:root {
  --bg: #f6f7f9;
  --panel: #ffffff;
  --text: #1d232b;
  --muted: #6a7480;
  --border: #e1e4e8;
  --accent: #2563eb;
  --accent-text: #ffffff;
  --and: #2563eb;
  --and-bg: #eaf1ff;
  --or: #15803d;
  --or-bg: #e8f6ec;
  --xor: #7c3aed;
  --xor-bg: #f1eaff;
  --leaf: #59626d;
  --leaf-bg: #f4f5f7;
  --not: #dc2626;
  --true: #16a34a;
  --false: #dc2626;
  --cite: #fff3bf;
  --warn: #d97706;
  --edge: #c1c8d0;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.07);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #12151a;
    --panel: #1a1f26;
    --text: #e6e9ee;
    --muted: #8d97a3;
    --border: #2c333d;
    --accent: #4f8cff;
    --and: #6ea0ff;
    --and-bg: #1c2a44;
    --or: #4ade80;
    --or-bg: #16301f;
    --xor: #b794ff;
    --xor-bg: #2a2142;
    --leaf: #a5afba;
    --leaf-bg: #222830;
    --not: #f87171;
    --cite: #4a3f12;
    --warn: #fbbf24;
    --edge: #47505c;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
    color-scheme: dark;
  }
}

/* Scale the whole UI up on big screens (graph pointer math accounts for this, see graph.js _ratio) */
@media (min-width: 1400px) { html { zoom: 1.25; } }
@media (min-width: 1800px) { html { zoom: 1.5; } }

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 14px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", sans-serif;
  display: flex;
  flex-direction: column;
}
button, input, select, textarea { font: inherit; color: inherit; }
button, select, input[type="text"], input[type="password"], input[type="search"], textarea {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 6px 11px;
}
button { cursor: pointer; }
button:hover:not(:disabled) { border-color: var(--accent); }
button:disabled { opacity: 0.5; cursor: default; }
button.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-text); font-weight: 600; }
button.icon { width: 36px; padding: 6px 0; }
button.active { border-color: var(--accent); color: var(--accent); }
.muted { color: var(--muted); }
.small { font-size: 12px; }
.spacer { flex: 1; }
code { font-size: 12px; background: var(--leaf-bg); padding: 1px 4px; border-radius: 4px; }
.check { display: inline-flex; gap: 6px; align-items: center; cursor: pointer; }

/* header */
.topbar { display: flex; gap: 16px; align-items: center; padding: 10px 16px; background: var(--panel); border-bottom: 1px solid var(--border); }
.brand { font-weight: 700; font-size: 17px; white-space: nowrap; }
.brand span { color: var(--accent); }
.url-form { display: flex; gap: 8px; flex: 1; min-width: 0; }
.url-form input { flex: 1; min-width: 0; }
.url-form select { max-width: 220px; min-width: 0; }
.options { display: flex; flex-wrap: wrap; gap: 8px 18px; align-items: center; padding: 10px 16px; background: var(--panel); border-bottom: 1px solid var(--border); }
.options label { display: flex; gap: 8px; align-items: center; color: var(--muted); }
.options label.grow { flex: 1; min-width: 240px; }
.options label.grow input { flex: 1; }

.status { padding: 8px 16px; border-bottom: 1px solid var(--border); }
.status.loading { background: var(--and-bg); }
.status.loading::before { content: "◌"; display: inline-block; margin-right: 8px; animation: spin 1s linear infinite; }
.status.error { background: #fdecec; color: #991b1b; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .status.error { background: #3b1717; color: #fecaca; } }
.status ul { margin: 4px 0 0; padding-left: 20px; }
@keyframes spin { to { transform: rotate(360deg); } }

/* layout */
.layout { flex: 1; display: grid; grid-template-columns: minmax(300px, 400px) 1fr; min-height: 0; }
.side { display: flex; flex-direction: column; min-height: 0; border-right: 1px solid var(--border); background: var(--panel); }
.tabs { display: flex; border-bottom: 1px solid var(--border); }
.tabs button { flex: 1; border: 0; border-radius: 0; background: none; padding: 9px; color: var(--muted); border-bottom: 2px solid transparent; }
.tabs button.active { color: var(--text); border-bottom-color: var(--accent); font-weight: 600; }
.tab { display: none; flex: 1; min-height: 0; overflow: auto; }
.tab.active { display: flex; flex-direction: column; }
.scope-head { padding: 12px 14px; border-bottom: 1px solid var(--border); }
.doc-title { font-weight: 600; }
.notes { padding: 8px 14px; border-bottom: 1px solid var(--border); font-size: 13px; color: var(--muted); }
.notes details { margin-top: 4px; }
.notes summary { cursor: pointer; color: var(--warn); }
.notes ul { margin: 4px 0; padding-left: 18px; }
.mark { display: inline-block; width: 10px; height: 10px; border-left: 3px solid var(--warn); }
.source { padding: 6px 14px 40px; overflow: auto; }
.source p { margin: 0; padding: 5px 8px; border-radius: 4px; cursor: pointer; border-left: 3px solid transparent; }
.source p:hover { background: var(--leaf-bg); }
.source p.uncovered { border-left-color: var(--warn); }
.source p.cited { background: var(--cite); }
.source .h-chapter { font-weight: 700; margin-top: 10px; }
.source .h-article { font-weight: 600; margin-top: 8px; }
.tab-actions { display: flex; gap: 8px; align-items: center; padding: 8px 12px; border-bottom: 1px solid var(--border); }
.xml { margin: 0; padding: 12px 14px; font: 12px/1.5 ui-monospace, "SFMono-Regular", Menlo, monospace; white-space: pre-wrap; word-break: break-word; }

