:root {
  color-scheme: light;
  --bg: #eef3fb;
  --panel: #ffffff;
  --panel-soft: #f8fafc;
  --text: #172033;
  --muted: #64748b;
  --border: #d6deed;
  --primary: #5b5ce2;
  --primary-dark: #3730a3;
  --primary-soft: #eeefff;
  --success: #047857;
  --success-soft: #e9fbf3;
  --danger: #b42318;
  --danger-soft: #fff1f2;
  --warning: #b45309;
  --node-fill: #ffffff;
  --node-stroke: #7c8ba1;
  --edge: #8da0bb;
  --highlight: #f59e0b;
  --traversal: #10b981;
  --statement: #6157e8;
  --expression: #0891b2;
  --value-node: #059669;
  --statement-fill: #f0efff;
  --expression-fill: #eafcff;
  --value-fill: #ecfbf4;
  --shadow: 0 2px 4px rgba(30, 41, 59, 0.04), 0 16px 38px rgba(44, 56, 91, 0.09);
}

body.dark {
  color-scheme: dark;
  --bg: #07111f;
  --panel: #101a2d;
  --panel-soft: #0c1628;
  --text: #e5edf9;
  --muted: #9aacbf;
  --border: #293a56;
  --primary: #818cf8;
  --primary-dark: #a5b4fc;
  --primary-soft: #20284b;
  --success: #6ee7b7;
  --success-soft: #12372d;
  --danger: #fda4af;
  --danger-soft: #3a1720;
  --warning: #fbbf24;
  --node-fill: #172033;
  --node-stroke: #8192ad;
  --edge: #52627c;
  --highlight: #fbbf24;
  --traversal: #34d399;
  --statement: #818cf8;
  --expression: #22d3ee;
  --value-node: #4ade80;
  --statement-fill: #22234a;
  --expression-fill: #123341;
  --value-fill: #123628;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 7% 18%, color-mix(in srgb, var(--primary) 10%, transparent), transparent 27rem),
    radial-gradient(circle at 93% 34%, rgba(6, 182, 212, 0.09), transparent 29rem),
    radial-gradient(circle at 78% 88%, rgba(139, 92, 246, 0.06), transparent 26rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  transition: background 180ms ease, color 180ms ease;
}

button, input, select, textarea { font: inherit; }
button { cursor: pointer; }

.topbar {
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.35rem clamp(1rem, 4vw, 3.5rem);
  color: white;
  background: linear-gradient(118deg, #091a3a 0%, #25216f 34%, #5130b7 67%, #126b91 112%);
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
}
.topbar::before, .topbar::after { content: ''; position: absolute; border-radius: 50%; pointer-events: none; }
.topbar::before { width: 350px; height: 350px; right: 11%; top: -265px; border: 1px solid rgba(125, 211, 252, 0.25); box-shadow: 0 0 90px rgba(99, 102, 241, 0.2); }
.topbar::after { width: 230px; height: 230px; right: 2%; bottom: -175px; background: rgba(34, 211, 238, 0.2); filter: blur(6px); }
.topbar > * { position: relative; z-index: 1; }

.brand-block { display: flex; align-items: center; gap: 1rem; }
.brand-mark {
  flex: 0 0 auto;
  width: 62px;
  height: 62px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.42);
  border-radius: 19px;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.22), rgba(99, 102, 241, 0.24));
  box-shadow: inset 0 1px rgba(255, 255, 255, 0.28), 0 12px 28px rgba(5, 10, 40, 0.22);
  font: 800 0.92rem ui-monospace, monospace;
  letter-spacing: 0.04em;
}

.topbar h1 { margin: 0.08rem 0 0.2rem; font-size: clamp(1.75rem, 3vw, 2.55rem); letter-spacing: -0.025em; text-shadow: 0 5px 24px rgba(7, 14, 45, 0.28); }
.eyebrow { margin: 0; font-size: 0.78rem; letter-spacing: 0.16em; text-transform: uppercase; opacity: 0.82; }
.subtitle { margin: 0; max-width: 760px; opacity: 0.88; }
.project-badges { display: flex; flex-wrap: wrap; gap: 0.38rem; margin-top: 0.72rem; }
.project-badges span { padding: 0.3rem 0.56rem; border: 1px solid rgba(255, 255, 255, 0.25); border-radius: 999px; background: rgba(255, 255, 255, 0.11); color: rgba(255, 255, 255, 0.92); font-size: 0.67rem; font-weight: 700; backdrop-filter: blur(8px); }

