:root {
  --bg: #dce8f0;
  --bg-2: #c4d9e8;
  --bg-sheen: #ffffff;
  --panel: #f4f9fc;
  --panel-glass: #ffffff;
  --panel-2: #e7f0f7;
  --panel-grad-1: #ffffff;
  --panel-grad-2: #f4f9fc;
  --panel-grad-3: #e7f0f7;
  --line: #a9c2d6;
  --line-soft: #c9dae8;
  --text: #1d3142;
  --muted: #5a7488;
  --accent: #1f8fe0;
  --accent-2: #67c6f2;
  --heading: #2c5878;
  --hull: #0f6fb8;
  --solid: #5d84a3;
  --floor: #ffffff;
  --grid-line: #b9cdda;
  --engine: #c4860f;
  --extender: #cf5b28;
  --amplifier: #7142c4;
  --field: #1f8fe0;
  --outfield: #c91f1f;
  --marker-stroke: #ffffff;

  --sidebar-grad-1: #eef6fb;
  --sidebar-grad-2: #dfecf5;
  --texture-line: rgba(255,255,255,0.5);
  --texture-line-soft: rgba(255,255,255,0.35);
  --sheen: rgba(255,255,255,0.55);
  --sheen-strong: rgba(255,255,255,0.85);
  --shadow-color: rgba(31,90,130,0.12);
  --shadow-color-soft: rgba(31,90,130,0.1);
  --inset-hi: rgba(255,255,255,0.9);

  --track-grad-1: #b9cdda;
  --track-grad-2: #8fa9bb;
  --track-grad-3: #cfe0ea;
  --track-shadow: rgba(13,40,60,0.45);
  --thumb-border: #0c5e9c;
  --thumb-shadow: rgba(8,40,65,0.4);

  --input-bg: #ffffff;
  --input-shadow: rgba(31,90,130,0.08);
  --focus-ring: rgba(31,143,224,0.2);

  --check-grad-1: #f4f9fc;
  --check-grad-2: #d3e2ec;
  --check-border: #93b4c9;

  --btn-grad-1: #eaf3f9;
  --btn-grad-2: #cfe2ee;
  --btn-grad-3: #b9d4e6;
  --btn-grad-4: #d3e7f3;
  --btn-border: #94b8cf;
  --btn-text: #1d3142;
  --btn-sheen: rgba(255,255,255,0.85);
  --btn-shadow: rgba(31,90,130,0.15);

  --btn-primary-grad-1: #aee0ff;
  --btn-primary-grad-2: #4fb3ec;
  --btn-primary-grad-3: #1481cc;
  --btn-primary-grad-4: #2aa1ee;
  --btn-primary-border: #1577ba;
  --btn-primary-text: #07304a;
  --btn-primary-sheen: rgba(255,255,255,0.95);

  --canvas-grid: #e3edf4;
  --canvas-bg: #fbfdfe;
}

[data-theme="dark"] {
  --bg: #161c27;
  --bg-2: #0d1219;
  --bg-sheen: #2a3850;
  --panel: #1c2433;
  --panel-glass: #232d40;
  --panel-2: #161e2c;
  --panel-grad-1: #2a3650;
  --panel-grad-2: #1f2738;
  --panel-grad-3: #161d2a;
  --line: #3a4a63;
  --line-soft: #2b3850;
  --text: #dce8f4;
  --muted: #8298b3;
  --accent: #5fc4ff;
  --accent-2: #8fd6ff;
  --heading: #8fc4ec;
  --hull: #5fc4ff;
  --solid: #4a6280;
  --floor: #0e1420;
  --grid-line: #2c3a52;
  --engine: #e2b04f;
  --extender: #ef8a5a;
  --amplifier: #b08aef;
  --field: #5fc4ff;
  --outfield: #ff5a5a;
  --marker-stroke: #0e1420;

  --sidebar-grad-1: #1b2333;
  --sidebar-grad-2: #11161f;
  --texture-line: rgba(255,255,255,0.05);
  --texture-line-soft: rgba(255,255,255,0.04);
  --sheen: rgba(140,190,255,0.12);
  --sheen-strong: rgba(170,210,255,0.18);
  --shadow-color: rgba(0,0,0,0.45);
  --shadow-color-soft: rgba(0,0,0,0.35);
  --inset-hi: rgba(255,255,255,0.07);

  --track-grad-1: #1a2230;
  --track-grad-2: #0c1119;
  --track-grad-3: #263347;
  --track-shadow: rgba(0,0,0,0.6);
  --thumb-border: #1481c4;
  --thumb-shadow: rgba(0,0,0,0.5);

