body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f9f9f9;
}

.container {
  max-width: 900px;
  margin: auto;
  padding: 20px;
  background: #fff;
}

h1, h2 {
  text-align: center;
}

.form-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 20px;
}

.form-row input {
  padding: 8px;
  font-size: 1rem;
  flex: 1 1 150px;
}

.form-row button {
  padding: 8px 16px;
  font-size: 1rem;
  cursor: pointer;
}

.table-wrapper {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
}

th, td {
  border: 1px solid #ddd;
  padding: 8px;
  text-align: center;
}

th {
  background: #f0f0f0;
}

.delete-btn {
  background: red;
  color: #fff;
  border: none;
  padding: 5px 10px;
  cursor: pointer;
}

@media (max-width: 600px) {
  .form-row {
    flex-direction: column;
    align-items: stretch;
  }
}

/* ===== Nút quay lại ===== */
.btn-back-container {
  margin-top: 25px;
  text-align: left;
}

.btn-back {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 6px;
  background-color: #4CAF50;
  text-decoration: none;
  color: white;
  transition: 0.2s;
}

.btn-back:hover {
  background-color: #388e3c;
}