.icon-button {
  min-width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 12px;
  color: white;
  background: rgba(255, 255, 255, 0.14);
  transition: background 150ms ease, transform 150ms ease, border-color 150ms ease;
}
.icon-button:hover { transform: translateY(-1px); border-color: rgba(255, 255, 255, 0.58); background: rgba(255, 255, 255, 0.21); }
.theme-button { display: flex; align-items: center; justify-content: center; gap: 0.45rem; padding: 0 0.85rem; }
.theme-label { font-size: 0.78rem; font-weight: 700; }
.header-actions { display: flex; align-items: center; gap: 0.6rem; }
.live-badge { display: inline-flex; align-items: center; gap: 0.42rem; padding: 0.55rem 0.72rem; border: 1px solid rgba(255, 255, 255, 0.25); border-radius: 11px; background: rgba(15, 23, 42, 0.15); color: rgba(255, 255, 255, 0.92); font-size: 0.73rem; font-weight: 700; white-space: nowrap; }
.live-badge i, .inspector-status i { width: 7px; height: 7px; border-radius: 50%; background: #4ade80; box-shadow: 0 0 0 4px rgba(74, 222, 128, 0.14); }

.pipeline {
  width: min(1600px, calc(100% - 2.5rem));
  margin: 1rem auto 0;
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 1.5rem;
  padding: 0.72rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: linear-gradient(120deg, var(--panel), color-mix(in srgb, var(--primary-soft) 42%, var(--panel)));
  box-shadow: 0 8px 24px rgba(42, 53, 88, 0.07);
  color: var(--muted);
}
.pipeline-heading { padding-right: 1.2rem; border-right: 1px solid var(--border); }
.pipeline-heading span { display: block; color: var(--text); font-size: 0.78rem; font-weight: 800; }
.pipeline-heading small { display: block; margin-top: 0.16rem; color: var(--muted); font-size: 0.66rem; }
.pipeline-track { display: flex; align-items: center; justify-content: center; gap: 0.65rem; min-width: 0; }
.pipeline-track span { display: inline-flex; align-items: center; gap: 0.42rem; white-space: nowrap; }
.pipeline-track em { color: var(--muted); font-size: 0.76rem; font-style: normal; font-weight: 600; }
.pipeline-track b { width: 25px; height: 25px; display: grid; place-items: center; border-radius: 8px; background: linear-gradient(145deg, var(--primary-soft), color-mix(in srgb, #bfdbfe 52%, var(--primary-soft))); color: var(--primary-dark); font-size: 0.68rem; box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--primary) 10%, transparent); }
.pipeline-track i { color: var(--primary); font-style: normal; opacity: 0.75; }

.app-shell {
  width: min(1600px, 100%);
  margin: 0 auto;
  padding: 1rem 1.25rem 1.25rem;
  display: grid;
  grid-template-columns: minmax(270px, 0.85fr) minmax(480px, 1.7fr) minmax(290px, 0.95fr);
  gap: 1rem;
  align-items: start;
}

.panel {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: var(--shadow);
  transition: border-color 180ms ease, box-shadow 180ms ease, transform 180ms ease;
}
.panel:hover { border-color: color-mix(in srgb, var(--primary) 34%, var(--border)); box-shadow: 0 3px 5px rgba(30, 41, 59, 0.04), 0 20px 46px rgba(58, 68, 110, 0.11); }

.editor-panel { border-top: 3px solid #0891b2; }
.workspace-panel { border-top: 3px solid #6157e8; }
.details-panel { border-top: 3px solid #059669; }
.editor-panel > .panel-label { color: #0e7490; }
.workspace-label { color: #4f46e5; }
.details-panel .panel-label { color: #047857; }
body.dark .editor-panel > .panel-label { color: #22d3ee; }
body.dark .workspace-label { color: #a5b4fc; }
body.dark .details-panel .panel-label { color: #6ee7b7; }