/* graph */
.canvas-wrap { position: relative; min-width: 0; min-height: 0; display: flex; flex-direction: column; }
.graph-toolbar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; padding: 8px 12px; border-bottom: 1px solid var(--border); background: var(--panel); }
.graph-toolbar button { padding: 4px 11px; }
.stats { font-size: 12px; color: var(--muted); }
.seg { display: inline-flex; }
.seg button { border-radius: 0; }
.seg button:first-child { border-radius: 7px 0 0 7px; }
.seg button:last-child { border-radius: 0 7px 7px 0; border-left: 0; }
.seg button.active { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }
.root-value { font-weight: 700; font-size: 12px; padding: 3px 10px; border-radius: 6px; background: var(--leaf-bg); }
.root-value.is-true { background: var(--true); color: #fff; }
.root-value.is-false { background: var(--false); color: #fff; }

.graph {
  flex: 1; position: relative; overflow: hidden; cursor: grab;
  background-image: radial-gradient(var(--border) 1px, transparent 1px);
  background-size: 22px 22px;
}
.graph.panning { cursor: grabbing; }
.viewport { position: absolute; left: 0; top: 0; transform-origin: 0 0; }
.edges { position: absolute; left: 0; top: 0; overflow: visible; pointer-events: none; }
.edge { fill: none; stroke: var(--edge); stroke-width: 1.6; }
.edge-true { stroke: var(--true); stroke-width: 2.4; }
.edge-false { stroke: var(--false); stroke-width: 2.4; }
.nodes { position: absolute; left: 0; top: 0; }
.empty { position: absolute; inset: 0; display: flex; flex-direction: column; justify-content: center; align-items: center; text-align: center; padding: 24px; pointer-events: none; }

.node {
  position: absolute; left: 0; top: 0; width: 230px;
  background: var(--panel); border: 1px solid var(--border); border-left-width: 4px;
  border-radius: 8px; padding: 6px 10px 8px; box-shadow: var(--shadow); cursor: pointer;
}
.node:hover { box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 22%, transparent); }
.node.selected { outline: 2px solid var(--accent); outline-offset: 2px; }
.node.cites { outline: 2px dashed var(--warn); outline-offset: 2px; }
.node-head { display: flex; gap: 5px; align-items: center; margin-bottom: 2px; }
.badge { font-size: 10px; font-weight: 700; letter-spacing: 0.04em; padding: 0 5px; border-radius: 4px; }
.badge.not { background: var(--not); color: #fff; }
.node-id { display: none; }
.value { font-size: 11px; font-weight: 700; margin-left: auto; }
.node-title { font-size: 13px; line-height: 1.3; overflow-wrap: anywhere; }
.toggle {
  position: absolute; right: -11px; top: 50%; transform: translateY(-50%);
  min-width: 22px; height: 22px; padding: 0 4px; border-radius: 11px; font-size: 11px; line-height: 1; background: var(--panel);
}
.node.logic-and { border-left-color: var(--and); }
.node.logic-and .badge:first-child { background: var(--and-bg); color: var(--and); }
.node.logic-or { border-left-color: var(--or); }
.node.logic-or .badge:first-child { background: var(--or-bg); color: var(--or); }
.node.logic-xor { border-left-color: var(--xor); }
.node.logic-xor .badge:first-child { background: var(--xor-bg); color: var(--xor); }
.node.leaf { border-left-color: var(--leaf); border-radius: 14px; background: var(--leaf-bg); }
.node.leaf .node-head { display: none; }
.testing .node.leaf .node-head { display: flex; }
.node.inverted { border-style: dashed; border-color: var(--not); border-left-style: solid; }
.testing .node.leaf { cursor: cell; }
.node.is-true { background: color-mix(in srgb, var(--true) 16%, var(--panel)); }
.node.is-false { background: color-mix(in srgb, var(--false) 16%, var(--panel)); }
.node.is-true .value { color: var(--true); }
.node.is-false .value { color: var(--false); }

