body {
    font-family: 'Trebuchet MS', sans-serif;
    background: radial-gradient(circle at top, #1b2735, #090a0f);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.calculator {
    background: rgba(20, 25, 45, 0.95);
    padding: 60px;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.6), 0 0 20px rgba(0,255,255,0.2);
    width: 260px;
}

input[type="text"] {
    width: 90%;
    font-size: 1.8em;
    margin-bottom: 30px;
    padding: 13px;
    text-align: right;
    border: 2px solid #f1c40f;
    border-radius: 8px;
    background: #0d1117;
    color: #f1c40f;
    font-weight: bold;
    outline: none;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

button {
    font-size: 1.2em;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: #2c3e50;
    color: #fff;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px #111;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px #111;
}

button.operator {
    background: linear-gradient(135deg, #f39c12, #f1c40f);
    color: #111;
    font-weight: bold;
}

button.equal {
    background: linear-gradient(135deg, #00c6ff, #0072ff);
    color: #fff;
}

button.clear {
    background: linear-gradient(135deg, #e74c3c, #ff6f61);
    color: #fff;
    grid-column: span 4;
    font-weight: bold;
}

.creator {
    text-align: center;
    margin-top: 20px;
    font-size: 0.9em;
    color: #f1c40f;
    font-style: italic;
}