:root {
    --background-color: #fff;
    --text-color: #333;
    --input-background-color: #f4f4f4;
    --input-border-color: #ccc;
    --table-border-color: #ddd;
    --table-header-background-color: #e9e9e9;
    --readonly-background-color: #eee;
    --error-text-color: red;
    --shadow-color: rgba(0,0,0,0.1);
}

@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #121212;
        --text-color: #eee;
        --input-background-color: #1e1e1e;
        --input-border-color: #555;
        --table-border-color: #444;
        --table-header-background-color: #333;
        --readonly-background-color: #2a2a2a;
        --error-text-color: #ff6b6b;
        --shadow-color: rgba(255,255,255,0.1);
    }
}

/* --- General Styles --- */
body {
    font-family: sans-serif;
    margin: 20px;
    background-color: var(--background-color);
    color: var(--text-color);
}

/* --- Layout --- */
.input-section {
    background-color: var(--input-background-color);
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 5px;
    box-shadow: 0 1px 3px var(--shadow-color);
}

/* --- Forms --- */
label,
.input-section h3 {
    display: block;
    margin-top: 8px;
    margin-bottom: 4px;
    font-weight: bold;
    font-size: 0.9em;
}

input[type="number"],
input[type="text"],
select {
    width: 95%;
    padding: 6px;
    margin-bottom: 8px;
    border: 1px solid var(--input-border-color);
    border-radius: 4px;
    font-size: 0.9em;
    box-sizing: border-box;
    background-color: var(--background-color);
    color: var(--text-color);
}

input[readonly] {
    background-color: var(--readonly-background-color);
    cursor: default;
}

.unit-selector {
    margin-bottom: 10px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--readonly-background-color);
}

.unit-selector label {
    margin-right: 10px;
}

#unitSelect {
    font-size: 0.9em;
    vertical-align: middle;
}

/* --- Tables --- */
.results-table {
    width: auto;
    border-collapse: collapse;
    margin-top: 5px;
    margin-bottom: 20px;
    font-size: 0.85em;
}

.results-table th, 
.results-table td {
    border: 1px solid var(--table-border-color);
    padding: 5px;
    text-align: center;
    white-space: nowrap;
    vertical-align: middle;
}

.results-table th {
    background-color: var(--table-header-background-color);
    font-weight: bold;
}

#resultsTable td:first-child {
    font-weight: bold;
}

/* --- Error Messages --- */
.error {
    color: var(--error-text-color);
    font-weight: bold;
    margin-top: 10px;
    font-size: 0.9em;
}