  --input-bg: #141b27;
  --input-shadow: rgba(0,0,0,0.3);
  --focus-ring: rgba(95,196,255,0.25);

  --check-grad-1: #232d40;
  --check-grad-2: #131a26;
  --check-border: #3d5170;

  --btn-grad-1: #2c3a50;
  --btn-grad-2: #1f2c3f;
  --btn-grad-3: #182332;
  --btn-grad-4: #212e42;
  --btn-border: #3d5170;
  --btn-text: #e2ecf6;
  --btn-sheen: rgba(170,210,255,0.18);
  --btn-shadow: rgba(0,0,0,0.4);

  --btn-primary-grad-1: #6fd0ff;
  --btn-primary-grad-2: #2a9bdf;
  --btn-primary-grad-3: #0f6aa8;
  --btn-primary-grad-4: #1c84c4;
  --btn-primary-border: #0c5e9c;
  --btn-primary-text: #04202f;
  --btn-primary-sheen: rgba(220,240,255,0.55);

  --canvas-grid: #1b2433;
  --canvas-bg: #0e1320;
}

* { box-sizing: border-box; }

.panel, .toolbar, .view-toggles, .canvas-wrap, button,
input[type="text"], select, .check input[type="checkbox"] {
  transition: background-color 0.2s, border-color 0.2s, box-shadow 0.2s, color 0.2s;
}

body {
  margin: 0;
  background:
    radial-gradient(ellipse at 20% -10%, var(--bg-sheen) 0%, transparent 55%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 100%);
  color: var(--text);
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  font-size: 14px;
  transition: background-color 0.2s;
}

main {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 0;
  height: 100vh;
}

.controls {
  overflow-y: auto;
  padding: 16px;
  border-right: 1px solid var(--line);
  background:
    repeating-linear-gradient(135deg, var(--texture-line-soft) 0 1px, transparent 1px 5px),
    linear-gradient(180deg, var(--sidebar-grad-1) 0%, var(--sidebar-grad-2) 100%);
}

.panel {
  position: relative;
  background: linear-gradient(180deg, var(--panel-grad-1) 0%, var(--panel-grad-2) 60%, var(--panel-grad-3) 100%);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 14px;
  margin-bottom: 14px;
  overflow: hidden;
  box-shadow:
    0 1px 0 var(--inset-hi) inset,
    0 1px 3px var(--shadow-color);
}
.panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    repeating-linear-gradient(135deg, var(--texture-line) 0 1px, transparent 1px 6px);
  opacity: 0.5;
  pointer-events: none;
}
.panel::after {
  content: "";
  position: absolute;
  top: -60%;
  left: -20%;
  width: 70%;
  height: 90%;
  background: radial-gradient(ellipse at 50% 0%, var(--sheen) 0%, rgba(255,255,255,0) 70%);
  transform: rotate(-8deg);
  pointer-events: none;
}
.panel > * { position: relative; z-index: 1; }
.panel h2 {
  margin: 0 0 10px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: var(--heading);
  border-bottom: 1px solid var(--line-soft);
  padding-bottom: 6px;
}

.ctrl { display: block; margin-bottom: 12px; }
.ctrl:last-child { margin-bottom: 0; }
.lbl {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  margin-bottom: 6px;
}
.lbl em { color: var(--accent); font-style: normal; font-weight: 600; font-variant-numeric: tabular-nums; }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 18px;
  background: transparent;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 6px;
  border-radius: 4px;
  background: linear-gradient(180deg, var(--track-grad-1) 0%, var(--track-grad-2) 35%, var(--track-grad-3) 100%);
  box-shadow:
    0 1px 2px var(--track-shadow) inset,
    0 1px 0 var(--sheen);
}
input[type="range"]::-moz-range-track {
  height: 6px;
  border-radius: 4px;
  background: linear-gradient(180deg, var(--track-grad-1) 0%, var(--track-grad-2) 35%, var(--track-grad-3) 100%);
  box-shadow:
    0 1px 2px var(--track-shadow) inset,
    0 1px 0 var(--sheen);
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 17px;
  height: 17px;
  margin-top: -6px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 32% 28%, rgba(255,255,255,0.95) 0%, rgba(255,255,255,0.25) 35%, transparent 55%),
    linear-gradient(180deg, var(--accent-2) 0%, var(--accent) 55%, var(--hull) 100%);
  border: 1px solid var(--thumb-border);
  box-shadow:
    0 1px 2px var(--thumb-shadow),
    0 0 0 1px rgba(255,255,255,0.4) inset;
}
input[type="range"]::-moz-range-thumb {
  width: 17px;
  height: 17px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 32% 28%, rgba(255,255,255,0.95) 0%, rgba(255,255,255,0.25) 35%, transparent 55%),
    linear-gradient(180deg, var(--accent-2) 0%, var(--accent) 55%, var(--hull) 100%);
  border: 1px solid var(--thumb-border);
  box-shadow:
    0 1px 2px var(--thumb-shadow),
    0 0 0 1px rgba(255,255,255,0.4) inset;
}
input[type="range"]:hover::-webkit-slider-thumb { filter: brightness(1.08); }
input[type="range"]:active::-webkit-slider-thumb { filter: brightness(0.96); }
input[type="text"], select {
  width: 100%;
  padding: 7px 9px;
  background: var(--input-bg);
  border: 1px solid var(--line);
  border-radius: 5px;
  color: var(--text);
  font-size: 13px;
  box-shadow: 0 1px 2px var(--input-shadow) inset;
}
input[type="text"]:focus, select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--focus-ring);
}

