/* ===================================
   LOADING STATES & ANIMATIONS
   Enhanced user experience with loading feedback
   =================================== */

/* === BUTTON LOADING STATES === */
.btn.loading {
    cursor: not-allowed;
    opacity: 0.7;
    pointer-events: none;
}

.spinner {
    display: inline-block;
    margin-right: 8px;
    vertical-align: middle;
}

.spinner svg {
    width: 16px;
    height: 16px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* === SKELETON LOADING === */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

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

.skeleton-text {
    height: 1em;
    margin: 0.5em 0;
    border-radius: 4px;
}

.skeleton-title {
    height: 1.5em;
    width: 70%;
    margin: 0.5em 0;
    border-radius: 4px;
}

.skeleton-button {
    height: 2.5em;
    width: 120px;
    border-radius: 6px;
}

/* === CONTENT LOADING ANIMATIONS === */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* === LAZY LOADING STATES === */
.lazy-loading {
    opacity: 0.5;
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

.lazy-loaded {
    opacity: 1;
    transition: opacity 0.6s ease;
}

.lazy-image {
    transition: opacity 0.6s ease;
}

.lazy-image.lazy-loading {
    opacity: 0.6;
    filter: blur(5px);
}

.lazy-image.lazy-loaded {
    opacity: 1;
    filter: blur(0);
}

.lazy-image.lazy-error {
    opacity: 0.3;
    background: #f5f5f5;
    position: relative;
}

.lazy-image.lazy-error::after {
    content: '⚠️ Image failed to load';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 12px;
    color: #666;
    text-align: center;
}

/* === FORM LOADING STATES === */
.form-group.loading {
    position: relative;
    pointer-events: none;
}

.form-group.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    z-index: 10;
}

/* === PAGE LOADING OVERLAY === */
.page-loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    backdrop-filter: blur(5px);
}

.page-loading .spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #007bff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* === PROGRESSIVE ENHANCEMENT === */
@media (prefers-reduced-motion: reduce) {
    .skeleton,
    .fade-in,
    .spinner svg {
        animation: none;
    }

    .fade-in {
        opacity: 1;
        transform: none;
    }
}

/* === DARK MODE SUPPORT === */
@media (prefers-color-scheme: dark) {
    .skeleton {
        background: linear-gradient(90deg, #2a2a2a 25%, #3a3a3a 50%, #2a2a2a 75%);
    }

    .page-loading {
        background: rgba(0, 0, 0, 0.9);
    }
}