/* --- Paleta de Colores y Variables Globales --- */
:root {
    /* Colores Principales */
    --accent-primary: #007bff; /* Un azul vibrante para interacciones */
    --accent-secondary: #28a745; /* Un verde claro para éxito y totales */
    --accent-tertiary: #6f42c1; /* Un púrpura elegante para acentos */
    --accent-danger: #dc3545; /* Rojo para comisiones */
    --accent-warning: #ffc107; /* Amarillo para advertencias */

    /* Modo Claro (Default) */
    --bg-light: #f8f9fa;
    --card-bg-light: #ffffff;
    --text-primary-light: #212529;
    --text-secondary-light: #6c757d;
    --border-light: #dee2e6;

    /* Modo Oscuro */
    --bg-dark: #1d2434;
    --card-bg-dark: #2c3548;
    --text-primary-dark: #e9ecef;
    --text-secondary-dark: #adb5bd;
    --border-dark: #495057;

    /* Propiedades de Diseño */
    --border-radius: 12px;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --font-main: 'Poppins', sans-serif;
    --transition-speed: 0.3s;
}

/* --- Estilos Base y de Tema --- */
body {
    font-family: var(--font-main);
    transition: background-color var(--transition-speed), color var(--transition-speed);
    margin: 0;
    padding: 2rem 1rem;
    line-height: 1.6;
}
body.light-mode {
    background-color: var(--bg-light);
    color: var(--text-primary-light);
}
body.dark-mode {
    background-color: var(--bg-dark);
    color: var(--text-primary-dark);
}

.main-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

/* --- Encabezado y Selector de Tema --- */
.main-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 2.5rem;
    padding: 0 0.5rem;
}
.main-header h1 {
    margin: 0;
    font-size: 2.25rem;
    font-weight: 700;
}
.main-header .subtitle {
    font-size: 1.1rem;
    margin: 0.25rem 0 0 0;
}
.light-mode .main-header .subtitle { color: var(--text-secondary-light); }
.dark-mode .main-header .subtitle { color: var(--text-secondary-dark); }
.theme-switcher { display: flex; align-items: center; gap: 0.5rem; margin-top: 0.5rem; }
/* (Estilos para el switch del tema sin cambios) */
.switch { position: relative; display: inline-block; width: 40px; height: 20px; }
.switch input { opacity: 0; width: 0; height: 0; }
.slider { position: absolute; cursor: pointer; top: 0; left: 0; right: 0; bottom: 0; background-color: #ccc; transition: .4s; border-radius: 20px; }
.slider:before { position: absolute; content: ""; height: 14px; width: 14px; left: 3px; bottom: 3px; background-color: white; transition: .4s; border-radius: 50%; }
input:checked + .slider { background-color: var(--accent-primary); }
input:checked + .slider:before { transform: translateX(20px); }


/* --- Navegación por Pestañas --- */
.tab-nav {
    display: flex;
    border-bottom: 2px solid;
}
.light-mode .tab-nav { border-color: var(--border-light); }
.dark-mode .tab-nav { border-color: var(--border-dark); }
.tab-link {
    padding: 1rem 1.5rem;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    position: relative;
    transition: color var(--transition-speed);
}
.tab-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--accent-primary);
    transform: scaleX(0);
    transition: transform var(--transition-speed) ease;
}
.light-mode .tab-link { color: var(--text-secondary-light); }
.dark-mode .tab-link { color: var(--text-secondary-dark); }
.tab-link.active, .tab-link:hover {
    color: var(--accent-primary);
}
.tab-link.active::after {
    transform: scaleX(1);
}

.tab-content { display: none; }
.tab-content.active { display: block; animation: fadeIn 0.5s ease; }

/* --- Tarjetas (Cards) --- */
.card {
    padding: 2rem;
    border-radius: var(--border-radius);
    margin-top: 2rem;
    box-shadow: var(--shadow);
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}
.light-mode .card { background-color: var(--card-bg-light); border: 1px solid var(--border-light); }
.dark-mode .card { background-color: var(--card-bg-dark); border: 1px solid var(--border-dark); }
.card h2 {
    margin: 0 0 1.5rem 0;
    font-size: 1.25rem;
    font-weight: 600;
    display: flex;
    align-items: center;
}
.card h2 i {
    margin-right: 0.75rem;
    color: var(--accent-tertiary);
}

