/* ── Ohm's Law & DC Circuits Simulator ──────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b27;
  --surface2:  #1f2535;
  --border:    #2a3050;
  --accent:    #ffa000;
  --accent-lo: rgba(255,160,0,.22);
  --green:     #3ddc84;
  --red:       #ff5555;
  --gold:      #f5c842;
  --blue:      #42a5f5;
  --wire-hot:  #ff7043;
  --wire-cold: #64b5f6;
  --text:      #dde3f0;
  --text-dim:  #8b9dc3;
  --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 { text-align: center; padding: 4px 0; }
header h1 {
  font-size: 1.8rem; font-weight: 700;
  background: linear-gradient(120deg, #ffa000 0%, #ffd180 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 {
  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: #1a1a2e; box-shadow: 0 0 12px var(--accent-lo); }
.pill:hover:not(.active) { background: var(--surface2); color: var(--text); }

.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: #1a1a2e; }
.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); }

.btn-guide {
  margin-left: auto;
  padding: 6px 16px; border: none; border-radius: 8px; cursor: pointer;
  font-size: 0.82rem; font-weight: 700; text-decoration: none;
  background: var(--gold); color: #1a1a2e;
  transition: filter .18s, box-shadow .18s;
}
.btn-guide:hover { filter: brightness(1.1); box-shadow: 0 0 14px rgba(245,200,66,.35); }

.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 {
  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-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: 0.7rem; font-weight: 700; 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-item {
  display: flex; align-items: center; gap: 6px; padding: 8px 8px;
  border-radius: 6px; cursor: grab; transition: background .15s;
  font-size: 0.75rem; 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; }

.prebuilt-bar {
  display: flex; flex-wrap: wrap; gap: 6px;
  padding: 8px 10px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.prebuilt-label { font-size: 0.72rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: .06em; align-self: center; margin-right: 6px; }
.prebuilt-pill {
  padding: 6px 12px; border-radius: 16px; background: var(--bg); border: 1px solid var(--border);
  color: var(--text-dim); font-size: 0.78rem; cursor: pointer; transition: all .15s;
}
.prebuilt-pill:hover { border-color: var(--accent); color: var(--accent); background: var(--surface2); }

.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-scroll-wrap { width: 100%; overflow: hidden; position: relative; flex: 1; }
@media (max-width: 768px) {
  .canvas-scroll-wrap { overflow-x: auto; overflow-y: hidden; -webkit-overflow-scrolling: touch; }
  .canvas-scroll-wrap .canvas-card { min-width: 600px; overflow-x: visible; }
  .canvas-scroll-wrap::-webkit-scrollbar { height: 6px; }
  .canvas-scroll-wrap::-webkit-scrollbar-track { background: var(--surface); border-radius: 3px; }
  .canvas-scroll-wrap::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 3px; }
  .canvas-scroll-wrap { scrollbar-width: thin; scrollbar-color: var(--accent) var(--surface); }
}
@media (max-width: 500px) { .canvas-scroll-wrap .canvas-card { min-width: 520px; } }

.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 { flex: 1; font-size: 0.72rem; color: var(--text-dim); text-align: right; }

.properties-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px;
}
.props-title {
  font-size: 0.75rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--text-dim); margin-bottom: 10px; border-bottom: 1px solid var(--border); padding-bottom: 6px;
}
.props-body label {
  display: flex; flex-direction: column; gap: 3px; margin-bottom: 8px;
  font-size: 0.78rem; color: var(--text-dim);
}
.props-body input[type="range"] { width: 100%; accent-color: var(--accent); }
.props-body input[type="number"], .props-body select {
  padding: 5px 8px; border-radius: 6px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); font-size: 0.82rem;
}
.props-body .prop-val { font-weight: 600; color: var(--text); font-size: 0.85rem; }

