/* ========================================
   UNIT III & IV — Projection & Section of Solids
   Engineering Graphics Suite
   Alberto Felix & Aaron Mcgeo | CSE-A(I)
   ======================================== */

:root {
    --bg-app:        #0f1117;
    --bg-header:     #151820;
    --bg-sidebar:    #f4f5f7;
    --bg-card:       #ffffff;
    --bg-section:    #f9fafb;
    --bg-dark:       #1a1f2e;
    --bg-viewport:   #e8ecf0;

    --accent:        #2563eb;
    --accent-hover:  #1d4ed8;
    --accent-light:  #eff6ff;
    --accent-green:  #10b981;
    --accent-red:    #ef4444;
    --accent-orange: #f97316;
    --accent-purple: #a855f7;

    --text-primary:   #111827;
    --text-secondary: #4b5563;
    --text-muted:     #9ca3af;
    --text-dark:      #e5e7eb;
    --text-dark-muted:#6b7280;

    --border-light:  #e5e7eb;
    --border-medium: #d1d5db;
    --border-dark:   #1f2937;
    --border-accent: rgba(37,99,235,0.25);

    --sidebar-w:     290px;
    --header-h:      50px;
    --footer-h:      28px;

    --font-mono: 'Space Mono', 'Courier New', monospace;
    --font-body: 'DM Sans', system-ui, sans-serif;

    --hp-color:      #3b82f6;
    --vp-color:      #10b981;
}

/* ==============================
   RESET
   ============================== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html, body {
    height: 100%;
    overflow: hidden;
    font-family: var(--font-body);
    background: var(--bg-app);
    color: var(--text-primary);
    font-size: 13px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* ==============================
   APP SHELL
   ============================== */
.app-container {
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* ==============================
   HEADER
   ============================== */
.header {
    height: var(--header-h);
    background: var(--bg-header);
    border-bottom: 1px solid var(--border-dark);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    gap: 10px;
    flex-shrink: 0;
    z-index: 50;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
    min-width: 0;
}

.back-btn {
    padding: 5px 10px;
    background: rgba(255,255,255,0.07);
    border: 1px solid var(--border-dark);
    border-radius: 6px;
    color: var(--text-dark-muted);
    font-family: var(--font-mono);
    font-size: 10px;
    text-decoration: none;
    white-space: nowrap;
    transition: all 0.15s;
    flex-shrink: 0;
}
.back-btn:hover { background: rgba(255,255,255,0.13); color: var(--text-dark); }

.logo-mark {
    width: 36px;
    height: 32px;
    background: var(--accent);
    color: white;
    font-family: var(--font-mono);
    font-size: 9px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 7px;
    flex-shrink: 0;
    letter-spacing: 0.5px;
}

.title-block h1 {
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 700;
    color: var(--text-dark);
    line-height: 1.2;
    white-space: nowrap;
}
.title-block .subtitle {
    font-size: 10px;
    color: var(--text-dark-muted);
}

/* Header center — tab switcher */
.header-center { flex: 1; display: flex; justify-content: center; }

.tab-switcher {
    display: flex;
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--border-dark);
    border-radius: 8px;
    padding: 3px;
    gap: 2px;
}

.tab-btn {
    padding: 6px 14px;
    background: transparent;
    border: none;
    border-radius: 5px;
    color: var(--text-dark-muted);
    font-family: var(--font-body);
    font-size: 11px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s ease;
    display: flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

.tab-btn:hover {
    color: var(--text-dark);
    background: rgba(255,255,255,0.06);
}

.tab-btn.active {
    background: var(--accent);
    color: white;
    font-weight: 600;
}

.tab-icon {
    font-size: 13px;
}

/* Header right */
.header-right {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 12px;
}

.export-btn,
.about-btn {
    padding: 5px 12px;
    background: transparent;
    border: 1px solid var(--border-dark);
    border-radius: 6px;
    color: var(--text-dark-muted);
    font-family: var(--font-mono);
    font-size: 10px;
    cursor: pointer;
    transition: all 0.15s;
    white-space: nowrap;
}
.export-btn:hover { border-color: var(--accent-green); color: var(--accent-green); }
.about-btn:hover { border-color: var(--accent); color: #93c5fd; }