/* --- Formularios y Botones --- */
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; align-items: flex-end; }
.form-group { display: flex; flex-direction: column; }
label { font-weight: 600; margin-bottom: 0.5rem; font-size: 0.9rem; }
.form-control, .form-select {
    width: 100%; padding: 0.75rem 1rem; border-radius: 8px; font-size: 1rem;
    box-sizing: border-box; transition: all 0.2s;
}
.form-control.large-input { font-size: 1.75rem; font-weight: 700; padding: 1rem; }
.light-mode .form-control, .light-mode .form-select { background-color: #f1f3f5; border: 1px solid var(--border-light); color: var(--text-primary-light); }
.dark-mode .form-control, .dark-mode .form-select { background-color: #1a202c; border: 1px solid var(--border-dark); color: var(--text-primary-dark); }
.form-control:focus, .form-select:focus { outline: none; border-color: var(--accent-primary); box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25); }

.btn-swap {
    background: linear-gradient(45deg, var(--accent-primary), var(--accent-tertiary));
    color: white; border: none; width: 50px; height: 50px; border-radius: 50%;
    font-size: 1.2rem; cursor: pointer; transition: all 0.3s;
    display: flex; align-items: center; justify-content: center; box-shadow: var(--shadow);
}
.btn-swap:hover { transform: scale(1.1) rotate(180deg); }

/* --- Resultados y Resúmenes --- */
.simple-result-display {
    text-align: center; margin-top: 2rem; font-size: 2rem; font-weight: 700;
    color: var(--accent-secondary);
}

.rate-warning {
    margin-top: 1.5rem; padding: 1rem; border-radius: 8px;
    font-size: 0.9rem; text-align: center; border: 1px solid var(--accent-warning);
}
.light-mode .rate-warning { background-color: #fff9e6; color: #664d03; }
.dark-mode .rate-warning { background-color: rgba(255, 193, 7, 0.1); color: var(--accent-warning); }
.rate-warning a { font-weight: 700; text-decoration: none; }
.light-mode .rate-warning a { color: #664d03; }
.dark-mode .rate-warning a { color: var(--accent-warning); }

#exchangeResult ul { list-style: none; padding: 0; margin: 0; }
#exchangeResult li {
    display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center;
    padding: 1rem 0; border-bottom: 1px solid;
}
#exchangeResult li:last-child { border: none; }
.light-mode #exchangeResult li { border-color: var(--border-light); }
.dark-mode #exchangeResult li { border-color: var(--border-dark); }

#exchangeResult .label { font-weight: 600; font-size: 1rem; }
#exchangeResult .value { text-align: right; font-size: 1.1rem; }
#exchangeResult .update-info { width: 100%; font-size: 0.8rem; margin-top: 0.25rem; text-align: left; }
.light-mode #exchangeResult .update-info { color: var(--text-secondary-light); }
.dark-mode #exchangeResult .update-info { color: var(--text-secondary-dark); }
#exchangeResult .commission .value { color: var(--accent-danger); font-weight: 600; }
#exchangeResult .total {
    font-size: 1.75rem; font-weight: 700; padding: 1.5rem; margin-top: 1rem; border-radius: var(--border-radius);
    background: linear-gradient(45deg, rgba(40, 167, 69, 0.1), rgba(0, 123, 255, 0.1));
}
#exchangeResult .total .value { color: var(--accent-secondary); }

/* --- Adaptabilidad --- */
@media (max-width: 768px) {
    .main-header { flex-direction: column; align-items: flex-start; gap: 1rem; }
    .form-row { grid-template-columns: 1fr; }
    #simple-calculator .form-row { display: flex; flex-direction: column; align-items: stretch; }
    .swap-group { align-self: center; margin: 0.5rem 0; }
}
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }