/**
 * Filter Tree Styles
 *
 * Left sidebar panel with hierarchical checkbox tree
 * for filtering document sections.
 * Uses design tokens from variables.css
 */

/* ============================================================
   CSS VARIABLES (component-specific)
   ============================================================ */

:root {
    --filter-panel-width: 320px;
    --filter-panel-bg: var(--color-bg-primary);
    --filter-panel-border: var(--color-border-default);
    --filter-header-bg: var(--color-primary-500);
    --filter-header-text: var(--color-text-inverse);
    --tree-indent: 20px;
    --tree-row-height: 28px;
    --tree-hover-bg: var(--color-bg-hover);
    --tree-ref-color: var(--color-primary-500);
    --checkbox-size: 16px;
    --scroll-highlight-bg: rgba(33, 35, 73, 0.15);
    --scroll-highlight-duration: 2s;
}

/* ============================================================
   PANEL CONTAINER
   ============================================================ */

.filter-tree-panel {
    position: fixed;
    left: 0;
    top: var(--filter-panel-top, var(--space-12));
    width: var(--filter-panel-width);
    max-height: calc(100dvh - var(--filter-panel-top, var(--space-12)) - var(--space-2));
    transition: top 0.4s cubic-bezier(0.25, 0.1, 0.25, 1),
                max-height 0.4s cubic-bezier(0.25, 0.1, 0.25, 1),
                transform var(--duration-moderate) var(--ease-out);
    background-color: var(--filter-panel-bg);
    border: 1px solid var(--filter-panel-border);
    border-left: none;
    border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
    box-shadow: var(--shadow-lg);
    z-index: 100;
    display: flex;
    flex-direction: column;
    transition: transform var(--duration-moderate) var(--ease-out);
}

.filter-tree-panel.collapsed {
    transform: translateX(-100%);
}

/* ============================================================
   PANEL HEADER
   ============================================================ */

.filter-tree-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-3) var(--space-4);
    background: var(--gradient-primary);
    color: var(--filter-header-text);
    flex-shrink: 0;
    border-radius: 0 var(--radius-lg) 0 0;
}

.filter-tree-title {
    font-weight: var(--font-semibold);
    font-size: var(--text-sm);
    letter-spacing: var(--tracking-wide);
}

.filter-tree-collapse {
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: var(--radius-md);
    color: var(--filter-header-text);
    cursor: pointer;
    padding: var(--space-1) var(--space-2);
    font-size: var(--text-sm);
    backdrop-filter: blur(4px);
    transition: var(--transition-interactive);
}

.filter-tree-collapse:hover {
    background: rgba(255, 255, 255, 0.25);
}

.collapse-icon {
    display: block;
    transition: transform 0.2s;
}

/* ============================================================
   PROJECT TITLE
   ============================================================ */

.filter-tree-project-title {
    padding: var(--space-3) var(--space-4);
    background-color: var(--color-bg-secondary);
    border-bottom: 1px solid var(--filter-panel-border);
    flex-shrink: 0;
}

.project-title-text {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    color: var(--color-text-primary);
    display: block;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ============================================================
   PANEL CONTENT
   ============================================================ */

.filter-tree-content {
    flex: 1;
    min-height: 0; /* Allow shrinking below content size for proper scroll */
    display: flex;
    flex-direction: column;
}

/* ============================================================
   TOOLBAR
   ============================================================ */

.filter-tree-toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    padding: var(--space-3);
    border-bottom: 1px solid var(--filter-panel-border);
    background-color: var(--color-bg-secondary);
    flex-shrink: 0;
}

.filter-btn {
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-xs);
    font-family: inherit;
    font-weight: var(--font-medium);
    background-color: var(--color-bg-primary);
    border: 1px solid var(--color-border-default);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-colors), var(--transition-shadow);
    color: var(--color-text-secondary);
}

.filter-btn:hover {
    background-color: var(--color-primary-50);
    border-color: var(--color-primary-300);
    color: var(--color-primary-600);
}

