/* ── Hydraulic Circuit Builder ────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b27;
  --surface2:  #1f2535;
  --border:    #2a3050;
  --accent:    #00bcd4;
  --accent-lo: rgba(0,188,212,.22);
  --green:     #3ddc84;
  --red:       #ff5555;
  --gold:      #f5c842;
  --text:      #dde3f0;
  --text-dim:  #6b7a99;
  --font:      'Segoe UI', system-ui, sans-serif;
  --mono:      'Courier New', monospace;
  --radius:    12px;
}

body { background: var(--bg); color: var(--text); font-family: var(--font); min-height: 100vh; padding: 0 16px; }
#app { max-width: 1140px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }

/* ── Header ──────────────────────────────────────────────────── */
header { text-align: center; padding: 4px 0; }
header h1 {
  font-size: 1.8rem; font-weight: 700;
  background: linear-gradient(120deg, #00bcd4 0%, #4dd0e1 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.subtitle { color: var(--text-dim); font-size: 0.85rem; margin-top: 3px; }

/* ── Controls bar ────────────────────────────────────────────── */
.controls-bar {
  display: flex; flex-wrap: wrap; align-items: center; gap: 14px;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.ctrl-group { display: flex; align-items: center; gap: 8px; }
.ctrl-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); white-space: nowrap; }

.pill-tabs { display: flex; background: var(--bg); border-radius: 8px; padding: 3px; gap: 2px; flex-wrap: wrap; }
.pill {
  padding: 7px 14px; border: none; background: transparent; color: var(--text-dim);
  border-radius: 6px; cursor: pointer; font-size: 0.81rem; min-height: 44px;
  transition: background .18s, color .18s, box-shadow .18s;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.pill.active { background: var(--accent); color: #fff; box-shadow: 0 0 12px var(--accent-lo); }
.pill:hover:not(.active) { background: var(--surface2); color: var(--text); }

/* ── Buttons ─────────────────────────────────────────────────── */
.btn {
  padding: 8px 18px; border: none; border-radius: 8px; cursor: pointer;
  font-size: 0.84rem; font-weight: 600; transition: filter .18s, box-shadow .18s, opacity .18s;
}
.btn:disabled { opacity: 0.38; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:not(:disabled):hover { filter: brightness(1.12); box-shadow: 0 0 12px var(--accent-lo); }
.btn-ghost { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--border); }

/* ── Builder layout ──────────────────────────────────────────── */
.builder-layout { display: flex; gap: 12px; min-height: 480px; }
.canvas-area { flex: 1; display: flex; flex-direction: column; gap: 8px; min-width: 0; }

/* ── Component palette ───────────────────────────────────────── */
.component-palette {
  width: 200px; flex-shrink: 0; align-self: flex-start;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 8px 6px; display: flex; flex-direction: column; gap: 2px;
  overflow-y: auto; max-height: 520px;
}
.palette-title {
  font-size: 0.72rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--text-dim); text-align: center; padding-bottom: 6px;
  border-bottom: 1px solid var(--border); margin-bottom: 4px;
}
.palette-item {
  display: flex; align-items: center; gap: 6px; padding: 8px 8px;
  border-radius: 6px; cursor: grab; transition: background .15s;
  font-size: 0.72rem; color: var(--text-dim); min-height: 44px;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.palette-item:hover { background: var(--surface2); color: var(--text); }
.palette-item:active { cursor: grabbing; }
.palette-icon { flex-shrink: 0; border-radius: 4px; }

/* ── Collapsible category header ── */
.palette-cat {
  display: flex; align-items: center; justify-content: space-between;
  padding: 5px 6px; margin-top: 2px; border-radius: 6px;
  cursor: pointer; user-select: none;
  font-size: 0.72rem; font-weight: 600; text-transform: uppercase; letter-spacing: .04em;
  color: var(--blue); transition: background .15s;
}
.palette-cat:hover { background: var(--surface2); }
.palette-cat .cat-arrow {
  font-size: 0.6rem; transition: transform .2s; display: inline-block;
}
.palette-cat.collapsed .cat-arrow { transform: rotate(-90deg); }
.palette-cat-items {
  display: flex; flex-direction: column; gap: 1px;
  overflow: hidden; transition: max-height .25s ease;
  max-height: 1200px; flex-shrink: 0;
}
.palette-cat.collapsed + .palette-cat-items {
  max-height: 0;
}

