/* ============================================
   SISTEMA DE PRÉSTAMO DE LIBROS - ESTILOS
   Diseño Minimalista Moderno
   ============================================ */

/* ============================================
   VARIABLES CSS
   ============================================ */
:root {
    /* Colores principales - Escala de grises minimalista */
    --color-primary: #2c2c2c;
    --color-primary-dark: #1a1a1a;
    --color-primary-light: #404040;

    --color-secondary: #555555;
    --color-secondary-dark: #3a3a3a;

    --color-success: #2d7a4f;
    --color-warning: #d97706;
    --color-danger: #dc2626;
    --color-info: #4a5568;

    /* Colores de fondo */
    --bg-primary: #f5f5f5;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e5e5e5;
    --bg-card: #ffffff;
    --bg-hover: #fafafa;

    /* Colores de texto */
    --text-primary: #1a1a1a;
    --text-secondary: #525252;
    --text-muted: #737373;

    /* Bordes */
    --border-color: #e5e5e5;
    --border-color-dark: #d4d4d4;

    /* Sombras sutiles */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 2px 4px 0 rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 4px 8px 0 rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 8px 16px 0 rgba(0, 0, 0, 0.12);

    /* Bordes redondeados */
    --border-radius: 8px;
    --border-radius-sm: 4px;
    --border-radius-lg: 12px;

    /* Espaciado */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;

    /* Transiciones */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
}

/* ============================================
   RESET Y BASE
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ============================================
   UTILIDADES
   ============================================ */
.vista {
    display: none;
}

.vista.activa {
    display: block;
}

.seccion {
    display: none;
}

.seccion.activa {
    display: block;
    animation: fadeIn var(--transition-normal);
}

.auth-form {
    display: none;
}

.auth-form.activa {
    display: block;
    animation: fadeIn var(--transition-normal);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================
   VISTA DE AUTENTICACIÓN
   ============================================ */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
    background: linear-gradient(135deg, #fafafa 0%, #f0f0f0 100%);
}

.auth-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    width: 100%;
    max-width: 450px;
    box-shadow: var(--shadow-xl);
}

.auth-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Pestañas */
.tabs {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-lg);
    background: var(--bg-tertiary);
    padding: 4px;
    border-radius: var(--border-radius);
}

.tab {
    flex: 1;
    padding: var(--spacing-sm);
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-weight: 500;
    cursor: pointer;
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
}

.tab:hover {
    color: var(--text-primary);
    background: rgba(0, 0, 0, 0.05);
}

.tab.activa {
    background: var(--color-primary);
    color: white;
}

/* Formularios */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9rem;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(44, 44, 44, 0.1);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

.hint {
    margin-top: var(--spacing-md);
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Botones */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius-sm);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary {
    background: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-hover);
    border-color: var(--border-color-dark);
}

.btn-success {
    background: var(--color-success);
    color: white;
}

.btn-success:hover {
    background: #246139;
}

.btn-danger {
    background: var(--color-danger);
    color: white;
}

.btn-danger:hover {
    background: #b91c1c;
}

.btn-block {
    width: 100%;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* ============================================
   NAVBAR
   ============================================ */
.navbar {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
}

.nav-brand h2 {
    font-size: 1.5rem;
    color: var(--color-primary);
    font-weight: 700;
}

.nav-menu {
    display: flex;
    gap: var(--spacing-xs);
    flex: 1;
    justify-content: center;
}

.nav-link {
    padding: 0.75rem 1.25rem;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-weight: 500;
    cursor: pointer;
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.nav-link.activa {
    background: var(--color-primary);
    color: white;
}

.nav-user {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-name {
    color: var(--text-secondary);
    font-weight: 500;
}

/* ============================================
   CONTENIDO PRINCIPAL
   ============================================ */
.main-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
}

.section-header {
    margin-bottom: var(--spacing-lg);
}

.section-header h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
    color: var(--color-primary);
    font-weight: 700;
}

.section-header p {
    color: var(--text-secondary);
}

/* ============================================
   BUSCADOR
   ============================================ */
.search-bar {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.search-bar input {
    flex: 1;
    min-width: 250px;
    padding: 0.75rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-family: inherit;
}

.search-bar select {
    padding: 0.75rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    cursor: pointer;
}

/* ============================================
   GRID DE LIBROS
   ============================================ */
.libros-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(450px, 1fr));
    gap: var(--spacing-lg);
}

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

.libro-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    transition: all var(--transition-normal);
    cursor: pointer;
}

.libro-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.libro-header {
    margin-bottom: var(--spacing-md);
}

.libro-titulo {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.libro-autor {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.libro-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.libro-info-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
}

.libro-info-label {
    color: var(--text-muted);
}

.libro-info-value {
    color: var(--text-secondary);
    font-weight: 500;
}

.libro-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.badge-disponible {
    background: rgba(45, 122, 79, 0.15);
    color: var(--color-success);
}

.badge-prestado {
    background: rgba(220, 38, 38, 0.15);
    color: var(--color-danger);
}

.libro-actions {
    display: flex;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-md);
}

