.card {
    position: relative;
    width: 60px;
    height: 90px;
    background: #fff;
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    margin: 2px;
    display: inline-flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 3px;
    font-family: Arial, sans-serif;
    cursor: pointer;
    user-select: none;
    transition: transform 0.2s;
  }
  
  .card:hover {
    transform: translateY(-5px);
  }
  
  .card.selected {
    box-shadow: 0 0 0 2px #007bff;
  }
  
  .card.dragging {
    opacity: 0.5;
  }
  
  .card-corner {
    display: flex;
    align-items: center;
    font-size: 16px;
    font-weight: bold;
  }
  
  .card-corner.top-left {
    position: absolute;
    top: 5px;
    left: 5px;
  }
  
  .card-corner.bottom-right {
    position: absolute;
    bottom: 5px;
    right: 5px;
    transform: rotate(180deg);
  }
  
  .card-center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 24px;
  }
  
  .card-red {
    color: #d40000;
  }
  
  .card-black {
    color: #000;
  }
  
  .card-blue {
    color: #0066cc;
  }
  
  .card-green {
    color: #009900;
  }
  
  .card.submitted-card {
    background-color: #f8f9fa;
  }
  
  .card.exchange-selected {
    box-shadow: 0 0 0 2px #28a745;
    animation: pulse 1s infinite;
  }
  
  @keyframes pulse {
    0% {
      box-shadow: 0 0 0 2px rgba(40, 167, 69, 0.8);
    }
    50% {
      box-shadow: 0 0 0 4px rgba(40, 167, 69, 0.4);
    }
    100% {
      box-shadow: 0 0 0 2px rgba(40, 167, 69, 0.8);
    }
  } 
  @media (max-width: 768px) {
    .card {
        position: relative;
        width: 45px;
        height: 65px;
        background: #fff;
        border-radius: 4px;
        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
        margin: 2px;
        display: inline-flex;
        flex-direction: column;
        justify-content: space-between;
        padding: 3px;
        font-family: Arial, sans-serif;
        cursor: pointer;
        user-select: none;
        transition: transform 0.2s;
      }
      
      .card:hover {
        transform: translateY(-5px);
      }
      
      .card.selected {
        box-shadow: 0 0 0 2px #007bff;
      }
      
      .card.dragging {
        opacity: 0.5;
      }
      
      .card-corner {
        display: flex;
        align-items: center;
        font-size: 10px;
        font-weight: bold;
      }
      
      .card-corner.top-left {
        position: absolute;
        top: 5px;
        left: 5px;
      }
      
      .card-corner.bottom-right {
        position: absolute;
        bottom: 5px;
        right: 5px;
        transform: rotate(180deg);
      }
      
      .card-center {
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        font-size: 18px;
      }
      
      .card-red {
        color: #d40000;
      }
      
      .card-black {
        color: #000;
      }
      
      .card-blue {
        color: #0066cc;
      }

      .card-green {
        color: #009900;
      }
      
      .cards-header {
        flex-direction: column;
        align-items: flex-start;
      }
      
      .color-option {
        margin-left: 0;
        margin-top: 5px;
      }
      
      .card.submitted-card {
        background-color: #f8f9fa;
      }
      
      .card.exchange-selected {
        box-shadow: 0 0 0 2px #28a745;
        animation: pulse 1s infinite;
      }
      
      @keyframes pulse {
        0% {
          box-shadow: 0 0 0 2px rgba(40, 167, 69, 0.8);
        }
        50% {
          box-shadow: 0 0 0 4px rgba(40, 167, 69, 0.4);
        }
        100% {
          box-shadow: 0 0 0 2px rgba(40, 167, 69, 0.8);
        }
      } 
  }


/* 四色选项样式 */
.cards-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.color-option {
  font-size: 14px;
  margin-left: 20px;
}

/* 添加換牌區按鈕樣式 */
.exchange-deck-btn {
  /* background-color: #4a76a8; */
  color: black;
}

/* .active-deck-btn {
  background-color: #3a5a7a;
  font-weight: bold;
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.5);
} */

/* 換牌區選中樣式 */
#exchange-cards.selected-deck {
  background-color: rgba(74, 118, 168, 0.1);
  border: 2px solid #4a76a8;
}