.check {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
  font-size: 13px;
  cursor: pointer;
}
.check input[type="checkbox"] {
  -webkit-appearance: none;
  appearance: none;
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
  border-radius: 4px;
  background: linear-gradient(180deg, var(--check-grad-1) 0%, var(--check-grad-2) 100%);
  border: 1px solid var(--check-border);
  box-shadow: 0 1px 2px var(--track-shadow) inset, 0 1px 0 var(--sheen);
  cursor: pointer;
  position: relative;
}
.check input[type="checkbox"]:checked {
  background:
    radial-gradient(circle at 32% 28%, rgba(255,255,255,0.9) 0%, rgba(255,255,255,0.15) 40%, transparent 60%),
    linear-gradient(180deg, var(--accent-2) 0%, var(--accent) 55%, var(--hull) 100%);
  border-color: var(--thumb-border);
}
.check input[type="checkbox"]:checked::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 1px;
  width: 4px;
  height: 8px;
  border: solid #ffffff;
  border-width: 0 2px 2px 0;
  transform: rotate(40deg);
}

/* Collapsible sub-menus (wings / flanks) */
details > summary {
  list-style: none;
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: var(--heading);
}
details > summary::-webkit-details-marker { display: none; }
details > summary::before {
  content: "▶";
  font-size: 9px;
  color: var(--muted);
  transition: transform 0.15s;
}
details[open] > summary::before { transform: rotate(90deg); }
.check.inline { margin: 0; font-size: 13px; text-transform: none; letter-spacing: 0; font-weight: 400; color: var(--text); }
.check.inline span { font-weight: 600; }
.exp-title { font-weight: 700; }
.hint { margin: 6px 0 0; font-size: 12px; color: var(--muted); line-height: 1.4; word-break: break-all; }
.hint b { color: var(--accent); font-variant-numeric: tabular-nums; }
.warn-hint { color: var(--outfield); }
details .sub {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line-soft);
}

/* Give the Blueprint dropdown room so it doesn't smush against the button above. */
#blueprintDetails {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px solid var(--line-soft);
}

.btn-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 6px; }
button {
  position: relative;
  flex: 1 1 auto;
  padding: 8px 12px;
  background: linear-gradient(180deg, var(--btn-grad-1) 0%, var(--btn-grad-2) 45%, var(--btn-grad-3) 46%, var(--btn-grad-4) 100%);
  border: 1px solid var(--btn-border);
  border-radius: 14px;
  color: var(--btn-text);
  cursor: pointer;
  font-size: 13px;
  font-weight: 600;
  overflow: hidden;
  box-shadow:
    0 1px 0 var(--inset-hi) inset,
    0 1px 2px var(--btn-shadow);
  transition: filter 0.12s, box-shadow 0.12s, transform 0.05s;
}
button::before {
  content: "";
  position: absolute;
  top: -75%;
  left: 4%;
  width: 92%;
  height: 100%;
  background: radial-gradient(ellipse at 50% 0%, var(--btn-sheen) 0%, rgba(255,255,255,0) 65%);
  border-radius: 50%;
  pointer-events: none;
}
button span, button { position: relative; }
button:hover { filter: brightness(1.04); border-color: var(--accent); }
button:active { transform: translateY(1px); box-shadow: 0 1px 1px var(--btn-shadow) inset; }
button.primary {
  background: linear-gradient(180deg, var(--btn-primary-grad-1) 0%, var(--btn-primary-grad-2) 45%, var(--btn-primary-grad-3) 46%, var(--btn-primary-grad-4) 100%);
  color: var(--btn-primary-text);
  border-color: var(--btn-primary-border);
  text-shadow: 0 1px 0 rgba(255,255,255,0.35);
}
button.primary::before {
  background: radial-gradient(ellipse at 50% 0%, var(--btn-primary-sheen) 0%, rgba(255,255,255,0) 65%);
}
button.primary:hover { filter: brightness(1.06); }

