* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
  scroll-behavior: smooth;
}

body {
  background: #f9f9f9;
  color: #333;
  line-height: 1.6;
}

/* Thanh điều hướng (Menu) */
header {
  position: fixed;
  width: 100%;
  top: 0;
  left: 0;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(5px);
  padding: 10px 20px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  z-index: 999;
}

/* Container chung cho tất cả các trang */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Responsive padding cho mobile */
@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 12px;
  }
}

nav ul {
  display: flex;
  list-style: none;
  justify-content: center;
  gap: 25px;
  margin: 0;
  padding: 0;
  white-space: nowrap;
}

nav ul li {
  position: relative;
}

nav ul li a {
  text-decoration: none;
  color: #333;
  font-weight: 500;
  font-size: 1rem;
  transition: color 0.3s;
  padding: 10px 0;
  display: block;
}

nav ul li a:hover {
  color: #c62828;
}

/* Dropdown menu */
nav ul li .dropdown {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  min-width: 200px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  border-radius: 8px;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 1000;
}

/* Hover effect cho desktop */
@media (hover: hover) {
  nav ul li:hover .dropdown {
    opacity: 1;
    visibility: visible;
  }
  
  nav ul li .dropdown:hover {
    opacity: 1;
    visibility: visible;
  }
}

/* Click effect cho mobile */
nav ul li .dropdown.show {
  opacity: 1;
  visibility: visible;
}

nav ul li .dropdown a {
  padding: 12px 20px;
  border-bottom: 1px solid #f0f0f0;
  color: #333;
  font-size: 0.95rem;
  transition: all 0.3s ease;
}

nav ul li .dropdown a:last-child {
  border-bottom: none;
}

nav ul li .dropdown a:hover {
  background: #f8f8f8;
  color: #c62828;
  padding-left: 25px;
}

/* Responsive: Giảm kích thước chữ trên màn hình nhỏ */
@media (max-width: 768px) {
  nav ul {
    gap: 15px;
  }
  nav ul li a {
    font-size: 0.9rem;
  }
}

/* Page Header */
.page-header {
  margin-top: 80px;
  padding: 60px 20px;
  background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)), 
              url('https://blog.checkpoint.com/wp-content/uploads/2024/03/DALL%C2%B7E-2024-03-04-04.32.57-Create-a-version-of-the-previously-generated-image-that-visualizes-the-future-of-cybersecurity-in-the-age-of-generative-AI-excluding-any-textual-elem-1200x600.webp') center/cover no-repeat;
  text-align: center;
  color: #fff;
}

.page-header h1 {
  font-size: 3rem;
  margin-bottom: 20px;
  text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.5);
}

.page-header p {
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto;
  text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.5);
}

/* Section chung */
section {
  padding: 60px 20px;
  max-width: 1200px;
  margin: 0 auto;
}

section h2 {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 40px;
  position: relative;
  color: #c62828;
}

section h2::after {
  content: "";
  width: 80px;
  height: 4px;
  background: #c62828;
  display: block;
  margin: 15px auto;
  border-radius: 2px;
}

section h3 {
  font-size: 1.8rem;
  margin: 30px 0 20px;
  color: #333;
  border-left: 4px solid #c62828;
  padding-left: 15px;
}

section p {
  color: #555;
  line-height: 1.8;
  margin-bottom: 20px;
  font-size: 1.1rem;
}

section ul {
  list-style-type: disc;
  margin: 20px 0 20px 30px;
  color: #555;
}

section li {
  margin-bottom: 10px;
  line-height: 1.7;
}

/* Vision Cards */
.vision-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin: 40px 0;
}

.vision-card {
  background: #fff;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  border-top: 4px solid #c62828;
}

.vision-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.vision-card h4 {
  font-size: 1.4rem;
  color: #c62828;
  margin-bottom: 15px;
  text-align: center;
}

.vision-card p {
  text-align: center;
  margin-bottom: 0;
}

/* Values Grid */
.values-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 25px;
  margin: 40px 0;
}

.value-item {
  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
  padding: 25px;
  border-radius: 12px;
  text-align: center;
  border: 2px solid transparent;
  transition: all 0.3s ease;
}

.value-item:hover {
  border-color: #c62828;
  transform: scale(1.02);
}

.value-item i {
  font-size: 3rem;
  color: #c62828;
  margin-bottom: 15px;
}

.value-item h4 {
  font-size: 1.3rem;
  color: #333;
  margin-bottom: 10px;
}

/* Footer */
footer {
  text-align: center;
  padding: 20px;
  background: #333;
  color: #fff;
}

/* Responsive */
@media (max-width: 768px) {
  .page-header h1 {
    font-size: 2rem;
  }
  
  .page-header p {
    font-size: 1rem;
  }
  
  section h2 {
    font-size: 2rem;
  }
  
  .vision-cards {
    grid-template-columns: 1fr;
  }
  
  .values-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  }
}

/* Companies Grid */
.companies-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  margin: 40px 0;
}

.company-column {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.company-item {
  background: #fff;
  padding: 15px 20px;
  border-radius: 10px;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
  border-left: 4px solid #c62828;
  transition: all 0.3s ease;
  font-size: 0.95rem;
  line-height: 1.4;
}

.company-item:hover {
  transform: translateX(5px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.12);
  border-left-color: #e53935;
}

/* Responsive cho Companies Grid */
@media (max-width: 1024px) {
  .companies-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 25px;
  }
}

@media (max-width: 768px) {
  .companies-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  
  .company-item {
    padding: 12px 16px;
    font-size: 0.9rem;
  }
}

@media (max-width: 480px) {
  .companies-grid {
    gap: 15px;
  }
  
  .company-item {
    padding: 10px 14px;
    font-size: 0.85rem;
  }
}