* {
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #fff;
  padding: 30px;
}

.faq {
  max-width: 900px;
  margin: auto;
}

.faq-item {
  margin-bottom: 10px;
}

/* Ẩn checkbox */
.faq-item input {
  display: none;
}

/* Tiêu đề */
.faq-title {
  display: flex;
  align-items: center;
  background: #e65c2a;
  color: #fff;
  padding: 15px 20px;
  cursor: pointer;
  font-weight: bold;
}

/* Icon */
.faq-title .icon {
  margin-right: 10px;
  font-size: 18px;
  transition: transform 0.3s;
}

/* Nội dung */
.faq-content {
  max-height: 0;
  overflow: hidden;
  background: #fff;
  padding: 0 20px;
  border: 1px solid #ddd;
  border-top: none;
  transition: max-height 0.4s ease, padding 0.3s ease;
}

/* Khi checked → mở */
.faq-item input:checked ~ .faq-content {
  max-height: 500px;
  padding: 20px;
}

/* Đổi icon khi mở */
.faq-item input:checked + .faq-title .icon {
  transform: rotate(45deg); /* + thành x */
}