.readout-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 10px; }
.readout-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 10px 14px; text-align: center;
}
.readout-label { font-size: 0.68rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: .05em; margin-bottom: 4px; }
.readout-val { font-size: 1.25rem; font-weight: 700; color: var(--accent); }
.readout-unit { font-size: 0.75rem; color: var(--text-dim); margin-left: 2px; }

.warning-bar {
  padding: 8px 14px; border-radius: 8px; font-size: 0.82rem; font-weight: 600;
  background: rgba(255,85,85,.12); color: var(--red); border: 1px solid rgba(255,85,85,.3);
}
.circuit-desc {
  padding: 10px 16px; border-radius: 8px; font-size: 0.82rem;
  background: var(--surface); border: 1px solid var(--border); color: var(--text-dim); line-height: 1.5;
}

.item-selector {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px;
}
.is-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 8px; margin-top: 8px; }
.is-card {
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px; cursor: pointer; transition: border-color .15s, background .15s;
}
.is-card:hover { border-color: var(--accent); background: var(--surface2); }
.is-card.active { border-color: var(--accent); background: var(--accent-lo); }
.is-card-name { font-size: 0.82rem; font-weight: 600; color: var(--text); }
.is-card-symbol { font-size: 0.7rem; color: var(--text-dim); margin-top: 2px; }

.item-info {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px; line-height: 1.6;
}
.item-info h3 { font-size: 1.1rem; color: var(--accent); margin-bottom: 8px; }
.item-info h4 { font-size: 0.9rem; color: var(--blue); margin: 12px 0 4px; }
.item-info p { font-size: 0.85rem; color: var(--text-dim); margin-bottom: 8px; }
.item-info ul, .item-info ol { font-size: 0.83rem; color: var(--text-dim); padding-left: 20px; margin-bottom: 8px; }
.item-info li { margin-bottom: 3px; }
.item-info .formula-box {
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 14px; font-family: var(--mono); font-size: 0.85rem; color: var(--gold); margin: 8px 0;
}
.item-info .example-box {
  background: rgba(255,160,0,.06); border: 1px solid rgba(255,160,0,.2); border-radius: 8px;
  padding: 10px 14px; margin-top: 10px;
}
.item-info .example-box .step { font-size: 0.82rem; color: var(--text-dim); font-family: var(--mono); }

.practice-panel, .question-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px 20px;
}
.pp-prompt, .q-prompt { font-size: 0.95rem; line-height: 1.5; margin-bottom: 14px; }
.pp-input-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.pp-input, .q-num-input input {
  width: 120px; padding: 8px 12px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); font-size: 1rem;
}
.pp-unit { font-size: 0.85rem; color: var(--text-dim); }
.pp-bottom { margin-top: 12px; }
.feedback { font-weight: 600; font-size: 0.9rem; }
.feedback.correct { color: var(--green); }
.feedback.wrong { color: var(--red); }
.solution-panel {
  margin-top: 12px; padding: 12px 14px; border-radius: 8px;
  background: var(--bg); border: 1px solid var(--border);
  font-size: 0.85rem; line-height: 1.6; color: var(--text-dim);
}
.practice-bar, .quiz-bar {
  display: flex; align-items: center; gap: 14px;
  padding: 10px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.pbar-score { font-size: 0.85rem; color: var(--accent); font-weight: 600; }

.q-options { display: flex; flex-direction: column; gap: 8px; }
.q-opt {
  padding: 10px 14px; border-radius: 8px; cursor: pointer;
  background: var(--bg); border: 1px solid var(--border);
  font-size: 0.88rem; transition: border-color .15s, background .15s;
}
.q-opt:hover { border-color: var(--accent); background: var(--surface2); }
.q-opt.selected { border-color: var(--accent); background: var(--accent-lo); }
.q-opt.correct { border-color: var(--green); background: rgba(61,220,132,.12); color: var(--green); }
.q-opt.wrong { border-color: var(--red); background: rgba(255,85,85,.12); color: var(--red); }
.q-num-input { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.qbar-counter { display: flex; align-items: baseline; gap: 4px; }
.qbar-q-label { font-size: 0.7rem; color: var(--text-dim); text-transform: uppercase; }
.qbar-q-num { font-size: 1.2rem; 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; text-align: center;
}
.quiz-result h3 { font-size: 1.3rem; color: var(--accent); margin-bottom: 8px; }
.quiz-result .score { font-size: 2rem; font-weight: 700; color: var(--gold); }