.credits-block { text-align: right; }
.credits-names { display: block; font-family: var(--font-mono); font-size: 10px; font-weight: 700; color: var(--text-dark); }
.credits-class { font-size: 9px; color: var(--text-dark-muted); }

/* ==============================
   MAIN LAYOUT
   ============================== */
.main-layout {
    flex: 1;
    display: flex;
    overflow: hidden;
    min-height: 0;
}

/* ==============================
   SIDEBAR
   ============================== */
.sidebar {
    width: var(--sidebar-w);
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border-light);
    overflow-y: auto;
    overflow-x: hidden;
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
}

.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border-medium); border-radius: 3px; }

/* Panel sections */
.panel-section {
    padding: 12px 14px;
    border-bottom: 1px solid var(--border-light);
    background: var(--bg-card);
}

.section-label {
    font-family: var(--font-mono);
    font-size: 9px;
    font-weight: 700;
    color: var(--text-muted);
    letter-spacing: 0.13em;
    margin-bottom: 9px;
}

/* ==============================
   SELECT INPUT
   ============================== */
.select-input {
    width: 100%;
    padding: 7px 9px;
    background: var(--bg-section);
    border: 1.5px solid var(--border-light);
    border-radius: 7px;
    color: var(--text-primary);
    font-size: 12px;
    font-family: var(--font-body);
    margin-bottom: 10px;
    outline: none;
    cursor: pointer;
    transition: border-color 0.15s;
}
.select-input:focus { border-color: var(--accent); }
.select-input option { background: white; color: var(--text-primary); }

/* ==============================
   DIMENSION ROWS
   ============================== */
.dim-row { margin-bottom: 9px; }
.dim-row:last-child { margin-bottom: 0; }

.dim-label-text {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 11px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 5px;
}
.unit {
    font-family: var(--font-mono);
    font-size: 9px;
    color: var(--text-muted);
    font-weight: 400;
}

.dim-control {
    display: flex;
    gap: 7px;
    align-items: center;
}

.dim-control input[type="range"] {
    flex: 1;
    height: 3px;
    -webkit-appearance: none;
    appearance: none;
    background: var(--border-medium);
    border-radius: 2px;
    outline: none;
    cursor: pointer;
    accent-color: var(--accent);
}
.dim-control input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    background: var(--accent);
    border-radius: 50%;
    border: 2px solid white;
    box-shadow: 0 1px 4px rgba(37,99,235,0.4);
    cursor: pointer;
}

.dim-control input[type="number"] {
    width: 50px;
    padding: 4px 5px;
    border: 1px solid var(--border-medium);
    border-radius: 5px;
    font-family: var(--font-mono);
    font-size: 10px;
    text-align: center;
    color: var(--text-primary);
    background: var(--bg-card);
    outline: none;
    transition: border-color 0.15s;
}
.dim-control input[type="number"]:focus { border-color: var(--accent); }

/* ==============================
   RADIO PILLS
   ============================== */
.radio-row {
    display: flex;
    gap: 6px;
    margin-bottom: 4px;
}

.radio-pill {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 7px 6px;
    border-radius: 7px;
    border: 1.5px solid var(--border-light);
    font-size: 11px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.15s;
    background: var(--bg-section);
    text-align: center;
}
.radio-pill input { display: none; }
.radio-pill:has(input:checked) {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
}

/* ==============================
   BUTTONS
   ============================== */
.btn {
    width: 100%;
    padding: 8px 12px;
    border: none;
    border-radius: 7px;
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.04em;
    cursor: pointer;
    transition: all 0.15s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-family: var(--font-body);
    margin-top: 4px;
}

.btn-primary {
    background: var(--accent);
    color: white;
}
.btn-primary:hover { background: var(--accent-hover); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(37,99,235,0.35); }

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-light);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-light); }

/* ==============================
   TOGGLE SWITCH
   ============================== */
.toggle-row {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 8px;
    margin-bottom: 8px;
}
.toggle-row:last-child { margin-bottom: 0; }

.toggle-label {
    font-size: 11px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    flex: 1;
    line-height: 1.3;
}

.toggle {
    position: relative;
    flex-shrink: 0;
}
.toggle input { position: absolute; opacity: 0; width: 0; height: 0; }