.filter-btn:active {
    transform: scale(0.98);
    background-color: var(--color-primary-100);
}

.filter-tree-hint {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    text-align: center;
    font-style: italic;
    padding: var(--space-2) var(--space-3) 0;
}

/* ============================================================
   TREE CONTAINER
   ============================================================ */

#filter-tree {
    flex: 1;
    min-height: 0; /* Allow shrinking below content size for proper scroll */
    overflow-y: auto;
    padding: 8px 0;
}

/* ============================================================
   TREE STRUCTURE
   ============================================================ */

.tree-root {
    list-style: none;
    margin: 0;
    padding: 0 8px;
}

.tree-children {
    list-style: none;
    margin: 0;
    padding: 0;
    padding-left: var(--tree-indent);
    overflow: hidden;
}

.tree-node[aria-expanded="false"] > .tree-children {
    display: none;
}

/* ============================================================
   TREE NODE
   ============================================================ */

.tree-node {
    margin: 1px 0;
}

.tree-node-row {
    display: flex;
    align-items: center;
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-md);
    min-height: var(--tree-row-height);
    transition: background-color var(--duration-fast) var(--ease-out);
}

.tree-node-row:hover {
    background-color: var(--color-primary-50);
}

/* ============================================================
   TOGGLE BUTTON
   ============================================================ */

.tree-toggle {
    width: 20px;
    height: 20px;
    padding: 0;
    margin-right: 4px;
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-color, #333);
    opacity: 0.6;
    transition: opacity 0.15s;
    flex-shrink: 0;
}

.tree-toggle:hover {
    opacity: 1;
}

.toggle-icon {
    font-size: 10px;
    transition: transform 0.15s;
}

.tree-toggle-spacer {
    width: 20px;
    margin-right: 4px;
    flex-shrink: 0;
}

/* ============================================================
   CHECKBOX
   ============================================================ */

.tree-checkbox {
    width: var(--checkbox-size);
    height: var(--checkbox-size);
    margin: 0;
    margin-right: 8px;
    cursor: pointer;
    accent-color: var(--primary-color, #212349);
    flex-shrink: 0;
}

.tree-checkbox:indeterminate {
    opacity: 0.8;
}

/* ============================================================
   LABEL
   ============================================================ */

.tree-label {
    display: flex;
    align-items: baseline;
    gap: 6px;
    cursor: pointer;
    font-size: 13px;
    flex: 1;
    min-width: 0;
    line-height: 1.3;
}

.tree-ref {
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 11px;
    color: var(--tree-ref-color);
    white-space: nowrap;
    flex-shrink: 0;
}

.tree-title {
    color: var(--text-color, #333);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ============================================================
   LEVEL-SPECIFIC STYLES
   ============================================================ */

.tree-node.level-1 > .tree-node-row .tree-label {
    /*font-weight: 600;*/
}

.tree-node.level-1 > .tree-node-row .tree-ref {
    font-size: 12px;
}

.tree-node.level-2 > .tree-node-row .tree-label {
    font-weight: 500;
}

.tree-node.level-3 > .tree-node-row .tree-label {
    font-weight: 400;
    font-size: 12px;
}

.tree-node.level-3 > .tree-node-row .tree-ref {
    font-size: 10px;
}

/* ============================================================
   COLLAPSED TAB
   ============================================================ */

.filter-tree-tab {
    position: fixed;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    background: var(--gradient-primary);
    color: var(--filter-header-text);
    padding: var(--space-3) var(--space-2);
    writing-mode: vertical-lr;
    text-orientation: mixed;
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    letter-spacing: var(--tracking-wide);
    border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
    cursor: pointer;
    z-index: 99;
    box-shadow: var(--shadow-md), var(--shadow-primary-md);
    transition: var(--transition-interactive), opacity var(--duration-moderate) var(--ease-out);
    opacity: 0;
    pointer-events: none;
}

