:root {
            --primary-color: #1e40af;
            --primary-dark: #1e3a8a;
            --accent-color: #006dd4b6;
            --accent-hover: #037ae994;
            --dark-bg: #0f172a;
            --light-bg: #f8fafc;
            --card-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        html, body {
            height: 100%;
            overflow-x: hidden;
        }
        
        body {
            background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
            min-height: 100vh;
            position: relative;
            display: flex;
            flex-direction: column;
        }
        
        /* Patrón de fondo sutil */
        .bg-pattern {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-image: 
                radial-gradient(circle at 10% 20%, rgba(30, 64, 175, 0.03) 0%, transparent 20%),
                radial-gradient(circle at 90% 80%, rgba(0, 212, 170, 0.03) 0%, transparent 20%);
            z-index: -1;
        }
        
        /* Header superior minimalista */
        .main-header {
            padding: 1.5rem 0;
            position: relative;
            z-index: 10;
            flex-shrink: 0;
        }
        
        .brand-logo {
            font-size: 1.75rem;
            font-weight: 700;
            color: var(--primary-color);
            text-decoration: none;
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
        }
        
        .brand-logo span {
            color: var(--accent-color);
        }
        
        /* Contenedor principal */
        main.container {
            flex: 1;
            display: flex;
            flex-direction: column;
            padding-bottom: 2rem;
            min-height: 0;
        }
        
        /* Tarjeta principal centrada */
        .main-card {
            max-width: 500px;
            margin: 1.5rem auto 3rem;
            background: white;
            border-radius: 24px;
            box-shadow: var(--card-shadow);
            border: 1px solid rgba(255, 255, 255, 0.8);
            overflow: hidden;
            position: relative;
            flex-shrink: 0;
        }
        
        .card-header {
            padding: 2.5rem 2.5rem 0;
            text-align: center;
        }
        
        .card-body {
            padding: 2rem 2.5rem 2.5rem;
        }
        
        /* Estilo de icono de acceso */
        .access-icon {
            width: 80px;
            height: 80px;
            background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
            border-radius: 20px;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 1.5rem;
            box-shadow: 0 10px 20px rgba(30, 64, 175, 0.2);
        }
        
        .access-icon i {
            font-size: 2.5rem;
            color: white;
        }
        
        /* Mejoras en el formulario */
        .form-floating-custom {
            position: relative;
            margin-bottom: 1.75rem;
        }
        
        .form-floating-custom:last-of-type {
            margin-bottom: 1rem;
        }
        
        .form-floating-custom .form-control {
            height: 60px;
            padding: 1.5rem 1rem 0.5rem 3rem;
            border: 2px solid #e2e8f0;
            border-radius: 12px;
            font-size: 1rem;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }
        
        .form-floating-custom .form-control:focus {
            border-color: var(--accent-color);
            box-shadow: 0 0 0 4px rgba(0, 212, 170, 0.1);
            transform: translateY(-2px);
        }
        
        .form-floating-custom label {
            padding-left: 3rem;
            color: #64748b;
            font-size: 0.95rem;
            height: auto;
            line-height: 1.5;
        }
        
        .form-floating-custom .input-icon {
            position: absolute;
            left: 1rem;
            top: 50%;
            transform: translateY(-50%);
            color: #94a3b8;
            z-index: 5;
            transition: all 0.3s ease;
        }
        
        .form-floating-custom .form-control:focus ~ .input-icon {
            color: var(--accent-color);
            transform: translateY(-50%) scale(1.1);
        }
        
        /* Botón de acceso mejorado */
        .btn-access {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            color: white;
            padding: 1rem;
            border: none;
            border-radius: 12px;
            font-weight: 600;
            font-size: 1.1rem;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
            margin-top: 0.5rem;
        }
        
        .btn-access:hover {
            transform: translateY(-3px);
            box-shadow: 0 15px 30px rgba(30, 64, 175, 0.2);
        }
        
        .btn-access:active {
            transform: translateY(-1px);
        }
        
        /* Toggle de contraseña mejorado */
        .password-toggle-btn {
            position: absolute;
            right: 1rem;
            top: 50%;
            transform: translateY(-50%);
            background: none;
            border: none;
            color: #94a3b8;
            padding: 0.5rem;
            cursor: pointer;
            border-radius: 6px;
            transition: all 0.3s ease;
            z-index: 10;
            width: 40px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .password-toggle-btn:hover {
            background: #f1f5f9;
            color: var(--primary-color);
        }
        
        /* Checkbox moderno */
        .form-check-input-custom {
            width: 18px;
            height: 18px;
            border: 2px solid #cbd5e1;
            border-radius: 4px;
            cursor: pointer;
            position: relative;
            appearance: none;
            transition: all 0.2s ease;
            margin-top: 0.25rem;
        }
        
        .form-check-input-custom:checked {
            background-color: var(--accent-color);
            border-color: var(--accent-color);
        }
        
        .form-check-input-custom:checked::after {
            content: '✓';
            position: absolute;
            color: white;
            font-size: 12px;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
        }
        
        /* Barra de seguridad mejorada */
        .security-meter {
            height: 6px;
            background: #e2e8f0;
            border-radius: 3px;
            margin-top: 0.75rem;
            overflow: hidden;
            position: relative;
            clear: both;
        }
        
