/* BabPls – layout and theme. Colours are tokens so light/dark switch in one place. */
:root {
  --bg: #f6f7fb; --bg2: #eef0f6; --panel: #ffffff; --ink: #1c2333; --muted: #6b7280; --line: #d5d9e3; --grid: #eceff5;
  --accent: #1d4ed8; --accent-ink: #fff; --sel: #f59e0b;
  --c1: #2563eb; --c2: #db2777; --c3: #059669; --c4: #d97706; --c5: #7c3aed; --c6: #0891b2;
  --neg: #dc2626; --warn: #b45309; --good: #047857; --bad: #b91c1c;
  --good-bg: #d1fae5; --bad-bg: #fee2e2; --warn-bg: #fef3c7;
  --lv: #dbeafe; --lv-ink: #1e3a8a; --ind: #fef9c3; --edge: #475569;
  --radius: 8px; --shadow: 0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.05);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f141d; --bg2: #18202c; --panel: #151c27; --ink: #e5e9f0; --muted: #94a0b4; --line: #2c3646; --grid: #1f2836;
    --accent: #3b82f6; --c1: #60a5fa; --c2: #f472b6; --c3: #34d399; --c4: #fbbf24; --c5: #a78bfa; --c6: #22d3ee;
    --neg: #f87171; --warn: #fbbf24; --good: #34d399; --bad: #f87171;
    --good-bg: #064e3b; --bad-bg: #7f1d1d; --warn-bg: #78350f;
    --lv: #1e3a8a; --lv-ink: #dbeafe; --ind: #3f3a16; --edge: #94a3b8; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f141d; --bg2: #18202c; --panel: #151c27; --ink: #e5e9f0; --muted: #94a0b4; --line: #2c3646; --grid: #1f2836;
  --accent: #3b82f6; --c1: #60a5fa; --c2: #f472b6; --c3: #34d399; --c4: #fbbf24; --c5: #a78bfa; --c6: #22d3ee;
  --neg: #f87171; --warn: #fbbf24; --good: #34d399; --bad: #f87171;
  --good-bg: #064e3b; --bad-bg: #7f1d1d; --warn-bg: #78350f;
  --lv: #1e3a8a; --lv-ink: #dbeafe; --ind: #3f3a16; --edge: #94a3b8; color-scheme: dark;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { height: 100%; margin: 0; }
body { background: var(--bg); color: var(--ink); font: 14px/1.5 system-ui, -apple-system, "Segoe UI", Tahoma, "Noto Sans Arabic", sans-serif; display: flex; flex-direction: column; overflow: hidden; }
button { font: inherit; color: var(--ink); background: var(--panel); border: 1px solid var(--line); border-radius: 6px; padding: 5px 11px; cursor: pointer; white-space: nowrap; }
button:hover:not(:disabled) { border-color: var(--accent); }
button:disabled { opacity: .5; cursor: default; }
button.on { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); }
button.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); font-weight: 600; }
button.danger { color: var(--bad); }
button.icon { padding: 5px 9px; min-width: 32px; }
button.mini { padding: 1px 7px; font-size: 12px; }
button:focus-visible, input:focus-visible, select:focus-visible, li:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
input, select { font: inherit; color: var(--ink); background: var(--panel); border: 1px solid var(--line); border-radius: 6px; padding: 5px 8px; }
h1, h2, h3, h4 { margin: 0 0 .5em; line-height: 1.25; }
h3 { font-size: 15px; } h4 { font-size: 13px; color: var(--muted); margin-top: 1em; }
.note { color: var(--muted); font-size: 12.5px; margin: .3em 0 .8em; }
.ok { color: var(--good); } .warn { color: var(--warn); }
.grow { flex: 1; }
.pill { background: var(--bg2); border-radius: 99px; padding: 2px 10px; font-size: 12.5px; }

/* header & tabs */
.top { display: flex; align-items: center; gap: 10px; padding: 8px 14px; background: var(--panel); border-bottom: 1px solid var(--line); flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 8px; font-size: 17px; }
.pname { width: 200px; font-weight: 600; }
.tbar { display: flex; gap: 6px; flex-wrap: wrap; }
.tabs { display: flex; align-items: center; gap: 4px; padding: 6px 14px 0; background: var(--panel); border-bottom: 1px solid var(--line); }
.tabs > button[data-view] { border: none; border-bottom: 3px solid transparent; border-radius: 0; background: none; padding: 8px 16px; color: var(--muted); font-weight: 600; }
.tabs > button[data-view].on { color: var(--accent); border-bottom-color: var(--accent); background: none; }
.calc { position: relative; padding-bottom: 6px; }
.menu { position: absolute; inset-inline-end: 0; top: 100%; z-index: 20; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); display: flex; flex-direction: column; min-width: 250px; padding: 6px; }
.menu button { border: none; text-align: start; padding: 8px 10px; }
.menu button:hover { background: var(--bg2); }
.menu hr { border: none; border-top: 1px solid var(--line); margin: 4px 0; }

main { flex: 1; min-height: 0; display: flex; }
.view { flex: 1; min-width: 0; min-height: 0; }
.view[hidden] { display: none !important; }
.scroll { overflow: auto; padding: 16px; }

/* data */
.datahead { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; }
.datahead h2 { margin: 0 8px 0 0; font-size: 18px; }
.welcome { max-width: 640px; margin: 6vh auto; text-align: center; }
.welcome h1 { font-size: 34px; margin: 8px 0 4px; }
.welcome .actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin: 20px 0; }
.welcome .actions button { padding: 10px 18px; font-size: 15px; }
.steps { text-align: start; display: inline-block; color: var(--muted); }

/* cards & tables */
.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; margin-bottom: 14px; box-shadow: var(--shadow); }
.card > header { display: flex; align-items: center; gap: 8px; margin-bottom: 4px; }
.card > header h3 { margin: 0; flex: 1; }
.cardtools { display: flex; gap: 4px; }
.tablewrap { overflow: auto; max-height: 560px; border: 1px solid var(--line); border-radius: 6px; margin: 8px 0; }
table.grid { border-collapse: collapse; width: max-content; min-width: 100%; font-size: 13px; font-variant-numeric: tabular-nums; }
.grid th, .grid td { padding: 5px 10px; border-bottom: 1px solid var(--grid); text-align: start; white-space: nowrap; }
.grid thead th { position: sticky; top: 0; background: var(--bg2); font-weight: 600; z-index: 1; }
.grid tbody th { font-weight: 500; position: sticky; inset-inline-start: 0; background: var(--panel); }
.grid td.num { text-align: end; direction: ltr; unicode-bidi: isolate; }
[dir="rtl"] .grid td.num { text-align: left; }
.grid td.good { background: var(--good-bg); } .grid td.bad { background: var(--bad-bg); } .grid td.warn { background: var(--warn-bg); }
.grid td.diag { font-weight: 700; } .grid td.blank { color: transparent; }
.grid.clickable tbody tr { cursor: pointer; }
.grid.clickable tbody tr:hover td, .grid tr.picked td { background: var(--bg2); }
.chartbox { margin: 10px 0; overflow-x: auto; }
.chartbox svg { max-width: 100%; height: auto; direction: ltr; }
.chartbox figcaption { display: flex; gap: 4px; justify-content: flex-end; }
.chartgrid { display: flex; flex-wrap: wrap; gap: 12px; align-items: flex-start; }
.chartgrid > * { flex: 1 1 440px; min-width: 0; }