.guide-overlay {
  position: fixed; inset: 0; z-index: 1000;
  background: rgba(0,0,0,.65); display: flex; align-items: center; justify-content: center;
}
.guide-modal {
  background: var(--surface); border: 1px solid var(--border); border-radius: 16px;
  max-width: 780px; width: 92%; max-height: 85vh;
  display: flex; flex-direction: column; box-shadow: 0 12px 48px rgba(0,0,0,.6);
}
.guide-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 24px; border-bottom: 1px solid var(--border);
}
.guide-header h2 { font-size: 1.15rem; color: var(--accent); }
.guide-close {
  background: none; border: none; color: var(--text-dim); font-size: 1.6rem;
  cursor: pointer; padding: 4px 8px; border-radius: 6px; transition: color .15s, background .15s;
}
.guide-close:hover { color: var(--red); background: rgba(255,85,85,.12); }
.guide-body { overflow-y: auto; padding: 20px 24px; flex: 1; }
.guide-body h3 { color: var(--accent); font-size: 1rem; margin: 18px 0 8px; padding-bottom: 4px; border-bottom: 1px solid var(--border); }
.guide-body h3:first-child { margin-top: 0; }
.guide-body h4 { color: var(--blue); font-size: 0.88rem; margin: 12px 0 4px; }
.guide-body p { font-size: 0.84rem; color: var(--text-dim); line-height: 1.6; margin-bottom: 8px; }
.guide-body ul, .guide-body ol { font-size: 0.83rem; color: var(--text-dim); padding-left: 20px; margin-bottom: 8px; line-height: 1.5; }
.guide-body li { margin-bottom: 3px; }
.guide-body kbd {
  display: inline-block; padding: 1px 6px; border-radius: 4px;
  background: var(--bg); 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: 8px 0 12px; font-size: 0.82rem; }
.guide-body th { text-align: left; padding: 6px 10px; border-bottom: 2px solid var(--border); color: var(--text); font-weight: 600; }
.guide-body td { padding: 5px 10px; border-bottom: 1px solid var(--border); color: var(--text-dim); }
.guide-body strong { color: var(--text); }

.ctx-item:hover { background: var(--surface2); }

.seo-article {
  padding: 28px 24px; line-height: 1.75;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.seo-article h2 { font-size: 1.3rem; color: var(--text); margin-bottom: 12px; }
.seo-article h3 { font-size: 1.05rem; color: var(--accent); margin: 18px 0 6px; }
.seo-article p { font-size: 0.92rem; color: var(--text-dim); margin-bottom: 10px; }
.seo-article a { color: var(--accent); text-decoration: underline; }
.seo-article a:hover { color: #ffcc80; }

.pill:focus-visible, .btn:focus-visible, .btn-guide:focus-visible,
.palette-item:focus-visible, .pp-input:focus-visible, .q-opt:focus-visible,
.q-num-input input:focus-visible, .props-body select:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 2px;
}

.hint-banner {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 16px;
  background: rgba(245,200,66,.08); border: 1px solid rgba(245,200,66,.25); border-radius: var(--radius);
  font-size: 0.84rem; color: var(--gold); line-height: 1.5;
}
.hint-banner .hint-icon { font-size: 1.1rem; flex-shrink: 0; }
.hint-banner .hint-dismiss {
  margin-left: auto; background: none; border: none; color: var(--text-dim);
  font-size: 1.2rem; cursor: pointer; padding: 2px 6px; border-radius: 4px;
  transition: color .15s;
}
.hint-banner .hint-dismiss:hover { color: var(--red); }

