/* ===== VARIABLES Y CONFIGURACIÓN GENERAL ===== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Playfair+Display:wght@400;500;600;700&display=swap');

:root {
    --azul-profundo: #0B2B4A;
    --azul-acero: #2C4B6B;
    --gris-plata: #F8F9FA;
    --gris-medio: #E9ECEF;
    --gris-oscuro: #495057;
    --blanco-puro: #FFFFFF;
    --verde-institucional: #1B8C5E;
    --rojo-elegante: #B22234;
    --dorado: #C49A6C;
    --sombra-suave: 0 10px 30px rgba(0,0,0,0.05);
    --sombra-media: 0 15px 35px rgba(11, 43, 74, 0.15);
    --sombra-fuerte: 0 20px 40px rgba(0,0,0,0.08);
    --transicion: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    font-weight: 400;
    line-height: 1.6;
    color: var(--gris-oscuro);
    background-color: var(--gris-plata);
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px 30px;
    flex: 1;
    width: 100%;
    box-sizing: border-box;
}

/* ===== TIPOGRAFÍA ===== */
h1, h2, h3, h4 {
    font-family: 'Playfair Display', serif;
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--azul-profundo);
}

h1 {
    font-size: 2.5rem;
    position: relative;
    display: inline-block;
}

h1::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--dorado), var(--azul-acero));
    border-radius: 2px;
}

h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    position: relative;
}

h2::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--dorado), transparent);
}

/* ===== HEADER MODERNO - VERSIÓN CORREGIDA ===== */
header {
    background: linear-gradient(135deg, var(--azul-profundo) 0%, var(--azul-acero) 100%);
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    box-shadow: var(--sombra-media);
    width: 100%;
    left: 0;
    right: 0;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    box-sizing: border-box;
}

.logo {
    flex-shrink: 0;
}

.logo h1 {
    font-family: 'Playfair Display', serif;
    font-weight: 700;
    font-size: 1.8rem;
    background: linear-gradient(135deg, #fff, #e0e0e0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 5px;
    white-space: nowrap;
}

.logo h1::after {
    display: none;
}

.logo span {
    font-size: 0.9rem;
    opacity: 0.9;
    color: var(--gris-plata);
    letter-spacing: 2px;
    font-weight: 300;
    display: block;
}

/* ===== NAVEGACIÓN ===== */
nav {
    flex-shrink: 1;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 10px;
    margin: 0;
    padding: 0;
}

nav a {
    color: var(--blanco-puro);
    text-decoration: none;
    padding: 0.7rem 1.2rem;
    border-radius: 8px;
    font-weight: 500;
    position: relative;
    transition: var(--transicion);
    display: flex;
    align-items: center;
    gap: 8px;
    white-space: nowrap;
}

nav a i {
    font-size: 1.1rem;
}

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--dorado);
    transition: width 0.3s ease;
}

nav a:hover {
    background: rgba(255,255,255,0.1);
}

nav a:hover::after {
    width: 70%;
}

nav a.active {
    background: rgba(255,255,255,0.15);
}

nav a.active::after {
    width: 70%;
}

/* ===== BUSCADOR MODERNO ===== */
.search-section {
    background: linear-gradient(135deg, var(--blanco-puro), var(--gris-plata));
    padding: 40px;
    border-radius: 24px;
    box-shadow: var(--sombra-fuerte);
    margin: 30px 0;
    border: 1px solid rgba(255,255,255,0.8);
    backdrop-filter: blur(10px);
    position: relative;
    overflow: hidden;
}

.search-section::before {
    content: '⚖️';
    position: absolute;
    right: 20px;
    bottom: 20px;
    font-size: 4rem;
    opacity: 0.1;
    transform: rotate(15deg);
}

.search-section h2 {
    font-size: 2.2rem;
    margin-bottom: 25px;
    color: var(--azul-profundo);
}