/* model editor */
#modelview { display: flex; }
.side { width: 240px; flex: none; background: var(--panel); border-inline-end: 1px solid var(--line); padding: 12px; overflow: auto; }
.side.props { border-inline-end: none; border-inline-start: 1px solid var(--line); width: 270px; }
.side label { display: block; margin: 8px 0; font-size: 13px; color: var(--muted); }
.side label input, .side label select { display: block; width: 100%; margin-top: 3px; color: var(--ink); }
.side button { margin: 4px 4px 0 0; white-space: normal; text-align: start; }
#indsearch { width: 100%; }
.indlist { list-style: none; margin: 0; padding: 0; }
.indlist li { padding: 4px 8px; border-radius: 5px; cursor: grab; display: flex; justify-content: space-between; gap: 6px; user-select: none; border: 1px solid transparent; }
.indlist li:hover { background: var(--bg2); }
.indlist li.sel { background: var(--lv); color: var(--lv-ink); border-color: var(--accent); }
.indlist li.used span { opacity: .65; }
.indlist li small { color: var(--muted); font-size: 11px; overflow: hidden; text-overflow: ellipsis; }
.chips { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 4px; }
.chips li { background: var(--ind); border: 1px solid var(--line); border-radius: 99px; padding: 1px 4px 1px 10px; font-size: 12.5px; display: flex; align-items: center; gap: 2px; }
.chips .x { border: none; background: none; padding: 0 5px; margin: 0; line-height: 1; }
.errs { color: var(--bad); padding-inline-start: 18px; font-size: 13px; }
.stage { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.etools { display: flex; gap: 5px; padding: 8px; flex-wrap: wrap; align-items: center; border-bottom: 1px solid var(--line); background: var(--panel); }
.etools .sep { width: 1px; height: 22px; background: var(--line); margin: 0 4px; }
#canvas { flex: 1; width: 100%; min-height: 300px; background: var(--bg); background-image: radial-gradient(var(--grid) 1px, transparent 1px); background-size: 22px 22px; touch-action: none; user-select: none; direction: ltr; }
#canvas[data-tool="construct"] { cursor: crosshair; } #canvas[data-tool="path"] { cursor: alias; }
#canvas text { font-size: 12px; fill: var(--ink); pointer-events: none; }
#canvas .lv > ellipse, #canvas .lv > rect { fill: var(--lv); stroke: var(--accent); stroke-width: 1.6; cursor: move; }
#canvas .lv.empty > * { stroke-dasharray: 5 4; }
#canvas .lv text { fill: var(--lv-ink); }
#canvas .lv .lvname { font-weight: 600; font-size: 12.5px; }
#canvas .lv .r2 { font-size: 11px; }
#canvas .lv .modeb { font-size: 10px; font-weight: 700; fill: var(--c2); }
#canvas .lv.sel > ellipse, #canvas .lv.sel > rect, #canvas .inter.sel ellipse { stroke: var(--sel); stroke-width: 3; }
#canvas .lv.pend > ellipse, #canvas .lv.pend > rect { stroke: var(--c3); stroke-width: 3; stroke-dasharray: 6 3; }
#canvas .ind rect { fill: var(--ind); stroke: var(--edge); stroke-width: 1; cursor: pointer; }
#canvas .ind.sel rect { stroke: var(--sel); stroke-width: 2.5; }
#canvas .ind text { font-size: 11px; }
#canvas line.outer { stroke: var(--edge); stroke-width: 1.1; }
#canvas .path line.inner { stroke: var(--edge); stroke-width: 1.8; }
#canvas .path line.hit { stroke: transparent; stroke-width: 14; cursor: pointer; }
#canvas .path.sel line.inner { stroke: var(--accent); stroke-width: 3; }
#canvas .modline { stroke: var(--c3); stroke-width: 1.8; stroke-dasharray: 6 3; }
#canvas .inter ellipse { fill: var(--good-bg); stroke: var(--c3); stroke-width: 1.6; cursor: move; }
#canvas .plab rect { fill: var(--panel); stroke: var(--line); }
#canvas .plab text { font-size: 11px; font-weight: 600; }
#canvas .olab { font-size: 10px; fill: var(--muted); }

/* results */
#resultsview { display: flex; flex-direction: column; }
.restabs { display: flex; gap: 6px; padding: 8px 14px; background: var(--panel); border-bottom: 1px solid var(--line); flex-wrap: wrap; align-items: center; }
.resbody { flex: 1; min-height: 0; display: flex; }
.secnav { width: 230px; flex: none; overflow: auto; padding: 12px; border-inline-end: 1px solid var(--line); background: var(--panel); }
.secnav h4 { margin: 12px 0 4px; text-transform: uppercase; font-size: 11px; letter-spacing: .04em; }
.secnav button { display: block; width: 100%; text-align: start; border: none; background: none; padding: 6px 10px; border-radius: 6px; white-space: normal; }
.secnav button:hover { background: var(--bg2); }
.secnav button.on { background: var(--lv); color: var(--lv-ink); font-weight: 600; }
.secout { flex: 1; min-width: 0; overflow: auto; padding: 16px; }
.meta { color: var(--muted); font-size: 12.5px; margin: 0 0 12px; }
.empty { margin: 12vh auto; text-align: center; }
h2.rep { margin-top: 28px; }