.editor-panel, .details-panel { padding: 1rem; }
.workspace-panel { overflow: hidden; }
.panel-label { margin-bottom: 0.65rem; color: var(--primary-dark); font-size: 0.66rem; font-weight: 850; letter-spacing: 0.13em; text-transform: uppercase; }
.workspace-label { padding: 1rem 1rem 0; margin-bottom: 0; }
.section-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 0.8rem; margin-bottom: 0.75rem; }
.section-heading h2, .tab-content h2 { margin: 0; font-size: 1.05rem; }
.title-with-icon { display: flex; align-items: center; gap: 0.48rem; }
.title-with-icon > span { width: 28px; height: 28px; display: grid; place-items: center; border-radius: 8px; background: linear-gradient(145deg, var(--primary-soft), color-mix(in srgb, #bae6fd 45%, var(--primary-soft))); color: var(--primary-dark); box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--primary) 10%, transparent); font: 800 0.72rem ui-monospace, monospace; }
.section-heading p { margin: 0.28rem 0 0; color: var(--muted); font-size: 0.84rem; line-height: 1.45; }

.sample-picker { min-width: 115px; color: var(--muted); font-size: 0.78rem; }
.sample-picker select, .traversal-bar select {
  width: 100%;
  margin-top: 0.25rem;
  padding: 0.55rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--panel-soft);
  color: var(--text);
}

.editor-frame { overflow: hidden; border: 1px solid #26344b; border-radius: 15px; background: #0f172a; box-shadow: inset 0 1px rgba(255,255,255,0.04), 0 8px 20px rgba(15,23,42,0.12); }
.editor-bar { display: flex; align-items: center; gap: 0.6rem; height: 38px; padding: 0 0.75rem; border-bottom: 1px solid #26344b; background: #111c30; color: #94a3b8; font: 0.72rem ui-monospace, monospace; }
.editor-bar kbd { margin-left: auto; padding: 0.2rem 0.42rem; border: 1px solid #34445e; border-radius: 5px; background: #0b1323; color: #cbd5e1; font: inherit; }
.window-dots { display: flex; gap: 0.3rem; }
.window-dots i { width: 8px; height: 8px; border-radius: 50%; background: #fb7185; }
.window-dots i:nth-child(2) { background: #fbbf24; }
.window-dots i:nth-child(3) { background: #34d399; }

#sourceInput {
  width: 100%;
  min-height: 410px;
  resize: vertical;
  display: block;
  border: 0;
  border-radius: 0;
  padding: 0.9rem;
  background: #0f172a;
  color: #e2e8f0;
  caret-color: white;
  font: 0.9rem/1.6 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  tab-size: 2;
}

#sourceInput:focus, select:focus, input:focus, button:focus-visible { outline: 3px solid color-mix(in srgb, var(--primary) 35%, transparent); outline-offset: 2px; }

.button-row, .export-row { display: flex; gap: 0.55rem; margin-top: 0.75rem; }
.primary-button, .secondary-button {
  border-radius: 10px;
  padding: 0.68rem 0.9rem;
  border: 1px solid transparent;
  font-weight: 750;
  transition: transform 150ms ease, border-color 150ms ease, background 150ms ease, box-shadow 150ms ease;
}
.primary-button { flex: 1; background: linear-gradient(135deg, #4f46e5, #7c3aed 58%, #0891b2 125%); color: white; box-shadow: 0 8px 18px rgba(79, 70, 229, 0.25); }
.primary-button:hover { transform: translateY(-1px); box-shadow: 0 10px 22px color-mix(in srgb, var(--primary) 29%, transparent); }
.secondary-button { background: var(--panel-soft); border-color: var(--border); color: var(--text); }
.secondary-button:hover { transform: translateY(-1px); border-color: var(--primary); }
.compact { padding: 0.54rem 0.72rem; white-space: nowrap; }
.helper-text { color: var(--muted); font-size: 0.78rem; line-height: 1.45; }
.helper-text code { color: var(--primary-dark); }

