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.7;
}

.research-list {
  display: grid;
  gap: var(--space-8);
}

.research-list-item {
  background: var(--white);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--gray-200);
  transition: var(--transition);
}

.research-list-item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

/* Contact Section */
.contact {
  padding: var(--space-20) 0;
  background-color: var(--white);
}

.contact-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.contact-form {
  max-width: 600px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: var(--space-6);
}

.form-label {
  display: block;
  font-weight: 500;
  color: var(--gray-700);
  margin-bottom: var(--space-2);
}

.form-control {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 1rem;
  transition: var(--transition);
  background-color: var(--white);
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgb(37 99 235 / 0.1);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

.form-submit {
  width: 100%;
}

/* Footer */
.footer {
  background-color: var(--gray-900);
  color: var(--gray-300);
  padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}

.footer-brand {
  text-align: center;
}

.footer-logo {
  margin-bottom: var(--space-4);
}

.footer-logo img {
  height: 40px;
  width: auto;
  margin: 0 auto;
}

.footer-text {
  color: var(--gray-400);
  margin-bottom: var(--space-6);
}

.footer-column h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--white);
  margin-bottom: var(--space-4);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--space-2);
}

.footer-links a {
  color: var(--gray-400);
  text-decoration: none;
  transition: var(--transition);
}

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

.social-links {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  list-style: none;
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: var(--gray-800);
  color: var(--gray-400);
  border-radius: var(--radius);
  transition: var(--transition);
}

.social-links a:hover {
  background-color: var(--primary);
  color: var(--white);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-8);
  border-top: 1px solid var(--gray-800);
  color: var(--gray-500);
}

/* Utility Classes */
.text-sm { font-size: 0.875rem; }
.text-lg { font-size: 1.125rem; }
.text-xl { font-size: 1.25rem; }
.text-2xl { font-size: 1.5rem; }
.text-3xl { font-size: 1.875rem; }

.font-medium { font-weight: 500; }
.font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; }

.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }
.mb-12 { margin-bottom: var(--space-12); }
.mb-16 { margin-bottom: var(--space-16); }

.text-gray-600 { color: var(--gray-600); }
.text-gray-700 { color: var(--gray-700); }
.text-gray-900 { color: var(--gray-900); }
.hover:text-primary:hover { color: var(--primary); }

/* Animation Classes */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.6s ease-out forwards;
}

.fade-in:nth-child(1) { animation-delay: 0.1s; }
.fade-in:nth-child(2) { animation-delay: 0.2s; }
.fade-in:nth-child(3) { animation-delay: 0.3s; }
.fade-in:nth-child(4) { animation-delay: 0.4s; }

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

/* Responsive Design - Tablet */
@media (min-width: 768px) {
  .container {
    padding: 0 var(--space-6);
  }
  
  h1 { font-size: 3rem; }
  h2 { font-size: 2.25rem; }
  h3 { font-size: 1.875rem; }
  
  .hero-title {
    font-size: 3.5rem;
  }
  
  .hero-cta {
    flex-direction: row;
    justify-content: center;
  }
  
  .grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .work-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .client-logo-grid {
    grid-template-columns: repeat(6, 1fr);
  }
  
  .form-row {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .footer-content {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .navbar-menu {
    display: flex;
    align-items: center;
    gap: var(--space-8);
  }
  
  .navbar-toggle {
    display: none;
  }
  
  .navbar-item {
    font-weight: 500;
    color: var(--gray-700);
    text-decoration: none;
    transition: var(--transition);
  }
  
  .navbar-item:hover {
    color: var(--primary);
  }
  
  /* Magazine Layout - Tablet */
  .magazine-grid {
    grid-template-columns: 2fr 1fr;
    gap: var(--space-8);
  }
  
  .regular-articles {
    grid-template-columns: 1fr;
  }
  
  .featured-article-header {
    height: 250px;
  }
}

/* Responsive Design - Desktop */
@media (min-width: 1024px) {
  .container {
    padding: 0 var(--space-8);
  }
  
  .section {
    padding: var(--space-24) 0;
  }
  
  .hero {
    padding: var(--space-24) 0;
  }
  
  .hero-title {
    font-size: 4rem;
  }
  
  .grid-3 {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .work-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .footer-content {
    grid-template-columns: 2fr 1fr 1fr 1fr;
    text-align: left;
  }
  
  .footer-brand {
    text-align: left;
  }
  
  .footer-logo img {
    margin: 0;
  }
  
  .social-links {
    justify-content: flex-start;
  }
  
  /* Magazine Layout - Desktop */
  .magazine-grid {
    grid-template-columns: 2fr 1fr;
    gap: var(--space-12);
  }
  
  .regular-articles {
    grid-template-columns: 1fr;
  }
  
  .featured-article-header {
    height: 300px;
  }
  
  .featured-article-title {
    font-size: 2.25rem;
  }
}

/* Large Desktop */
@media (min-width: 1280px) {
  .hero-title {
    font-size: 4.5rem;
  }
  
  /* Large Desktop Magazine Layout */
  .magazine-grid {
    grid-template-columns: 2fr 1fr;
    gap: var(--space-16);
  }
}