:root{
  /* App palette (Excel/SolidWorks-ish, light) */
  --bg:#eef1f6;
  --surface:#ffffff;
  --surface2:#f7f9fc;
  --text:#0f172a;
  --muted:#55627a;
  --border:rgba(15,23,42,.12);
  --shadow: 0 10px 24px rgba(15,23,42,.10);
  --shadow2: 0 6px 14px rgba(15,23,42,.08);
  --radius:14px;

  /* Astra accents */
  --accent:#2879ad;
  --accent-weak: rgba(40,121,173,.12);
  --gold:#e0b82c;
  --danger:#d33a4a;

  --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, "Apple Color Emoji","Segoe UI Emoji";
}

*{ box-sizing:border-box; }
html,body{ height:100%; }
body{
  margin:0;
  font-family:var(--font);
  background:var(--bg);
  color:var(--text);
  overflow:hidden; /* app-like */
}

/* ===== App shell ===== */
#layout{
  height:100%;
  display:grid;
  grid-template-columns: 360px 1fr;
  grid-template-rows: 94px 1fr 34px;
}

/* ===== Ribbon / Topbar ===== */
#topbar{
  grid-column: 1 / -1;
  grid-row: 1;
  display:grid;
  grid-template-columns: 260px 1fr auto;
  grid-template-rows: 40px 1fr;
  align-items:center;
  gap:10px 12px;
  padding:10px 12px;
  background: linear-gradient(180deg, #ffffff, #f6f8fc);
  border-bottom:1px solid var(--border);
}

.brand{ display:flex; align-items:center; gap:10px; }
.brandMark{
  width:34px; height:34px;
  border-radius:10px;
  background: linear-gradient(135deg, var(--accent), #1f4f73);
  box-shadow: inset 0 0 0 1px rgba(255,255,255,.35);
}
.brandText{ display:flex; flex-direction:column; line-height:1.05; }
.logo{ font-weight:900; letter-spacing:.2px; font-size:16px; }
.subtitle{ color:var(--muted); font-size:11px; margin-top:2px; }

.tabs{
  display:flex;
  gap:6px;
  align-items:center;
  grid-column: 2;
  grid-row: 1;
  overflow:auto;
  padding-bottom:2px;
}
.tabs::-webkit-scrollbar{ height:8px; }
.tabs::-webkit-scrollbar-thumb{ background: rgba(15,23,42,.12); border-radius:999px; }

.tabbtn{
  border:1px solid var(--border);
  background: rgba(40,121,173,.06);
  color:var(--text);
  padding:7px 10px;
  border-radius:12px;
  cursor:pointer;
  font-weight:900;
  font-size:12px;
  white-space:nowrap;
  transition: background .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.tabbtn.active{
  background: var(--accent-weak);
  border-color: rgba(40,121,173,.35);
  box-shadow: 0 0 0 3px rgba(40,121,173,.10);
}

.top-actions{
  grid-column: 3;
  grid-row: 1;
  display:flex;
  gap:8px;
  align-items:center;
}

.tbtn, .btn{
  border:1px solid var(--border);
  background: rgba(40,121,173,.06);
  color:var(--text);
  padding:8px 10px;
  border-radius:12px;
  cursor:pointer;
  font-weight:900;
  font-size:12px;
  display:inline-flex;
  align-items:center;
  gap:7px;
  user-select:none;
  transition: transform .06s ease, background .15s ease, border-color .15s ease, box-shadow .15s ease;
}
.tbtn:hover,.btn:hover{ background: rgba(40,121,173,.10); }
.tbtn:active,.btn:active{ transform: translateY(1px); }
.tbtn .ico{ width:16px; height:16px; display:inline-flex; }
.tbtn .ico svg{ width:16px; height:16px; fill: currentColor; }
.tbtn.primary{
  background: var(--accent);
  color:#fff;
  border-color: rgba(40,121,173,.35);
}
.tbtn.primary:hover{ background: rgba(40,121,173,.92); }
.tbtn.ghost{ background: rgba(15,23,42,.04); }
.tbtn.gold{ background: rgba(224,184,44,.22); border-color: rgba(224,184,44,.40); }

.tabpanels{
  grid-column: 1 / -1;
  grid-row: 2;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:6px 0 4px;
}
.tabpanel{ display:none; gap:8px; flex-wrap:wrap; justify-content:center; }
.tabpanel.active{ display:flex; }

