body {
    background-image: url('img2/bj2.jpg'); /* 页面背景为 bj1.jpg */
    background-size: cover;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    font-family: Arial, sans-serif;
    color: blue; /* 文字颜色为蓝色 */
}

.title {
    font-size: 24px;
    color: blue; /* 标题文字颜色为蓝色 */
    text-align: center;
    margin-bottom: 20px; /* 标题和纸牌之间的间距 */
}

.game-board {
    display: grid;
    grid-template-columns: repeat(8, 120px); /* 每行10个，每个80px */
    grid-gap: 10px;
    margin-bottom: 20px; /* 纸牌和计时器之间的间距 */
}

.card {
    width: 120px;
    height: 120px;
    position: relative;
    perspective: 1000px;
    cursor: pointer;
}

.card .front,
.card .back {
    width: 100%;
    height: 100%;
    position: absolute;
    backface-visibility: hidden;
    transition: transform 0.6s;
    border-radius: 10px; /* 圆角效果 */
}

.card .front {
    transform: rotateY(180deg);
    background-size: cover;
}

.card .back {
    background-image: url('img/bj.jpg'); /* 纸牌背面背景 */
    background-size: cover;
}

.card.flipped .front {
    transform: rotateY(0deg);
}

.card.flipped .back {
    transform: rotateY(180deg);
}

.card.matched {
    visibility: hidden;
    transition: visibility 0.5s; /* 0.5秒后消失 */
}

.timer {
    font-size: 24px;
    text-align: center; /* 计时器居中 */
    color: blue; /* 计时文字颜色为蓝色 */
}

#success-message {
    font-size: 24px;
    text-align: center;
    display: none; /* 初始隐藏 */
}

#success-message.visible {
    display: block; /* 显示成功消息 */
}

#action-button {
    font-size: 20px;
    padding: 10px 20px;
    margin-top: 10px;
    cursor: pointer;
    background-color: blue;
    color: white;
    border: none;
    border-radius: 5px;
}

#action-button:hover {
    background-color: darkblue;
}