.details {
  position: absolute; right: 14px; bottom: 14px; width: 320px; max-height: 45%; overflow: auto;
  background: var(--panel); border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}
.details-title { font-weight: 600; padding-right: 20px; }
.details p { margin: 8px 0 0; }
.details .close { position: absolute; right: 6px; top: 6px; border: 0; background: none; font-size: 18px; padding: 0 6px; }

/* dialogs */
dialog { border: 1px solid var(--border); border-radius: 10px; background: var(--panel); color: var(--text); width: min(640px, 92vw); padding: 18px 20px; }
dialog::backdrop { background: rgba(0, 0, 0, 0.35); }
dialog h3 { margin: 0 0 6px; }
dialog input[type="search"], dialog textarea { width: 100%; margin: 8px 0; }
dialog textarea { font: 12px ui-monospace, monospace; }
.outline { max-height: 55vh; overflow: auto; border: 1px solid var(--border); border-radius: 6px; }
.ol { display: block; width: 100%; text-align: left; border: 0; border-radius: 0; border-bottom: 1px solid var(--border); background: none; padding: 6px 10px; }
.ol:hover { background: var(--and-bg); }
.ol-part { font-weight: 800; text-transform: uppercase; font-size: 12px; background: var(--leaf-bg); }
.ol-section { font-weight: 700; }
.ol-chapter { font-weight: 600; }
.ol-article { color: var(--muted); }
.dialog-actions { display: flex; gap: 8px; margin-top: 12px; }

@media (max-width: 860px) {
  .topbar { flex-direction: column; align-items: stretch; gap: 8px; }
  .url-form { flex-wrap: wrap; }
  .url-form input { flex-basis: 100%; }
  .url-form select { flex: 1 1 0; max-width: none; width: 0; }
  .options label, .options label.grow { flex: 1 1 100%; min-width: 0; }
  .options label select, .options label input[type="text"] { flex: 1; min-width: 0; }
  .layout { grid-template-columns: 1fr; grid-template-rows: 38vh 1fr; }
  .side { border-right: 0; border-bottom: 1px solid var(--border); }
  .graph { min-height: 60vh; }
  .details { width: auto; left: 14px; }
}

/* loading overlay: a small tree that draws itself while the model works */
.loader {
  position: absolute; inset: 0; z-index: 5;
  display: flex; align-items: center; justify-content: center;
  background: color-mix(in srgb, var(--bg) 72%, transparent);
  backdrop-filter: blur(3px);
}
.loader-card {
  width: min(360px, 86%); padding: 22px 24px 18px; text-align: center;
  background: var(--panel); border: 1px solid var(--border); border-radius: 12px;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.14);
}
.loader-text { font-weight: 600; font-size: 15px; margin-top: 14px; }
.loader-sub { font-size: 12px; margin-top: 6px; min-height: 1.2em; overflow-wrap: anywhere; }
.loader-bar { position: relative; height: 4px; margin-top: 12px; border-radius: 2px; overflow: hidden; background: var(--leaf-bg); }
.loader-bar span { position: absolute; top: 0; bottom: 0; width: 35%; border-radius: 2px; background: var(--accent); animation: bar 1.4s ease-in-out infinite; }
@keyframes bar { 0% { left: -35%; } 100% { left: 100%; } }

.loader-tree { position: relative; width: 210px; height: 92px; margin: 0 auto; }
.loader-tree .ln {
  position: absolute; height: 14px; border-radius: 4px; border-left: 4px solid;
  background: var(--leaf-bg); opacity: 0; animation: grow 3.2s ease-in-out infinite;
}
.loader-tree .n0 { left: 0; top: 39px; width: 46px; border-color: var(--and); animation-delay: 0s; }
.loader-tree .n1 { left: 70px; top: 10px; width: 52px; border-color: var(--or); animation-delay: 0.25s; }
.loader-tree .n2 { left: 70px; top: 39px; width: 52px; border-color: var(--and); animation-delay: 0.4s; }
.loader-tree .n3 { left: 70px; top: 68px; width: 52px; border-color: var(--not); animation-delay: 0.55s; }
.loader-tree .n4 { left: 146px; top: 0; width: 64px; border-color: var(--leaf); animation-delay: 0.8s; }
.loader-tree .n5 { left: 146px; top: 22px; width: 64px; border-color: var(--leaf); animation-delay: 0.95s; }
.loader-tree .n6 { left: 146px; top: 56px; width: 64px; border-color: var(--leaf); animation-delay: 1.1s; }
.loader-tree .n7 { left: 146px; top: 78px; width: 64px; border-color: var(--leaf); animation-delay: 1.25s; }
@keyframes grow {
  0% { opacity: 0; transform: translateX(-8px) scaleX(0.6); transform-origin: left; }
  15%, 70% { opacity: 1; transform: none; }
  90%, 100% { opacity: 0; transform: none; }
}
@media (prefers-reduced-motion: reduce) {
  .loader-tree .ln { animation: none; opacity: 1; }
  .loader-bar span { animation: pulse 1.6s ease-in-out infinite; left: 0; width: 100%; }
  @keyframes pulse { 50% { opacity: 0.35; } }
}