.filter-tree-tab:hover {
    box-shadow: var(--shadow-lg), var(--shadow-primary-lg);
    transform: translateY(-50%) translateX(2px);
}

.filter-tree-panel.collapsed ~ .filter-tree-tab {
    opacity: 1;
    pointer-events: auto;
}

/* ============================================================
   CONTENT SHIFT WHEN PANEL IS OPEN
   Only shift when panel would overlap centered content.
   Formula: shift needed when viewport < content_width + (panel_width * 2)
   At 320px panel: 900 + 640 = 1540px
   ============================================================ */

.brand-header,
.document-content {
    transition: margin-left var(--duration-moderate) var(--ease-out);
}

@media (max-width: 1540px) {
    .filter-tree-panel:not(.collapsed) ~ .brand-header,
    .filter-tree-panel:not(.collapsed) ~ .document-content {
        margin-left: var(--filter-panel-width);
    }
}

.document-content {
    padding: var(--space-5) var(--space-10);
}

/* ============================================================
   DOCUMENT FILTERING
   ============================================================ */

.filtered-hidden {
    display: none !important;
}

/* ============================================================
   SCROLL HIGHLIGHT
   ============================================================ */

.scroll-highlight {
    animation: highlight-fade var(--scroll-highlight-duration) ease-out;
}

@keyframes highlight-fade {
    0% {
        background-color: var(--scroll-highlight-bg);
    }
    100% {
        background-color: transparent;
    }
}

h3[data-tree-node],
h4[data-tree-node] {
    transition: background-color 0.3s;
    padding: 2px 4px;
    margin-left: -4px;
    margin-right: -4px;
    border-radius: 2px;
}

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

@media (max-width: 1200px) {
    :root {
        --filter-panel-width: 280px;
    }
}

@media (max-width: 900px) {
    :root {
        --filter-panel-width: 250px;
    }

    .filter-tree-toolbar {
        gap: 4px;
        padding: 8px 10px;
    }

    .filter-btn {
        padding: 4px 8px;
        font-size: 11px;
    }
}

@media (max-width: 768px) {
    .filter-tree-panel {
        width: 85vw;
        max-width: 320px;
        transform: translateX(-100%);
    }

    .filter-tree-panel:not(.collapsed) {
        transform: translateX(0);
    }

    /* On mobile, panel overlays - no shift needed */
    .filter-tree-panel:not(.collapsed) ~ .brand-header,
    .filter-tree-panel:not(.collapsed) ~ .document-content {
        margin-left: 0;
    }

    .document-content {
        padding: 15px 20px;
    }

    .filter-tree-tab {
        opacity: 1;
        pointer-events: auto;
    }

    .filter-tree-panel:not(.collapsed) ~ .filter-tree-tab {
        opacity: 0;
        pointer-events: none;
    }
}

/* ============================================================
   PRINT
   ============================================================ */

@media print {
    .filter-tree-panel,
    .filter-tree-tab {
        display: none !important;
    }

    .document-content {
        margin-left: 0 !important;
        padding: 0 !important;
    }

    .filtered-hidden {
        display: block !important;
    }

    .scroll-highlight {
        animation: none;
        background-color: transparent;
    }
}

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

.tree-toggle:focus-visible,
.tree-checkbox:focus-visible,
.filter-btn:focus-visible {
    outline: 2px solid var(--primary-color, #212349);
    outline-offset: 2px;
}

.tree-label:focus-visible {
    outline: 2px solid var(--primary-color, #212349);
    outline-offset: 1px;
    border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {
    .filter-tree-panel,
    .document-content,
    .toggle-icon,
    .tree-node-row,
    .filter-btn,
    .scroll-highlight {
        transition: none;
        animation: none;
    }
}

@media (prefers-contrast: high) {
    .tree-checkbox {
        outline: 1px solid currentColor;
    }

    .tree-node-row:hover {
        background-color: rgba(0, 0, 0, 0.1);
    }
}