/* -----------------------------------
   SISTEMA DE CAPAS
----------------------------------- */
:root {
    --z-loader: 9999;
    --z-modal: 9998;
    --z-alerts: 9997;
    --z-ui: 9990;
}

/* -----------------------------------
   LOADER GLOBAL
----------------------------------- */
#loader {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.55);
    backdrop-filter: blur(4px);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: var(--z-loader);
}

#loader.active {
    display: flex;
}

.loader-content {
    text-align: center;
    color: #fff;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 5px solid rgba(255,255,255,0.3);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* -----------------------------------
   ALERTAS / TOASTS
----------------------------------- */
#alerts {
    position: fixed;
    top: 1rem;
    right: 1rem;
    width: 280px;
    z-index: var(--z-alerts);
}

.alert {
    padding: 1rem 1.2rem;
    border-radius: var(--radius);
    margin-bottom: 0.8rem;
    color: #fff;
    font-weight: 600;
    animation: fadeIn 0.3s ease;
    box-shadow: var(--shadow-md);
}

.alert-info { background: var(--primary); }
.alert-success { background: var(--success); }
.alert-warning { background: var(--warning); color: #000; }
.alert-danger { background: var(--danger); }

.alert.fade-out {
    opacity: 0;
    transform: translateY(-10px);
    transition: 0.4s ease;
}

/* -----------------------------------
   MODALES
----------------------------------- */
.modal {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.55);
    backdrop-filter: blur(4px);
    display: none;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    z-index: var(--z-modal);
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--theme-surface, #fff);
    padding: 2rem;
    border-radius: var(--radius);
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-lg);
    animation: fadeIn 0.3s ease;
}

/* -----------------------------------
   TRANSICIONES ENTRE VISTAS
----------------------------------- */
.fade-in {
    animation: fadeIn 0.4s ease forwards;
}

.fade-out {
    animation: fadeOut 0.4s ease forwards;
}

.slide-in {
    animation: slideIn 0.4s ease forwards;
}

.slide-out {
    animation: slideOut 0.4s ease forwards;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeOut {
    from { opacity: 1; transform: translateY(0); }
    to { opacity: 0; transform: translateY(-10px); }
}

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

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

/* -----------------------------------
   MICROINTERACCIONES
----------------------------------- */
.pulse {
    animation: pulseAnim 0.6s ease;
}

@keyframes pulseAnim {
    50% { transform: scale(1.05); }
}

.shake {
    animation: shakeAnim 0.6s ease;
}

@keyframes shakeAnim {
    20%, 60% { transform: translateX(-5px); }
    40%, 80% { transform: translateX(5px); }
}

/* -----------------------------------
   GLASS UI (OPCIONAL)
----------------------------------- */
.glass {
    background: rgba(255,255,255,0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
    box-shadow: var(--shadow-md);
    border-radius: var(--radius);
}

/* -----------------------------------
   BOTONES DE MODAL
----------------------------------- */
.modal .btn-primary,
.modal .btn-outline {
    min-width: 100px;
}