/* Modern CSS Framework */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary: #f59e0b;
  --secondary-dark: #d97706;
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --white: #ffffff;
  --black: #000000;
  --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);
  --border-radius: 0.5rem;
  --border-radius-lg: 0.75rem;
  --border-radius-xl: 1rem;
  --transition: all 0.15s ease-in-out;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  color: var(--gray-700);
  background: var(--gray-50);
  font-size: 16px;
  scroll-behavior: smooth;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  color: var(--gray-900);
}

.display-1 { font-size: 5rem; font-weight: 800; }
.display-2 { font-size: 4.5rem; font-weight: 800; }
.display-3 { font-size: 4rem; font-weight: 700; }
.display-4 { font-size: 3.5rem; font-weight: 700; }

/* Modern Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  border-radius: var(--border-radius);
  border: none;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  font-size: 1rem;
  line-height: 1.5;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--white);
  box-shadow: var(--shadow);
}

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

.btn-secondary {
  background: linear-gradient(135deg, var(--secondary) 0%, var(--secondary-dark) 100%);
  color: var(--white);
  box-shadow: var(--shadow);
}

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

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

.btn-outline:hover {
  background: var(--primary);
  color: var(--white);
  transform: translateY(-1px);
}

.btn-lg {
  padding: 1rem 2rem;
  font-size: 1.125rem;
  border-radius: var(--border-radius-lg);
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

/* Modern Cards */
.card {
  background: var(--white);
  border-radius: var(--border-radius-xl);
  box-shadow: var(--shadow);
  border: 1px solid var(--gray-200);
  overflow: hidden;
  transition: var(--transition);
}

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

.card-glass {
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

/* Modern Navbar */
.navbar {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--gray-200);
  box-shadow: var(--shadow-sm);
}

.navbar-brand {
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--primary) !important;
}

.nav-link {
  font-weight: 500;
  color: var(--gray-600) !important;
  transition: var(--transition);
  position: relative;
}

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -0.5rem;
  left: 50%;
  transform: translateX(-50%);
  width: 2rem;
  height: 2px;
  background: var(--primary);
  border-radius: 1px;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--white);
  padding: 4rem 0;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="rgba(255,255,255,0.1)"/><circle cx="75" cy="75" r="1" fill="rgba(255,255,255,0.1)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
  opacity: 0.1;
}

/* Section Spacing */
.section {
  padding: 5rem 0;
}

.section-sm {
  padding: 3rem 0;
}

.section-lg {
  padding: 8rem 0;
}

/* Modern Grid */
.grid {
  display: grid;
  gap: 2rem;
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* Utilities */
.text-gradient {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.glass {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.animate-fade-in {
  animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-slide-up {
  animation: slideUp 0.6s ease-out;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(50px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Floating Elements */
.floating-btn {
  position: fixed;
  right: 1.5rem;
  z-index: 1000;
  border-radius: 3rem;
  box-shadow: var(--shadow-xl);
  transition: var(--transition);
}

.floating-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 25px 50px -12px rgb(0 0 0 / 0.25);
}

.floating-zalo {
  bottom: 6rem;
  background: linear-gradient(135deg, #0068ff 0%, #0052cc 100%);
}

.floating-call {
  bottom: 2.5rem;
  background: linear-gradient(135deg, var(--secondary) 0%, var(--secondary-dark) 100%);
}

.floating-btn a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  color: var(--white);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 640px) {
  .floating-btn a span:not(.icon) {
    display: none;
  }
  .floating-btn a {
    padding: 0.75rem;
    border-radius: 50%;
    width: 3.5rem;
    height: 3.5rem;
    justify-content: center;
  }
}

/* Modern Footer */
.footer {
  background: var(--gray-900);
  color: var(--gray-300);
  padding: 3rem 0 1rem;
}

.footer h5, .footer h6 {
  color: var(--white);
  margin-bottom: 1rem;
}

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

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

.footer-bottom {
  border-top: 1px solid var(--gray-800);
  margin-top: 2rem;
  padding-top: 2rem;
}

/* Modern Forms */
.form-control {
  border-radius: var(--border-radius);
  border: 2px solid var(--gray-200);
  padding: 0.75rem 1rem;
  font-size: 1rem;
  transition: var(--transition);
}

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

.form-label {
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 0.5rem;
}

/* Modern Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

.badge-secondary {
  background: var(--secondary);
  color: var(--white);
}

.badge-outline {
  background: transparent;
  border: 1px solid var(--primary);
  color: var(--primary);
}

/* Price Calculator Modern Style */
.price-calculator {
  background: linear-gradient(135deg, var(--gray-50) 0%, var(--white) 100%);
  border-radius: var(--border-radius-xl);
  padding: 3rem;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--gray-200);
}

.price-result {
  background: var(--white);
  border-radius: var(--border-radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow);
  border-left: 4px solid var(--primary);
}

/* Breadcrumb Modern */
.breadcrumb {
  background: transparent;
  padding: 1rem 0;
}

.breadcrumb-item a {
  color: var(--gray-500);
  text-decoration: none;
  transition: var(--transition);
}

.breadcrumb-item a:hover {
  color: var(--primary);
}

.breadcrumb-item.active {
  color: var(--gray-700);
  font-weight: 600;
}

/* Stats Cards */
.stats-card {
  background: var(--white);
  padding: 2rem;
  border-radius: var(--border-radius-xl);
  box-shadow: var(--shadow);
  text-align: center;
  transition: var(--transition);
}

.stats-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.stats-number {
  font-size: 3rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.stats-label {
  color: var(--gray-600);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: 0.875rem;
}

/* Animation Delays */
.animate-delay-1 { animation-delay: 0.1s; }
.animate-delay-2 { animation-delay: 0.2s; }
.animate-delay-3 { animation-delay: 0.3s; }
.animate-delay-4 { animation-delay: 0.4s; }

/* Modern Loading States */
.loading {
  position: relative;
  overflow: hidden;
}

.loading::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  animation: loading 1.5s infinite;
}

@keyframes loading {
  0% { left: -100%; }
  100% { left: 100%; }
}