/* --- Estilos Globales y Variables (Filosofía de Diseño) --- */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    
    --light-bg: #f8f9fa;
    --light-surface: #ffffff;
    --light-text: #212529;
    --light-border: #dee2e6;

    --dark-bg: #121212;
    --dark-surface: #1e1e1e;
    --dark-text: #e0e0e0;
    --dark-border: #444;

    --font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    --border-radius: 8px;
    --box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    --transition-speed: 0.3s ease;
}

body {
    font-family: var(--font-family);
    margin: 0;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

body.light-theme {
    background-color: var(--light-bg);
    color: var(--light-text);
}

body.dark-theme {
    background-color: var(--dark-bg);
    color: var(--dark-text);
}

/* --- Estructura Principal de la App --- */
#app-container {
    display: grid;
    grid-template-columns: 240px 1fr;
    grid-template-rows: 60px 1fr;
    grid-template-areas:
        "header header"
        "nav main";
    height: 100vh;
    transition: grid-template-columns var(--transition-speed);
}

.app-header {
    grid-area: header;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    border-bottom: 1px solid var(--light-border);
    background-color: var(--light-surface);
}

.app-nav {
    grid-area: nav;
    padding: 20px 0;
    border-right: 1px solid var(--light-border);
    background-color: var(--light-surface);
    transition: transform var(--transition-speed), width var(--transition-speed);
}

.app-main {
    grid-area: main;
    overflow-y: auto;
    padding: 2rem;
}

/* Tema Oscuro */
body.dark-theme .app-header,
body.dark-theme .app-nav {
    background-color: var(--dark-surface);
    border-color: var(--dark-border);
}

/* --- Componentes Reutilizables --- */
.card {
    background-color: var(--light-surface);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.5rem;
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}
.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px rgba(0,0,0,0.1);
}
body.dark-theme .card {
    background-color: var(--dark-surface);
    box-shadow: 0 4px 8px rgba(0,0,0,0.3);
}

/* --- Dashboard --- */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.stat-card {
    display: flex;
    align-items: center;
}
.stat-card .icon {
    font-size: 2.5rem;
    margin-right: 1rem;
    color: var(--primary-color);
}
.stat-card .value {
    font-size: 2rem;
    font-weight: bold;
}
.stat-card .label {
    font-size: 0.9rem;
    color: var(--secondary-color);
}

/* --- Navegación --- */
.app-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}
.app-nav .nav-link {
    display: flex;
    align-items: center;
    padding: 15px 20px;
    color: inherit;
    text-decoration: none;
    transition: background-color var(--transition-speed);
}
.app-nav .nav-link i {
    margin-right: 15px;
    width: 20px;
    text-align: center;
}
.app-nav .nav-link.active,
.app-nav .nav-link:hover {
    background-color: rgba(0, 123, 255, 0.1);
    color: var(--primary-color);
    font-weight: bold;
}

/* --- Toggle de Tema Animado --- */
#theme-toggle .fa-moon { display: block; }
#theme-toggle .fa-sun { display: none; }
body.dark-theme #theme-toggle .fa-moon { display: none; }
body.dark-theme #theme-toggle .fa-sun { display: block; color: var(--warning-color); }
#theme-toggle {
    position: relative;
    width: 40px;
    height: 40px;
    overflow: hidden;
}
#theme-toggle i {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: transform 0.5s ease-out;
}
body.dark-theme #theme-toggle .fa-moon { transform: translate(-50%, 150%); }
body.dark-theme #theme-toggle .fa-sun { transform: translate(-50%, -50%); }
body.light-theme #theme-toggle .fa-moon { transform: translate(-50%, -50%); }
body.light-theme #theme-toggle .fa-sun { transform: translate(-50%, -150%); }

/* --- Diseño Responsivo (Mobile-First) --- */
@media (max-width: 768px) {
    #app-container {
        grid-template-columns: 1fr;
        grid-template-areas:
            "header"
            "main";
    }
    .app-nav {
        position: fixed;
        left: 0;
        top: 0;
        bottom: 0;
        transform: translateX(-100%);
        z-index: 1000;
        width: 240px;
        box-shadow: var(--box-shadow);
    }
    .app-nav.open {
        transform: translateX(0);
    }
    .app-header .header-left h1 {
        display: none;
    }
    /* Estilos de tablas responsivas vendrán en la sección de UI */
    .table-responsive {
        width: 100%;
        overflow-x: auto;
    }
}