.message { margin-top: 0.7rem; border-radius: 11px; padding: 0.75rem; font-size: 0.85rem; line-height: 1.45; }
.message.error { color: var(--danger); background: var(--danger-soft); border: 1px solid color-mix(in srgb, var(--danger) 28%, transparent); }
.message.success { color: var(--success); background: var(--success-soft); border: 1px solid color-mix(in srgb, var(--success) 28%, transparent); }
.hidden { display: none !important; }

.tree-heading { padding: 0.65rem 1rem 0; }
.toolbar { display: flex; gap: 0.4rem; }
.tool-button {
  min-width: 38px;
  height: 36px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--panel-soft);
  color: var(--text);
  font-weight: 800;
}
.tool-button:hover { border-color: var(--primary); background: var(--primary-soft); color: var(--primary-dark); }
.text-tool { padding: 0 0.65rem; font-size: 0.78rem; }
.zoom-level { min-width: 44px; align-self: center; color: var(--muted); text-align: center; font: 0.72rem ui-monospace, monospace; }

.tree-stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0.55rem; padding: 0 1rem 0.8rem; }
.tree-stats > div { position: relative; overflow: hidden; display: flex; align-items: center; justify-content: space-between; gap: 0.5rem; padding: 0.58rem 0.68rem; border: 1px solid var(--border); border-radius: 11px; background: linear-gradient(145deg, var(--panel-soft), var(--panel)); }
.tree-stats > div::before { content: ''; position: absolute; inset: 0 auto 0 0; width: 3px; background: var(--primary); opacity: 0.9; }
.tree-stats > div:nth-child(2)::before { background: #8b5cf6; }
.tree-stats > div:nth-child(3)::before { background: #0891b2; }
.tree-stats > div:nth-child(4)::before { background: #059669; }
.tree-stats span { color: var(--muted); font-size: 0.7rem; }
.tree-stats strong { font-size: 0.8rem; }
.status-ready { color: var(--success); }
.status-error { color: var(--danger); }

.canvas-wrap {
  position: relative;
  height: 590px;
  overflow: hidden;
  background:
    linear-gradient(color-mix(in srgb, var(--border) 72%, transparent) 1px, transparent 1px),
    linear-gradient(90deg, color-mix(in srgb, var(--border) 72%, transparent) 1px, transparent 1px),
    radial-gradient(circle at 50% 0%, color-mix(in srgb, var(--primary) 7%, transparent), transparent 45%),
    var(--panel-soft);
  background-size: 28px 28px;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

#treeSvg { width: 100%; height: 100%; touch-action: none; user-select: none; }
#treeSvg.panning { cursor: grabbing; }

.edge { fill: none; stroke: var(--edge); stroke-width: 2; }
.node-group { cursor: pointer; }
.node-rect { fill: var(--node-fill); stroke: var(--node-stroke); stroke-width: 2; rx: 12; ry: 12; filter: drop-shadow(0 3px 4px rgba(15,23,42,0.08)); transition: stroke 160ms ease, stroke-width 160ms ease, fill 160ms ease, filter 160ms ease; }
.node-group:hover .node-rect { stroke: var(--primary); stroke-width: 3; }
.node-group.selected .node-rect { stroke: var(--highlight); stroke-width: 4; fill: color-mix(in srgb, var(--highlight) 10%, var(--node-fill)); }
.node-group.traversing .node-rect { stroke: var(--traversal); stroke-width: 5; fill: color-mix(in srgb, var(--traversal) 13%, var(--node-fill)); }
.node-group[data-kind="statement"] .node-rect { fill: var(--statement-fill); stroke: var(--statement); }
.node-group[data-kind="expression"] .node-rect { fill: var(--expression-fill); stroke: var(--expression); }
.node-group[data-kind="value"] .node-rect { fill: var(--value-fill); stroke: var(--value-node); }
.node-group.selected .node-rect { stroke: var(--highlight); }
.node-group.traversing .node-rect { stroke: var(--traversal); }
.node-title { fill: var(--text); font-size: 13px; font-weight: 700; text-anchor: middle; dominant-baseline: middle; pointer-events: none; }
.node-value { fill: var(--muted); font-size: 11px; text-anchor: middle; dominant-baseline: middle; pointer-events: none; }

