body{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    background: linear-gradient(to right, #434343,#000000);
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
}

.container{
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
}

.card{
    background: linear-gradient(to bottom, #222,#444);
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    padding: 30px;
    text-align: center;
    width: 300px;
}

.heading, .counter-machine{
    color: #fff;  
    margin: 0;  
}

.counter{
    background-color: #333;
    border-radius: 50%;
    padding: 20px;
    margin: 20px auto;
    width: 100px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    border: 2px solid transparent;
    transition: border-color 0.5s;
}

.btn-group{
    display: flex;
    justify-content: space-between;
    margin-top: 10px;
}

.btn-counter{
    background-color: #007bff;
    border: none;
    border-radius: 5px;
    color: #fff;
    cursor: pointer;
    padding: 8px 12px;
    transition: background-color 0.3s;
}

.btn-counter:hover{
   background-color: #0056b3;
}


.positive{
    border-color: green;
}

.negative{
    border-color: red;
}