/* ─── Design tokens ─── */
:root {
  --bg:            #EDEAE4;
  --surface:       #E4E1DA;
  --border:        #C8C4BC;

  --panel:         #111111;
  --panel-s:       #191919;
  --panel-b:       #252525;
  --panel-b2:      #2E2E2E;

  --canvas-bg:     #0A0A0A;

  --txt:           #0E0C0A;
  --txt-muted:     #6E6B65;
  --ptxt:          #D8D4CC;
  --ptxt-muted:    #5A5854;

  --accent:        #D6D6D6;
  --accent-h:      #BABABA;
  --success:       #5A9A6A;
  --warn:          #C8884A;

  --r:             6px;
  --r-lg:          10px;
  --trans:         0.18s ease;
  --font:          'Inter', system-ui, sans-serif;
  --mono:          'JetBrains Mono', 'Fira Code', monospace;
}

/* ─── Reset ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; overflow: hidden; }
body { font-family: var(--font); font-size: 13px; background: var(--bg); color: var(--txt); display: flex; flex-direction: column; }

/* ─── Header ─── */
#app-header {
  height: 46px; background: var(--panel); border-bottom: 1px solid var(--panel-b);
  display: flex; align-items: center; padding: 0 18px; gap: 12px; flex-shrink: 0;
  z-index: 10;
}
.header-logo {
  display: flex; align-items: center; gap: 8px;
}
.logo-mark {
  width: 26px; height: 26px; background: var(--accent); border-radius: 4px;
  display: grid; place-items: center; font-size: 14px; font-weight: 700; color: var(--panel);
}
.header-title { color: var(--ptxt); font-weight: 600; font-size: 14px; letter-spacing: -0.2px; }
.header-sub   { color: var(--ptxt-muted); font-size: 11px; }
.header-spacer { flex: 1; }
.header-badge {
  font-size: 10px; font-family: var(--mono); color: var(--ptxt-muted);
  background: var(--panel-b); padding: 3px 8px; border-radius: 20px; border: 1px solid var(--panel-b2);
}

/* ─── Layout ─── */
#app-body { display: flex; flex: 1; overflow: hidden; }

/* ─── Sidebar ─── */
#sidebar {
  width: 290px; flex-shrink: 0;
  background: var(--panel); border-right: 1px solid var(--panel-b);
  display: flex; flex-direction: column; overflow-y: auto; overflow-x: hidden;
}
#sidebar::-webkit-scrollbar { width: 4px; }
#sidebar::-webkit-scrollbar-track { background: transparent; }
#sidebar::-webkit-scrollbar-thumb { background: var(--panel-b2); border-radius: 4px; }

/* ─── Section ─── */
.section {
  padding: 14px 16px; border-bottom: 1px solid var(--panel-b);
}
.section-label {
  font-size: 10px; font-weight: 600; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ptxt-muted); margin-bottom: 10px; display: flex; align-items: center; gap: 6px;
}
.section-label::after {
  content: ''; flex: 1; height: 1px; background: var(--panel-b);
}

/* ─── Drop zone ─── */
#drop-zone {
  border: 1.5px dashed var(--panel-b2); border-radius: var(--r-lg);
  padding: 20px 12px; text-align: center; cursor: pointer;
  transition: border-color var(--trans), background var(--trans);
  color: var(--ptxt-muted);
}
#drop-zone:hover, #drop-zone.drag-over {
  border-color: var(--accent); background: rgba(214,214,214,0.06); color: var(--accent);
}
.drop-icon { font-size: 28px; margin-bottom: 6px; }
.drop-primary { font-size: 12px; font-weight: 500; color: var(--ptxt); margin-bottom: 3px; }
.drop-secondary { font-size: 10px; color: var(--ptxt-muted); }