.empty-state { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; color: var(--muted); pointer-events: none; }
.empty-state h3 { margin: 0.4rem 0 0.15rem; color: var(--text); }
.empty-state p { margin: 0; font-size: 0.85rem; }
.empty-icon { width: 58px; height: 58px; margin: 0 auto; display: grid; place-items: center; border: 1px solid var(--border); border-radius: 16px; background: var(--panel); font-size: 1.5rem; }
.tree-legend { position: absolute; left: 12px; bottom: 12px; display: flex; gap: 0.7rem; padding: 0.45rem 0.6rem; border: 1px solid var(--border); border-radius: 9px; background: color-mix(in srgb, var(--panel) 92%, transparent); color: var(--muted); font-size: 0.68rem; backdrop-filter: blur(8px); }
.tree-legend span { display: inline-flex; align-items: center; gap: 0.3rem; }
.legend-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--statement); }
.legend-dot.expression { background: var(--expression); }
.legend-dot.value { background: var(--value-node); }

.traversal-bar {
  display: grid;
  grid-template-columns: minmax(120px, 0.8fr) minmax(130px, 1fr) auto auto auto;
  align-items: end;
  gap: 0.65rem;
  padding: 0.8rem 1rem;
}
.traversal-bar label { color: var(--muted); font-size: 0.78rem; }
.traversal-bar input[type="range"] { width: 100%; margin-top: 0.72rem; accent-color: var(--primary); }
.traversal-output { margin: 0 1rem 1rem; min-height: 46px; padding: 0.7rem; border: 1px dashed var(--border); border-radius: 10px; color: var(--muted); font: 0.78rem/1.5 ui-monospace, monospace; overflow-wrap: anywhere; }

.inspector-heading { display: flex; align-items: center; justify-content: space-between; gap: 0.7rem; margin: -0.05rem 0 0.8rem; padding: 0.15rem 0 0.8rem; border-bottom: 1px solid var(--border); }
.inspector-heading .panel-label { margin: 0 0 0.22rem; }
.inspector-heading strong { display: block; font-size: 1rem; }
.inspector-status { display: inline-flex; align-items: center; gap: 0.38rem; padding: 0.36rem 0.52rem; border-radius: 999px; background: var(--success-soft); color: var(--success); font-size: 0.68rem; font-weight: 800; }
.inspector-status i { width: 6px; height: 6px; box-shadow: none; }

.tabs { display: grid; grid-template-columns: repeat(5, 1fr); gap: 0.2rem; padding-bottom: 0.8rem; border-bottom: 1px solid var(--border); }
.tab { border: 0; border-radius: 8px; padding: 0.55rem 0.25rem; background: transparent; color: var(--muted); font-size: 0.78rem; font-weight: 700; }
.tab.active { background: linear-gradient(145deg, var(--primary-soft), color-mix(in srgb, #dbeafe 45%, var(--primary-soft))); color: var(--primary-dark); box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--primary) 14%, transparent); }
.tab-content { display: none; padding-top: 0.9rem; }
.tab-content.active { display: block; }
.placeholder-copy { color: var(--muted); font-size: 0.86rem; line-height: 1.55; }
.tab-title-row { display: flex; align-items: center; justify-content: space-between; gap: 0.6rem; }
.badge { border-radius: 999px; padding: 0.25rem 0.55rem; background: var(--primary-soft); color: var(--primary-dark); font-size: 0.72rem; font-weight: 700; }
.link-button { border: 0; padding: 0; background: transparent; color: var(--primary); font-weight: 700; font-size: 0.78rem; }
.inline-actions { display: flex; gap: 0.7rem; }
.panel-note { margin: 0.4rem 0 0.75rem; color: var(--muted); font-size: 0.75rem; line-height: 1.4; }

.property-list { display: grid; gap: 0.48rem; margin: 0; }
.property-row { display: grid; grid-template-columns: 90px minmax(0, 1fr); gap: 0.6rem; padding: 0.55rem; border-radius: 9px; background: var(--panel-soft); }
.property-row dt { color: var(--muted); font-size: 0.75rem; }
.property-row dd { margin: 0; font: 0.78rem/1.45 ui-monospace, monospace; overflow-wrap: anywhere; }