/* ===== Sidebar (Property grid) ===== */
#leftPanel{
  grid-column: 1;
  grid-row: 2;
  background: var(--surface);
  border-right:1px solid var(--border);
  overflow:auto;
  padding:12px;
  position:relative;
}

/* Sidebar resize handle (desktop) */
.resize-handle{
  position:absolute;
  top:0;
  right:0;
  width:10px;
  height:100%;
  cursor: col-resize;
  background: linear-gradient(90deg, rgba(0,0,0,0), rgba(15,23,42,.06));
}

.panelTitle{
  font-weight:900;
  font-size:12px;
  letter-spacing:.35px;
  text-transform:uppercase;
  color:var(--muted);
  margin:10px 4px 10px;
}

.muted{ color:var(--muted); }

.formBlock, .sectionMini, .quoteBox{
  border:1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface2);
  box-shadow: var(--shadow2);
  padding:12px;
}
.formBlock{ margin-bottom:10px; }
.sectionMini{ margin-top:12px; }

.row{ margin-bottom:10px; }
.row label{ display:block; font-size:12px; color:var(--muted); margin-bottom:6px; }
input,select{
  width:100%;
  border:1px solid var(--border);
  border-radius:12px;
  padding:10px 10px;
  background:#fff;
  color:var(--text);
  font-size:13px;
  outline:none;
}
input:focus,select:focus{
  border-color: rgba(40,121,173,.45);
  box-shadow: 0 0 0 3px rgba(40,121,173,.12);
}

.grid2{ display:grid; grid-template-columns: 1fr 1fr; gap:10px; }
.check{ display:flex; align-items:center; gap:10px; font-size:13px; margin:8px 0; }
.check input{ width:16px; height:16px; }

.rangeWrap{ display:flex; align-items:center; gap:10px; }
.rangeWrap input[type="range"]{ flex:1; }
.rangeWrap input[type="number"]{ width:92px; }

.miniList{ border:1px solid var(--line); border-radius:12px; padding:6px; background:rgba(255,255,255,0.85); max-height:160px; overflow:auto; }
.miniItem{ display:flex; align-items:center; justify-content:space-between; gap:10px; padding:6px 8px; border-radius:10px; }
.miniItem:nth-child(odd){ background:rgba(19,26,41,0.04); }
.miniItem .tag{ font-size:11px; color:var(--muted); }
.miniItem button{ border:1px solid var(--line); background:#fff; border-radius:10px; padding:4px 10px; font-size:12px; cursor:pointer; }
.miniItem button:hover{ border-color:rgba(41,110,255,0.45); }

.btn-row{ display:flex; gap:8px; margin-top:10px; }
.btn{ justify-content:center; }
.btn.danger{ background: rgba(211,58,74,.10); border-color: rgba(211,58,74,.30); }
.btn.danger:hover{ background: rgba(211,58,74,.16); }

.panelHint{
  margin-top:12px;
  padding:10px 12px;
  border-radius: var(--radius);
  border:1px dashed rgba(15,23,42,.18);
  background: rgba(40,121,173,.04);
  font-size:12px;
  line-height:1.35;
}

.quoteBox{ white-space:pre-wrap; font-size:13px; line-height:1.35; }

/* ===== Viewport ===== */
#viewport{
  grid-column: 2;
  grid-row: 2;
  position:relative;
  overflow:hidden;
  background: radial-gradient(1200px 700px at 20% 0%, #ffffff 0%, #eef1f6 55%, #e7ebf4 100%);
}
#c{ width:100%; height:100%; display:block; touch-action:none; }

#hud{
  position:absolute;
  left:10px; top:10px;
  display:flex;
  gap:8px;
  z-index:3;
}
.hud-pill{
  padding:7px 10px;
  border-radius:999px;
  border:1px solid var(--border);
  background: rgba(255,255,255,.82);
  box-shadow: var(--shadow2);
  font-size:12px;
  color:var(--muted);
}

