body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #fff;
}

/* ==== HEADER ==== */
.main-header {
  background: linear-gradient(to right, #ff4e00, #ff9966);
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-container {
  max-width: 1400px;
  margin: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 15px 40px;
}

/* Logo bên trái */
.logo {
  font-size: 32px;
  font-weight: bold;
  color: white;
  letter-spacing: 2px;
}

/* ==== MENU ==== */
.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: 30px;
}

.main-nav > ul > li {
  position: relative;
}

.main-nav > ul > li > a {
  display: block; /* Giúp phần nền bao trọn toàn bộ box */
  color: white;
  text-decoration: none;
  font-weight: bold;
  font-size: 20px;
  padding: 15px 25px;
  border-radius: 8px;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Khi hover thì nền cam phủ hết box */
.main-nav > ul > li > a:hover {
  background-color: #ff4e00;
  color: #fff;
}

/* Menu con */
.main-nav ul ul {
  position: absolute;
  top: 100%;
  left: 0;
  background: white;
  display: none;
  flex-direction: column;
  box-shadow: 0 4px 15px rgba(0,0,0,0.4);
  border-radius: 12px;
  min-width: 200px;
  overflow: hidden;
  opacity: 0;
  transform: translateY(-10px);
  transition: all 0.3s ease;
  padding: 0;
  margin: 0;
}

.main-nav ul ul li {
  margin: 0;
  padding: 0;
  list-style: none;
  width: 100%;
}

.main-nav ul ul li a {
  color: #ff4e00;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  font-weight: 600;
  font-size: 16px;
  transition: all 0.3s ease;
  width: 100%;
  box-sizing: border-box;
  text-align: center;
}

/* Hiệu ứng khi hover vào từng item - tạo khung bao quanh */
.main-nav ul ul li a:hover {
  background: linear-gradient(135deg, #ff4e00, #ff9966);
  color: white;
  transform: scale(1.02);
}

/* Hiệu ứng xuất hiện menu */
.main-nav > ul > li:hover > ul {
  display: flex;
  opacity: 1;
  transform: translateY(0);
}

/* ==== Đăng nhập / Đăng ký ==== */
.user-links a {
  color: white;
  background-color: rgba(0,0,0,0.2);
  padding: 8px 16px;
  margin-left: 10px;
  border-radius: 25px;
  text-decoration: none;
  font-weight: bold;
  transition: 0.3s;
}

.user-links a:hover {
  background-color: yellow;
  color: orangered;
}

/* ==== MAIN & FOOTER ==== */
main {
  margin: 0;
}

iframe {
  border: none;
  width: 100%;
  height: 1200px;
  display: block;
  overflow: hidden;
}

/* ==== PHẦN LIÊN HỆ ==== */
.contact-section {
  background-color: #111820;
  color: #fff;
  padding: 80px 20px;
  margin: 0;
  display: block;
}

.contact-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  max-width: 1200px;
  margin: auto;
  gap: 40px;
}

/* Cột thông tin */
.contact-info {
  flex: 1;
  min-width: 280px;
}

.contact-info h2 {
  font-size: 28px;
  color: #ff5b2d;
  margin-bottom: 10px;
}

.contact-info p {
  color: #ccc;
  line-height: 1.6;
  margin-bottom: 20px;
}

.contact-info ul {
  list-style: none;
  padding: 0;
  line-height: 1.8;
}

/* Mạng xã hội */
.contact-social {
  flex: 1;
  min-width: 280px;
}

.contact-social h3 {
  color: #ff9966;
  margin-bottom: 10px;
}

.social-icons {
  margin-top: 10px;
}

.social-icons a {
  margin-right: 15px;
  display: inline-block;
}

.social-icons img {
  width: 40px;
  height: 40px;
  transition: transform 0.3s ease;
}

.social-icons img:hover {
  transform: scale(1.2);
}

/* Placeholder cho chat */
.contact-placeholder {
  flex: 1;
  min-width: 280px;
  background: #1b232d;
  border-radius: 12px;
  padding: 20px;
  text-align: center;
  opacity: 0.9;
}

.contact-placeholder h3 {
  color: #ff9966;
  margin-bottom: 10px;
}

/* Chat toggle */
.chat-toggle {
  display: none;
}

.chat-button {
  display: inline-block;
  background: linear-gradient(135deg, #ff4e00, #ff9966);
  color: white;
  padding: 15px 30px;
  font-size: 18px;
  font-weight: bold;
  border-radius: 25px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(255, 78, 0, 0.3);
  margin-bottom: 20px;
}

.chat-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(255, 78, 0, 0.4);
}

/* Chat widget - ẩn mặc định */
.chat-widget {
  display: none;

}

/* Hiển thị chat khi checkbox được check */
.chat-toggle:checked + .chat-button + .chat-widget {
  display: block;
}

/* Thay đổi nút khi chat được bật */
.chat-toggle:checked + .chat-button::after {
  content: " (Đang bật)";
}

/* Cuộn mượt khi nhấn Contact */
html {
  scroll-behavior: smooth;
}


footer {
  background: #1b232d;
  color: white;
  text-align: center;
  padding: 15px 0;
  font-size: 20px;
  font-weight: bold;
}