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

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    font-family: 'Arial', sans-serif;
}

#container {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    width: 350px;
}

#title h1 {
    color: white;
    text-align: center;
    margin-bottom: 20px;
    font-size: 32px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

#display {
    background: rgba(255, 255, 255, 0.95);
    color: #333;
    text-align: right;
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 10px;
    min-height: 80px;
    font-size: 48px;
    word-wrap: break-word;
    box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.1);
}

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

.btn {
    padding: 20px;
    font-size: 24px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

.btn:active {
    transform: translateY(0);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
}

.btn[data-type="number"] {
    background: skyblue;
    color: white;
}

.btn[data-type="number"]:hover {
    background: mediumblue;
}

.btn[data-type="operator"] {
    background: orange;
    color: white;
}

.btn[data-type="operator"]:hover {
    background: orangered;
}

.btn[data-type="clear"] {
    background: orangered;
    color: white;
}

.btn[data-type="clear"]:hover {
    background: red;
}

.btn[data-type="equals"] {
    background: greenyellow;
    color: white;
}

.btn[data-type="equals"]:hover {
    background: green;
}