body {
  background: linear-gradient(180deg, #f61c3a 0%, #fbf9f7 80%);
  margin: 0;
  font-family: 'Arial Rounded MT Bold', Arial, system-ui, sans-serif;
  color: #e83948;
  min-height: 100vh;
}

.main-container {
  max-width: 400px;
  margin: 0 auto;
  background: transparent;
  box-sizing: border-box;
}

.header {
  background: #f61c3a;
  color: #fff;
  position: relative;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 0 0 20px 20px;
}
.header h1 {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 1px;
  margin: 0;
}
.back-btn {
  position: absolute;
  left: 15px;
  top: 16px;
  font-size: 25px;
  background: transparent;
  color: #dce1ec;
  border: none;
  cursor: pointer;
  transition: color 0.2s;
}
.back-btn:hover {
  color: #fff;
}

.banner {
  text-align: center;
  margin-top: 20px;
  margin-bottom: 12px;
}
.gift-img {
  width: 90%;
  max-width: 320px;
  border-radius: 18px;
  margin: 0 auto;
  display: block;
}

.form-section {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.form-box {
  background: #fff7f3;
  border-radius: 18px;
  padding: 24px 18px 20px;
  box-shadow: 0 2px 16px 0 rgba(232, 167, 158, 0.21);
  max-width: 370px;
  width: 95%;
  margin: 0 auto;
}
.form-title {
  font-size: 1.12rem;
  font-weight: bold;
  text-align: center;
  color: #e83948;
  letter-spacing: 1px;
  margin-bottom: 16px;
}
.code-row {
  display: flex;
  align-items: center;
  gap: 7px;
  margin-bottom: 8px;
}
.icon-ma-code {
  width: 19px;
  height: 13px;
}
.label {
  color: #c6985f;
  font-weight: 500;
  font-size: 1rem;
}
.code-input {
  width: 100%;
  font-size: 1.08rem;
  border: 1.5px solid #efcfa4;
  border-radius: 12px;
  padding: 10px 12px;
  margin: 0 0 14px 0;
  outline: none;
  transition: border 0.16s;
  background: #fff;
  color: #e83948;
}
.code-input:focus {
  border: 1.5px solid #e83948;
}
.submit-btn {
  display: block;
  width: 100%;
  background: #fff; /* Nền trắng */
  color: #e83948; /* Màu chữ nổi bật */
  font-size: 1.12rem;
  font-weight: bold;
  border: 2px solid #e83948; /* Tăng viền cho rõ */
  border-radius: 14px;
  margin: 7px 0 13px;
  padding: 11px 0;
  cursor: pointer;
  letter-spacing: 1px;
  transition: background 0.22s, color 0.22s;
  box-shadow: 0 4px 13px 0 rgba(236, 90, 122, 0.13);
}

.submit-btn:hover {
  background: #e83948;
  color: #fff;
}
.btn-row {
  display: flex;
  gap: 10px;
  justify-content: space-between;
}
.event-btn, .history-btn {
  border: 1px solid #e83948;
  color: #e83948;
  border-radius: 10px;
  background: #fff;
  font-size: 0.99rem;
  padding: 7px 18px;
  cursor: pointer;
  transition: background 0.20s, color 0.20s;
}
.event-btn:hover, .history-btn:hover {
  background: #e83948;
  color: #fff;
}

@media (max-width: 480px) {
  .main-container { max-width: 98vw; }
  .banner { margin-top: 16px; }
  .form-box { padding: 15px 4vw 14px; }
  .gift-img { max-width: 97vw; }
}