/* busy, toasts, dialog */
.busy { position: fixed; bottom: 16px; inset-inline-start: 50%; transform: translateX(-50%); z-index: 50; background: var(--panel); border: 1px solid var(--line); box-shadow: var(--shadow); border-radius: 10px; padding: 10px 14px; display: flex; gap: 12px; align-items: center; min-width: 320px; }
[dir="rtl"] .busy { transform: translateX(50%); }
.prog { flex: 1; height: 8px; background: var(--bg2); border-radius: 99px; overflow: hidden; }
#busybar { height: 100%; width: 0; background: var(--accent); transition: width .2s; }
#toasts { position: fixed; bottom: 80px; inset-inline-end: 16px; z-index: 60; display: flex; flex-direction: column; gap: 8px; max-width: min(420px, calc(100vw - 32px)); }
.toast { background: var(--panel); border: 1px solid var(--line); border-inline-start: 4px solid var(--accent); box-shadow: var(--shadow); padding: 9px 14px; border-radius: 6px; transition: opacity .4s; }
.toast.good { border-inline-start-color: var(--good); } .toast.bad { border-inline-start-color: var(--bad); }
.toast.out { opacity: 0; }
dialog { border: 1px solid var(--line); border-radius: 12px; background: var(--panel); color: var(--ink); padding: 20px 22px; width: min(480px, calc(100vw - 32px)); box-shadow: var(--shadow); }
dialog::backdrop { background: rgba(0,0,0,.35); }
.fields label { display: block; margin: 10px 0; color: var(--muted); font-size: 13px; }
.fields label input:not([type=checkbox]), .fields label select { display: block; width: 100%; margin-top: 3px; }
.fields label.check { color: var(--ink); }
.fields small { color: var(--muted); }
dialog menu { display: flex; justify-content: flex-end; gap: 8px; padding: 0; margin: 18px 0 0; }

/* small screens */
@media (max-width: 900px) {
  body { overflow: auto; height: auto; }
  main { display: block; }
  #modelview { flex-direction: column; }
  .side, .side.props { width: auto; border: none; border-bottom: 1px solid var(--line); max-height: 260px; }
  #canvas { height: 60vh; }
  .resbody { flex-direction: column; }
  .secnav { width: auto; display: flex; flex-wrap: wrap; gap: 4px; border: none; border-bottom: 1px solid var(--line); }
  .secnav h4 { width: 100%; }
  .secnav button { width: auto; }
  .pname { width: 140px; }
}
@media print {
  .top, .tabs, .secnav, .restabs, .cardtools, figcaption { display: none !important; }
  body { overflow: visible; height: auto; }
}

/* appearance dialog */
dialog.wide { width: min(980px, calc(100vw - 24px)); max-height: calc(100vh - 32px); }
.presets { display: flex; flex-wrap: wrap; gap: 8px; margin: 6px 0 14px; }
.preset { display: flex; flex-direction: column; align-items: center; gap: 2px; padding: 6px 8px; font-size: 12px; background: var(--bg); }
.preset svg { display: block; direction: ltr; }
.stgrid { display: grid; grid-template-columns: repeat(auto-fit, minmax(270px, 1fr)); gap: 12px; }
.stgrid fieldset, .elstyle { border: 1px solid var(--line); border-radius: var(--radius); padding: 8px 12px 10px; margin: 0; }
.stgrid legend { font-weight: 600; padding: 0 6px; }
.stgrid label, .elstyle label { display: block; margin: 7px 0; font-size: 13px; color: var(--muted); }
.stgrid select, .elstyle select { display: block; width: 100%; margin-top: 3px; }
.stgrid input[type=range], .elstyle input[type=range] { display: block; width: 100%; accent-color: var(--accent); }
.stgrid output, .elstyle output { color: var(--ink); font-variant-numeric: tabular-nums; }
label.cf { display: flex !important; align-items: center; justify-content: space-between; gap: 8px; }
label.cf span { display: flex; gap: 4px; align-items: center; }
label.cf input[type=color] { width: 40px; height: 26px; padding: 1px 2px; cursor: pointer; }
label.check { color: var(--ink) !important; }
.swatches { display: flex; gap: 4px; margin: -2px 0 6px; }
.swatches i { width: 22px; height: 12px; border-radius: 3px; display: inline-block; }
.elstyle { margin: 12px 0 6px; }
.elstyle summary { cursor: pointer; font-weight: 600; color: var(--ink); }

