* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background: linear-gradient(135deg, #00f0ff, #44ff00);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    flex-direction: column;
    padding: 20px;
    font-family: Arial, sans-serif;
}

/* Heading */
h1 {
    font-family: Georgia, 'Times New Roman', Times, serif;
    font-style: italic;
    font-weight: bold;
    font-size: 3rem;
    background: linear-gradient(90deg, #fb00ff, #0073ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 30px;
    text-align: center;
    transition: all 0.3s ease;
}

h1:hover {
    text-shadow: 2px 2px 10px rgba(0, 255, 255, 0.8);
    cursor: pointer;
}

/* Calculator Box */
main {
    background: rgba(0, 0, 0, 0.9);
    border-radius: 15px;
    padding: 20px;
    width: 100%;
    max-width: 340px;
    box-shadow: 0 8px 20px rgba(0, 255, 255, 0.5);
    transition: transform 0.3s ease;
}

main:hover {
    transform: translateY(-5px);
}

/* Row Layout */
.row {
    display: flex;
    justify-content: space-between;
    margin: 10px 0;
}

/* Buttons */
button {
    background: linear-gradient(145deg, #00d4ff, #0073ff);
    width: 60px;
    height: 60px;
    border: none;
    border-radius: 10px;
    color: white;
    cursor: pointer;
    font-size: 1.6rem;
    box-shadow: 2px 2px 6px rgba(0, 255, 255, 0.5);
    transition: all 0.3s ease;
}

button:hover {
    background: linear-gradient(145deg, #00f0ff, #0051ff);
    box-shadow: 4px 4px 12px rgba(0, 255, 255, 0.8);
    transform: scale(1.05);
}

/* Input Area */
.input-container {
    background-color: rgb(18, 29, 255);
    border-radius: 10px;
    margin-bottom: 15px;
    padding: 10px;
    box-shadow: inset 0 0 8px rgba(0, 255, 255, 0.6);
}

input {
    background: transparent;
    border: none;
    width: 100%;
    height: 60px;
    font-size: 1.5rem;
    color: white;
    border-radius: 10px;
    text-align: right;
    padding: 10px;
}

/* Remove default outline */
input:focus {
    outline: none;
}

/* 🔁 Responsive Design */
@media (max-width: 768px) {
    h1 {
        font-size: 2.5rem;
    }

    button {
        width: 50px;
        height: 50px;
        font-size: 1.4rem;
    }

    input {
        height: 50px;
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 2rem;
    }

    main {
        max-width: 100%;
    }

    .row {
        flex-wrap: wrap;
        justify-content: space-between;
    }

    button {
        font-size: 1.2rem;
        margin: 4px;
    }

    input {
        height: 45px;
        font-size: 1.2rem;
    }
}