/* ── Palette sub-category header ── */
.palette-subcat {
  font-size: 0.65rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: .07em; color: var(--text-dim);
  padding: 5px 6px 2px; margin-top: 3px;
  border-top: 1px solid var(--border);
  pointer-events: none; user-select: none;
}
.palette-subcat:first-child { border-top: none; margin-top: 0; }

/* ── Scrollable canvas wrapper (mobile) ──────────────────────── */
.canvas-scroll-wrap {
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  width: 100%;
}

/* ── Canvas card ─────────────────────────────────────────────── */
.canvas-card {
  width: 100%; background: #0a0e14;
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 0; position: relative; overflow-x: clip; flex: 1;
}
.canvas-card canvas { display: block; width: 100%; height: 100%; min-height: 420px; cursor: crosshair; touch-action: pan-y; }

/* ── Canvas toolbar ──────────────────────────────────────────── */
.canvas-toolbar {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
  padding: 8px 12px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.toolbar-hint { font-size: 0.74rem; color: var(--text-dim); margin-left: auto; }

/* ── Circuit description ─────────────────────────────────────── */
.circuit-desc {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 16px; font-size: 0.84rem; color: var(--text-dim); line-height: 1.5;
}
.circuit-desc strong { color: var(--accent); }

/* ── Properties panel ────────────────────────────────────────── */
.properties-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 18px;
}
.props-title {
  font-size: 0.76rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--accent); margin-bottom: 10px; font-weight: 700;
}
.props-body { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.props-body label {
  display: flex; align-items: center; gap: 8px; font-size: 0.82rem; color: var(--text-dim);
}
.props-body input[type="range"] {
  width: 120px; -webkit-appearance: none; appearance: none; height: 5px;
  background: var(--surface2); border-radius: 3px; outline: none;
}
.props-body input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 14px; height: 14px; border-radius: 50%;
  background: var(--accent); cursor: pointer;
}
.props-body select {
  padding: 4px 8px; border-radius: 6px; border: 1px solid var(--border);
  background: var(--surface2); color: var(--text); font-size: 0.82rem;
}
.props-val { color: var(--text); font-weight: 700; font-size: 0.82rem; min-width: 50px; }

/* ── Readout row ─────────────────────────────────────────────── */
.readout-row {
  display: flex; flex-wrap: wrap; gap: 10px;
}
.readout-card {
  flex: 1; min-width: 130px; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 10px 14px; text-align: center;
}
.readout-label { font-size: 0.68rem; text-transform: uppercase; letter-spacing: .04em; color: var(--text-dim); margin-bottom: 4px; }
.readout-val { font-size: 1.25rem; font-weight: 700; color: var(--accent); font-family: var(--mono); }
.readout-unit { font-size: 0.72rem; color: var(--text-dim); }

/* ── Warning bar ─────────────────────────────────────────────── */
.warning-bar {
  background: rgba(255,85,85,.12); border: 1px solid var(--red); border-radius: var(--radius);
  padding: 10px 16px; font-size: 0.82rem; color: var(--red); line-height: 1.4;
}

/* ── Explore ─────────────────────────────────────────────────── */
.item-selector {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 16px;
}
.is-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 8px; margin-top: 10px; }
.is-card {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 12px; cursor: pointer; transition: border-color .18s, box-shadow .18s;
}
.is-card:hover, .is-card.active { border-color: var(--accent); box-shadow: 0 0 8px var(--accent-lo); }
.is-card-name { font-size: 0.82rem; font-weight: 600; color: var(--text); }
.is-card-formula { font-size: 0.72rem; color: var(--text-dim); font-family: var(--mono); margin-top: 2px; }