.toggle-track {
    display: block;
    width: 34px;
    height: 18px;
    background: var(--border-medium);
    border-radius: 9px;
    position: relative;
    cursor: pointer;
    transition: background 0.2s;
}
.toggle-track::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 14px;
    height: 14px;
    background: white;
    border-radius: 50%;
    transition: transform 0.2s;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
.toggle input:checked ~ .toggle-track { background: var(--accent); }
.toggle input:checked ~ .toggle-track::after { transform: translateX(16px); }

/* ==============================
   QUICK VIEWS
   ============================== */
.quick-view-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 5px;
}

.qv-btn {
    padding: 7px;
    background: var(--bg-section);
    border: 1px solid var(--border-light);
    border-radius: 6px;
    font-size: 10px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.15s;
    text-align: center;
    font-family: var(--font-body);
}
.qv-btn:hover { background: var(--accent); border-color: var(--accent); color: white; }

/* ==============================
   COLLAPSIBLE SECTIONS
   ============================== */
.collapsible .section-label.collapse-trigger {
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0;
    user-select: none;
    transition: color 0.15s;
}
.collapsible .section-label.collapse-trigger:hover {
    color: var(--accent);
}

.collapse-arrow {
    font-size: 10px;
    transition: transform 0.2s;
    display: inline-block;
}
.collapse-trigger.open .collapse-arrow {
    transform: rotate(90deg);
}

.collapse-content {
    margin-top: 10px;
    animation: slideDown 0.2s ease;
}
@keyframes slideDown {
    from { opacity: 0; transform: translateY(-6px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ==============================
   CTRL NOTE (inside advanced)
   ============================== */
.ctrl-note {
    font-size: 9px;
    color: var(--text-muted);
    font-family: var(--font-mono);
    margin: 6px 0 4px;
    padding-top: 6px;
    border-top: 1px solid var(--border-light);
}

/* ==============================
   PLANE BLOCKS (inside Reference Planes)
   ============================== */
.plane-block {
    border-radius: 7px;
    border: 1px solid;
    padding: 8px 10px 7px;
    margin-bottom: 8px;
}
.plane-block.hp { border-color: rgba(59,130,246,0.3); background: rgba(59,130,246,0.04); }
.plane-block.vp { border-color: rgba(16,185,129,0.3); background: rgba(16,185,129,0.04); }

.plane-block-title {
    font-family: var(--font-mono);
    font-size: 9px;
    font-weight: 700;
    letter-spacing: 0.8px;
    margin-bottom: 7px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.plane-block.hp .plane-block-title { color: #60a5fa; }
.plane-block.vp .plane-block-title { color: #34d399; }

.mini-toggle {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 9px;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
}
.mini-toggle input[type="checkbox"] {
    width: 12px;
    height: 12px;
    accent-color: var(--accent);
    cursor: pointer;
}

.plane-mode-row {
    display: flex;
    gap: 4px;
}

.plane-mode-pill {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 4px 5px;
    border-radius: 5px;
    border: 1px solid var(--border-light);
    font-family: var(--font-mono);
    font-size: 9px;
    font-weight: 700;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.15s;
    background: var(--bg-section);
}
.plane-mode-pill input { display: none; }
.plane-block.hp .plane-mode-pill:has(input:checked) {
    border-color: #60a5fa;
    color: #60a5fa;
    background: rgba(59,130,246,0.08);
}
.plane-block.vp .plane-mode-pill:has(input:checked) {
    border-color: #34d399;
    color: #34d399;
    background: rgba(16,185,129,0.08);
}

/* ==============================
   QUICK LOAD BUTTONS
   ============================== */
.quick-btns-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 5px;
}

.quick-load-btn {
    padding: 7px 6px;
    background: var(--bg-section);
    border: 1px solid var(--border-light);
    border-radius: 6px;
    font-size: 10px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.15s;
    text-align: center;
    font-family: var(--font-body);
}
.quick-load-btn:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-light); }

/* ==============================
   LEGEND
   ============================== */
.legend-list {
    display: flex;
    flex-direction: column;
    gap: 5px;
}
.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 10px;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}
.legend-dot {
    width: 10px;
    height: 10px;
    border-radius: 3px;
    flex-shrink: 0;
}