.search-form {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.search-form input,
.search-form select {
    background: rgba(255,255,255,0.9);
    border: 2px solid var(--gris-medio);
    border-radius: 12px;
    padding: 14px 20px;
    font-size: 1rem;
    transition: var(--transicion);
    flex: 1;
    min-width: 250px;
}

.search-form input:focus,
.search-form select:focus {
    border-color: var(--dorado);
    box-shadow: 0 0 0 4px rgba(196, 154, 108, 0.1);
    outline: none;
    transform: translateY(-2px);
}

/* ===== BOTONES ===== */
.btn {
    padding: 14px 28px;
    background: linear-gradient(135deg, var(--azul-profundo), var(--azul-acero));
    color: var(--blanco-puro);
    border: none;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transicion);
    display: inline-flex;
    align-items: center;
    gap: 10px;
    box-shadow: 0 4px 15px rgba(11, 43, 74, 0.3);
    text-decoration: none;
}

.btn i {
    font-size: 1.1rem;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(11, 43, 74, 0.4);
    background: linear-gradient(135deg, var(--azul-acero), var(--azul-profundo));
}

.btn-secondary {
    background: linear-gradient(135deg, #6c757d, #495057);
    box-shadow: 0 4px 15px rgba(108, 117, 125, 0.3);
}

.btn-secondary:hover {
    background: linear-gradient(135deg, #5a6268, #3d4349);
}

.btn-danger {
    background: linear-gradient(135deg, var(--rojo-elegante), #8B0000);
    box-shadow: 0 4px 15px rgba(178, 34, 52, 0.3);
}

.btn-warning {
    background: linear-gradient(135deg, #ff9800, #f57c00);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* ===== TARJETAS DE LIBROS ===== */
.libros-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 30px;
    margin-top: 30px;
    padding: 10px 0;
}

.libro-card {
    background: var(--blanco-puro);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--sombra-suave);
    transition: var(--transicion);
    border: 1px solid rgba(0,0,0,0.05);
    position: relative;
    animation: fadeInUp 0.5s ease forwards;
    opacity: 0;
}

.libro-card:nth-child(1) { animation-delay: 0.1s; }
.libro-card:nth-child(2) { animation-delay: 0.2s; }
.libro-card:nth-child(3) { animation-delay: 0.3s; }
.libro-card:nth-child(4) { animation-delay: 0.4s; }
.libro-card:nth-child(5) { animation-delay: 0.5s; }

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.libro-card:hover {
    transform: translateY(-10px) scale(1.02);
    box-shadow: var(--sombra-media);
    border-color: var(--dorado);
}

.libro-card::before {
    content: '📚 JUR-' attr(data-id);
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    background: linear-gradient(90deg, var(--azul-profundo), var(--azul-acero));
    color: rgba(255,255,255,0.9);
    font-size: 0.75rem;
    padding: 5px 15px;
    font-family: 'Inter', monospace;
    letter-spacing: 1px;
    font-weight: 400;
    z-index: 1;
}

.libro-badge {
    position: absolute;
    top: 40px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--dorado), #b8860b);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    box-shadow: 0 4px 10px rgba(196, 154, 108, 0.3);
    z-index: 10;
}

.libro-content {
    padding: 30px 25px 25px;
}

.libro-categoria {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--gris-medio);
    padding: 6px 15px;
    border-radius: 30px;
    font-size: 0.85rem;
    color: var(--azul-profundo);
    font-weight: 500;
    margin-bottom: 15px;
}

.libro-categoria i {
    color: var(--dorado);
}

.libro-titulo {
    font-size: 1.4rem;
    margin: 10px 0 15px;
    color: var(--azul-profundo);
    line-height: 1.4;
    border-left: 4px solid var(--dorado);
    padding-left: 15px;
}

.libro-titulo a {
    color: inherit;
    text-decoration: none;
    transition: var(--transicion);
}