        .security-fill {
            height: 100%;
            width: 0%;
            border-radius: 3px;
            transition: all 0.4s ease;
            background: linear-gradient(90deg, #ef4444, #f59e0b, #10b981);
        }
        
        /* Footer de la tarjeta */
        .card-footer-links {
            border-top: 1px solid #e2e8f0;
            padding-top: 1.5rem;
            margin-top: 2rem;
            clear: both;
        }
        
        /* Sección de características (abajo) */
        .features-section {
            max-width: 1000px;
            margin: 0 auto 3rem;
            padding: 0 1rem;
            flex: 1;
        }
        
        .features-title {
            text-align: center;
            margin-bottom: 3rem !important;
        }
        
        .feature-box {
            background: white;
            padding: 1.75rem;
            border-radius: 16px;
            height: 100%;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            border: 1px solid #f1f5f9;
            margin-bottom: 1.5rem;
            display: flex;
            flex-direction: column;
            min-height: 220px;
        }
        
        .feature-box:hover {
            transform: translateY(-8px);
            box-shadow: var(--card-shadow);
        }
        
        .feature-icon {
            width: 60px;
            height: 60px;
            background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1.5rem;
            flex-shrink: 0;
        }
        
        .feature-icon i {
            color: white;
            font-size: 1.75rem;
        }
        
        .feature-box h5 {
            font-weight: 700;
            margin-bottom: 1rem;
            color: var(--dark-bg);
            line-height: 1.3;
        }
        
        .feature-box p {
            color: #64748b;
            line-height: 1.6;
            margin-bottom: 0;
            flex-grow: 1;
        }
        
        /* Espaciado entre filas de características */
        .features-row {
            margin-bottom: 2rem;
        }
        
        /* Animaciones */
        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        
        .animate-fade-in {
            animation: fadeInUp 0.6s ease-out forwards;
        }
        
        .animate-delay-1 { animation-delay: 0.2s; opacity: 0; }
        .animate-delay-2 { animation-delay: 0.4s; opacity: 0; }
        .animate-delay-3 { animation-delay: 0.6s; opacity: 0; }
        
        /* Alertas */
        .alert {
            border-radius: 12px;
            border: none;
            margin-bottom: 1.5rem;
            padding: 1rem 1.25rem;
        }
        
        /* Validación feedback */
        .valid-feedback, .invalid-feedback {
            margin-top: 0.5rem;
            display: block;
        }
        
        /* Footer */
        footer {
            padding: 1.5rem 0;
            background: transparent;
            border-top: 1px solid #e2e8f0;
            margin-top: auto;
            flex-shrink: 0;
            position: relative;
            z-index: 10;
        }
        
        footer p {
            margin-bottom: 0;
        }
        
        /* Responsive */
        @media (max-width: 768px) {
            .main-header {
                padding: 1rem 0;
            }
            
            .main-card {
                margin: 1rem auto 2.5rem;
                border-radius: 20px;
                width: 95%;
            }
            
            .card-header, .card-body {
                padding: 1.5rem;
            }
            
            .access-icon {
                width: 70px;
                height: 70px;
                margin-bottom: 1.25rem;
            }
            
            .access-icon i {
                font-size: 2rem;
            }
            
            .features-section {
                margin-bottom: 2rem;
            }
            
            .features-title {
                margin-bottom: 2rem !important;
            }
            
            .feature-box {
                padding: 1.5rem;
                min-height: 200px;
                margin-bottom: 1rem;
            }
            
            .feature-icon {
                width: 50px;
                height: 50px;
                margin-bottom: 1rem;
            }
            
            .feature-icon i {
                font-size: 1.5rem;
            }
            
            .form-floating-custom .form-control {
                height: 56px;
                padding: 1.25rem 1rem 0.5rem 3rem;
            }
            
            .btn-access {
                padding: 0.875rem;
                font-size: 1rem;
            }
            
            /* Ajustes para móviles pequeños */
            @media (max-width: 576px) {
                .main-card {
                    margin: 0.75rem auto 2rem;
                    border-radius: 16px;
                }
                
                .card-header, .card-body {
                    padding: 1.25rem;
                }
                
                .d-flex.justify-content-between {
                    flex-direction: column;
                    gap: 1rem;
                }
                
                .d-flex.justify-content-between .form-check {
                    order: 2;
                }
                
                .d-flex.justify-content-between a {
                    order: 1;
                    text-align: left;
                    width: 100%;
                }
                
                .feature-box {
                    min-height: auto;
                    padding: 1.25rem;
                }
                
                .features-row {
                    margin-bottom: 1rem;
                }
            }
        }
        
        @media (min-width: 992px) {
            .features-section {
                max-width: 1200px;
            }
            
            .feature-box {
                min-height: 240px;
            }
        }
        
        /* Ajustes específicos para evitar superposiciones */
        #alertContainer {
            margin-top: 1rem;
            margin-bottom: 1rem;
        }
        
        .form-check {
            margin-bottom: 0;
        }
        
        .text-danger.small.mt-1 {
            display: block;
            margin-top: 0.5rem !important;
        }
        
        /* Mejoras en el espaciado de elementos flotantes */
        .clearfix::after {
            content: "";
            clear: both;
            display: table;
        }



        .logo-container {
            margin: bottom 2px;
        }

        .logo {
            max-height: 250px;
            width: auto;
        }