body {
    background-color: #c8c8c8;
    overflow: hidden;
    padding: 0;
    margin: 0;
    font-family: Lato;
}

#stage {
    display: block;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.center-box {
    text-align: center;
    position: absolute;
    width: 300px;
    height: 500px;
    margin: -250px 0 0 -150px;
    left: 50%;
    top: 50%;
    z-index: 10;
}

.title {
    color: #0a0a0a;
    font-size: 32px;
    margin-bottom: 30px;
    text-shadow: 0 -1px 0px rgba(0, 0, 0, .2);
}

.button {
    position: relative;
    width: 100px;
    height: 100px;
    margin: 30px auto;
    border: 2px solid #666;
    color: #666;
    border-radius: 15px;
    font-size: 55px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
}

.button .text {
    font-size: 10px;
    padding: 0 10px;
    width: 80px
}

.op {
    position: relative;
    width: 200px;
    height: 100px;
    margin: 20px auto;
    text-align: center;
}

.instructions {
    text-align: center;
    font-size: 16px;
    color: #555;
    margin: 20px 0;
}

.level-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 20px 0;
}

.level-btn {
    display: inline-block;
    width: 40px;
    height: 40px;
    margin: 0 10px;
    background-color: #666;
    color: white;
    border-radius: 5px;
    cursor: pointer;
    line-height: 40px;
    font-size: 20px;
    font-weight: bold;
}

.level-display {
    font-size: 18px;
    font-weight: bold;
    margin: 0 10px;
    min-width: 40px;
    text-align: center;
}

#btnReset {
    display: inline-block;
    margin: 10px auto;
    padding: 8px 15px;
    background-color: #666;
    color: white;
    border-radius: 5px;
    cursor: pointer;
}