.libro-titulo a:hover {
    color: var(--dorado);
}

.libro-autor {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--gris-oscuro);
    font-size: 1rem;
    margin-bottom: 20px;
    padding: 10px 0;
    border-bottom: 1px dashed var(--gris-medio);
}

.libro-autor i {
    color: var(--dorado);
    width: 20px;
}

/* ===== ESTADOS ===== */
.estado-disponible,
.estado-prestado {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 20px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 0.95rem;
    letter-spacing: 0.3px;
    width: 100%;
    margin: 15px 0;
    border: 1px solid transparent;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.estado-disponible {
    background: linear-gradient(135deg, #E8F5E9, #C8E6C9);
    color: #1B5E20;
    border-color: rgba(27, 94, 32, 0.2);
}

.estado-prestado {
    background: linear-gradient(135deg, #FFEBEE, #FFCDD2);
    color: #B71C1C;
    border-color: rgba(183, 28, 28, 0.2);
}

.indicador {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    position: relative;
    display: inline-block;
}

.indicador.verde {
    background: #4CAF50;
    box-shadow: 0 0 15px rgba(76, 175, 80, 0.5);
    animation: pulse 2s infinite;
}

.indicador.rojo {
    background: #F44336;
    box-shadow: 0 0 15px rgba(244, 67, 54, 0.5);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { 
        transform: scale(1); 
        box-shadow: 0 0 10px currentColor;
    }
    50% { 
        transform: scale(1.2); 
        box-shadow: 0 0 20px currentColor;
    }
    100% { 
        transform: scale(1); 
        box-shadow: 0 0 10px currentColor;
    }
}

.prestamo-info {
    background: rgba(0,0,0,0.02);
    padding: 12px 15px;
    border-radius: 10px;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 10px;
    border: 1px solid rgba(0,0,0,0.05);
}

.prestamo-info i {
    color: var(--dorado);
}

.dias-transcurridos {
    background: rgba(0,0,0,0.05);
    padding: 3px 10px;
    border-radius: 30px;
    font-weight: 600;
    margin-left: auto;
}

.dias-transcurridos.alerta-roja {
    background: rgba(244, 67, 54, 0.1);
    color: var(--rojo-elegante);
}

.btn-ver-mas {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--azul-profundo);
    text-decoration: none;
    font-weight: 500;
    margin-top: 15px;
    padding: 8px 0;
    transition: var(--transicion);
    border-bottom: 2px solid transparent;
}

.btn-ver-mas:hover {
    color: var(--dorado);
    border-bottom-color: var(--dorado);
    gap: 12px;
}

/* ===== PÁGINA DE DETALLE ===== */
.libro-detalle {
    background: white;
    border-radius: 30px;
    padding: 50px;
    box-shadow: var(--sombra-fuerte);
    margin-top: 30px;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.detalle-header {
    display: grid;
    grid-template-columns: 1fr 350px;
    gap: 50px;
    margin-bottom: 50px;
    padding-bottom: 40px;
    border-bottom: 2px solid var(--gris-medio);
}

.detalle-metadata {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.metadata-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 10px;
    border-radius: 15px;
    transition: var(--transicion);
}

.metadata-item:hover {
    background: var(--gris-plata);
    transform: translateX(10px);
}

.metadata-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--azul-profundo), var(--azul-acero));
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
    box-shadow: 0 5px 15px rgba(11, 43, 74, 0.2);
}

.metadata-content {
    flex: 1;
}

.metadata-label {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: #6c757d;
    margin-bottom: 5px;
    font-weight: 500;
}

.metadata-value {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--azul-profundo);
}

.detalle-actions {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
    margin-top: 20px;
}

.indice-container {
    background: linear-gradient(135deg, #f8f9fa, #ffffff);
    border-radius: 20px;
    padding: 40px;
    border-left: 5px solid var(--dorado);
    margin-top: 30px;
    box-shadow: inset 0 2px 10px rgba(0,0,0,0.02);
}