/* ==============================
   CONTENT AREA
   ============================== */
.content-area {
    flex: 1;
    overflow: hidden;
    background: var(--bg-viewport);
    min-width: 0;
    position: relative;
}

.tab-content {
    display: none;
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    overflow: hidden;
}
.tab-content.active { display: flex; flex-direction: column; }

/* ==============================
   3D VIEWPORT
   ============================== */
.viewport-wrap {
    flex: 1;
    position: relative;
    overflow: hidden;
}
#threeContainer {
    width: 100%;
    height: 100%;
}
#threeContainer canvas {
    display: block;
    cursor: grab;
}
#threeContainer canvas:active { cursor: grabbing; }

.viewport-overlay {
    position: absolute;
    top: 12px;
    left: 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
    pointer-events: none;
}

.info-chip {
    background: rgba(15,17,23,0.85);
    color: #93c5fd;
    font-family: var(--font-mono);
    font-size: 10px;
    padding: 4px 10px;
    border-radius: 5px;
    border-left: 2px solid var(--accent);
    backdrop-filter: blur(6px);
}

.controls-hint {
    position: absolute;
    bottom: 12px;
    left: 12px;
    background: rgba(15,17,23,0.65);
    color: var(--text-muted);
    font-family: var(--font-mono);
    font-size: 9px;
    padding: 4px 10px;
    border-radius: 20px;
    pointer-events: none;
    backdrop-filter: blur(6px);
}

/* ==============================
   2D CANVASES (True Shape, Development, Projection)
   ============================== */
.canvas2d-wrap {
    flex: 1;
    position: relative;
    overflow: hidden;
    min-height: 0;
}
.canvas2d-wrap canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: block;
}

/* Development toolbar */
.dev-toolbar {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 14px;
    background: var(--bg-header);
    border-bottom: 1px solid var(--border-dark);
    flex-shrink: 0;
    flex-wrap: wrap;
}

.dev-label {
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 700;
    color: var(--text-dark-muted);
    letter-spacing: 0.08em;
}

.dev-radio {
    padding: 5px 12px;
    border-radius: 5px;
    border: 1px solid var(--border-dark);
    font-size: 10px;
    font-weight: 600;
    color: var(--text-dark-muted);
    cursor: pointer;
    font-family: var(--font-body);
    transition: all 0.15s;
    background: transparent;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}
.dev-radio input { display: none; }
.dev-radio:has(input:checked) {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(37,99,235,0.1);
}

.dev-unroll-btn {
    padding: 5px 14px;
    border-radius: 5px;
    border: 1px solid var(--border-dark);
    background: transparent;
    color: var(--text-dark-muted);
    font-size: 10px;
    font-weight: 700;
    cursor: pointer;
    font-family: var(--font-mono);
    transition: all 0.15s;
}
.dev-unroll-btn:hover { border-color: var(--accent-green); color: var(--accent-green); }

/* ==============================
   FOOTER
   ============================== */
.footer {
    height: var(--footer-h);
    background: var(--bg-header);
    border-top: 1px solid var(--border-dark);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    font-size: 10px;
    color: var(--text-dark-muted);
    font-family: var(--font-body);
    flex-shrink: 0;
}

.footer-left {
    display: flex;
    align-items: center;
    gap: 8px;
}
.footer-right {
    display: flex;
    align-items: center;
    gap: 8px;
}
.footer-sep { color: var(--border-dark); }

.status-dot {
    width: 6px;
    height: 6px;
    background: var(--accent-green);
    border-radius: 50%;
    animation: pulse 2s infinite;
}
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }

/* ==============================
   ABOUT MODAL
   ============================== */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.72);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.22s;
}
.modal-overlay.open {
    opacity: 1;
    pointer-events: all;
}

.modal {
    background: #151820;
    border: 1px solid var(--border-dark);
    border-radius: 14px;
    width: 580px;
    max-width: 95vw;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 24px 80px rgba(0,0,0,0.7);
    transform: translateY(18px);
    transition: transform 0.22s;
}
.modal-overlay.open .modal { transform: translateY(0); }

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px 14px;
    border-bottom: 1px solid var(--border-dark);
}