.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(255,160,0,0.15); border-color: var(--accent); color: var(--accent); }

.ctx-canvas-menu {
  display: none; position: fixed; z-index: 999;
  background: #151c2c; border: 1px solid #2a3a5a; border-radius: 6px;
  padding: 4px 0; min-width: 160px; box-shadow: 0 6px 20px rgba(0,0,0,.5);
  font-size: 0.82rem;
}
.ctx-canvas-menu .ctx-item { padding: 7px 14px; color: #c0d0e8; cursor: pointer; }
.ctx-canvas-menu .ctx-item:hover { background: var(--surface2); }
.ctx-canvas-menu .ctx-sep { height: 1px; background: #2a3a5a; margin: 3px 0; }

.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;
  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: #1a1a2e; 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: #1a1a2e; border-color: var(--accent);
}

.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;
}
.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-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; }
.sketch-colors { display: flex; gap: 6px; margin-bottom: 8px; }
.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); }
.sketch-widths { display: flex; gap: 6px; }
.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:hover { background: var(--surface2); color: var(--text); }
.width-btn.active { background: var(--accent); color: #1a1a2e; border-color: var(--accent); }
.wline { display: block; border-radius: 2px; background: currentColor; }
.wline-thin  { width: 20px; height: 2px; }
.wline-med   { width: 20px; height: 4px; }
.wline-thick { width: 20px; height: 7px; }
.shape-picker { display: grid; grid-template-columns: repeat(4, 1fr); gap: 4px; margin-bottom: 8px; }
.shape-pick {
  padding: 6px 0; border: 1px solid var(--border); border-radius: 6px;
  background: transparent; color: var(--text-dim); cursor: pointer;
  font-size: 1rem; text-align: center; transition: all .15s; min-height: 34px;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.shape-pick:hover { background: var(--surface2); color: var(--text); }
.shape-pick.active { background: var(--accent); color: #1a1a2e; border-color: var(--accent); }
.shape-fill-row { display: flex; gap: 6px; }
.fill-btn {
  flex: 1; padding: 6px 0; border: 1px solid var(--border); border-radius: 6px;
  background: transparent; color: var(--text-dim); cursor: pointer;
  font-size: 0.78rem; transition: all .15s; text-align: center;
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.fill-btn:hover { background: var(--surface2); color: var(--text); }
.fill-btn.active { background: var(--accent); color: #1a1a2e; border-color: var(--accent); }

.shape-text-input {
  position: absolute; z-index: 50; padding: 4px 8px;
  background: rgba(13,17,23,.9); border: 1px solid var(--accent);
  border-radius: 6px; color: #fff; font-size: 13px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  outline: none; min-width: 80px; max-width: 220px;
}

/* Fault warning banner — shown when checkFaults() finds short-circuit / wiring issues */
.fault-banner {
  position: absolute; top: 56px; left: 50%; transform: translateX(-50%);
  z-index: 80; max-width: min(560px, 90%);
  background: linear-gradient(180deg, rgba(120,20,20,.95), rgba(80,10,10,.95));
  border: 1px solid #ff5555; border-radius: 8px;
  padding: 10px 36px 10px 14px; color: #ffe4e4;
  font-size: 0.84rem; line-height: 1.4;
  box-shadow: 0 4px 18px rgba(255,40,40,.35);
  animation: faultPulse 0.9s ease-in-out infinite;
}
@keyframes faultPulse {
  0%,100% { box-shadow: 0 4px 18px rgba(255,40,40,.35); border-color: #ff5555; }
  50%     { box-shadow: 0 4px 28px rgba(255,40,40,.7);  border-color: #ff8888; }
}
.fault-banner .fb-text > div { margin: 2px 0; }
.fault-banner .fb-close {
  position: absolute; top: 4px; right: 6px;
  background: none; border: none; color: #ffd0d0;
  font-size: 20px; line-height: 1; cursor: pointer; padding: 2px 6px;
}
.fault-banner .fb-close:hover { color: #fff; }

