/* ==========================================================================
   PHME Curriculum Interactive Skill Tree & Prerequisite Roadmap
   Component Stylesheet (Cache-busted: ?v=1)
   ========================================================================== */

/* Outer Canvas Container */
.skilltree-wrapper {
    position: relative;
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    overflow: hidden;
    margin-top: 1rem;
    user-select: none;
    -webkit-user-select: none;
}

/* Dedicated Legend Bar */
.skilltree-legend-bar {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    padding: 0.65rem 1.15rem;
    background: #f8fafc;
    border-bottom: 1px solid var(--border-color);
}

.legend-title {
    font-size: 0.76rem;
    font-weight: 800;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-right: 0.25rem;
}

/* Floating Controls in Top-Left of Viewport */
.skilltree-controls {
    position: absolute;
    top: 12px;
    left: 12px;
    z-index: 10;
    display: flex;
    gap: 0.35rem;
    background: transparent;
    padding: 0;
    border: none;
    box-shadow: none;
}

.skilltree-btn {
    background: #ffffff;
    border: 1px solid var(--border-color);
    color: var(--primary);
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.3rem 0.65rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: background 0.15s ease, border-color 0.15s ease;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.skilltree-btn:hover {
    background: var(--accent-subtle);
    border-color: var(--primary-hover);
}

.skilltree-legend {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-size: 0.74rem;
    font-weight: 600;
}

.legend-row {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    align-items: center;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.2rem 0.45rem;
    border-radius: 0.25rem;
    border: 1px solid var(--border-color);
    background: #ffffff;
}

.legend-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.legend-border-box {
    width: 14px;
    height: 10px;
    border-radius: 2px;
    background: #ffffff;
}

/* Viewport for Panning & Zooming */
.skilltree-viewport {
    width: 100%;
    height: 610px;
    cursor: grab;
    overflow: hidden;
    position: relative;
    background-color: #ffffff;
}

.skilltree-viewport:active {
    cursor: grabbing;
}

/* SVG Text Unselectable & Click-Through */
.skilltree-viewport,
.node-card,
#tree-svg text {
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

#tree-svg text {
    pointer-events: none;
}

/* SVG Connectors */
.tree-connector {
    stroke: #cbd5e1;
    stroke-width: 2px;
    fill: none;
    transition: stroke 0.2s ease, stroke-width 0.2s ease;
}

.tree-connector.active-prereq {
    stroke: #2563eb;
    stroke-width: 1px;
    stroke-dasharray: none;
}

.tree-connector.active-unlocked {
    stroke: #ea580c;
    stroke-width: 1px;
    stroke-dasharray: none;
}

/* SVG Course Node Cards */
.node-card {
    cursor: pointer;
    transition: transform 0.15s ease;
}

.node-card:hover {
    filter: drop-shadow(0 3px 8px rgba(15, 41, 66, 0.12));
}

.node-rect {
    fill: #ffffff;
    stroke: #cbd5e1;
    rx: 6px;
    transition: fill 0.15s ease, stroke 0.15s ease, stroke-width 0.15s ease;
}

/* 4 Distinct Category Border Colors */
.type-physics .node-rect {
    stroke: #2563eb;
}

.type-physics .node-bar {
    fill: #2563eb;
}

.type-math .node-rect {
    stroke: #16a34a;
}

.type-math .node-bar {
    fill: #16a34a;
}

.type-micro .node-rect {
    stroke: #ea580c;
}

.type-micro .node-bar {
    fill: #ea580c;
}

.type-capstone .node-rect {
    stroke: #dc2626;
}

.type-capstone .node-bar {
    fill: #dc2626;
}

/* Core vs Elective Card Styles: Chromatic Tint for Core, Crisp White for Electives */
.is-core .node-rect,
.is-elective .node-rect {
    stroke-width: 1.5px;
    stroke-dasharray: none;
}

/* Elective courses: clean white background */
.is-elective .node-rect {
    fill: #ffffff;
}

/* Core courses: subtle chromatic background tint matching category */
.is-core.type-math .node-rect {
    fill: #f0fdf4;
}

.is-core.type-physics .node-rect {
    fill: #eff6ff;
}

.is-core.type-micro .node-rect {
    fill: #fff7ed;
}

.is-core.type-capstone .node-rect {
    fill: #fef2f2;
}

.node-title {
    font-size: 10.5px;
    font-weight: 700;
    fill: #0f2942;
}

.node-code {
    font-size: 9.5px;
    font-weight: 600;
    fill: #475569;
}

/* Active Highlight & Dimmed States */
.node-card.highlight-selected {
    filter: drop-shadow(0 2px 10px rgba(15, 41, 66, 0.35));
}

.node-card.highlight-selected .node-rect {
    stroke-width: 3px;
    fill: #ffffff !important;
}

/* Dim non-selected, non-prereq, non-subsequent nodes and connectors */
#tree-canvas.has-selection .node-card.is-dimmed {
    opacity: 0.20;
    filter: grayscale(85%);
    transition: opacity 0.25s ease, filter 0.25s ease;
}

#tree-canvas.has-selection .tree-connector.is-dimmed {
    opacity: 0.10;
    transition: opacity 0.25s ease;
}

/* Directional Flow Arrow Marker */
.flow-arrow-marker {
    pointer-events: none;
}

/* Bottom Detail Panel */
.skilltree-detail-panel {
    background: #ffffff;
    border-top: 1px solid var(--border-color);
    padding: 1.25rem 1.5rem;
    min-height: 95px;
    box-sizing: border-box;
}

.detail-placeholder {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--text-muted);
    font-size: 0.88rem;
    padding: 0.6rem 0;
}

.detail-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
}

.detail-badge {
    display: inline-block;
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 0.2rem 0.55rem;
    border-radius: 0.25rem;
    background: #f1f5f9;
    color: var(--primary);
    border: 1px solid var(--border-color);
}

.detail-body {
    display: grid;
    grid-template-columns: 1.8fr 1.2fr;
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .detail-body {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }
}


/* ==========================================================================
   Skill Tree Click-to-Interact Overlay Shield
   ========================================================================== */
.skilltree-overlay {
    position: absolute;
    inset: 0;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(15, 23, 42, 0.03);
    cursor: pointer;
    transition: background 0.2s ease, opacity 0.2s ease, visibility 0.2s ease;
}

.skilltree-overlay:hover {
    background: rgba(15, 23, 42, 0.12);
}

.skilltree-overlay-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.85rem;
    padding: 1.25rem 1.75rem;
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    box-shadow: 0 10px 25px rgba(15, 41, 66, 0.12);
    pointer-events: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
    max-width: 90%;
    text-align: center;
}

.skilltree-overlay:hover .skilltree-overlay-card {
    transform: translateY(-2px);
    border-color: var(--primary);
    box-shadow: 0 14px 30px rgba(15, 41, 66, 0.16);
}

.skilltree-overlay-trigger {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--primary);
    font-size: 1.02rem;
    font-weight: 700;
}

.skilltree-overlay-hints {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    justify-content: center;
}

.overlay-hint-pill {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.35rem 0.75rem;
    border-radius: 9999px;
    background: var(--bg-dark);
    border: 1px solid var(--border-color);
    font-size: 0.78rem;
    color: var(--text-muted);
}

.overlay-hint-pill strong {
    color: var(--text-main);
    font-weight: 600;
}



.skilltree-overlay.is-active {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}