.token-list { max-height: 500px; overflow: auto; margin-top: 0.7rem; display: grid; gap: 0.4rem; }
.token-item { display: grid; grid-template-columns: 1fr auto; gap: 0.5rem; padding: 0.52rem; border: 1px solid var(--border); border-radius: 9px; background: var(--panel-soft); }
.token-main { min-width: 0; }
.token-type { display: block; color: var(--primary-dark); font-size: 0.7rem; font-weight: 800; }
.token-value { font: 0.78rem ui-monospace, monospace; overflow-wrap: anywhere; }
.token-location { color: var(--muted); font-size: 0.68rem; white-space: nowrap; }

.symbol-table { overflow: hidden; border: 1px solid var(--border); border-radius: 10px; }
.symbol-table.placeholder-copy { padding: 0.7rem; }
.symbol-row { display: grid; grid-template-columns: 1fr 0.8fr 1.2fr; gap: 0.4rem; padding: 0.58rem 0.62rem; border-bottom: 1px solid var(--border); font-size: 0.74rem; }
.symbol-row:last-child { border-bottom: 0; }
.symbol-row.header { background: var(--panel-soft); color: var(--muted); font-weight: 700; }
.symbol-row code { color: var(--primary-dark); overflow-wrap: anywhere; }

.code-output, .grammar-block { max-height: 500px; overflow: auto; margin: 0.7rem 0 0; padding: 0.75rem; border: 1px solid var(--border); border-radius: 10px; background: #0f172a; color: #dbeafe; font: 0.75rem/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; white-space: pre-wrap; overflow-wrap: anywhere; }
.grammar-block { max-height: none; color: #d1fae5; }
.export-row .secondary-button { width: 100%; }

footer { padding: 0.15rem 1.25rem 1.5rem; text-align: center; color: var(--muted); font-size: 0.75rem; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }

@media (max-width: 1180px) {
  .app-shell { grid-template-columns: minmax(280px, 0.8fr) minmax(500px, 1.4fr); }
  .details-panel { grid-column: 1 / -1; }
  .pipeline { grid-template-columns: 1fr; gap: 0.65rem; }
  .pipeline-heading { padding: 0 0 0.55rem; border-right: 0; border-bottom: 1px solid var(--border); text-align: center; }
}

@media (max-width: 820px) {
  .app-shell { grid-template-columns: 1fr; padding: 0.75rem; }
  .details-panel { grid-column: auto; }
  #sourceInput { min-height: 300px; }
  .canvas-wrap { height: 500px; }
  .traversal-bar { grid-template-columns: 1fr 1fr; }
  .pipeline-track { overflow-x: auto; justify-content: flex-start; padding-bottom: 0.2rem; }
}

@media (max-width: 520px) {
  .topbar { padding: 1rem; }
  .brand-mark, .theme-label, .live-badge { display: none; }
  .pipeline { width: calc(100% - 1.5rem); }
  .project-badges span:last-child { display: none; }
  .section-heading { flex-direction: column; }
  .sample-picker { width: 100%; }
  .tree-heading { align-items: stretch; }
  .toolbar { width: 100%; }
  .tool-button { flex: 1; }
  .traversal-bar { grid-template-columns: 1fr; }
  .tree-stats { grid-template-columns: repeat(2, 1fr); }
  .tree-legend { flex-wrap: wrap; max-width: calc(100% - 24px); }
  .tabs { grid-template-columns: repeat(3, 1fr); }
}

