:root {
    --primary-color: #7a5c3e; /* Marrón oscuro para texto y bordes */
    --secondary-color: #c2a27c; /* Marrón claro para acentos */
    --background-color: #f4f0e8; /* Color pergamino/papel viejo */
    --card-background: #fffdf9;
    --header-footer-bg: #3e3228;
    --profit-color: #2e8b57; /* Verde */
    --loss-color: #b22222; /* Rojo */
    --font-title: 'Cinzel', serif;
    --font-body: 'Lora', serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-body);
    background-color: var(--background-color);
    color: var(--primary-color);
    line-height: 1.6;
}

.container {
    max-width: 960px;
    margin: auto;
    padding: 0 20px;
}

header {
    background-color: var(--header-footer-bg);
    color: var(--background-color);
    padding: 2rem 0;
    text-align: center;
    border-bottom: 5px solid var(--secondary-color);
}

header h1 {
    font-family: var(--font-title);
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.version-badge {
    color: var(--secondary-color);
    font-size: 1.2rem;
    vertical-align: middle;
}

main {
    padding: 2rem 0;
}

.card {
    background: var(--card-background);
    border: 1px solid var(--secondary-color);
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.card h2 {
    font-family: var(--font-title);
    text-align: center;
    margin-bottom: 0.5rem;
    font-size: 2rem;
}

.subtitle {
    text-align: center;
    margin-bottom: 2rem;
    font-style: italic;
    color: #666;
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}

@media (min-width: 768px) {
    .form-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.form-column h3 {
    font-family: var(--font-title);
    border-bottom: 2px solid var(--secondary-color);
    padding-bottom: 0.5rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ccc;
    border-radius: 5px;
    font-family: var(--font-body);
    font-size: 1rem;
    background: #f9f9f9;
}

.button-container {
    text-align: center;
    margin-top: 2rem;
}

.calculate-btn {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2.5rem;
    border: none;
    border-radius: 5px;
    font-family: var(--font-title);
    font-size: 1.2rem;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
}

.calculate-btn:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

/* --- Results --- */
.hidden {
    display: none;
}

#results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.5rem;
    text-align: center;
    margin-bottom: 2rem;
}

.result-item h4 {
    font-family: var(--font-title);
    font-size: 1rem;
    color: #666;
}

.result-item p {
    font-size: 1.8rem;
    font-weight: bold;
}

.result-item.profit p {
    color: var(--profit-color);
}

.result-item.efficiency p {
    color: var(--secondary-color);
}

#merchant-advice {
    background: var(--background-color);
    border-left: 5px solid var(--secondary-color);
    padding: 1.5rem;
    margin-top: 1rem;
    border-radius: 5px;
}

#merchant-advice h3 {
    font-family: var(--font-title);
    margin-bottom: 0.5rem;
}

footer {
    background-color: var(--header-footer-bg);
    color: var(--background-color);
    text-align: center;
    padding: 1.5rem 0;
    margin-top: 2rem;
    font-size: 0.9rem;
}