:root {
  --primary: #4CAF50;
  --white: #ffffff;
  --dark: #333333;
  --gray: #666666;
  --light-gray: #f5f5f5;
  --primary-color: #4CAF50;
  --secondary-color: #66BB6A;
  --text-color: #333333;
  --light-bg: #F1F8E9;
  --dark-green: #388E3C;
}

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

body {
  font-family: 'Montserrat', sans-serif;
  line-height: 1.6;
  color: var(--dark);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header Styles */
header {
  background-color: var(--white);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
}

.header-flex {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
  height: 70px;
}

.logo {
  height: 40px;
  width: auto;
}

/* Navigation */
.main-nav {
  display: flex;
  align-items: center;
}

.main-nav a {
  color: var(--dark);
  text-decoration: none;
  padding: 0.5rem 1rem;
  transition: color 0.3s;
}

.main-nav a:hover {
  color: var(--primary-color);
}

/* Burger Menu */
.burger-menu {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  z-index: 1000;
}

.burger-menu span {
  display: block;
  width: 25px;
  height: 3px;
  background-color: var(--dark);
  margin: 5px 0;
  transition: all 0.3s ease;
}

/* Language Switcher */
.lang-switcher {
  display: flex;
  align-items: center;
  background: rgba(76, 175, 80, 0.1);
  padding: 3px;
  border-radius: 24px;
  border: 1px solid var(--primary-color);
  transition: all 0.3s ease;
}

.lang-btn {
  padding: 6px 12px;
  font-size: 14px;
  font-weight: 500;
  color: var(--primary-color);
  background: none;
  border: none;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.3s ease;
  letter-spacing: 0.5px;
}

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

.lang-btn.active {
  background: var(--primary-color);
  color: var(--white);
  box-shadow: 0 2px 4px rgba(76, 175, 80, 0.2);
}

/* Mobile Navigation */
@media (max-width: 768px) {
  .header-wrapper {
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: transform 0.3s ease;
    transform: translateY(-100%);
  }

  .header-wrapper.visible {
    transform: translateY(0);
  }

  header {
    position: relative;
    background-color: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  }

  .header-flex {
    height: 60px;
    padding: 10px 15px;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    gap: 15px;
  }

  .logo {
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: flex-start;
  }

  .burger-menu {
    height: 40px;
    width: 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
    margin: 0 auto;
  }

  .burger-menu span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--dark);
    margin: 3px 0;
    transition: all 0.3s ease;
  }

  .lang-switcher {
    height: 32px;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    background: var(--primary-color);
    padding: 2px;
    border-radius: 20px;
    border: none;
  }

  .lang-btn {
    padding: 4px 8px;
    font-size: 14px;
    color: var(--white);
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    letter-spacing: normal;
  }

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

  .lang-btn.active {
    background: var(--white);
    color: var(--primary-color);
    box-shadow: none;
  }

  .main-nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    max-width: 300px;
    height: 100vh;
    background-color: var(--white);
    padding: 80px 2rem 2rem;
    transition: right 0.3s ease;
    box-shadow: -2px 0 5px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav.active {
    right: 0;
  }

  .main-nav [lang] {
    display: flex;
    flex-direction: column;
    width: 100%;
  }

  .main-nav a {
    padding: 1rem 0;
    width: 100%;
    border-bottom: 1px solid var(--light-gray);
    color: var(--dark);
    text-decoration: none;
    transition: color 0.3s;
  }

  .main-nav a:hover {
    color: var(--primary-color);
  }

  /* Burger Animation */
  .burger-menu.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .burger-menu.active span:nth-child(2) {
    opacity: 0;
  }

  .burger-menu.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
  }
}

/* Language handling */
[lang="vi"],
[lang="en"] {
  display: none;
}

[lang="vi"].active {
  display: block;
}

[lang="en"].active {
  display: block;
}

/* Special cases for flex containers */
nav [lang="vi"].active,
nav [lang="en"].active {
  display: flex;
  gap: 1rem;
}

nav a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: 20px;
  transition: all 0.3s ease;
  position: relative;
}

nav a:hover {
  color: var(--primary-color);
  background-color: var(--light-bg);
}

nav a.active {
  color: var(--white);
  background-color: var(--primary-color);
}

nav a.active:hover {
  background-color: var(--secondary-color);
  color: var(--white);
}

/* Hero Section */
.hero {
  background: linear-gradient(rgba(76, 175, 80, 0.9), rgba(56, 142, 60, 0.9)), url('https://images.unsplash.com/photo-1504868584819-f8e8b4b6d7e3?ixlib=rb-1.2.1&auto=format&fit=crop&w=1950&q=80');
  background-size: cover;
  background-position: center;
  color: var(--white);
  padding: 120px 0 4rem;
  text-align: center;
  min-height: 80vh;
  display: flex;
  align-items: center;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
  line-height: 1.2;
}

.hero .subtitle {
  font-size: 1.2rem;
  opacity: 0.9;
  max-width: 800px;
  margin: 0 auto;
}

/* Services Section */
.services {
  padding: 5rem 0;
  background-color: var(--light-bg);
}

.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-top: 3rem;
}

.service-card {
  background: var(--white);
  border-radius: 10px;
  padding: 2rem;
  text-align: center;
  transition: transform 0.3s, box-shadow 0.3s;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  border-top: 4px solid var(--primary-color);
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.service-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 12px rgba(0,0,0,0.15);
}

.product-icon {
  font-size: 3rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.service-title {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--primary-color);
}

.service-description {
  color: var(--text-color);
  font-size: 1rem;
  line-height: 1.6;
  flex-grow: 1;
}