.item-info {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px; line-height: 1.6;
}
.ii-title { font-size: 1.1rem; font-weight: 700; color: var(--accent); margin-bottom: 6px; }
.ii-formula { font-family: var(--mono); font-size: 0.88rem; color: var(--gold); margin-bottom: 8px; }
.ii-desc { font-size: 0.86rem; color: var(--text); margin-bottom: 12px; }
.ii-example {
  background: var(--surface2); border-radius: 8px; padding: 12px 14px;
}
.ii-example-title { font-size: 0.76rem; text-transform: uppercase; color: var(--accent); font-weight: 700; margin-bottom: 6px; }
.ii-step { font-size: 0.82rem; color: var(--text-dim); margin: 2px 0; font-family: var(--mono); }

/* ── Practice ────────────────────────────────────────────────── */
.practice-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px;
}
.pp-prompt { font-size: 0.94rem; line-height: 1.5; margin-bottom: 14px; }
.pp-input-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.pp-input {
  width: 140px; padding: 8px 12px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--surface2); color: var(--text); font-size: 0.92rem; font-family: var(--mono);
}
.pp-unit { font-size: 0.82rem; color: var(--text-dim); }
.pp-bottom { margin-top: 10px; }
.feedback.ok { color: var(--green); font-size: 0.88rem; font-weight: 600; }
.feedback.err { color: var(--red); font-size: 0.88rem; font-weight: 600; }
.solution-panel {
  background: var(--surface2); border-radius: 8px; padding: 14px 16px; margin-top: 12px;
}
.sol-step { font-size: 0.82rem; color: var(--text-dim); margin: 2px 0; font-family: var(--mono); }

.practice-bar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.pbar-score { font-size: 0.84rem; color: var(--text-dim); margin-left: auto; }
.pbar-score span { color: var(--text); font-weight: 700; }

/* ── Quiz ────────────────────────────────────────────────────── */
.question-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px;
}
.qp-question { font-size: 0.94rem; line-height: 1.5; margin-bottom: 14px; }
.qp-options { display: flex; flex-direction: column; gap: 8px; }
.qp-option {
  display: flex; align-items: center; gap: 10px; padding: 10px 14px;
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  cursor: pointer; transition: border-color .15s;
}
.qp-option:hover { border-color: var(--accent); }
.qp-option.selected { border-color: var(--accent); background: var(--accent-lo); }
.qp-option.correct { border-color: var(--green); background: rgba(61,220,132,.1); }
.qp-option.wrong { border-color: var(--red); background: rgba(255,85,85,.1); }
.qp-option input { accent-color: var(--accent); }
.qp-numeric { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.qp-numeric input {
  width: 140px; padding: 8px 12px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--surface2); color: var(--text); font-size: 0.92rem; font-family: var(--mono);
}
.qp-btn-row { display: flex; gap: 10px; margin-top: 14px; }

.quiz-bar {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.qbar-counter { display: flex; align-items: baseline; gap: 4px; }
.qbar-q-label { font-size: 0.72rem; text-transform: uppercase; color: var(--text-dim); }
.qbar-q-num { font-size: 1.1rem; font-weight: 700; color: var(--accent); }
.qbar-q-sep { color: var(--text-dim); }
.qbar-q-total { font-size: 0.9rem; color: var(--text-dim); }

.quiz-result {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px;
}
.qr-title { font-size: 1rem; font-weight: 700; margin-bottom: 6px; }
.qr-score { font-size: 1.6rem; font-weight: 700; margin-bottom: 10px; }
.qr-score.perfect { color: var(--gold); }
.qr-score.good { color: var(--green); }
.qr-score.poor { color: var(--red); }
.qr-stars { font-size: 1.3rem; margin-bottom: 14px; }
.qr-row {
  padding: 8px 12px; margin: 4px 0; border-radius: 6px;
  background: var(--surface2); font-size: 0.82rem;
}
.qr-row.ok { border-left: 3px solid var(--green); }
.qr-row.err { border-left: 3px solid var(--red); }

