body {
    font-family: 'Segoe UI', sans-serif;
    background: linear-gradient(to right, #4facfe, #00f2fe);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    background: #ffffff;
    padding: 2rem 3rem;
    border-radius: 20px;
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.2);
    text-align: center;
    width: 350px;
}

h1 {
    color: #333;
    margin-bottom: 20px;
}

input {
    width: 90%;
    padding: 10px;
    font-size: 16px;
    border-radius: 10px;
    border: 1px solid #aaa;
    margin-bottom: 20px;
}

.unit-select {
    margin-bottom: 20px;
    font-size: 16px;
}

.unit-select label {
    margin-right: 15px;
}

button {
    background-color: #4facfe;
    border: none;
    color: white;
    padding: 10px 25px;
    font-size: 16px;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.3s ease;
}

button:hover {
    background-color: #00c6ff;
}

.result {
    margin-top: 20px;
    font-size: 18px;
    font-weight: bold;
    color: #222;
}