body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background: url('/assets/images/background_img.jpg') no-repeat center center/cover;
    font-family: 'Segoe UI', sans-serif;
}

.calculator {
    background: transparent;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.5);
    border: 2px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(1px);
    display: flex;
    flex-direction: column;
    width: 100%;
    max-width: 420px;
}

.display-container {
    display: flex;
    align-items: center;
    margin-bottom: 12px;
}

#display {
    height: 50px;
    font-size: 1.5em;
    padding: 10px 15px;
    border: none;
    border-radius: 5px;
    background-color: rgba(60, 60, 60, 0.85);
    color: white;
    text-align: right;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.5);
    flex: 1;
    margin-left: 8px;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
}

button {
    height: 60px;
    font-size: 1.2em;
    border-radius: 3px;
    border: 1px solid rgba(0, 0, 0, 0.3);
    background-color: rgba(255, 255, 255, 0.4);
    color: #000;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s;
}

button:hover {
    background-color: rgba(255, 255, 255, 0.6);
    transform: scale(1.03);
}

.operator {
    background-color: rgba(255, 222, 185, 0.8);
    color: #333;
}

.operator:hover {
    background-color: rgba(255, 200, 150, 0.9);
}

.equal {
    background-color: rgba(125, 255, 255, 0.8);
    color: #000;
}

.equal:hover {
    background-color: rgba(90, 230, 230, 1);
}

.clear {
    background-color: #ffbb99;
    color: white;
    font-weight: bold;
    border-radius: 4px;
    height: 50px;
    width: 60px;
    margin-right: 8px;
}

.clear:hover {
    background-color: #ff9966;
}

/* Responsive Design */
@media (max-width: 425px) {
    .calculator {
        width: 90%;
    }

    button {
        height: 50px;
        font-size: 1em;
    }
}

@media (min-width: 426px) and (max-width: 768px) {
    .calculator {
        width: 80%;
    }

    button {
        height: 55px;
        font-size: 1.1em;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .calculator {
        width: 70%;
    }

    button {
        height: 60px;
        font-size: 1.2em;
    }
}

@media (min-width: 1025px) and (max-width: 1440px) {
    .calculator {
        width: 60%;
    }

    button {
        height: 65px;
        font-size: 1.3em;
    }
}

@media (min-width: 1441px) {
    .calculator {
        width: 50%;
    }

    button {
        height: 70px;
        font-size: 1.4em;
    }
}