/* ── SEO article ─────────────────────────────────────────────── */
.seo-article { padding: 24px 0; line-height: 1.7; }
.seo-article h2 { font-size: 1.3rem; margin-bottom: 12px; color: var(--text); }
.seo-article h3 { font-size: 1.05rem; margin: 18px 0 8px; color: var(--text); }
.seo-article p { font-size: 0.9rem; margin-bottom: 12px; color: var(--text-dim); }
.seo-article a { color: var(--accent); text-decoration: none; }
.seo-article a:hover { text-decoration: underline; }

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 768px) {
  .builder-layout { flex-direction: column; }
  .component-palette {
    width: 100%; flex-direction: row; flex-wrap: wrap; max-height: none;
    padding: 8px; gap: 4px;
  }
  .palette-title { display: none; }
  .palette-item { flex-direction: column; padding: 4px 8px; min-width: 60px; text-align: center; }
  .palette-item span { font-size: 0.64rem; }
  .palette-cat-items { flex-direction: row; flex-wrap: wrap; }
  .canvas-card canvas { min-height: 360px; }
  .readout-row { gap: 6px; }
  .readout-card { min-width: 100px; padding: 8px 10px; }
  .readout-val { font-size: 1rem; }
  .is-grid { grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); }
  .controls-bar { gap: 10px; }
}

@media (max-width: 500px) {
  header h1 { font-size: 1.4rem; }
  .subtitle { font-size: 0.78rem; }
  .controls-bar { padding: 10px 12px; gap: 8px; }
  .pill { padding: 5px 10px; font-size: 0.76rem; }
  .canvas-card canvas { min-height: 300px; }
  .readout-card { min-width: 90px; }
  .is-grid { grid-template-columns: 1fr 1fr; }
  .toolbar-hint { display: none; }
  .props-body { flex-direction: column; }
}

/* ── User Guide button ───────────────────────────────────────── */
.btn-guide {
  margin-left: auto;
  background: var(--gold);
  color: #1a1a2e;
  border: none;
  padding: 6px 16px;
  border-radius: 6px;
  font-weight: 700;
  font-size: 0.82rem;
  cursor: pointer;
  transition: background .2s, box-shadow .2s;
  white-space: nowrap;
}
.btn-guide:hover { background: #ffd95a; box-shadow: 0 0 12px rgba(245,200,66,.35); }

/* ── User Guide modal overlay ────────────────────────────────── */
.guide-overlay {
  position: fixed; inset: 0; z-index: 1000;
  background: rgba(0,0,0,.72);
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.guide-modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: 90%; max-width: 780px; max-height: 85vh;
  display: flex; flex-direction: column;
  box-shadow: 0 12px 48px rgba(0,0,0,.6);
}
.guide-header {
  display: flex; justify-content: space-between; align-items: center;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.guide-header h2 {
  font-size: 1.1rem; font-weight: 700; color: var(--accent); margin: 0;
  line-height: 1.3;
}
.guide-close {
  background: none; border: none; color: var(--text-dim);
  font-size: 1.6rem; cursor: pointer; padding: 0 4px;
  transition: color .15s;
}
.guide-close:hover { color: var(--text); }

