/* ===== Cấu hình chung ===== */
body {
  margin: 0;
  padding-top: 70px;
  font-family: 'Segoe UI', sans-serif;
  background-color: #121212;
  color: #fff;
}

/* ===== Header cố định ===== */
header.sticky-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: #1f1f1f;
  z-index: 999;
  padding: 10px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: 0 2px 5px rgba(0,0,0,0.5);
}

.logo {
  font-size: 24px;
  font-weight: bold;
}

/* ===== Menu ===== */
.nav-menu {
  list-style: none;
  display: flex;
  gap: 20px;
  margin: 0;
  padding: 0;
}

.nav-menu li {
  position: relative;
}

.nav-menu a {
  color: #fff;
  text-decoration: none;
  padding: 8px 12px;
  display: block;
}

/* ===== Dropdown ===== */
.login-menu:hover .dropdown {
  display: block;
}

.dropdown {
  display: none;
  list-style: none;
  position: absolute;
  top: 100%;
  right: 0;
  background-color: #2a2a2a;
  border: 1px solid #444;
  min-width: 180px;
  z-index: 1000;
}

.dropdown li {
  border-bottom: 1px solid #444;
}

.dropdown li a {
  padding: 10px;
  color: #fff;
  text-decoration: none;
  display: block;
}

.dropdown li a:hover {
  background-color: #3a3a3a;
}

/* ===== Article căn giữa ===== */
.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== Banner ===== */
.banner {
  position: relative;
  width: 100%;
  height: 300px;
  overflow: hidden;
  margin-bottom: 20px;
}

.banner-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: brightness(0.6);
}

.banner-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}

.banner-overlay h1 {
  font-size: 32px;
  margin-bottom: 10px;
}

.banner-nav a {
  margin: 0 10px;
  color: #fff;
  text-decoration: none;
  padding: 8px 16px;
  border: 1px solid #fff;
  border-radius: 5px;
}

/* ===== Marquee ===== */
.marquee {
  background-color: #222;
  padding: 10px;
  font-weight: bold;
  font-size: 16px;
  color: #fff;
  margin-bottom: 20px;
}

/* ===== Sản phẩm iframe ===== */
.product-frame {
  width: 100%;
  height: 800px;
}

.product-frame iframe {
  width: 100%;
  height: 100%;
  border: none;
}

/* ===== Popup Đăng nhập và Đăng ký ===== */
.popup {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.7);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 10000;
}

.popup:target {
  display: flex;
}

.popup-content {
  background-color: #1f1f1f;
  padding: 0;
  border-radius: 8px;
  width: 90%;
  max-width: 500px;
  height: 600px;
  overflow: hidden;
  position: relative;
}

.popup-content iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.close-btn {
  position: absolute;
  bottom: 10px;
  left: 50%;
  transform: translateX(-50%);
  background: #444;
  color: #fff;
  padding: 8px 16px;
  border-radius: 5px;
  text-decoration: none;
}

footer {
  line-height: 50px;
  background-color: #222;
  text-align: center;
  font-variant: small-caps;
  clear: both;
  color: white; 
}