/* Dock panels */
#layersPanel{
  position:absolute;
  right:12px;
  bottom:12px;
  width:330px;
  max-height: 48%;
  border:1px solid var(--border);
  border-radius: 16px;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(8px);
  box-shadow: var(--shadow);
  overflow:hidden;
  z-index:4;
}
.layersTitle{
  padding:10px 12px;
  font-weight:900;
  font-size:12px;
  letter-spacing:.35px;
  text-transform:uppercase;
  color:var(--muted);
  border-bottom:1px solid var(--border);
  background: rgba(40,121,173,.05);
}
.layersList{ padding:10px; overflow:auto; max-height: calc(100% - 42px); display:flex; flex-direction:column; gap:8px; }
.layerItem{
  border:1px solid var(--border);
  border-radius: 14px;
  padding:10px;
  background:#fff;
  cursor:pointer;
  transition: background .12s ease, box-shadow .12s ease, border-color .12s ease;
}
.layerItem:hover{ background: rgba(40,121,173,.06); }
.layerItem.active{ border-color: rgba(40,121,173,.45); box-shadow: 0 0 0 3px rgba(40,121,173,.12); }
.layerItem .t{ font-weight:900; font-size:13px; }
.layerItem .s{ margin-top:4px; color:var(--muted); font-size:12px; }

/* Attach picker */
.attachPicker{
  position:absolute;
  right:12px;
  top:12px;
  transform: translateY(54px);
  width:330px;
  border:1px solid var(--border);
  border-radius: 16px;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(8px);
  box-shadow: var(--shadow);
  padding:12px;
  z-index:5;
}
.attachTitle{
  font-weight:900;
  font-size:12px;
  letter-spacing:.35px;
  text-transform:uppercase;
  color:var(--muted);
  margin-bottom:10px;
}
.attachButtons{ display:flex; gap:8px; }
.attachButtons .btn{ flex:1; }

/* ===== Status bar ===== */
#statusbar{
  grid-column: 1 / -1;
  grid-row: 3;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  padding:0 12px;
  border-top:1px solid var(--border);
  background: #ffffff;
  color:var(--muted);
  font-size:12px;
}
.statusLeft, .statusRight{ display:flex; align-items:center; gap:10px; }
.statusPill{
  padding:6px 10px;
  border-radius:999px;
  border:1px solid var(--border);
  background: rgba(40,121,173,.04);
}

/* ===== Mobile navigation ===== */
#mobileNav{
  position:fixed;
  left:0; right:0; bottom:0;
  display:none;
  gap:6px;
  padding:8px 10px;
  background: rgba(255,255,255,.95);
  border-top:1px solid var(--border);
  z-index:10;
}
.mnavbtn{
  flex:1;
  border:1px solid var(--border);
  background: rgba(40,121,173,.06);
  color:var(--text);
  padding:10px 8px;
  border-radius: 12px;
  font-weight:900;
  font-size:12px;
}
.mnavbtn.active{ background: var(--accent-weak); border-color: rgba(40,121,173,.35); }

/* ===== Responsive behavior ===== */
@media (max-width: 1100px){
  #layout{ grid-template-columns: 320px 1fr; }
}

@media (max-width: 920px){
  #layout{ grid-template-columns: 1fr; grid-template-rows: 94px 1fr 34px; }
  #leftPanel{
    position:fixed;
    top:94px;
    bottom:34px;
    left:0;
    width:min(420px, 92vw);
    transform: translateX(-105%);
    transition: transform .18s ease;
    z-index:9;
    box-shadow: var(--shadow);
  }
  body.sidebar-open #leftPanel{ transform: translateX(0); }
  #viewport{ grid-column: 1; }
  #layersPanel{ width:min(330px, calc(100vw - 24px)); }
  #mobileNav{ display:flex; }
  #statusbar{ padding-bottom: 48px; }
}

@media (max-width: 520px){
  #topbar{ grid-template-columns: 1fr auto; grid-template-rows: auto auto auto; }
  .brand{ grid-column: 1; grid-row: 1; }
  .tabs{ grid-column: 1 / -1; grid-row: 2; justify-content:flex-start; }
  .top-actions{ grid-column: 2; grid-row: 1; }
  .tabpanels{ grid-column: 1 / -1; grid-row: 3; justify-content:flex-start; overflow:auto; }
  .tabpanels::-webkit-scrollbar{ height:8px; }
  .tabpanels::-webkit-scrollbar-thumb{ background: rgba(15,23,42,.12); border-radius:999px; }
  #layersPanel{ right:10px; left:10px; width:auto; }
}