/* Google Font */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600&display=swap');

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

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(135deg, #1e3c72, #2a5298);
    color: white;
    flex-direction: column;
    transition: background 0.3s ease;
}

.container {
    text-align: center;
    background: rgba(0, 0, 0, 0.85);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0px 0px 15px rgba(255, 255, 255, 0.3);
    width: 90%;
    max-width: 400px;
    position: relative;
}

h2 {
    margin-bottom: 10px;
    color: #ffcc00;
    font-weight: bold;
}

.input-group {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 10px 0;
}

input, select {
    width: 45%;
    padding: 10px;
    border-radius: 5px;
    border: none;
    font-size: 16px;
    text-align: center;
}

button {
    padding: 10px;
    background-color: #ffcc00;
    border: none;
    color: black;
    font-weight: bold;
    cursor: pointer;
    border-radius: 5px;
    font-size: 16px;
    width: 100%;
    margin-top: 10px;
    transition: 0.3s ease;
}

button:hover {
    background-color: #ff9900;
}

.swap-btn {
    margin: 10px 0;
    background: #00ffcc;
    color: black;
    padding: 5px 10px;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    transition: 0.3s ease;
}

.swap-btn:hover {
    background: #008080;
}

#result {
    margin-top: 15px;
    font-size: 18px;
    font-weight: bold;
}

.dark-mode {
    background: linear-gradient(135deg, #000000, #434343);
}

.toggle-dark-mode {
    position: absolute;
    top: -50px;
    right: -0px;
    cursor: pointer;
    background: white;
    color: black;
    border: none;
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 14px;
    font-weight: bold;
}