.indice-container h2 {
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.indice-container h2 i {
    color: var(--dorado);
}

.indice-content {
    white-space: pre-line;
    line-height: 1.8;
    font-size: 1.05rem;
    color: #2d3e50;
    column-count: 2;
    column-gap: 40px;
}

/* ===== DASHBOARD ADMIN ===== */
.dashboard-header {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    margin: 30px 0;
}

.metric-card {
    background: linear-gradient(135deg, var(--blanco-puro), var(--gris-plata));
    padding: 30px;
    border-radius: 20px;
    box-shadow: var(--sombra-suave);
    border: 1px solid rgba(0,0,0,0.03);
    transition: var(--transicion);
    position: relative;
    overflow: hidden;
}

.metric-card::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 100px;
    height: 100px;
    background: linear-gradient(135deg, var(--dorado), transparent);
    opacity: 0.1;
    border-radius: 50%;
    transform: translate(50%, -50%);
}

.metric-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--sombra-media);
    border-color: var(--dorado);
}

.metric-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--azul-profundo), var(--azul-acero));
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.metric-icon i {
    font-size: 1.8rem;
    color: white;
}

.metric-number {
    font-size: 2.8rem;
    font-weight: 700;
    color: var(--azul-profundo);
    margin-bottom: 5px;
    line-height: 1;
}

.metric-label {
    color: #6c757d;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 500;
}

.metric-trend {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid var(--gris-medio);
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 5px;
}

.metric-trend i {
    color: var(--verde-institucional);
}

/* ===== TABLAS ADMIN ===== */
.table-responsive {
    overflow-x: auto;
    border-radius: 20px;
    background: white;
    box-shadow: var(--sombra-suave);
    margin: 30px 0;
    width: 100%;
    -webkit-overflow-scrolling: touch;
}

.admin-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 800px;
}

.admin-table th {
    background: linear-gradient(135deg, var(--azul-profundo), var(--azul-acero));
    color: white;
    font-weight: 500;
    padding: 18px 15px;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    white-space: nowrap;
}

.admin-table th:first-child {
    border-top-left-radius: 20px;
}

.admin-table th:last-child {
    border-top-right-radius: 20px;
}

.admin-table td {
    padding: 15px;
    border-bottom: 1px solid var(--gris-medio);
    transition: var(--transicion);
}

.admin-table tr {
    transition: var(--transicion);
}

.admin-table tr:hover {
    background: linear-gradient(90deg, #f8f9fa, #ffffff);
    transform: scale(1.01);
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.admin-table tr.alerta-demora {
    background: linear-gradient(90deg, #ffebee, #ffffff);
    border-left: 4px solid var(--rojo-elegante);
}

/* ===== BOTONES DE ACCIÓN ===== */
.action-buttons {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.action-btn {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: var(--transicion);
    text-decoration: none;
    border: none;
    cursor: pointer;
}

.action-btn i {
    font-size: 1rem;
}

.action-btn.edit {
    background: #e3f2fd;
    color: #0d47a1;
    border: 1px solid rgba(13, 71, 161, 0.2);
}

.action-btn.delete {
    background: #ffebee;
    color: #b71c1c;
    border: 1px solid rgba(183, 28, 28, 0.2);
}

.action-btn.view {
    background: #f3e5f5;
    color: #4a148c;
    border: 1px solid rgba(74, 20, 140, 0.2);
}

.action-btn:hover {
    transform: translateY(-2px);
    filter: brightness(0.95);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

/* ===== ALERTAS Y NOTIFICACIONES ===== */
.alerta-sistema {
    position: fixed;
    top: 100px;
    right: 30px;
    z-index: 9999;
    max-width: 400px;
    animation: slideInRight 0.3s ease;
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideOutRight {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