/* Component popover (in-canvas quick value editor) */
.comp-popover {
  position: absolute; z-index: 60;
  background: rgba(13,17,23,.97);
  border: 1px solid var(--accent);
  border-radius: 8px; padding: 10px 12px;
  min-width: 220px; max-width: 280px;
  color: var(--text); font-size: 0.82rem;
  box-shadow: 0 6px 20px rgba(0,0,0,.55);
  user-select: none;
}
.comp-popover .cp-head {
  display: flex; justify-content: space-between; align-items: center;
  font-weight: 600; margin-bottom: 8px; color: var(--accent); font-size: 0.85rem;
}
.comp-popover .cp-close {
  background: none; border: none; color: var(--text-dim);
  font-size: 18px; cursor: pointer; line-height: 1; padding: 0 4px;
}
.comp-popover .cp-close:hover { color: #fff; }
.comp-popover .cp-label {
  display: block; margin-bottom: 8px; color: var(--text-dim); font-size: 0.78rem;
}
.comp-popover .cp-row {
  display: flex; gap: 6px; margin: 4px 0;
}
.comp-popover .cp-row input[type="number"] {
  flex: 1; min-width: 0; padding: 4px 6px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 4px; color: #fff; font-size: 0.9rem; font-family: inherit;
}
.comp-popover .cp-row input[type="number"]:focus { outline: 1px solid var(--accent); border-color: var(--accent); }
.comp-popover .cp-row select {
  padding: 4px 6px; background: var(--surface2); border: 1px solid var(--border);
  border-radius: 4px; color: #fff; font-size: 0.85rem;
}
.comp-popover input[type="number"]:not(.cp-row input) {
  width: 100%; padding: 4px 6px; margin-top: 4px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 4px; color: #fff; font-size: 0.9rem;
}
.comp-popover input[type="range"] { width: 100%; margin-top: 6px; }
.comp-popover .cp-actions {
  display: flex; gap: 6px; margin-top: 8px;
  padding-top: 8px; border-top: 1px solid var(--border);
}
.comp-popover .cp-actions .btn { flex: 1; padding: 4px 6px; font-size: 0.78rem; }

.confirm-overlay {
  position: absolute; inset: 0; z-index: 200;
  background: rgba(0,0,0,.55); backdrop-filter: blur(3px);
  display: flex; align-items: center; justify-content: center;
}
.confirm-dialog {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; padding: 20px 24px; max-width: 320px; width: 90%;
  text-align: center; box-shadow: 0 8px 32px rgba(0,0,0,.4);
}
.confirm-icon { font-size: 2rem; margin-bottom: 8px; }
.confirm-title { font-size: 1rem; font-weight: 700; color: var(--text); margin-bottom: 6px; }
.confirm-msg { font-size: 0.8rem; color: var(--text-dim); line-height: 1.45; margin-bottom: 10px; }
.clear-select {
  width: 100%; padding: 10px 12px; margin: 8px 0 6px;
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  color: var(--text); font-size: 0.85rem; font-family: var(--font);
  cursor: pointer; appearance: auto; outline: none;
}
.clear-select:focus { border-color: var(--accent); }
.clear-hint { font-size: 0.7rem; color: var(--text-dim); text-align: center; margin-bottom: 12px; line-height: 1.4; min-height: 2em; }
.confirm-actions { display: flex; gap: 10px; justify-content: center; }
.confirm-actions .btn { flex: 1; padding: 8px 0; font-size: 0.82rem; border-radius: 8px; cursor: pointer; }
.btn-danger { background: #d32f2f; color: #fff; border: none; font-weight: 600; }
.btn-danger:hover { background: #b71c1c; }