.guide-body {
  overflow-y: auto; padding: 24px;
  line-height: 1.75; color: var(--text); font-size: 0.88rem;
}
.guide-body h3 {
  color: var(--accent); font-size: 1rem; font-weight: 700;
  margin: 28px 0 10px; padding-bottom: 4px;
  border-bottom: 1px solid var(--border);
}
.guide-body h3:first-child { margin-top: 0; }
.guide-body h4 {
  color: var(--gold); font-size: 0.88rem; font-weight: 600;
  margin: 16px 0 6px;
}
.guide-body p { margin-bottom: 10px; color: var(--text-dim); }
.guide-body strong { color: var(--text); }
.guide-body ul, .guide-body ol { margin: 0 0 12px 20px; color: var(--text-dim); }
.guide-body li { margin-bottom: 5px; }
.guide-body kbd {
  display: inline-block; padding: 2px 7px; border-radius: 4px;
  background: var(--surface2); border: 1px solid var(--border);
  font-family: var(--mono); font-size: 0.78rem; color: var(--text);
}
.guide-body table {
  width: 100%; border-collapse: collapse; margin: 10px 0 16px;
  font-size: 0.82rem;
}
.guide-body th {
  background: var(--surface2); color: var(--accent); text-align: left;
  padding: 8px 12px; border: 1px solid var(--border); font-weight: 600;
}
.guide-body td {
  padding: 7px 12px; border: 1px solid var(--border); color: var(--text-dim);
}
.guide-body tr:hover td { background: rgba(0,188,212,.04); }

/* Guide responsive */
@media (max-width: 768px) {
  .guide-modal { width: 95%; max-height: 90vh; }
  .guide-header { padding: 14px 18px; }
  .guide-header h2 { font-size: 0.95rem; }
  .guide-body { padding: 18px; }
}
@media (max-width: 500px) {
  .guide-overlay { padding: 8px; }
  .guide-modal { width: 100%; max-height: 92vh; border-radius: 8px; }
  .guide-header { padding: 12px 14px; }
  .guide-header h2 { font-size: 0.88rem; }
  .guide-body { padding: 14px; font-size: 0.84rem; }
  .guide-body table { font-size: 0.78rem; }
  .btn-guide { padding: 5px 10px; font-size: 0.76rem; }
}

/* Context menu hover */
.ctx-item:hover { background: rgba(0,188,212,.12); }

/* ── Annotation Mark-Bar ──────────────────────────────────── */
.mark-bar {
  display: flex; align-items: center; gap: 4px; flex-wrap: wrap;
  padding: 6px 8px; background: var(--surface); border-bottom: 1px solid var(--border);
  border-radius: var(--radius) var(--radius) 0 0; flex-shrink: 0;
  overflow-x: auto; -webkit-overflow-scrolling: touch;
}
.tool-btn {
  padding: 6px 10px; border: 1px solid var(--border); border-radius: 8px;
  background: transparent; color: var(--text-dim); font-size: 0.82rem;
  cursor: pointer; transition: all .15s; min-height: 44px; min-width: 44px;
  display: flex; align-items: center; justify-content: center; gap: 4px;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
  -webkit-user-select: none; user-select: none;
}
.tool-btn:hover { background: var(--surface2); color: var(--text); }
.tool-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); }

.tool-btn-group { position: relative; display: flex; flex-shrink: 0; }
.tool-btn-group .tool-btn-sketch,
.tool-btn-group .tool-btn-shape { border-top-right-radius: 0; border-bottom-right-radius: 0; border-right: none; }
.tool-btn-drop {
  padding: 6px 6px; border: 1px solid var(--border); border-radius: 0 8px 8px 0;
  background: transparent; color: var(--text-dim); font-size: 0.72rem;
  cursor: pointer; transition: all .15s; min-height: 44px;
  display: flex; align-items: center;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.tool-btn-drop:hover { background: var(--surface); color: var(--text); }
.tool-btn-group .tool-btn-sketch.active ~ .tool-btn-drop,
.tool-btn-group .tool-btn-sketch.active + .tool-btn-drop,
.tool-btn-group .tool-btn-shape.active ~ .tool-btn-drop,
.tool-btn-group .tool-btn-shape.active + .tool-btn-drop {
  background: var(--accent); color: #fff; border-color: var(--accent);
}

/* Sketch color dot indicator */
.tool-btn-sketch::after {
  content: ''; display: inline-block; width: 8px; height: 8px;
  border-radius: 50%; margin-left: 4px; vertical-align: middle;
  background: var(--sketch-color, #fff); border: 1px solid rgba(255,255,255,.3); flex-shrink: 0;
}
/* Shape color dot indicator */
.tool-btn-shape::after {
  content: ''; display: inline-block; width: 8px; height: 8px;
  border-radius: 50%; margin-left: 4px; vertical-align: middle;
  background: var(--shape-color, #fff); border: 1px solid rgba(255,255,255,.3); flex-shrink: 0;
}

