body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f0f5; /* Lighter, modern background */
}

#converter-container {
    padding: 30px;
    width: 380px; /* Fixed width for compact look */
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

/* --- Input and Dropdown Styling --- */
input[type="number"], select {
    padding: 10px;
    margin: 5px 0 15px 0; /* More spacing below inputs/selects */
    border: 2px solid #ddd;
    border-radius: 6px;
    font-size: 16px;
    box-sizing: border-box;
    width: 100%; /* Make them fill the container width */
    /* Remove default dropdown appearance for a cleaner look */
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background-color: #f9f9f9;
}

/* --- Layout for From/To Dropdowns --- */
.input-group {
    display: flex;
    gap: 15px; /* Space between the two columns */
    margin-bottom: 20px;
}

.unit-section {
    flex: 1; /* Makes each section take equal width */
    display: flex;
    flex-direction: column;
}
.unit-section label {
    font-weight: 600;
    margin-bottom: 5px;
    color: #555;
}

/* --- Button Styling --- */
button {
    padding: 12px 15px;
    width: 100%;
    background-color: #2c3e50; /* Darker, more professional blue/gray */
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1.1em;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #34495e;
}

/* --- Result Styling --- */
#output-result {
    font-size: 2.5em;
    font-weight: 700;
    color: #27ae60; /* Clear success color */
    background-color: #ecf0f1;
    padding: 15px;
    margin-top: 20px;
    border-radius: 8px;
    display: block; /* Takes full width */
    text-align: center;
}
#swap-button {
    /* Basic button styling */
    background-color: #f0f0f0; /* Light background */
    color: #333;
    border: 1px solid #ccc;
    cursor: pointer;
    font-size: 1.2em;
    padding: 5px 10px;
    border-radius: 6px;
    
    /* Positioning it nicely between the sections */
    align-self: flex-end; /* Aligns the button to the bottom of the flex container */
    margin-bottom: 25px; /* Adjust margin to center it vertically */
    height: 40px; /* Give it a fixed height */
    width: 40px;
}

#swap-button:hover {
    background-color: #ddd;
}