:root {
    --primary-color: #4a90e2;
    --danger-color: #e74c3c;
    --bg-color: #f5f6fa;
    --card-bg: #ffffff;
    --text-color: #2c3e50;
    --border-color: #dcdde1;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding: 15px;
    background-color: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    font-size: 14px;
    transition: background-color 0.2s;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: #357abd;
}

.btn-primary:disabled {
    background-color: #a0c4e8;
    cursor: not-allowed;
}

.dropzone {
    border: 2px dashed var(--primary-color);
    border-radius: 8px;
    padding: 40px;
    text-align: center;
    background-color: #ebf5fb;
    cursor: pointer;
    margin-bottom: 20px;
    transition: background-color 0.2s;
}

.dropzone.dragover {
    background-color: #d6eaf8;
    border-color: #2980b9;
}

.pages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
    min-height: 200px;
}

.page-card {
    background-color: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 10px;
    position: relative;
    cursor: grab;
    display: flex;
    flex-direction: column;
    align-items: center;
    border: 1px solid var(--border-color);
}

.page-card:active {
    cursor: grabbing;
}

.page-card.sortable-ghost {
    opacity: 0.4;
    background-color: #f1f2f6;
}

.page-preview {
    width: 100%;
    max-height: 250px;
    object-fit: contain;
    border: 1px solid var(--border-color);
    margin-bottom: 10px;
    pointer-events: none;
}

.page-controls {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.control-buttons {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 6px;
}

.page-number {
    font-size: 14px;
    color: #7f8c8d;
    font-weight: bold;
}

.btn-delete {
    background-color: var(--danger-color);
    color: white;
    padding: 5px 10px;
    border-radius: 4px;
    border: none;
    cursor: pointer;
    font-size: 12px;
}

.btn-delete:hover {
    background-color: #c0392b;
}

.btn-rotate {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    border: 1px solid #8fd3ff;
    background-color: #e6f7ff;
    color: #2aa7e0;
    cursor: pointer;
    font-size: 12px;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.btn-rotate:hover {
    background-color: #d6f1ff;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(255, 255, 255, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.loading-overlay.hidden {
    display: none;
}

.spinner {
    border: 4px solid rgba(0, 0, 0, 0.1);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border-left-color: var(--primary-color);
    animation: spin 1s linear infinite;
    margin-bottom: 10px;
}

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