/* Sketch / Shape dropdowns — fixed position to escape overflow:clip */
.sketch-dropdown, .shape-dropdown {
  position: fixed; z-index: 400;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 10px; padding: 10px 12px; min-width: 180px;
  box-shadow: 0 6px 24px rgba(0,0,0,.4);
}
.shape-dropdown { min-width: 200px; }
.sketch-dd-label {
  font-size: 0.68rem; color: var(--text-dim); text-transform: uppercase;
  letter-spacing: 0.05em; margin-bottom: 6px; margin-top: 4px;
}
.sketch-dd-label:first-child { margin-top: 0; }
.swatch {
  width: 28px; height: 28px; border-radius: 50%; border: 2px solid var(--border);
  cursor: pointer; transition: all .15s; flex-shrink: 0;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.swatch:hover { transform: scale(1.15); }
.swatch.active { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent); }
.width-btn {
  flex: 1; padding: 6px 0; border: 1px solid var(--border); border-radius: 6px;
  background: transparent; color: var(--text-dim); cursor: pointer;
  transition: all .15s; display: flex; align-items: center; justify-content: center; min-height: 32px;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.width-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.fill-btn {
  flex: 1; padding: 6px 0; border: 1px solid var(--border); border-radius: 6px;
  background: transparent; color: var(--text-dim); cursor: pointer;
  transition: all .15s; display: flex; align-items: center; justify-content: center; min-height: 32px;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.fill-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.shape-pick {
  padding: 6px 0; min-height: 34px; border: 1px solid var(--border); border-radius: 6px;
  background: transparent; color: var(--text-dim); font-size: 1rem; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all .15s; touch-action: manipulation;
}
.shape-pick:hover { background: var(--surface2); }
.shape-pick.active { background: var(--accent); color: #fff; border-color: var(--accent); }

/* Shape text input (floats over canvas) */
.shape-text-input {
  position: absolute; z-index: 300; background: rgba(13,17,23,0.95); color: #fff;
  border: 1px solid var(--accent); border-radius: 4px; padding: 4px 8px;
  font: bold 14px var(--font); outline: none; min-width: 60px;
}

/* Confirm overlay / dialog */
.confirm-overlay {
  position: fixed; inset: 0; z-index: 500; background: rgba(0,0,0,.6);
  display: flex; align-items: center; justify-content: center;
}
.confirm-dialog {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 10px;
  padding: 18px 22px; max-width: 320px; width: 90%; color: var(--text);
}

/* Canvas overlay buttons (export) — bottom-right to avoid fullscreen button */
.canvas-overlay-btns {
  position: absolute; bottom: 10px; right: 10px;
  display: flex; gap: 6px; z-index: 5;
}
.canvas-overlay-btn {
  width: 34px; height: 34px; border-radius: 8px;
  background: rgba(22,27,39,0.8); border: 1px solid var(--border);
  color: var(--text-dim); font-size: 0.9rem; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background .18s, color .18s, border-color .18s;
  backdrop-filter: blur(4px);
}
.canvas-overlay-btn:hover { background: rgba(0,188,212,0.15); border-color: var(--accent); color: var(--accent); }

/* Fullscreen button */
.fullscreen-btn {
  position: absolute; top: 50px; right: 10px; z-index: 6;
  width: 36px; height: 36px; border-radius: 8px;
  background: rgba(22,27,39,0.8); border: 1px solid var(--border);
  color: var(--text); font-size: 1.1rem; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all .2s; backdrop-filter: blur(4px);
  text-shadow: 0 0 6px rgba(241,250,140,.6);
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.fullscreen-btn:hover { border-color: var(--accent); color: var(--accent); background: var(--surface2); }

