body { 
    font-size: 12px; 
    line-height: 150%; 
    text-align: center; 
    margin: 0; 
    padding: 0; 
    background-position: center 0; 
    background-repeat: no-repeat; 
    background-attachment: fixed;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* 棋盘容器 - 缩放1.5倍 */
.chess_box {
    display: none;  /* 默认隐藏，由JS控制显示 */
    position: relative;
    width: 795px;   /* 530 * 1.5 = 795px */
    margin: 0;
    padding: 0;
    transform: none;
}

/* 画布 - 缩放1.5倍 */
#chess {
    display: block;
    margin: 0 auto;
    width: 795px;
    height: auto;
    background: transparent;
    box-shadow: 0 0 30px rgba(0,0,0,0.6);
    border-radius: 6px;
}

/* ===== 按钮垂直排列 - 相应调整位置和大小 ===== */
/* 左侧按钮容器 */
.left-buttons {
    position: absolute;
    left: -120px;           /* 距离增加，适应缩放 */
    top: 50%;
    transform: translateY(-50%);
    z-index: 100;
    display: flex;
    flex-direction: column;
    gap: 22px;              /* 间距增大 */
    width: 100px;            /* 按钮宽度增加 */
}

/* 右侧按钮容器 */
.right-buttons {
    position: absolute;
    right: -120px;           /* 距离增加，适应缩放 */
    top: 50%;
    transform: translateY(-50%);
    z-index: 100;
    display: flex;
    flex-direction: column;
    gap: 22px;
    width: 100px;
}

/* 通用按钮样式 - 放大1.5倍 */
.side-btn {
    font: normal 21px/51px "Microsoft YaHei", "Microsoft YaHei", "寰?杞???榛?", sans-serif;  /* 14*1.5=21px */
    background: rgba(70, 53, 33, 0.95);
    border: 3px solid #FFA433;        /* 2*1.5=3px */
    color: #FF8A00;
    padding: 0;
    height: 57px;                      /* 38*1.5=57px */
    width: 100%;
    border-radius: 28px;               /* 19*1.5=28.5 ≈28px */
    cursor: pointer;
    box-shadow: 0 6px 15px rgba(0,0,0,0.5);
    transition: all 0.2s;
    letter-spacing: 1.5px;
    border: none;
    outline: none;
    font-weight: bold;
    text-align: center;
    backdrop-filter: blur(3px);
    white-space: nowrap;
}

.side-btn:hover {
    background: #5a4030;
    color: #FFD700;
    transform: scale(1.08);
    box-shadow: 0 9px 22px rgba(0,0,0,0.6);
    border-color: #FFD700;
}

/* 隐藏原底部按钮盒子和菜单区域 */
.bn_box, .menu_box {
    display: none !important;
}

/* 菜单弹出层 - 放大1.5倍 */
.popup-menu {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 420px;            /* 280*1.5=420px */
    background: #463521;
    border: 3px solid #FFA433;  /* 2*1.5=3px */
    border-radius: 12px;         /* 8*1.5=12px */
    padding: 30px 0;             /* 20*1.5=30px */
    z-index: 2000;
    box-shadow: 0 8px 45px rgba(0,0,0,0.8);
}

.popup-menu .menu-info {
    background: #2f241b;
    color: #FFF;
    padding: 22px;              /* 15*1.5=22.5≈22px */
    margin: 0 30px 22px;         /* 20*1.5=30px, 15*1.5=22.5≈22px */
    border-radius: 6px;          /* 4*1.5=6px */
    text-align: left;
    line-height: 200%;
}

.popup-menu .menu-info label {
    display: block;
    color: #FFA433;
    cursor: pointer;
    font-size: 21px;            /* 14*1.5=21px */
    margin-bottom: 8px;
}

.popup-menu .menu-info input {
    margin-right: 12px;
    vertical-align: middle;
    width: 18px;
    height: 18px;
    transform: scale(1.2);
}

.popup-menu .menu-btn {
    width: 300px;                /* 200*1.5=300px */
    height: 60px;                /* 40*1.5=60px */
    background: url(../img/btn_bg.png) center 0 no-repeat;
    background-size: 100% 120px; /* 80*1.5=120px */
    margin: 15px auto 0;          /* 10*1.5=15px */
    text-align: center;
    line-height: 60px;
    font-size: 27px;             /* 18*1.5=27px */
    color: #FF8A00;
    cursor: pointer;
}

.popup-menu .menu-btn:hover {
    background: url(../img/btn_bg.png) center -60px no-repeat;  /* 40*1.5=60px */
    color: #FFA433;
}

.popup-menu .close-btn {
    position: absolute;
    top: 15px;                   /* 10*1.5=15px */
    right: 22px;                  /* 15*1.5=22.5≈22px */
    width: 30px;                  /* 20*1.5=30px */
    height: 30px;                 /* 20*1.5=30px */
    background: url(../img/btn_fh.png);
    background-size: contain;
    cursor: pointer;
    opacity: 0.8;
}

.popup-menu .close-btn:hover {
    opacity: 1;
}

/* 针对小屏幕的优化 */
@media (max-width: 1000px) {
    .chess_box {
        transform: scale(0.8);    /* 在较小屏幕上适当缩小 */
    }
    .left-buttons {
        left: -100px;
        width: 85px;
    }
    .right-buttons {
        right: -100px;
        width: 85px;
    }
    .side-btn {
        font-size: 18px;
        height: 48px;
        line-height: 48px;
    }
}