/* help */
#helpview { display: flex; flex-direction: column; }
.helpout { max-width: 980px; line-height: 1.7; }
.helpout h2 { margin-top: 0; }
.guide li { margin: 4px 0; }
.guide table.grid { width: auto; min-width: 0; margin: 8px 0; }
.method p { margin: 6px 0; }
.formula { direction: ltr; text-align: left; font-family: "Cambria Math", "STIX Two Math", "Times New Roman", serif; font-size: 15px; background: var(--bg2); border-radius: 6px; padding: 8px 12px; margin: 8px 0; overflow-x: auto; }
.refs { font-size: 13px; color: var(--muted); }
.refs a, .about a { color: var(--accent); }
.biblio { direction: ltr; text-align: left; padding-left: 28px; }
.biblio li { margin: 6px 0; padding-left: 26px; text-indent: -26px; list-style-position: outside; }
.about { text-align: center; max-width: 720px; margin: 0 auto; }
.about p { text-align: start; }
.about code { display: block; direction: ltr; text-align: left; white-space: normal; background: var(--bg2); padding: 8px 10px; border-radius: 6px; margin-top: 4px; }
kbd { border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 4px; padding: 0 5px; font-size: 12px; background: var(--panel); }
.flash { animation: flash 1.6s ease; }
@keyframes flash { 0%, 60% { box-shadow: 0 0 0 3px var(--sel); } 100% { box-shadow: none; } }
@media print { #helpview .secnav { display: none; } }
.menu { max-height: calc(100vh - 140px); overflow-y: auto; }
.menu h5 { margin: 8px 10px 2px; font-size: 11px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); border-top: 1px solid var(--line); padding-top: 8px; }
a.btn { display: inline-flex; align-items: center; gap: 4px; text-decoration: none; color: var(--accent-ink); background: var(--accent); border: 1px solid var(--accent); border-radius: 6px; padding: 5px 11px; font-weight: 600; white-space: nowrap; }
a.btn:hover { filter: brightness(1.1); }
.is-desktop #dlapp { display: none; }
.author { display: flex; gap: 16px; align-items: flex-start; text-align: start; background: var(--bg2); border-radius: var(--radius); padding: 14px 16px; margin: 18px 0; }
.author .avatar { flex: none; width: 64px; height: 64px; border-radius: 50%; background: linear-gradient(135deg, #312e81, #0e7490); color: #fff; display: grid; place-items: center; font-size: 22px; font-weight: 700; }
.author h3 { margin: 0 0 4px; }
.downloads { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin: 10px 0; }
.checklist { list-style: none; padding: 0; margin: 6px 0; }
.checklist li { display: flex; gap: 10px; padding: 6px 10px; border-radius: 6px; margin: 4px 0; background: var(--bg2); }
.checklist li span { font-weight: 700; width: 1.2em; text-align: center; }
.checklist li.ok span { color: var(--good); } .checklist li.warn span { color: var(--warn); } .checklist li.bad span { color: var(--bad); } .checklist li.info span { color: var(--accent); }
.writeup { line-height: 1.8; background: var(--bg2); padding: 10px 14px; border-radius: 6px; }
p.big { font-size: 18px; }
.modeltabs { display: flex; gap: 4px; align-items: center; padding: 6px 8px 0; background: var(--panel); flex-wrap: wrap; }
.mtab { display: inline-flex; align-items: center; border: 1px solid var(--line); border-bottom: none; border-radius: 6px 6px 0 0; background: var(--bg2); }
.mtab button { border: none; background: none; border-radius: 6px 6px 0 0; }
.mtab.on { background: var(--panel); border-color: var(--accent); }
.mtab.on button:first-child { font-weight: 600; color: var(--accent); }
.mtab .x { padding: 2px 6px; }
.pill.warn { background: var(--warn-bg); color: var(--warn); }
.is-desktop #installbtn { display: none !important; }

/* example gallery */
.exgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 14px; }
.card.exan > header { display: flex; align-items: center; justify-content: space-between; gap: 10px; flex-wrap: wrap; }
.card.exan h4 { margin: 12px 0 4px; }
.card.exan ol { margin: 4px 0; padding-inline-start: 22px; }
.card.exan .expect { border-inline-start: 3px solid var(--accent); padding: 6px 10px; background: color-mix(in srgb, var(--accent) 8%, transparent); border-radius: 4px; }
.actions a.btn { margin-inline-start: 6px; }