/* ============================================
   TARJETAS DE LIBRO MODERNAS CON PORTADA
   ============================================ */
.libro-card-modern {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
    transition: all var(--transition-normal);
    cursor: pointer;
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
}

.libro-card-modern:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.libro-cover {
    flex-shrink: 0;
    width: 120px;
    height: 180px;
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    background: var(--bg-tertiary);
    box-shadow: var(--shadow-md);
}

.libro-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.libro-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    min-width: 0;
    /* Para que funcione el text-overflow */
}

.libro-content .libro-header {
    margin-bottom: 0;
}

.libro-content .libro-titulo {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.libro-content .libro-autor {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 0;
}

.libro-meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin: var(--spacing-xs) 0;
}

.libro-meta-item {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    background: var(--bg-tertiary);
    padding: 4px 10px;
    border-radius: 999px;
}

.meta-icon {
    font-size: 0.9rem;
}

.libro-status {
    margin: var(--spacing-xs) 0;
}

.libro-content .libro-actions {
    margin-top: auto;
    padding-top: var(--spacing-sm);
}

/* Responsive: En pantallas pequeñas, apilar verticalmente */
@media (max-width: 600px) {
    .libro-card-modern {
        flex-direction: column;
    }

    .libro-cover {
        width: 100%;
        height: 240px;
    }

    .libro-content .libro-titulo {
        white-space: normal;
    }
}

/* ============================================
   LISTA DE PRÉSTAMOS
   ============================================ */
.prestamos-container {
    display: none;
}

.prestamos-container.activa {
    display: block;
}

.prestamos-lista {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.prestamo-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    transition: all var(--transition-fast);
}

.prestamo-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-md);
}

.prestamo-info {
    flex: 1;
}

.prestamo-libro {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.prestamo-detalles {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.prestamo-dias {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border-radius: var(--border-radius-sm);
    font-weight: 600;
}

.dias-numero {
    font-size: 1.5rem;
    color: var(--color-primary);
}

.prestamo-actions {
    display: flex;
    gap: var(--spacing-xs);
}

/* ============================================
   ESTADÍSTICAS (ADMIN)
   ============================================ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    transition: all var(--transition-fast);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.stat-icon {
    font-size: 3rem;
}

.stat-info h3 {
    font-size: 2rem;
    color: var(--color-primary);
    margin-bottom: 0.25rem;
}

.stat-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ============================================
   LISTA DE USUARIOS (ADMIN)
   ============================================ */
.admin-container {
    display: none;
}

.admin-container.activa {
    display: block;
}

.usuarios-lista {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.usuario-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
}

.usuario-info h4 {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xs);
}

.usuario-info p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ============================================
   BOTONES DE ACCIÓN
   ============================================ */
.action-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

/* ============================================
   MODALES
   ============================================ */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.modal.activo {
    display: flex;
    animation: fadeIn var(--transition-normal);
}

.modal-content {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    line-height: 1;
    padding: 0.5rem;
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--border-radius-sm);
}

.modal-close:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.modal-body {
    padding: var(--spacing-lg);
}

.modal-body code {
    background: var(--bg-tertiary);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--color-primary);
}

.modal form {
    padding: var(--spacing-lg);
}

.modal-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
    margin-top: var(--spacing-lg);
}

/* Estilos específicos para modal de confirmación */
.modal-content .modal-body p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-primary);
}

.modal-content .modal-header h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 600;
}

/* Mejorar botones en modal de confirmación */
.modal-actions .btn {
    min-width: 100px;
    font-weight: 500;
}

.modal-actions .btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.modal-actions .btn-secondary:hover {
    background: var(--border-color-dark);
}

.modal-actions .btn-primary {
    background: var(--color-primary);
    color: white;
}

.modal-actions .btn-primary:hover {
    background: var(--color-primary-dark);
}

/* ============================================
   NOTIFICACIONES TOAST
   ============================================ */
#toast-container {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    min-width: 300px;
    box-shadow: var(--shadow-xl);
    animation: slideIn var(--transition-normal);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.toast-success {
    border-left: 4px solid var(--color-success);
}

.toast-error {
    border-left: 4px solid var(--color-danger);
}

.toast-info {
    border-left: 4px solid var(--color-info);
}

.toast-warning {
    border-left: 4px solid var(--color-warning);
}

@keyframes slideIn {
    from {
        transform: translateX(400px);
        opacity: 0;
    }

    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ============================================
   ESTADOS VACÍOS
   ============================================ */
.empty-state {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--text-muted);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.empty-state h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .nav-menu {
        width: 100%;
        flex-direction: column;
    }

    .nav-link {
        width: 100%;
        text-align: center;
    }

    .nav-user {
        width: 100%;
        justify-content: space-between;
    }

    .libros-grid {
        grid-template-columns: 1fr;
    }

    .search-bar {
        flex-direction: column;
    }

    .search-bar input {
        min-width: 100%;
    }

    .prestamo-card {
        flex-direction: column;
        align-items: flex-start;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    #toast-container {
        left: var(--spacing-sm);
        right: var(--spacing-sm);
    }

    .toast {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .auth-card {
        padding: var(--spacing-lg);
    }

    .logo {
        font-size: 2rem;
    }

    .section-header h2 {
        font-size: 1.5rem;
    }
}