/* Reset default styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(45deg, #000000, #000000);
}

/* Calculator container */
.calculator {
    background: #0837f1;
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    width: 300px;
    text-align: center;
}

/* Display field */
.display {
    width: 100%;
    height: 50px;
    text-align: right;
    font-size: 2em;
    border: none;
    border-radius: 10px;
    padding: 10px;
    margin-bottom: 20px;
    background-color: #f2f2f2;
    color: #333;
    box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.1);
}

/* Buttons grid layout */
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
}

/* Button base styles */
.btn {
    background-color: #f9f9f9;
    border: none;
    border-radius: 10px;
    padding: 20px;
    font-size: 1.5em;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.btn:hover {
    background-color: #e0e0e0;
    transform: translateY(-2px);
}

.btn:active {
    background-color: #d1d1d1;
    transform: translateY(2px);
}

/* Special button styles */
.func-btn {
    background-color: #f29c11;
    color: white;
}

.operator-btn {
    background-color: #ff9f00;
    color: white;
}

.equal-btn {
    background-color: #1dbf73;
    color: white;
    grid-column: span 2;
    box-shadow: 0 4px 10px rgba(0, 255, 0, 0.2);
}

.func-btn:hover, .operator-btn:hover, .equal-btn:hover {
    background-color: #f0a300;
}

.equal-btn:active {
    background-color: #1f9e63;
}

/* Focus and active state */
input:focus, button:focus {
    outline: none;
}