:root {
  --bg: #0b1020;
  --panel: #131a2e;
  --panel-2: #1a2340;
  --text: #e8ecf8;
  --muted: #98a3c4;
  --accent: #4f8cff;
  --accent-2: #4a90c2;
  --brand: #4a90c2;
  --danger: #ff5d6c;
  --border: #263252;
  --radius: 10px;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 15px/1.55 system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---- nav ---- */
nav {
  display: flex; align-items: center; gap: 22px;
  padding: 14px 28px;
  background: rgba(11, 16, 32, 0.9);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 10;
}
nav .brand { font-family: Verdana, 'DejaVu Sans', Geneva, sans-serif; font-weight: 700; font-style: italic; font-size: 21px; line-height: 1; letter-spacing: 0; color: var(--brand); }
nav .brand .brand-l { font-family: 'Cambria Math', 'STIX Two Math', 'Segoe UI Symbol', 'Apple Symbols', 'Times New Roman', serif; font-style: normal; font-weight: 400; font-size: 1.42em; color: var(--brand); }
nav a.nav-link { color: var(--muted); font-weight: 500; }
nav a.nav-link:hover { color: var(--text); text-decoration: none; }
nav .spacer { flex: 1; }
#nav-user { display: flex; gap: 12px; align-items: center; color: var(--muted); }

/* ---- layout ---- */
.container { max-width: 1060px; margin: 0 auto; padding: 34px 24px 70px; }
.hero { text-align: center; padding: 72px 20px 40px; }
.hero h1 { font-size: 44px; margin: 0 0 14px; letter-spacing: -0.5px; }
.hero h1 em { color: var(--accent-2); font-style: normal; }
.hero p.sub { color: var(--muted); font-size: 18px; max-width: 640px; margin: 0 auto 30px; }
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 46px; }
@media (max-width: 780px) { .steps { grid-template-columns: 1fr; } .hero h1 { font-size: 32px; } }

/* ---- cards / panels ---- */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}
.card h3 { margin-top: 0; }
.card .kicker { color: var(--accent-2); font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: 1.2px; }
.grid { display: grid; gap: 18px; }
.grid.cols-2 { grid-template-columns: 1fr 1fr; }
@media (max-width: 780px) { .grid.cols-2 { grid-template-columns: 1fr; } }
.muted { color: var(--muted); }
.price { font-size: 22px; font-weight: 700; color: var(--accent-2); }
.price small { font-size: 13px; color: var(--muted); font-weight: 400; }

/* ---- forms & buttons ---- */
label { display: block; font-size: 13px; color: var(--muted); margin: 12px 0 4px; }
input, select {
  width: 100%; padding: 9px 11px;
  border-radius: 8px; border: 1px solid var(--border);
  background: var(--panel-2); color: var(--text); font: inherit;
}
input:focus, select:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
button, .btn {
  display: inline-block; cursor: pointer;
  padding: 9px 16px; border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--panel-2); color: var(--text);
  font: inherit; font-weight: 600;
}
button:hover, .btn:hover { border-color: var(--accent); text-decoration: none; }
button.primary, .btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
button.primary:hover, .btn.primary:hover { filter: brightness(1.1); }
button.success { background: var(--accent-2); border-color: var(--accent-2); color: #06281e; }
button.danger { background: transparent; border-color: var(--danger); color: var(--danger); }
button:disabled { opacity: 0.5; cursor: not-allowed; }
.form-narrow { max-width: 400px; margin: 40px auto; }
.error-msg { color: var(--danger); min-height: 20px; font-size: 14px; margin-top: 10px; }
.ok-msg { color: var(--accent-2); min-height: 20px; font-size: 14px; margin-top: 10px; }

/* ---- tables ---- */
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--border); }
th { color: var(--muted); font-weight: 600; font-size: 12px; text-transform: uppercase; letter-spacing: 0.8px; }
code, .code {
  background: #0a0f1d; border: 1px solid var(--border);
  border-radius: 6px; padding: 2px 6px;
  font-family: ui-monospace, 'Cascadia Code', Consolas, monospace; font-size: 13px;
}
pre.code { padding: 14px; overflow-x: auto; white-space: pre; }