/* Later compiler stages use a full-width work area so code stays readable. */
.compiler-lab { margin: 1.5rem auto; width: calc(100% - 3rem); max-width: 1880px; padding: 1.5rem; }
.compiler-lab .section-heading { flex-wrap: wrap; gap: 1rem; }
.compiler-lab h2 { margin: .4rem 0; }
.compiler-lab h3 { font-size: 1rem; margin: 1rem 0; }
.compiler-lab p, .compiler-lab td { font-size: 1rem; }
.compiler-summary { border: 1px solid var(--border); background: var(--panel-soft); padding: 1rem; border-radius: 8px; line-height: 1.6; }
.lab-tabs { display: flex; flex-wrap: wrap; gap: .5rem; padding: .5rem 0 1rem; border-bottom: 1px solid var(--border); }
.lab-tab { padding: .8rem 1rem; background: var(--panel-soft); color: var(--text); border: 1px solid var(--border); border-radius: 8px; font: inherit; font-size: .875rem; cursor: pointer; }
.lab-tab.active { background: var(--primary); color: #fff; border-color: var(--primary); }
body.dark .lab-tab.active { color: #101a2d; }
.lab-tab:focus-visible, .compiler-lab button:focus-visible { outline: 3px solid var(--highlight); outline-offset: 3px; }
.lab-panel[hidden] { display: none; }
.lab-columns { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 1.5rem; }
.lab-columns > div { min-width: 0; }
.table-scroll { overflow: auto; max-height: 32rem; }
.compiler-table { width: 100%; border-collapse: collapse; text-align: left; }
.compiler-table th, .compiler-table td { padding: .75rem; border-bottom: 1px solid var(--border); overflow-wrap: anywhere; }
.compiler-table th { font-size: .875rem; background: var(--panel-soft); position: sticky; top: 0; }
.compiler-table td { font-family: ui-monospace, monospace; }
.compiler-lab .code-output { font-size: .875rem; line-height: 1.7; max-height: 32rem; overflow: auto; }
.diagnostic { padding: 1rem; margin-bottom: .75rem; border-radius: 8px; border: 1px solid var(--border); }
.diagnostic p { margin: .5rem 0; }
.diagnostic-error { background: var(--danger-soft); border-left: 4px solid var(--danger); }
.diagnostic-info { background: var(--panel-soft); border-left: 4px solid var(--primary); }
.compiler-lab button:disabled { opacity: .55; cursor: not-allowed; }
.cfg-graph { overflow: auto; max-height: 40rem; border: 1px solid var(--border); border-radius: 8px; padding: 1rem; background: var(--panel-soft); }
.cfg-graph > svg { display: block; max-width: none; color: var(--muted); }
.cfg-block rect { fill: var(--panel); stroke: var(--primary); stroke-width: 1.5; }
.cfg-block.unreachable rect { stroke-dasharray: 6 4; stroke: var(--muted); }
.cfg-block-title { fill: var(--primary-dark); font: 600 16px system-ui, sans-serif; }
.cfg-instruction { fill: var(--text); font: 14px ui-monospace, monospace; }
.cfg-edge-label { fill: var(--muted); font: 14px system-ui, sans-serif; }
.cfg-graph summary { cursor: pointer; padding: 1rem 0; color: var(--text); }
.pipeline-track { flex-wrap: wrap; }
@media (max-width: 900px) { .lab-columns { grid-template-columns: minmax(0, 1fr); } .compiler-lab { width: calc(100% - 1.5rem); padding: 1rem; } }

.workbench-nav { display: flex; gap: .75rem; flex-wrap: wrap; margin: 1rem 1.5rem; }
.workbench-nav a { font-size: .875rem; color: var(--primary-dark); background: var(--panel); padding: .65rem 1rem; border: 1px solid var(--border); border-radius: 8px; text-decoration: none; }
.workbench-nav a:focus-visible { outline: 3px solid var(--highlight); outline-offset: 2px; }
#compilerLab, #grammarLab { scroll-margin-top: 1rem; }
.backend-controls, .trace-heading { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem; margin-top: 1rem; }
.backend-controls label { display: flex; gap: .75rem; align-items: center; font-size: .875rem; }
.grammar-editor, .grammar-token-input { display: block; width: 100%; border: 1px solid var(--border); border-radius: 8px; color: var(--text); background: var(--panel-soft); font: 1rem/1.7 ui-monospace, monospace; padding: 1rem; margin-top: .5rem; }
.grammar-editor { min-height: 220px; resize: vertical; tab-size: 2; }
.grammar-editor:focus, .grammar-token-input:focus { outline: 2px solid var(--primary); outline-offset: 2px; }
#grammarLab .compiler-table td { white-space: nowrap; }
#grammarWarnings p { font-size: .875rem; }
.trace-heading .inline-actions { flex-wrap: wrap; }