/**
 * Loading Animations & Page Transitions
 * Modern, professional loading states for page navigation
 */

/* ==================== PAGE TRANSITION OVERLAY ==================== */

.page-loader-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 999999;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.page-loader-overlay.active {
    opacity: 1;
    visibility: visible;
}

.page-loader-overlay.fade-out {
    opacity: 0;
}

/* Loader Content */
.loader-content {
    text-align: center;
    color: white;
}

.loader-logo {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 30px;
    animation: pulse 2s ease-in-out infinite;
}

/* Modern Spinner */
.modern-spinner {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    position: relative;
}

.spinner-ring {
    position: absolute;
    width: 100%;
    height: 100%;
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s linear infinite;
}

.spinner-ring:nth-child(2) {
    width: 80%;
    height: 80%;
    top: 10%;
    left: 10%;
    border-width: 3px;
    animation-duration: 1.5s;
    animation-direction: reverse;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.8; transform: scale(0.95); }
}

/* Loading Text */
.loader-text {
    font-size: 16px;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.9);
    margin-top: 10px;
}

/* Progress Bar */
.loader-progress {
    width: 200px;
    height: 4px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 2px;
    overflow: hidden;
    margin: 20px auto 0;
}

.loader-progress-bar {
    height: 100%;
    background: white;
    border-radius: 2px;
    animation: progress 2s ease-in-out infinite;
}

@keyframes progress {
    0% { width: 0%; transform: translateX(0); }
    50% { width: 70%; }
    100% { width: 100%; transform: translateX(0); }
}

/* ==================== SKELETON LOADING ==================== */

.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
    border-radius: 4px;
}

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

/* Skeleton Variants */
.skeleton-text {
    height: 16px;
    margin: 8px 0;
    border-radius: 4px;
}

.skeleton-text.large {
    height: 24px;
}

.skeleton-text.small {
    height: 12px;
}

.skeleton-card {
    padding: 20px;
    border-radius: 8px;
    background: white;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.skeleton-card-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.skeleton-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
}

.skeleton-table-row {
    display: flex;
    gap: 15px;
    padding: 15px;
    border-bottom: 1px solid #f0f0f0;
}

.skeleton-table-cell {
    flex: 1;
    height: 20px;
}

/* ==================== INLINE LOADERS ==================== */

.inline-loader {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: #667eea;
}

.inline-spinner {
    width: 16px;
    height: 16px;
    border: 2px solid rgba(102, 126, 234, 0.2);
    border-top-color: #667eea;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

/* Dots Loader */
.dots-loader {
    display: inline-flex;
    gap: 4px;
}

.dots-loader span {
    width: 8px;
    height: 8px;
    background: #667eea;
    border-radius: 50%;
    animation: dots-bounce 1.4s ease-in-out infinite;
}

.dots-loader span:nth-child(1) { animation-delay: 0s; }
.dots-loader span:nth-child(2) { animation-delay: 0.2s; }
.dots-loader span:nth-child(3) { animation-delay: 0.4s; }

@keyframes dots-bounce {
    0%, 60%, 100% { transform: translateY(0); opacity: 1; }
    30% { transform: translateY(-10px); opacity: 0.7; }
}

/* ==================== BUTTON LOADING STATES ==================== */

.btn-loading {
    position: relative;
    pointer-events: none;
    opacity: 0.7;
}

.btn-loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 16px;
    height: 16px;
    margin: -8px 0 0 -8px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

.btn-loading span {
    opacity: 0;
}

/* ==================== CONTENT FADE-IN ==================== */

.content-fade-in {
    animation: fadeIn 0.4s ease-in-out;
}

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

/* ==================== DARK MODE SUPPORT ==================== */

.dark-mode .skeleton {
    background: linear-gradient(90deg, #2d3748 25%, #1a202c 50%, #2d3748 75%);
    background-size: 200% 100%;
}

.dark-mode .skeleton-card {
    background: #2d3748;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.dark-mode .skeleton-table-row {
    border-bottom-color: #4a5568;
}

/* ==================== RESPONSIVE ==================== */

@media (max-width: 768px) {
    .loader-logo {
        font-size: 36px;
        margin-bottom: 20px;
    }

    .modern-spinner {
        width: 50px;
        height: 50px;
    }

    .loader-progress {
        width: 160px;
    }

    .loader-text {
        font-size: 14px;
    }
}

/* ==================== ACCESSIBILITY ==================== */

@media (prefers-reduced-motion: reduce) {
    .page-loader-overlay,
    .skeleton,
    .modern-spinner,
    .inline-spinner,
    .dots-loader span,
    .btn-loading::after,
    .content-fade-in {
        animation: none !important;
    }

    .page-loader-overlay.active {
        opacity: 1;
    }
}