/* ─── Mesh info ─── */
#mesh-info.hidden { display: none; }
.info-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 6px;
}
.info-cell {
  background: var(--panel-s); border-radius: var(--r); padding: 7px 10px;
  border: 1px solid var(--panel-b);
}
.info-cell-label { font-size: 9px; color: var(--ptxt-muted); text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 2px; }
.info-cell-value { font-family: var(--mono); font-size: 12px; color: var(--ptxt); font-weight: 500; }
.info-full { grid-column: 1/-1; }

/* ─── Sliders ─── */
.slider-row {
  display: flex; align-items: center; gap: 8px; margin-bottom: 8px;
}
.slider-label { font-size: 11px; color: var(--ptxt-muted); width: 16px; flex-shrink: 0; }
.slider-label-wide { width: 48px; font-size: 11px; color: var(--ptxt-muted); flex-shrink: 0; }
input[type=range] {
  flex: 1; -webkit-appearance: none; appearance: none; height: 3px; background: var(--panel-b2);
  border-radius: 2px; outline: none; cursor: pointer;
  transition: background var(--trans);
}
input[type=range]:hover { background: var(--panel-b); }
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 13px; height: 13px; border-radius: 50%;
  background: var(--accent); border: 2px solid var(--panel); cursor: pointer;
  transition: transform var(--trans), box-shadow var(--trans);
}
input[type=range]::-webkit-slider-thumb:hover {
  transform: scale(1.2); box-shadow: 0 0 0 3px rgba(214,214,214,0.2);
}
.slider-val {
  font-family: var(--mono); font-size: 11px; color: var(--ptxt);
  min-width: 48px; text-align: right; 
  background: transparent; border: 1px solid transparent; border-radius: var(--r);
  padding: 2px 4px; outline: none; transition: all var(--trans);
  -moz-appearance: textfield;
}
input[type=number].slider-val::-webkit-outer-spin-button,
input[type=number].slider-val::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
input[type=number].slider-val:hover, input[type=number].slider-val:focus {
  background: var(--panel-b); border-color: var(--panel-b2);
}

/* ─── Text inputs ─── */
.field-row { display: flex; flex-direction: column; gap: 4px; margin-bottom: 10px; }
.field-label { font-size: 10px; color: var(--ptxt-muted); text-transform: uppercase; letter-spacing: 0.06em; }
input[type=text], select {
  background: var(--panel-s); border: 1px solid var(--panel-b2); border-radius: var(--r);
  color: var(--ptxt); font-size: 12px; font-family: var(--font); padding: 6px 10px;
  outline: none; transition: border-color var(--trans);
  width: 100%;
}
input[type=text]:focus, select:focus { border-color: var(--accent); }
select option { background: var(--panel-s); }

/* ─── Buttons ─── */
.btn {
  display: flex; align-items: center; justify-content: center; gap: 6px;
  width: 100%; padding: 9px 14px; border-radius: var(--r);
  font-family: var(--font); font-size: 12px; font-weight: 500;
  cursor: pointer; border: none; transition: all var(--trans);
  letter-spacing: 0.01em;
}
.btn:disabled { opacity: 0.35; cursor: not-allowed; pointer-events: none; }
.btn-primary {
  background: var(--accent); color: var(--panel);
}
.btn-primary:hover { background: var(--accent-h); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(0,0,0,0.3); }
.btn-primary:active { transform: translateY(0); }
.btn-secondary {
  background: var(--panel-s); border: 1px solid var(--panel-b2); color: var(--ptxt);
}
.btn-secondary:hover { background: var(--panel-b); border-color: var(--accent); }
.btn-gap { height: 8px; }

/* ─── Edge badge ─── */
.edge-badge {
  display: flex; align-items: center; justify-content: space-between;
  background: var(--panel-s); border: 1px solid var(--panel-b); border-radius: var(--r);
  padding: 6px 10px; margin-bottom: 10px;
}
.edge-badge-label { font-size: 10px; color: var(--ptxt-muted); text-transform: uppercase; letter-spacing: 0.06em; }
.edge-badge-val { font-family: var(--mono); font-size: 13px; color: var(--accent); font-weight: 600; }

