body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f8f9fa;
  color: #333;
}

a {
  text-decoration: none;
}

/* Header */
header {
  background: #111;
  color: #fff;
  padding: 10px 0;
  border-bottom: 3px solid #e0a800;
}

header .container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 15px;
}

header .logo {
  font-size: 22px;
  font-weight: bold;
  color: #fff;
  cursor: pointer;
}

header nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 25px;
}

header nav ul li a {
  color: #fff;
  font-weight: bold;
  padding: 8px 0;
}

header nav ul li a:hover {
  color: #e0a800;
}

header .btns {
  display: flex;
  gap: 10px;
}

header .btns a {
  padding: 8px 16px;
  border-radius: 5px;
  font-weight: bold;
}

header .btn-login {
  background: #ffc107;
  color: #222;
}

header .btn-login:hover {
  background: #e0a800;
}

header .btn-register {
  background: #e63946;
  color: #fff;
}

header .btn-register:hover {
  background: #c92a34;
}

/* Footer */
footer {
  background: #111;
  color: #bbb;
  text-align: center;
  padding: 20px;
  margin-top: 40px;
}
.banner {
  width: 100%;
  height: 300px;
  display: flex;
  justify-content: center; /* căn giữa ngang */
  align-items: center;     /* căn giữa dọc */
  overflow: hidden;
  margin-bottom: 30px;
  background: #000; /* nền đen khi ảnh không đủ */
}

.banner img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain; /* giữ nguyên tỉ lệ ảnh, không crop */
  bor