.stage {
  display: flex;
  flex-direction: column;
  padding: 16px 20px;
  overflow: hidden;
}

.toolbar {
  position: relative;
  display: flex;
  align-items: stretch;
  gap: 12px;
  margin-bottom: 12px;
  background: var(--panel-glass);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 1px 0 var(--inset-hi) inset, 0 1px 3px var(--shadow-color-soft);
  overflow: hidden;
}
.toolbar::before {
  content: "";
  position: absolute;
  top: -120%;
  left: 0;
  width: 50%;
  height: 140%;
  background: radial-gradient(ellipse at 50% 0%, var(--sheen) 0%, rgba(255,255,255,0) 70%);
  transform: rotate(-6deg);
  pointer-events: none;
}
.toolbar > * { position: relative; z-index: 1; }

.view-toggles {
  display: flex;
  align-items: center;
  flex: 0 0 auto;
  gap: 14px;
  padding: 0 14px;
  background: linear-gradient(180deg, var(--sidebar-grad-1) 0%, var(--sidebar-grad-2) 100%);
  border-left: 1px solid var(--line-soft);
  white-space: nowrap;
}
.view-toggles .check.inline { font-size: 12px; color: var(--muted); }

.generate-btn {
  flex: 0 0 auto;
  padding: 5px 12px;
  font-size: 12px;
  border-radius: 12px;
}

.stats {
  display: flex;
  flex: 1 1 auto;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
  padding: 8px 12px;
  font-size: 13px;
  color: var(--muted);
}
.stats b { color: var(--text); font-variant-numeric: tabular-nums; }
.stats .warn { color: var(--outfield); }
.stats .warn b { color: var(--outfield); }

.canvas-wrap {
  position: relative;
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background:
    repeating-linear-gradient(0deg, var(--canvas-grid) 0 1px, transparent 1px 24px),
    repeating-linear-gradient(90deg, var(--canvas-grid) 0 1px, transparent 1px 24px),
    var(--canvas-bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 1px 3px var(--shadow-color-soft) inset, 0 1px 3px var(--shadow-color);
}
.canvas-wrap::before {
  content: "";
  position: absolute;
  top: -90%;
  left: -10%;
  width: 60%;
  height: 110%;
  background: radial-gradient(ellipse at 50% 0%, var(--sheen-strong) 0%, rgba(255,255,255,0) 70%);
  transform: rotate(-8deg);
  pointer-events: none;
}
canvas { image-rendering: pixelated; max-width: 100%; max-height: 100%; }

.legend {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: baseline;
  gap: 12px;
  margin-top: 10px;
  font-size: 12px;
  color: var(--muted);
}
.legend-swatches {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  min-width: 0;
}
.tagline {
  text-align: center;
  font-style: italic;
  color: var(--muted);
  white-space: nowrap;
  justify-self: center;
}
.handles {
  display: flex;
  justify-self: end;
  gap: 14px;
  white-space: nowrap;
}
.legend i.sw {
  display: inline-block;
  width: 12px; height: 12px;
  border-radius: 3px;
  margin-right: 5px;
  vertical-align: -1px;
  box-shadow: 0 0 0 1px rgba(31,90,130,0.25);
}
.sw.hull { background: var(--hull); }
.sw.solid { background: var(--solid); }
.sw.floor { background: var(--floor); border: 1px solid var(--line); }
.sw.engine { background: var(--engine); border-radius: 50%; }
.sw.extender { background: var(--extender); border-radius: 50%; }
.sw.amplifier { background: var(--amplifier); border-radius: 50%; }
.sw.outfield { background: var(--outfield); }

.theme-toggle {
  flex: 0 0 auto;
  width: 30px;
  height: 30px;
  padding: 0;
  border-radius: 50%;
  font-size: 14px;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

@media (max-width: 800px) {
  main { grid-template-columns: 1fr; height: auto; }
  .controls { border-right: none; border-bottom: 1px solid var(--line); }
  .stage { min-width: 0; }

  .toolbar { flex-wrap: wrap; }
  .view-toggles {
    flex: 1 1 100%;
    flex-wrap: wrap;
    white-space: normal;
    border-left: none;
    gap: 8px 14px;
  }

  .legend {
    grid-template-columns: 1fr;
    justify-items: stretch;
    text-align: center;
    gap: 8px;
    min-width: 0;
  }
  .legend-swatches {
    width: 100%;
    justify-content: center;
    gap: 10px 16px;
  }
  .tagline {
    justify-self: center;
    white-space: normal;
  }
  .handles {
    justify-self: center;
    flex-wrap: wrap;
    justify-content: center;
  }
}