/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Light mode colors */
    --bg-primary: #f8f9fa;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f5f7fa;
    --text-primary: #2d3436;
    --text-secondary: #636e72;
    --text-tertiary: #495057;
    --border-primary: #e9ecef;
    --border-secondary: #dee2e6;
    --border-tertiary: #dfe6e9;
    --accent-primary: #0984e3;
    --accent-hover: #0770c7;
    --accent-focus: rgba(116, 185, 255, 0.1);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
    --error-color: #d63031;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 12px;
    --spacing-lg: 16px;
    --spacing-xl: 20px;
    --spacing-2xl: 30px;
    --spacing-3xl: 40px;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-xs: 11px;
    --font-size-sm: 12px;
    --font-size-md: 13px;
    --font-size-base: 14px;
    --font-size-lg: 15px;
    --font-size-xl: 18px;
    --font-size-2xl: 24px;
    --font-size-3xl: 28px;
    
    /* Border radius */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 25px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-primary: #1a1a1a;
        --bg-secondary: #2d3436;
        --bg-tertiary: #34495e;
        --text-primary: #e9ecef;
        --text-secondary: #b2bec3;
        --text-tertiary: #e9ecef;
        --border-primary: #495057;
        --border-secondary: #495057;
        --border-tertiary: #495057;
        --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    }
}

/* Base styles */
body {
    font-family: var(--font-family);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.4;
    padding: var(--spacing-xl);
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
}

/* Header */
.header {
    margin-bottom: var(--spacing-2xl);
}

.header-top {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
}

.header h1 {
    font-size: var(--font-size-3xl);
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.karakeep-link {
    position: absolute;
    right: 0;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
    padding: var(--spacing-sm);
}

.karakeep-link:hover {
    color: var(--accent-primary);
}

.karakeep-link svg {
    display: block;
}

/* Search bar */
.search-bar {
    max-width: 500px;
    margin: 0 auto;
    text-align: center;
}

.search-bar input {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-xl);
    border: 1px solid var(--border-tertiary);
    border-radius: var(--radius-full);
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    outline: none;
    transition: all var(--transition-base);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
}

.search-bar input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-focus);
}

.search-bar input::placeholder {
    color: var(--text-secondary);
}

/* Loading state */
.loading {
    text-align: center;
    padding: var(--spacing-3xl);
    color: var(--text-secondary);
}

.spinner {
    width: 40px;
    height: 40px;
    margin: 0 auto var(--spacing-xl);
    border: 3px solid var(--border-primary);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Error state */
.error {
    text-align: center;
    padding: var(--spacing-3xl);
    color: var(--error-color);
}

.error small {
    display: block;
    margin-top: var(--spacing-sm);
    color: var(--text-secondary);
}

/* MODIFIED: Replaced column-count with a Flexbox grid system */
.grid-container {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xl);
    align-items: flex-start;
}

.grid-column {
    flex: 1;
    min-width: 280px; /* Adjust as needed */
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
    min-height: 200px; /* Ensures empty columns are a valid drop target */
    padding: 2px; /* Helps with drop detection */
    border-radius: var(--radius-lg);
    transition: background-color var(--transition-fast);
}

/* Add a visual indicator to columns when dragging over them */
.grid-column.drag-over-column {
    background-color: var(--accent-focus);
}

/* List sections */
.list-section {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
    /* `break-inside: avoid` is no longer needed */
    position: relative;
    cursor: grab;
}

.list-section:active {
    cursor: grabbing;
}

.list-section:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.sortable-ghost {
    background: var(--bg-secondary);
    border: 2px dashed var(--accent-primary);
    opacity: 0.6;
}

.sortable-drag {
    opacity: 0.8;
    transform: rotate(2deg);
}

/* List header */
.list-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--border-primary);
}

.list-icon {
    font-size: var(--font-size-xl);
    line-height: 1;
}

.list-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    flex: 1;
}

/* Bookmark grid */
.bookmark-grid {
    display: grid;
    gap: var(--spacing-sm);
}

/* Bookmark items */
.bookmark-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-sm);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-secondary);
    font-size: var(--font-size-md);
    transition: all var(--transition-fast);
    cursor: pointer;
    overflow: hidden;
}

.bookmark-item:hover {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    transform: translateX(2px);
}

.bookmark-favicon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    object-fit: contain;
}

.bookmark-title {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* Nested lists - Level 1 */
.nested-list-1 {
    margin-top: var(--spacing-lg);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    position: relative;
    margin-left: var(--spacing-sm);
    /* `break-inside: avoid` is no longer needed */
}

.nested-list-1::before {
    content: '';
    position: absolute;
    left: calc(-1 * var(--spacing-sm));
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--border-primary);
    border-radius: 2px;
}

.nested-list-1 .list-header {
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
    border-bottom-color: var(--border-secondary);
}

.nested-list-1 .list-title {
    font-size: var(--font-size-base);
    font-weight: 500;
}

.nested-list-1 .list-icon {
    font-size: var(--font-size-lg);
}

.nested-list-1 .bookmark-item {
    font-size: var(--font-size-sm);
    padding: calc(var(--spacing-sm) - 1px) var(--spacing-sm);
}

.nested-list-1 .bookmark-favicon {
    width: 14px;
    height: 14px;
}

/* Nested lists - Level 2 */
.nested-list-2 {
    margin-top: var(--spacing-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    position: relative;
    margin-left: var(--spacing-sm);
    /* `break-inside: avoid` is no longer needed */
}

.nested-list-2::before {
    content: '';
    position: absolute;
    left: calc(-1 * var(--spacing-sm));
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-secondary);
    border-radius: 1px;
}

.nested-list-2 .list-header {
    margin-bottom: var(--spacing-sm);
    padding-bottom: var(--spacing-xs);
}

.nested-list-2 .list-title {
    font-size: var(--font-size-md);
    font-weight: 500;
    color: var(--text-tertiary);
}

.nested-list-2 .list-icon {
    font-size: var(--font-size-base);
}

.nested-list-2 .bookmark-item {
    font-size: var(--font-size-xs);
    padding: var(--spacing-xs) calc(var(--spacing-sm) - 1px);
}

.nested-list-2 .bookmark-favicon {
    width: 12px;
    height: 12px;
}

/* Mobile responsiveness */
@media (max-width: 768px) {
    body {
        padding: var(--spacing-md);
    }
    .grid-container {
        flex-direction: column;
    }

    .header h1 {
        font-size: var(--font-size-2xl);
    }

    .list-section {
        padding: var(--spacing-md);
    }

    .bookmark-item {
        padding: var(--spacing-sm);
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
a:focus-visible,
input:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* Hidden elements */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Smooth transitions for search filtering */
.grid-column {
    transition: opacity var(--transition-fast), width var(--transition-fast);
}

.grid-column[style*="display: none"] {
    width: 0;
    opacity: 0;
    overflow: hidden;
}

.list-section,
.nested-list-1,
.nested-list-2 {
    transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.bookmark-item {
    transition: all var(--transition-fast);
}

/* Remove min-height from columns during search to prevent empty space */
.grid-container:has(.bookmark-item[style*="display: none"]) .grid-column {
    min-height: auto;
}

/* Ensure hidden bookmarks don't take up space */
.bookmark-item[style*="display: none"] {
    position: absolute;
    visibility: hidden;
}