/* Section Headers */
.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-title {
  font-size: 2.5rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.2rem;
  color: var(--text-color);
  max-width: 600px;
  margin: 0 auto;
}

/* Contact Section */
.contact-section {
  padding: 80px 0;
  background-color: var(--light-gray);
}

.contact-container {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 40px;
  margin-top: 40px;
}

.contact-info {
  background: var(--white);
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.info-item {
  display: flex;
  align-items: flex-start;
  margin-bottom: 25px;
}

.info-item:last-child {
  margin-bottom: 0;
}

.info-item i {
  font-size: 24px;
  color: var(--primary-color);
  margin-right: 15px;
  margin-top: 5px;
}

.info-item h3 {
  font-size: 18px;
  margin-bottom: 5px;
  color: var(--dark);
}

.info-item p {
  color: var(--gray);
  line-height: 1.6;
}

.contact-form {
  background: var(--white);
  padding: 40px;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
}

.form-group {
  position: relative;
  margin-bottom: 25px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid #e0e0e0;
  border-radius: 5px;
  font-size: 16px;
  transition: all 0.3s ease;
  background: transparent;
}

/* Hide placeholder by default */
.form-group input::placeholder,
.form-group textarea::placeholder {
  color: transparent;
}

.form-group textarea {
  height: 150px;
  resize: none;
}

.form-group label {
  position: absolute;
  left: 12px;
  top: 12px;
  font-size: 16px;
  color: var(--gray);
  transition: all 0.2s ease;
  background: var(--white);
  padding: 0 5px;
  pointer-events: none;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(76, 175, 80, 0.1);
  outline: none;
}

/* Hide labels when input has value */
.form-group input:not(:placeholder-shown) ~ label,
.form-group textarea:not(:placeholder-shown) ~ label {
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
}

/* Hide the second label (Vietnamese) when English is active */
html[lang="en"] .form-group label[lang="vi"] {
  display: none;
}

/* Hide the first label (English) when Vietnamese is active */
html[lang="vi"] .form-group label[lang="en"] {
  display: none;
}

.submit-btn {
  background: var(--primary-color);
  color: var(--white);
  padding: 12px 30px;
  border: none;
  border-radius: 5px;
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
  width: 100%;
}

.submit-btn:hover {
  background: #43a047;
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(76, 175, 80, 0.2);
}

@media (max-width: 768px) {
  .contact-container {
    grid-template-columns: 1fr;
  }
  
  .contact-form {
    padding: 25px;
  }
  
  .info-item {
    margin-bottom: 20px;
  }
  
  .info-item i {
    font-size: 20px;
  }
  
  .info-item h3 {
    font-size: 16px;
  }
}

/* Footer */
footer {
  background: var(--primary-color);
  color: var(--white);
  text-align: center;
  padding: 1.5rem 0;
}

/* Products Section */
.products {
  padding: 5rem 0;
  background-color: var(--white);
}

.products-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.product-card {
  background: var(--light-bg);
  border-radius: 15px;
  padding: 2rem;
  text-align: center;
  transition: transform 0.3s, box-shadow 0.3s;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  position: relative;
  overflow: hidden;
}

.product-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
}

.product-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 15px rgba(0,0,0,0.15);
}

.product-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto 1.5rem;
  background: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.product-icon i {
  font-size: 2.5rem;
  color: var(--primary-color);
}

.product-title {
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--text-color);
  min-height: 3.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.product-description {
  color: var(--text-color);
  font-size: 1rem;
  margin-bottom: 1.5rem;
  min-height: 4.8rem;
}

.product-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.product-link:hover {
  color: var(--dark-green);
}

.product-tech-badge {
  display: inline-block;
  padding: 0.5rem 1rem;
  background: var(--primary-color);
  color: var(--white);
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 500;
}

/* About Section Styles */
.about-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 3rem;
  margin-top: 3rem;
}

.mission-vision-card {
  background: var(--white);
  border-radius: 15px;
  padding: 2rem;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.mission-vision-card h3 {
  color: var(--primary-color);
  font-size: 1.8rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.mission-vision-card h3 i {
  font-size: 2rem;
}

.mission-vision-card p {
  color: var(--text-color);
  line-height: 1.8;
  margin-bottom: 1rem;
}

.values-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.value-item {
  background: var(--light-bg);
  padding: 1.2rem;
  border-radius: 10px;
  display: flex;
  align-items: center;
  gap: 1rem;
  transition: transform 0.3s, box-shadow 0.3s;
}

.value-item:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.value-item i {
  color: var(--primary-color);
  font-size: 1.5rem;
}

.value-item span {
  color: var(--text-color);
  font-weight: 500;
}

/* Responsive Design */
@media (max-width: 1200px) {
  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .header-flex {
    flex-direction: column;
    padding: 1rem 0;
  }

  nav [lang].active {
    flex-direction: column;
    width: 100%;
    align-items: center;
    gap: 0.5rem;
  }

  nav a {
    width: 100%;
    text-align: center;
    padding: 0.8rem 1rem;
  }

  .lang-switcher {
    padding-left: 0;
    border-left: none;
    padding-top: 1rem;
    margin-top: 0.5rem;
    border-top: 2px solid var(--light-bg);
    width: 100%;
    justify-content: center;
  }
  
  .services-grid {
    grid-template-columns: 1fr;
  }
  
  .products-grid {
    grid-template-columns: 1fr;
  }
  
  .product-title {
    min-height: auto;
  }
  
  .product-description {
    min-height: auto;
  }
  
  .about-grid {
    grid-template-columns: 1fr;
  }
  
  .values-list {
    grid-template-columns: 1fr;
  }
  
  .service-card {
    padding: 1.5rem;
  }
}