/* Zoom/Pan toolbar */
.graph-toolbar {
  position: absolute; bottom: 10px; left: 10px; z-index: 5;
  display: flex; flex-direction: column; gap: 4px;
  background: rgba(13,17,23,.85); border: 1px solid var(--border);
  border-radius: 10px; padding: 4px;
  backdrop-filter: blur(4px);
}
.tb-btn {
  width: 38px; height: 38px;
  display: flex; align-items: center; justify-content: center;
  background: var(--surface); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text-dim); cursor: pointer; font-size: 1.1rem;
  transition: color .15s, border-color .15s, background .15s;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.tb-btn:hover { color: var(--accent); border-color: var(--accent); background: var(--surface2); }
.tb-btn.active { color: #f1fa8c; border-color: #f1fa8c; background: rgba(241,250,140,.15); }

/* ── Fullscreen state — targets #sim-panel so palette + toolbar + readouts are visible ── */
#sim-panel.is-fullscreen {
  position: fixed !important; inset: 0; z-index: 9999;
  background: var(--bg);
  display: flex; flex-direction: column;
  overflow-y: auto;
  width: 100vw !important; height: 100vh !important;
  max-width: none; max-height: none;
  padding: 0 8px 8px;
}
#sim-panel.is-fullscreen #prebuilt-bar,
#sim-panel.is-fullscreen #circuit-desc { display: none; }
#sim-panel.is-fullscreen .builder-layout { flex: 1; min-height: 0; flex-direction: row !important; }
#sim-panel.is-fullscreen .component-palette { max-height: none; align-self: stretch; width: 200px !important; flex-shrink: 0; flex-direction: column !important; overflow-y: auto; }
#sim-panel.is-fullscreen .canvas-area { flex: 1; min-height: 0; display: flex; flex-direction: column; }
/* Hydraulic DOM nesting is canvas-card > mark-bar + canvas-scroll-wrap > canvas.
   Make canvas-card a flex column so the scroll-wrap takes the remaining height
   after the toolbar; otherwise the canvas only fills its natural (tiny) area
   and the bottom portion of the card is unreachable in fullscreen. */
#sim-panel.is-fullscreen .canvas-card {
  flex: 1; min-height: 0; height: auto;
  display: flex; flex-direction: column;
}
#sim-panel.is-fullscreen .canvas-card .canvas-scroll-wrap {
  flex: 1; min-height: 0; width: 100%;
  overflow: hidden;
}
#sim-panel.is-fullscreen .canvas-card canvas {
  min-height: 0; width: 100%; height: 100%;
}
#sim-panel.is-fullscreen .readout-row { flex-shrink: 0; }
#sim-panel.is-fullscreen .fullscreen-btn { top: 50px; }

/* ═══ ADVANCED INSTRUMENTATION: Diagnostics / Faults / Oscilloscope ══ */
.hc-advanced {
  margin-top: 14px; display: flex; flex-direction: column; gap: 10px;
}
.hc-adv-card {
  background: #0f1623; border: 1px solid #1e2a44; border-radius: 8px;
  overflow: hidden;
}
.hc-adv-card > summary {
  list-style: none; cursor: pointer; padding: 10px 14px;
  font-weight: 600; color: #d0dcf0; font-size: 0.9rem;
  display: flex; align-items: center; gap: 8px;
  user-select: none;
}
.hc-adv-card > summary::-webkit-details-marker { display: none; }
.hc-adv-card > summary:hover { background: #131d30; }
.hc-adv-card[open] > summary { border-bottom: 1px solid #1e2a44; }
.hc-adv-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 50%;
  background: #1c2a44; color: #00bcd4; font-size: 0.85rem;
}
.hc-adv-sub { color: #8899bb; font-weight: 400; font-size: 0.78rem; }
.hc-adv-body { padding: 12px 14px; }

