* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

.container {
    width: 100%;
    min-height: 100vh;
    background: linear-gradient(135deg, #4203a9, #90bafc);
    color: #fff;

    display: flex;
    justify-content: center;
    align-items: center;

    padding: 20px;
}

.calculator {
    width: 100%;
    max-width: 600px;
}

.calculator h1 {
    font-size: 60px;
    margin-bottom: 30px;
}

.calculator h1 span {
    color: #ffff76;
}

.input-box {
    width: 100%;
    padding: 35px;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.3);

    display: flex;
    align-items: center;
    gap: 20px;
}

.input-box input {
    flex: 1;
    padding: 14px 20px;
    border: 0;
    outline: 0;
    font-size: 18px;
    border-radius: 5px;
}

.input-box button {
    background: #ffff76;
    border: 0;
    outline: 0;
    padding: 15px 30px;
    border-radius: 5px;
    font-weight: 500;
    color: #333;
    cursor: pointer;
}

#result {
    margin-top: 20px;
    font-size: 20px;
}

#result span {
    color: #ffff76;
}

/* mobile responsive */
@media (max-width:600px) {

    .calculator h1 {
        font-size: 36px;
    }

    .input-box {
        flex-direction: column;
        padding: 25px;
    }

    .input-box button {
        width: 100%;
    }

}