/* ---- editor ---- */
.editor-wrap {
  display: grid; grid-template-columns: 280px 1fr;
  gap: 0; height: calc(100vh - 57px);
}
.palette {
  background: var(--panel); border-right: 1px solid var(--border);
  padding: 18px; overflow-y: auto;
}
.palette h3 { font-size: 13px; text-transform: uppercase; letter-spacing: 1px; color: var(--muted); margin: 20px 0 8px; }
.palette h3:first-child { margin-top: 0; }
.palette .tool { width: 100%; text-align: left; margin-bottom: 8px; }
.palette .tool.active { border-color: var(--accent-2); color: var(--accent-2); }
.canvas-area { position: relative; overflow: auto; background: #070b16; }
.canvas-stack { display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 18px 12px 30px; }
.board-wrap { position: relative; }
#board { background: #f6f8fa; cursor: crosshair; }
#coords {
  position: absolute; left: 12px; bottom: 10px;
  color: #5f6a73; font-size: 12px; font-family: ui-monospace, monospace;
  pointer-events: none;
}
.view-toggle {
  display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden;
}
.view-toggle button { border: 0; border-radius: 0; padding: 8px 22px; background: var(--panel); color: var(--muted); }
.view-toggle button.active { background: var(--accent); color: #fff; }
.panel-3d { text-align: center; position: relative; }
#skip-anim { position: absolute; top: 34px; right: 16px; z-index: 5; }
.panel-3d-label { color: var(--muted); font-size: 12px; text-transform: uppercase; letter-spacing: 1px; margin-bottom: 6px; }
#board3d { background: #e9edf0; border: 1px solid var(--border); border-radius: 8px; cursor: grab; }
#board3d:active { cursor: grabbing; }
#hud3d {
  position: absolute; top: 34px; left: 16px; z-index: 5;
  text-align: left; font-family: ui-monospace, 'Cascadia Code', Consolas, monospace;
  pointer-events: none;
}
#hud3d .h-1 { font-weight: 700; font-size: 13px; color: #0b7f63; letter-spacing: 0.4px; }
#hud3d .h-2 { font-size: 12px; color: #5b6670; margin-top: 2px; }
.keyguide {
  position: absolute; right: 12px; bottom: 10px; z-index: 5;
  display: flex; gap: 10px; align-items: center; white-space: nowrap;
  padding: 6px 10px; border-radius: 8px;
  background: rgba(255, 255, 255, 0.92); border: 1px solid #ccd3da;
  font-size: 11px; color: #4a5560; pointer-events: none;
}
.keyguide kbd {
  display: inline-block; min-width: 14px; text-align: center;
  padding: 1px 4px; margin: 0 1px; border-radius: 4px;
  border: 1px solid #b9c2ca; border-bottom-width: 2px;
  background: #fff; color: #2e3941;
  font: 600 10px ui-monospace, 'Cascadia Code', Consolas, monospace;
}
.keyguide .kg-note { color: #7a8590; }
.prop-row { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.prop-row label { margin: 0; flex: 1; }
.prop-row input { width: 90px; }
.prop-row input[type="text"] { width: 120px; }

/* ---- CAD part library ---- */
.part-row { display: flex; align-items: stretch; gap: 4px; margin-bottom: 8px; }
.part-row .tool { margin-bottom: 0; flex: 1; min-width: 0; overflow: hidden; }
.part-row .tool .muted { display: block; font-size: 11px; }
.part-row .icon-btn { padding: 6px 9px; line-height: 1; flex: 0 0 auto; }
#parts-list:empty { display: none; }
#parts-count { font-size: 12px; letter-spacing: 0; text-transform: none; }
.hint { font-size: 12px; color: var(--muted); margin-top: 4px; }

/* ---- modal ---- */
.modal-backdrop {
  position: fixed; inset: 0; background: rgba(4, 7, 15, 0.75);
  display: flex; align-items: center; justify-content: center; z-index: 50;
}
.modal {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  max-width: 640px; width: 92%; max-height: 84vh; overflow-y: auto; padding: 24px;
}
[hidden] { display: none !important; }
footer { text-align: center; color: var(--muted); font-size: 13px; padding: 30px 0; border-top: 1px solid var(--border); }