.fullscreen-btn {
  position: absolute; top: 50px; right: 10px; z-index: 6;
  width: 38px; height: 38px; border-radius: 8px;
  background: rgba(22,27,39,0.85); border: 1.5px solid #f1fa8c;
  color: #f1fa8c; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all .18s; backdrop-filter: blur(4px);
  box-shadow: 0 0 10px rgba(241,250,140,.35);
  touch-action: manipulation; -webkit-tap-highlight-color: transparent;
}
.fullscreen-btn:hover { background: #f1fa8c; color: #1a1a2e; box-shadow: 0 0 14px rgba(241,250,140,.65); }
.fullscreen-btn .fs-icon { display: block; }
.fullscreen-btn .fs-exit { display: none; }
/* When fullscreen is active, show the X (close) icon and switch to a red accent */
#sim-panel.is-fullscreen .fullscreen-btn { border-color: #ff5555; color: #ff5555; box-shadow: 0 0 12px rgba(255,85,85,.5); }
#sim-panel.is-fullscreen .fullscreen-btn:hover { background: #ff5555; color: #fff; box-shadow: 0 0 16px rgba(255,85,85,.75); }
#sim-panel.is-fullscreen .fullscreen-btn .fs-enter { display: none; }
#sim-panel.is-fullscreen .fullscreen-btn .fs-exit { display: block; }

.graph-toolbar {
  position: absolute; bottom: 10px; left: 10px;
  display: flex; flex-direction: column; gap: 4px; z-index: 5;
}
.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;
  -webkit-user-select: none; user-select: none;
  backdrop-filter: blur(4px);
}
.tb-btn:hover { color: var(--accent); border-color: var(--accent); background: var(--surface2); }
.tb-btn:active { transform: scale(0.93); }
.tb-btn.active { color: #f1fa8c; border-color: #f1fa8c; background: rgba(241,250,140,.15); }

#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; }
#sim-panel.is-fullscreen .canvas-scroll-wrap { flex: 1; min-height: 0; }
#sim-panel.is-fullscreen .canvas-card { height: 100%; }
#sim-panel.is-fullscreen .canvas-card canvas { min-height: 0; height: 100%; }
#sim-panel.is-fullscreen .readout-row { flex-shrink: 0; }
#sim-panel.is-fullscreen .fullscreen-btn { top: 50px; }

.snippet-table-wrap { overflow-x: auto; margin: 1em 0; }
.snippet-table { width: 100%; border-collapse: collapse; font-size: 0.88rem; }
.snippet-table th {
  text-align: left; padding: 10px 12px;
  background: var(--surface2); color: var(--accent);
  font-weight: 700; font-size: 0.75rem; text-transform: uppercase; letter-spacing: .04em;
  border-bottom: 2px solid var(--accent);
}
.snippet-table td { padding: 8px 12px; border-bottom: 1px solid var(--border); color: var(--text-dim); }
.snippet-table tbody tr:hover { background: var(--surface2); }
.snippet-table strong { color: var(--text); }

@media (max-width: 768px) {
  .builder-layout { flex-direction: column; }
  .component-palette { width: 100%; max-height: 180px; flex-direction: row; flex-wrap: wrap; gap: 4px; overflow-x: auto; }
  .palette-cat-items { flex-direction: row; flex-wrap: wrap; }
  .readout-row { grid-template-columns: repeat(3, 1fr); }
  .guide-modal { width: 95%; max-height: 90vh; }
  .guide-header { padding: 14px 18px; }
  .guide-body { padding: 14px 18px; }
}
@media (max-width: 500px) {
  header h1 { font-size: 1.3rem; }
  .controls-bar { padding: 8px 10px; gap: 8px; }
  .pill { padding: 6px 12px; font-size: 0.75rem; min-height: 44px; }
  .component-palette { max-height: 140px; }
  .readout-row { grid-template-columns: repeat(2, 1fr); }
  .guide-modal { width: 100%; max-height: 100vh; border-radius: 0; }
  .guide-header h2 { font-size: 0.95rem; }
  .guide-body { padding: 12px 14px; }
}