/* Reset & base styles */
* {
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    box-sizing: border-box;
}

body {
    background: #e3f9ff;
}

/* Container */
.container {
    width: 100%;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Calculator box */
.calculator {
    background: #3a4452;
    padding: 30px 25px;
    border-radius: 20px;
    box-shadow: 5px 5px 20px rgba(0,0,0,0.3),
                -5px -5px 20px rgba(255,255,255,0.1);
}

/* Display container */
form .display {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 25px;
}

form .display input {
    flex: 1;
    font-size: 45px;
    text-align: right;
    background: transparent;
    border: none;
    outline: none;
    color: #fff;
    padding-right: 10px;
    box-shadow: none;
}

/* Buttons common style */
.calculator form input {
    border: none;
    outline: none;
    width: 60px;
    height: 60px;
    border-radius: 15px;
    background: #3a4452;
    font-size: 22px;
    color: #fff;
    margin: 10px;
    cursor: pointer;
    box-shadow: -5px -5px 10px rgba(225,255,255,0.1),
                 5px 5px 10px rgba(0,0,0,0.2);
    transition: all 0.2s ease;
}

/* Hover effect */
.calculator form input:hover {
    transform: translateY(-3px);
    box-shadow: -3px -3px 6px rgba(225,255,255,0.2),
                 3px 3px 6px rgba(0,0,0,0.3);
}

/* Equals button bigger */
form input.equal {
    width: 145px;
    background: #33ffd8;
    color: #3a4452;
    font-weight: bold;
    box-shadow: -5px -5px 15px rgba(0,255,210,0.2),
                5px 5px 15px rgba(0,0,0,0.2);
}

form input.equal:hover {
    transform: translateY(-3px);
    box-shadow: -3px -3px 10px rgba(0,255,210,0.3),
                3px 3px 10px rgba(0,0,0,0.3);
}

/* Operator buttons color */
form input.operator {
    color: #33ffd8;
    font-weight: bold;
}

form input.equal {
    width: 145px;
    background: linear-gradient(145deg, #33ffd8, #00c9a7); /* gradient */
    color: #3a4452;
    font-weight: bold;
    border-radius: 15px; /* keep rounded like others */
    box-shadow: -5px -5px 15px rgba(0,255,210,0.2),
                5px 5px 15px rgba(0,0,0,0.3),
                inset -2px -2px 5px rgba(255,255,255,0.3),
                inset 2px 2px 5px rgba(0,0,0,0.2);
}