* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body {
    height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
    background-color: rgba(0, 0, 0, 0.647);

}
body::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url(./images/bg.jpg);
    background-size: cover;
    opacity: 0.6; 
    z-index: -1; 
}
h1{
    color: white;
    text-align: center;
    font-size: 30px;
    font-weight: bolder;
    font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;

  }
.container {
    padding: 30px;
    margin: 30px;
    background-color: black;
    width: 380px;
}
.display {
    width: 100%;
    height: 50px;
    margin-bottom: 10px;
    font-size: 30px;
    font-weight: bold;
    text-align: right;
}
.btn {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}
.btn-end {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 10px;
    margin-top: 10px;
}
.button {
    width: 100%;
    height: 50px;
    border-radius: 3%;
    font-size: 20px;
    font-weight: bold;
    border: none;
}
.operator{
    background-color: #ffa003;
    color: white;
}
.operator:active{
    background-color: #fab547;
}
.top{
    background-color: #a6a6a7;
    color: black;
}
.top:active{
    background-color: #cac8c8;
}
.num{
    background-color: #303030;
    color: white;
}
.num:active{
    background-color: #656363;
}
@media screen and (max-width: 387px) {
    .container {
        width: 300px;
        padding: 20px;
        margin: 20px;
    }
    h1 {
        font-size: 24px;
    }
    .display {
        font-size: 20px;
        height: 40px;
    }
    .button {
        font-size: 16px;
        height: 40px;
    }
}
@media screen and (max-width: 296px) {
    .container {
        width: 250px;
        padding: 15px;
        margin: 15px;
    }
    h1 {
        font-size: 20px;
    }
    .display {
        font-size: 16px;
        height: 30px;
    }
    .button {
        font-size: 14px;
        height: 30px;
    }
}