body {
    margin: 0;
    background: linear-gradient(135deg, #1e1e2f, #3a3a5f);
    font-family: Arial, sans-serif;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

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

.calculator {
    background: #2b2b3c;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 0 25px rgba(0,0,0,0.5);
    width: 300px;
}

.title {
    text-align: center;
    color: white;
    margin-bottom: 10px;
    font-size: 22px;
}
#history {
    height: 60px;
    overflow-y: auto;
    color: #ccc;
    font-size: 14px;
    margin-bottom: 10px;
    text-align: right;
    padding-right: 5px;
}
#result {
    width: 100%;
    height: 50px;
    margin-bottom: 15px;
    font-size: 24px;
    text-align: right;
    padding: 5px;
    border-radius: 10px;
    border: none;
    outline: none;
    background: #1e1e2f;
    color: white;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

button {
    height: 50px;
    font-size: 18px;
    border: none;
    border-radius: 10px;
    background: #3a3a5f;
    color: white;
    cursor: pointer;
    transition: 0.2s;
}

button:hover {
    background: #5757a5;
    transform: scale(1.05);
}
button:active {
    transform: scale(0.95);
}

.clear {
    background: #ff4d4d;
}

.equal {
    background: #4caf50;
    grid-row: span 2;
}

.zero {
    grid-column: span 2;
}