/* ─── Viewer area ─── */
#viewer-area { flex: 1; display: flex; flex-direction: column; overflow: hidden; background: var(--canvas-bg); }

/* ─── Tab bar ─── */
#tab-bar {
  display: flex; align-items: center; gap: 2px;
  background: var(--panel); border-bottom: 1px solid var(--panel-b);
  padding: 6px 10px;
}
.tab-btn {
  font-family: var(--font); font-size: 11px; font-weight: 500;
  background: transparent; border: 1px solid transparent; border-radius: var(--r);
  color: var(--ptxt-muted); padding: 5px 14px; cursor: pointer;
  transition: all var(--trans); letter-spacing: 0.02em;
}
.tab-btn:hover { color: var(--ptxt); background: var(--panel-s); }
.tab-btn.active { background: var(--panel-b); color: var(--ptxt); border-color: var(--panel-b2); }
.tab-sep { margin-left: auto; display: flex; gap: 2px; }

/* ─── Canvas wrapper ─── */
#canvas-wrap { flex: 1; position: relative; overflow: hidden; }
#viewer-canvas { display: block; width: 100% !important; height: 100% !important; }

/* ─── Progress bar ─── */
#progress-wrap {
  position: absolute; bottom: 0; left: 0; right: 0;
  background: var(--panel); border-top: 1px solid var(--panel-b); padding: 8px 14px;
  transition: opacity var(--trans); z-index: 5;
}
#progress-wrap.hidden { opacity: 0; pointer-events: none; }
#progress-track { height: 3px; background: var(--panel-b2); border-radius: 2px; margin-bottom: 5px; overflow: hidden; }
#progress-bar {
  height: 100%; background: var(--accent); border-radius: 2px;
  transition: width 0.3s ease; width: 0%;
}
#progress-msg { font-size: 10px; color: var(--ptxt-muted); font-family: var(--mono); }

/* ─── Status bar ─── */
#status-bar {
  height: 28px; background: var(--panel); border-top: 1px solid var(--panel-b);
  display: flex; align-items: center; padding: 0 14px; gap: 18px; flex-shrink: 0;
}
.status-item {
  font-size: 10px; font-family: var(--mono); color: var(--ptxt-muted);
  display: flex; align-items: center; gap: 5px;
}
.status-dot { width: 5px; height: 5px; border-radius: 50%; background: var(--panel-b2); }
.status-dot.on { background: var(--success); box-shadow: 0 0 5px var(--success); }

/* ─── Toast ─── */
.toast {
  position: fixed; bottom: 48px; left: 50%; transform: translateX(-50%) translateY(12px);
  background: var(--panel-b); border: 1px solid var(--panel-b2); border-radius: var(--r);
  color: var(--ptxt); font-size: 12px; padding: 10px 18px;
  opacity: 0; transition: all 0.3s ease; pointer-events: none; z-index: 100;
  box-shadow: 0 6px 24px rgba(0,0,0,0.5);
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ─── Export type toggle ─── */
.toggle-group {
  display: flex; border: 1px solid var(--panel-b2); border-radius: var(--r); overflow: hidden;
  width: 100%;
}
.toggle-btn {
  flex: 1; background: transparent; border: none; border-right: 1px solid var(--panel-b2);
  color: var(--ptxt-muted); font-size: 11px; font-weight: 500; font-family: var(--font);
  padding: 6px 8px; cursor: pointer; transition: all var(--trans); letter-spacing: 0.01em;
}
.toggle-btn:last-child { border-right: none; }
.toggle-btn:hover { background: var(--panel-b); color: var(--ptxt); }
.toggle-btn.active { background: var(--panel-b2); color: var(--ptxt); }
.export-hint {
  font-size: 10px; color: var(--ptxt-muted); margin: 3px 0 8px; line-height: 1.5;
  font-style: italic;
}

/* ─── Utility ─── */
.hidden { display: none !important; }
.mt-8  { margin-top: 8px; }
.mb-4  { margin-bottom: 4px; }