.alerta-moderna {
    background: white;
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    display: flex;
    align-items: flex-start;
    gap: 15px;
    border-left: 4px solid;
    margin-bottom: 15px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
}

.alerta-moderna.success {
    border-left-color: var(--verde-institucional);
}

.alerta-moderna.warning {
    border-left-color: #ff9800;
}

.alerta-moderna.danger {
    border-left-color: var(--rojo-elegante);
}

.alerta-moderna.info {
    border-left-color: var(--azul-profundo);
}

.alerta-icon {
    width: 45px;
    height: 45px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
}

.alerta-moderna.success .alerta-icon {
    background: #e8f5e9;
    color: var(--verde-institucional);
}

.alerta-moderna.warning .alerta-icon {
    background: #fff3e0;
    color: #ff9800;
}

.alerta-moderna.danger .alerta-icon {
    background: #ffebee;
    color: var(--rojo-elegante);
}

.alerta-moderna.info .alerta-icon {
    background: #e3f2fd;
    color: var(--azul-profundo);
}

.alerta-content {
    flex: 1;
}

.alerta-title {
    font-weight: 700;
    margin-bottom: 5px;
    font-size: 1.1rem;
}

.alerta-message {
    color: #6c757d;
    font-size: 0.95rem;
}

.alerta-close {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: #999;
    transition: var(--transicion);
    padding: 5px;
}

.alerta-close:hover {
    color: #333;
    transform: scale(1.1);
}

/* ===== BREADCRUMBS ===== */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px 0;
    margin-bottom: 20px;
    background: transparent;
    flex-wrap: wrap;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    gap: 8px;
    color: #6c757d;
    text-decoration: none;
    font-size: 0.95rem;
    transition: var(--transicion);
}

.breadcrumb-item:hover {
    color: var(--azul-profundo);
}

.breadcrumb-item.active {
    color: var(--azul-profundo);
    font-weight: 500;
}

.breadcrumb-separator {
    color: #ccc;
}

/* ===== FORMULARIOS ===== */
.form-container {
    background: white;
    border-radius: 30px;
    padding: 40px;
    box-shadow: var(--sombra-fuerte);
    max-width: 800px;
    margin: 30px auto;
}

.form-group {
    margin-bottom: 25px;
    position: relative;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--azul-profundo);
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.form-group label i {
    color: var(--dorado);
}

.form-control {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid var(--gris-medio);
    border-radius: 12px;
    font-size: 1rem;
    transition: var(--transicion);
    background: var(--gris-plata);
}

.form-control:focus {
    border-color: var(--dorado);
    box-shadow: 0 0 0 4px rgba(196, 154, 108, 0.1);
    outline: none;
    background: white;
    transform: translateY(-2px);
}

textarea.form-control {
    min-height: 150px;
    resize: vertical;
}

.form-hint {
    font-size: 0.85rem;
    color: #6c757d;
    margin-top: 5px;
    display: flex;
    align-items: center;
    gap: 5px;
}

.form-hint i {
    color: var(--dorado);
    font-size: 0.8rem;
}

/* ===== FOOTER ===== */
footer {
    background: linear-gradient(135deg, var(--azul-profundo), #0a1a2f);
    color: var(--blanco-puro);
    padding: 50px 0 20px;
    margin-top: 80px;
    position: relative;
    overflow: hidden;
}

footer::before {
    content: '⚖️';
    position: absolute;
    right: 50px;
    bottom: 50px;
    font-size: 8rem;
    opacity: 0.1;
    transform: rotate(15deg);
}

.footer-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 30px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 50px;
    position: relative;
    z-index: 1;
}

.footer-section h3 {
    color: var(--dorado);
    margin-bottom: 25px;
    font-size: 1.3rem;
    border-bottom: 2px solid rgba(196, 154, 108, 0.3);
    padding-bottom: 10px;
}

.footer-section p {
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
    opacity: 0.9;
}