.modal-title { display: flex; align-items: center; gap: 10px; }
.modal-title-icon {
    width: 34px;
    height: 34px;
    background: var(--accent);
    border-radius: 9px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 17px;
    box-shadow: 0 2px 8px rgba(37,99,235,0.4);
}
.modal-title-main { font-size: 15px; font-weight: 800; color: var(--text-dark); }
.modal-title-sub {
    font-size: 10px;
    font-weight: 400;
    color: var(--text-dark-muted);
    font-family: var(--font-mono);
    margin-top: 1px;
}

.modal-close {
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border-dark);
    border-radius: 6px;
    cursor: pointer;
    color: var(--text-dark-muted);
    font-size: 16px;
    transition: all 0.15s;
    background: transparent;
}
.modal-close:hover { border-color: var(--accent); color: var(--accent); }

.modal-body { padding: 20px 24px 24px; }

.modal-intro {
    font-size: 12px;
    color: var(--text-dark-muted);
    line-height: 1.7;
    margin-bottom: 20px;
    font-family: var(--font-mono);
}
.modal-intro strong { color: var(--text-dark); }

.modal-divider {
    height: 1px;
    background: var(--border-dark);
    margin: 4px 0 18px;
}

/* Member cards */
.member-cards { display: flex; flex-direction: column; gap: 12px; }

.member-card {
    display: flex;
    align-items: flex-start;
    gap: 14px;
    padding: 14px 16px;
    border-radius: 10px;
    border: 1px solid var(--border-dark);
    background: rgba(255,255,255,0.02);
    transition: border-color 0.18s;
}
.member-card:hover { border-color: rgba(37,99,235,0.3); background: rgba(37,99,235,0.03); }
.member-card.professor:hover { border-color: rgba(59,130,246,0.4); background: rgba(59,130,246,0.04); }

.member-avatar {
    width: 46px;
    height: 46px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    flex-shrink: 0;
    font-weight: 800;
    color: #fff;
}
.member-avatar.prof { background: linear-gradient(135deg, #1d4ed8, #3b82f6); }
.member-avatar.s1   { background: linear-gradient(135deg, #f97316, #ea580c); }
.member-avatar.s2   { background: linear-gradient(135deg, #10b981, #059669); }

.member-info { flex: 1; min-width: 0; }
.member-name { font-size: 13px; font-weight: 700; color: var(--text-dark); margin-bottom: 2px; }
.member-role {
    font-size: 10px;
    font-family: var(--font-mono);
    color: var(--text-dark-muted);
    margin-bottom: 6px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}
.member-role.prof-role { color: #60a5fa; }
.member-role.student-role { color: #93c5fd; }
.member-dept {
    font-size: 10px;
    color: var(--text-dark-muted);
    font-family: var(--font-mono);
    margin-bottom: 8px;
}

/* Project info */
.modal-project {
    margin-top: 20px;
    padding: 14px 16px;
    border-radius: 10px;
    border: 1px solid rgba(37,99,235,0.2);
    background: rgba(37,99,235,0.04);
}
.modal-project-title {
    font-size: 11px;
    font-weight: 700;
    color: #93c5fd;
    margin-bottom: 8px;
    font-family: var(--font-mono);
    letter-spacing: 1px;
    text-transform: uppercase;
}
.modal-project-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6px;
}
.mpg-item {
    font-size: 10px;
    font-family: var(--font-mono);
    color: var(--text-dark-muted);
}
.mpg-item strong { color: var(--text-dark); display: block; margin-bottom: 1px; }

/* ==============================
   DIMENSION LABELS (CSS2D in 3D)
   ============================== */
.dim-label {
    background: rgba(37,99,235,0.9);
    color: white;
    font-family: var(--font-mono);
    font-size: 10px;
    padding: 2px 6px;
    border-radius: 4px;
    pointer-events: none;
    white-space: nowrap;
    box-shadow: 0 2px 6px rgba(37,99,235,0.4);
}

/* ==============================
   RESPONSIVE
   ============================== */
@media (max-width: 1100px) {
    :root { --sidebar-w: 260px; }
}
@media (max-width: 900px) {
    .header-center { display: none; }
    :root { --sidebar-w: 250px; }
}
@media (max-width: 700px) {
    .main-layout { flex-direction: column; }
    .sidebar {
        width: 100%;
        max-height: 40vh;
        border-right: none;
        border-bottom: 1px solid var(--border-light);
    }
    .content-area { flex: 1; }
}