/* login page */
.login-body { align-items: center; justify-content: center; min-height: 100%; padding: 24px 16px; }
.login-wrap { width: 100%; max-width: 380px; }
.login-card {
  display: flex; flex-direction: column; gap: 6px;
  background: var(--panel); border: 1px solid var(--border); border-radius: 14px;
  padding: 28px 26px 26px; box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
}
.login-logo { display: flex; justify-content: center; margin-bottom: 4px; }
.login-card h1 { margin: 0; text-align: center; font-size: 22px; }
.login-card h1 span { color: var(--accent); }
.login-sub { text-align: center; margin: 2px 0 14px; font-size: 13px; }
.login-card label:not(.check) { font-size: 13px; font-weight: 600; margin-top: 8px; }
.login-card input[type="text"], .login-card input[type="password"] { width: 100%; padding: 9px 11px; }
.login-card input:focus { outline: 2px solid color-mix(in srgb, var(--accent) 40%, transparent); outline-offset: 0; border-color: var(--accent); }
.password-row { position: relative; }
.password-row input { padding-right: 64px !important; }
button.link { position: absolute; right: 4px; top: 50%; transform: translateY(-50%); border: 0; background: none; color: var(--accent); font-size: 13px; padding: 4px 8px; }
.remember { margin-top: 10px; font-size: 13px; color: var(--muted); }
.login-error { margin-top: 8px; padding: 8px 10px; border-radius: 7px; font-size: 13px; background: #fdecec; color: #991b1b; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .login-error { background: #3b1717; color: #fecaca; } }
.login-btn { margin-top: 14px; padding: 10px; font-size: 15px; }

/* signed-in user in the header */
.user-box { display: flex; gap: 8px; align-items: center; white-space: nowrap; font-size: 13px; color: var(--muted); }
.user-box button { padding: 5px 10px; }

/* examples menu with tabs */
.picker { position: relative; flex: 0 1 260px; min-width: 0; }
.picker-btn { width: 100%; display: flex; align-items: center; gap: 6px; text-align: left; }
.picker-label { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--muted); }
.picker-btn.has-value .picker-label { color: var(--text); }
.caret { color: var(--muted); font-size: 12px; }
.picker-panel {
  position: absolute; right: 0; top: calc(100% + 6px); z-index: 20; width: min(440px, 92vw);
  background: var(--panel); border: 1px solid var(--border); border-radius: 10px;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.16); padding: 8px; display: flex; flex-direction: column; gap: 8px;
}
.picker-tabs { display: flex; gap: 4px; background: var(--leaf-bg); border-radius: 8px; padding: 3px; }
.picker-tabs button { flex: 1; border: 0; background: none; border-radius: 6px; padding: 6px; color: var(--muted); font-weight: 600; }
.picker-tabs button.active { background: var(--panel); color: var(--text); box-shadow: var(--shadow); }
.picker-tabs .count { font-weight: 400; font-size: 12px; color: var(--muted); margin-left: 2px; }
.picker-search { width: 100%; }
.picker-list { list-style: none; margin: 0; padding: 0; max-height: min(420px, 60vh); overflow: auto; }
.picker-list li { position: relative; }
.picker-list .item {
  display: flex; flex-direction: column; gap: 1px; width: 100%; text-align: left;
  border: 0; border-radius: 7px; background: none; padding: 7px 34px 7px 10px;
}
.picker-list .item:hover, .picker-list .item:focus-visible { background: var(--and-bg); outline: none; }
.picker-list .item.current { background: var(--and-bg); box-shadow: inset 3px 0 0 var(--accent); }
.item-title { font-size: 13px; }
.item-sub { font-size: 11px; color: var(--muted); }
.item-remove {
  position: absolute; right: 4px; top: 50%; transform: translateY(-50%);
  border: 0; background: none; color: var(--muted); font-size: 16px; padding: 2px 8px; line-height: 1;
}
.item-remove:hover { color: var(--not); }
.picker-empty { padding: 14px 10px; font-size: 13px; text-align: center; }
@media (max-width: 860px) {
  .url-form { position: relative; }
  .picker { flex: 1 1 0; position: static; }   /* panel spans the whole URL row */
  .picker-panel { left: 0; right: 0; width: auto; }
}