.footer-section i {
    color: var(--dorado);
    width: 20px;
}

.footer-section a {
    color: white;
    text-decoration: none;
    transition: var(--transicion);
}

.footer-section a:hover {
    color: var(--dorado);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    margin-top: 30px;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 0.9rem;
    opacity: 0.7;
}

/* ===== TOOLTIPS ===== */
[data-tooltip] {
    position: relative;
    cursor: help;
}

[data-tooltip]:before {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    padding: 8px 15px;
    background: var(--azul-profundo);
    color: white;
    font-size: 0.85rem;
    border-radius: 8px;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    pointer-events: none;
    z-index: 100;
}

[data-tooltip]:hover:before {
    opacity: 1;
    visibility: visible;
    bottom: 120%;
}

/* ===== LOADING SKELETON ===== */
.skeleton {
    background: linear-gradient(
        90deg,
        #f0f0f0 25%,
        #f8f8f8 50%,
        #f0f0f0 75%
    );
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
    border-radius: 8px;
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ===== SCROLLBAR PERSONALIZADA ===== */
::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

::-webkit-scrollbar-track {
    background: var(--gris-medio);
    border-radius: 6px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, var(--azul-profundo), var(--azul-acero));
    border-radius: 6px;
    border: 2px solid var(--gris-medio);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--dorado);
}

/* ===== PÁGINA DE LOGIN ===== */
.login-container {
    max-width: 450px;
    margin: 50px auto;
}

/* ===== MEDIA QUERIES UNIFICADAS ===== */
/* Tablet landscape y laptops pequeños */
@media (max-width: 1200px) {
    .container {
        padding: 15px 25px;
    }
    
    h1 {
        font-size: 2.2rem;
    }
    
    h2 {
        font-size: 1.8rem;
    }
    
    .detalle-header {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .indice-content {
        column-count: 1;
    }
    
    .metric-card {
        padding: 25px;
    }
    
    .metric-number {
        font-size: 2.2rem;
    }
}

/* Tablets vertical */
@media (max-width: 992px) {
    .header-content {
        flex-direction: column;
        text-align: center;
        gap: 15px;
        padding: 1rem 1.5rem;
    }
    
    .logo h1 {
        font-size: 1.6rem;
        white-space: normal;
    }
    
    nav ul {
        justify-content: center;
        flex-wrap: wrap;
        gap: 8px;
    }
    
    nav a {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }
    
    .libros-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
        gap: 20px;
    }
    
    .dashboard-header {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
    }
    
    .admin-table {
        font-size: 0.9rem;
        min-width: 700px;
    }
    
    .admin-table th,
    .admin-table td {
        padding: 12px 10px;
    }
    
    .action-buttons {
        flex-direction: column;
        gap: 5px;
    }
    
    .action-btn {
        width: 100%;
        justify-content: center;
        padding: 6px 12px;
    }
}

/* Móviles grandes */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    h2 {
        font-size: 1.6rem;
        margin-bottom: 1rem;
    }
    
    .header-content {
        padding: 0.8rem 1rem;
    }
    
    .logo h1 {
        font-size: 1.4rem;
        background: none;
        -webkit-text-fill-color: white;
        color: white;
    }
    
    .logo span {
        font-size: 0.8rem;
    }
    
    nav a {
        padding: 0.5rem 0.8rem;
        font-size: 0.85rem;
    }
    
    nav a i {
        font-size: 0.9rem;
    }
    
    .search-section {
        padding: 25px 20px;
        margin: 20px 0;
    }
    
    .search-section h2 {
        font-size: 1.6rem;
        margin-bottom: 20px;
    }
    
    .search-form {
        flex-direction: column;
        gap: 10px;
    }
    
    .search-form input,
    .search-form select,
    .search-form .btn {
        width: 100%;
        min-width: 100%;
    }
    
    .libro-detalle {
        padding: 20px;
        margin-top: 20px;
    }
    
    .detalle-header {
        gap: 20px;
        margin-bottom: 30px;
        padding-bottom: 20px;
    }
    