/* Diagnostics rows */
.hc-diag-empty { color: #8899bb; font-size: 0.85rem; font-style: italic; text-align: center; padding: 8px; }
.hc-diag-list { display: flex; flex-direction: column; gap: 6px; }
.hc-diag-item {
  display: flex; align-items: flex-start; gap: 8px;
  padding: 7px 10px; border-radius: 5px;
  background: rgba(255,255,255,0.02); border-left: 3px solid #00bcd4;
  font-size: 0.82rem; line-height: 1.45; color: #c0d0e8;
}
.hc-diag-item.sev-error   { border-left-color: #ff4757; background: rgba(255,71,87,0.08); }
.hc-diag-item.sev-warn    { border-left-color: #ffaa00; background: rgba(255,170,0,0.08); }
.hc-diag-item.sev-ok      { border-left-color: #3ddc84; background: rgba(61,220,132,0.06); }
.hc-diag-item.sev-info    { border-left-color: #00bcd4; background: rgba(0,188,212,0.06); }
.hc-diag-icon { flex-shrink: 0; font-size: 0.95rem; }
.hc-diag-msg strong { color: #e6ecf5; }
.hc-diag-summary-pill {
  display: inline-block; padding: 2px 8px; border-radius: 10px;
  font-size: 0.72rem; font-weight: 700; margin-left: auto;
}
.hc-diag-summary-pill.ok { background: rgba(61,220,132,0.15); color: #3ddc84; }
.hc-diag-summary-pill.warn { background: rgba(255,170,0,0.15); color: #ffaa00; }
.hc-diag-summary-pill.error { background: rgba(255,71,87,0.15); color: #ff4757; }

/* Fault injection */
.hc-fault-row {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  margin-bottom: 8px;
}
.hc-fault-row .ctrl-label { font-size: 0.82rem; color: #a0b0d0; }
#hc-fault-select {
  flex: 1; min-width: 200px; padding: 6px 10px;
  background: #0d1117; color: #c0d0e8;
  border: 1px solid #2a3a5a; border-radius: 5px; font-size: 0.85rem;
}
.hc-fault-desc {
  font-size: 0.8rem; color: #8899bb; line-height: 1.5;
  padding: 6px 10px; background: rgba(0,188,212,0.06);
  border-left: 2px solid #00bcd4; border-radius: 4px;
}
.hc-fault-desc.active { background: rgba(255,71,87,0.08); border-left-color: #ff4757; color: #ffb7bf; }

/* Oscilloscope */
.hc-scope-controls {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: center;
  margin-bottom: 10px;
}
.hc-scope-chan {
  display: flex; align-items: center; gap: 5px;
  background: rgba(255,255,255,0.02); padding: 4px 8px; border-radius: 5px;
  border: 1px solid #1e2a44;
}
.hc-scope-chan label {
  font-size: 0.78rem; color: #c0d0e8; font-weight: 600;
}
.hc-scope-chan select {
  padding: 3px 6px; background: #0d1117; color: #c0d0e8;
  border: 1px solid #2a3a5a; border-radius: 4px; font-size: 0.78rem;
  max-width: 140px;
}
.hc-scope-dot {
  display: inline-block; width: 10px; height: 10px; border-radius: 50%;
  box-shadow: 0 0 6px currentColor;
}
.hc-scope-actions { display: flex; gap: 6px; margin-left: auto; flex-wrap: wrap; }
.hc-scope-actions .btn { padding: 4px 10px; font-size: 0.78rem; }
#hc-scope-canvas {
  width: 100%; height: 220px; display: block;
  background: #060a11; border: 1px solid #1e2a44; border-radius: 6px;
}
.hc-scope-legend {
  margin-top: 6px; display: flex; flex-wrap: wrap; gap: 14px;
  font-size: 0.78rem; color: #a0b0d0;
}
.hc-scope-legend .lg-item { display: flex; align-items: center; gap: 5px; }

@media (max-width: 500px) {
  .hc-scope-controls { flex-direction: column; align-items: stretch; }
  .hc-scope-actions { margin-left: 0; }
  .hc-scope-chan select { max-width: none; flex: 1; }
}