:root {
    --bg-color: #f8fafc;
    --container-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --input-bg: #ffffff;
    --input-border: #cbd5e1;
    --input-text: #1e293b;
    --result-bg: #f1f5f9;
    --result-text: #334155;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

/* Forzamos que por defecto el navegador cargue el Modo Oscuro */
.dark-mode {
    --bg-color: #0f172a;
    --container-bg: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --input-bg: #334155;
    --input-border: #475569;
    --input-text: #f8fafc;
    --result-bg: #0f172a;
    --result-text: #e2e8f0;
    --shadow: none;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 420px;
    margin: 40px auto;
    padding: 30px 24px;
    background-color: var(--container-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: background-color 0.3s, box-shadow 0.3s;
}

h1 {
    text-align: center;
    font-size: 28px; /* Más grande */
    margin-top: 0;
    margin-bottom: 25px;
    font-weight: 700;
}

.header {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 15px;
}

.btn-mode {
    background: transparent;
    color: var(--text-muted);
    border: 1px solid var(--input-border);
    border-radius: 20px;
    font-size: 15px; /* Más grande */
    padding: 8px 16px;
    cursor: pointer;
    transition: all 0.2s;
}
.btn-mode:hover {
    background-color: var(--result-bg);
    color: var(--text-main);
}

form {
    display: flex;
    flex-direction: column;
}

label {
    margin-bottom: 8px;
    font-size: 17px; /* Más grande para que no cueste leerlo */
    font-weight: 600;
    color: var(--text-muted);
}

input[type="number"], select {
    margin-bottom: 20px;
    padding: 12px 14px;
    font-size: 19px; /* Texto de los campos más grande y cómodo al escribir */
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    color: var(--input-text);
    border-radius: 6px;
    transition: all 0.2s;
    outline: none;
    -moz-appearance: textfield;
}

input[type="number"]:focus, select:focus {
    border-color: #28a745;
    box-shadow: 0 0 0 3px rgba(40, 167, 69, 0.2);
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.btn-submit {
    background-color: #28a745;
    color: white;
    border: none;
    border-radius: 6px;
    padding: 14px;
    font-size: 19px; /* Botón de calcular más grande */
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-top: 5px;
}
.btn-submit:hover {
    background-color: #218838;
}

.result {
    margin-top: 24px;
    font-size: 18px; /* Resultados bastante más grandes y legibles */
    line-height: 1.7;
    color: var(--result-text);
    padding: 18px;
    background-color: var(--result-bg);
    border-radius: 8px;
    border-left: 5px solid #28a745;
}

@media (max-width: 480px) {
    .container {
        margin: 10px;
        padding: 20px 16px;
    }
    h1 {
        font-size: 25px;
    }
}