    .metadata-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .metadata-icon {
        width: 40px;
        height: 40px;
        font-size: 1rem;
    }
    
    .metadata-value {
        font-size: 1rem;
    }
    
    .detalle-actions {
        flex-direction: column;
        gap: 10px;
    }
    
    .detalle-actions .btn {
        width: 100%;
        justify-content: center;
    }
    
    .indice-container {
        padding: 20px;
    }
    
    .dashboard-header {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .metric-card {
        padding: 20px;
    }
    
    .metric-number {
        font-size: 2rem;
    }
    
    .metric-icon {
        width: 50px;
        height: 50px;
        margin-bottom: 15px;
    }
    
    .metric-icon i {
        font-size: 1.5rem;
    }
    
    .breadcrumb {
        font-size: 0.85rem;
        padding: 10px 0;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 30px;
    }
    
    .footer-section p {
        justify-content: center;
    }
    
    .alerta-sistema {
        left: 15px;
        right: 15px;
        max-width: none;
        top: 80px;
    }
    
    .form-container {
        padding: 25px 20px;
        margin: 20px auto;
    }
    
    .prestamo-info {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .dias-transcurridos {
        margin-left: 0;
        margin-top: 5px;
    }
}

/* Móviles pequeños */
@media (max-width: 480px) {
    h1 {
        font-size: 1.8rem;
    }
    
    h1::after {
        width: 60px;
        height: 3px;
    }
    
    h2 {
        font-size: 1.4rem;
    }
    
    h2::after {
        width: 40px;
    }
    
    .header-content {
        padding: 0.7rem 0.8rem;
    }
    
    .logo h1 {
        font-size: 1.2rem;
    }
    
    .logo span {
        font-size: 0.7rem;
    }
    
    nav ul {
        gap: 5px;
    }
    
    nav a {
        padding: 0.4rem 0.6rem;
        font-size: 0.75rem;
    }
    
    nav a i {
        font-size: 0.8rem;
    }
    
    .search-section {
        padding: 20px 15px;
    }
    
    .search-section h2 {
        font-size: 1.4rem;
    }
    
    .btn {
        padding: 12px 20px;
        font-size: 0.9rem;
    }
    
    .libros-grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }
    
    .libro-titulo {
        font-size: 1.2rem;
    }
    
    .estado-disponible,
    .estado-prestado {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }
    
    .action-buttons {
        flex-direction: column;
        gap: 5px;
    }
    
    .action-btn {
        width: 100%;
        justify-content: center;
    }
    
    .breadcrumb-item {
        font-size: 0.8rem;
    }
    
    .metric-number {
        font-size: 1.8rem;
    }
    
    .metric-label {
        font-size: 0.8rem;
    }
    
    .admin-table th,
    .admin-table td {
        padding: 10px 8px;
        font-size: 0.8rem;
    }
    
    .login-container {
        margin: 30px auto;
    }
}

/* ===== MODO IMPRESIÓN ===== */
@media print {
    header,
    footer,
    .search-section,
    .btn,
    .action-buttons,
    .breadcrumb,
    .alerta-sistema,
    .dashboard-header,
    .table-responsive,
    .form-container {
        display: none !important;
    }
    
    .libro-detalle {
        box-shadow: none;
        padding: 0;
        margin: 0;
    }
    
    .indice-content {
        column-count: 1;
    }
    
    body {
        background: white;
    }
    
    .container {
        padding: 0;
    }
}

/* ===== MENÚ DE PONENCIAS ===== */
nav a i.fa-file-pdf {
    color: #ff9800;
}

nav a.active i.fa-file-pdf {
    color: white;
}

/* Estilo para el badge de notificación (opcional) */
.nav-badge {
    background: var(--rojo-elegante);
    color: white;
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: 30px;
    margin-left: 5px;
}