.challenge-section {
  padding: 70px 20px;
  background: #f5f7fa;
  font-family: Arial, sans-serif;
}

.challenge-title {
  text-align: center;
  font-size: 34px;
  font-weight: 700;
  margin-bottom: 10px;
}

.challenge-subtitle {
  text-align: center;
  color: #666;
  margin-bottom: 50px;
  font-size: 16px;
}

.challenge-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 25px;
}

.challenge-card {
  flex: 1;
  min-width: 280px;
  display: flex;
  align-items: center;
  padding: 25px;
  border-radius: 12px;
  background: #fff;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.challenge-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 10px 30px rgba(0,0,0,0.12);
}

/* 左侧问题 */
.challenge-left {
  width: 40%;
  color: #e53935;
}

.challenge-left .icon {
  font-size: 26px;
  margin-bottom: 8px;
}

/* 中间箭头 */
.challenge-arrow {
  width: 20%;
  text-align: center;
  font-size: 24px;
  color: #bbb;
}

/* 右侧解决 */
.challenge-right {
  width: 40%;
  text-align: right;
  color: #2e7d32;
}

.challenge-right .icon {
  font-size: 26px;
  margin-bottom: 8px;
}

/* 标题 */
.challenge-title-small {
  font-weight: 700;
  font-size: 16px;
  margin-bottom: 6px;
}

/* 描述 */
.challenge-text {
  font-size: 14px;
  color: #555;
  line-height: 1.5;
}

/* Hover背景渐变 */
.challenge-card:hover {
  background: linear-gradient(135deg, #ffffff, #f0f7ff);
}

/* 响应式 */
@media(max-width:768px){
  .challenge-card {
    flex-direction: column;
    text-align: center;
  }
  .challenge-left, .challenge-right {
    width: 100%;
    text-align: center;
  }
  .challenge-arrow {
    margin: 10px 0;
  }
}