/* The playground as a small workbench: a title bar, an explorer of the specifications,
   the editor and the plot side by side, a terminal panel, a status bar. The palette
   follows the Light Modern and Dark Modern themes of VS Code, the accents the colours
   of the logo (promo/logo/draw.py): blue #2a78d6, orange #eb6834. */

:root {
  --bg: #ffffff;
  --fg: #3b3b3b;
  --fg-strong: #1f1f1f;
  --muted: #717171;
  --border: #e5e5e5;
  --side: #f8f8f8;
  --tabs: #f8f8f8;
  --tab-active: #ffffff;
  --hover: #ececec;
  --selected: #e4e6f1;
  --input-bg: #ffffff;
  --input-border: #cecece;
  --blue: #2a78d6;
  --orange: #eb6834;
  --green: #1baf7a;
  --amber: #eda100;
  --violet: #6250d6;
  --red: #e34948;
  --accent: var(--blue);
  --accent-fg: #ffffff;
  --status-bg: #2a78d6;
  --status-fg: #ffffff;
  --error-bg: #fdf0ef;
  --error-fg: #a1260d;
  --terminal-bg: #ffffff;
  --terminal-fg: #3b3b3b;
  --grid: #e8e8e8;
  --logo-axis: #c8c7c3;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #1f1f1f;
    --fg: #cccccc;
    --fg-strong: #ffffff;
    --muted: #9d9d9d;
    --border: #2b2b2b;
    --side: #181818;
    --tabs: #181818;
    --tab-active: #1f1f1f;
    --hover: #2a2d2e;
    --selected: #37373d;
    --input-bg: #313131;
    --input-border: #3c3c3c;
    --status-bg: #2a78d6;
    --status-fg: #ffffff;
    --error-bg: #3b1d1d;
    --error-fg: #f48771;
    --terminal-bg: #181818;
    --terminal-fg: #cccccc;
    --grid: #333333;
    --logo-axis: #4a4b50;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #1f1f1f;
  --fg: #cccccc;
  --fg-strong: #ffffff;
  --muted: #9d9d9d;
  --border: #2b2b2b;
  --side: #181818;
  --tabs: #181818;
  --tab-active: #1f1f1f;
  --hover: #2a2d2e;
  --selected: #37373d;
  --input-bg: #313131;
  --input-border: #3c3c3c;
  --status-bg: #2a78d6;
  --status-fg: #ffffff;
  --error-bg: #3b1d1d;
  --error-fg: #f48771;
  --terminal-bg: #181818;
  --terminal-fg: #cccccc;
  --grid: #333333;
  --logo-axis: #4a4b50;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.5);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font: 13px/1.45 -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
  overflow: hidden;
}
code, .mono, .cm-editor .cm-scroller, .terminal {
  font-family: "SF Mono", ui-monospace, SFMono-Regular, Menlo, "Cascadia Code", Consolas, monospace;
}
code { font-size: 0.95em; }
/* every zone scrolls in its own frame: a scroll that reaches the end of a zone stops
   there, it never moves the page nor triggers the back gesture of the browser */
.cm-scroller, .terminal, .tree, .sidebar-note, .chain, .error, .tab-strip { overscroll-behavior: contain; }
a { color: var(--accent); }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
button:disabled { opacity: 0.45; cursor: default; }
select {
  font: inherit; font-size: 12px; color: var(--fg); background: var(--input-bg);
  border: 1px solid var(--input-border); border-radius: 3px; padding: 2px 4px; max-width: 160px;
}
select:focus-visible, button:focus-visible { outline: 1px solid var(--accent); outline-offset: -1px; }

/* ---------------------------------------------------------------- the frame */

.app {
  height: 100vh; height: 100dvh;
  display: grid; grid-template-rows: 36px minmax(0, 1fr) 22px;
}
.workbench {
  --sidebar-w: 260px;
  --panel-h: 220px;
  --editor-w: 1fr;
  --plot-w: 1fr;
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  grid-template-rows: minmax(0, 1fr) 4px var(--panel-h);
  grid-template-areas: "side main" "side sash" "side panel";
  min-height: 0;
}
.sidebar { grid-area: side; }
.editor-area { grid-area: main; }
.sash-horizontal { grid-area: sash; }
.panel { grid-area: panel; }

/* ---------------------------------------------------------------- the title bar */

.titlebar {
  display: flex; align-items: center; gap: 10px; padding: 0 12px;
  background: var(--side); border-bottom: 1px solid var(--border); color: var(--fg);
  user-select: none; -webkit-user-select: none;
}
.brand { display: inline-flex; align-items: center; gap: 7px; color: var(--fg-strong); text-decoration: none; }
.logo { display: block; }
.logo-axis { stroke: var(--logo-axis); }
.wordmark { font-weight: 700; font-size: 15px; letter-spacing: -0.01em; }
.title-sep { width: 1px; height: 16px; background: var(--border); }
.page-name { color: var(--muted); }
.badge {
  font-size: 11px; color: var(--muted); border: 1px solid var(--border); border-radius: 10px;
  padding: 0 7px; line-height: 16px;
}
.title-center {
  flex: 1; display: flex; justify-content: center; min-width: 0;
}
.open-name {
  max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  color: var(--muted); font-size: 12px; padding: 2px 12px; border-radius: 6px;
  border: 1px solid var(--border); background: var(--bg);
}
.open-name:empty { display: none; }
.title-links { display: flex; align-items: center; gap: 4px; }
.title-links a {
  color: var(--fg); text-decoration: none; padding: 3px 8px; border-radius: 4px; font-size: 12.5px;
}
.title-links a:hover { background: var(--hover); }
.icon-button {
  display: inline-flex; align-items: center; justify-content: center; width: 26px; height: 26px;
  border-radius: 4px; color: var(--fg);
}
.icon-button:hover { background: var(--hover); }
.icon-moon { display: none; }
:root[data-theme="dark"] .icon-sun { display: none; }
:root[data-theme="dark"] .icon-moon { display: inline; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .icon-sun { display: none; }
  :root:not([data-theme="light"]) .icon-moon { display: inline; }
}
.explorer-toggle { display: none; }

/* ---------------------------------------------------------------- the explorer */

.sidebar {
  display: flex; flex-direction: column; min-height: 0;
  background: var(--side); border-right: 1px solid var(--border);
}
.sidebar-title {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 8px 0 20px; height: 35px; font-size: 11px; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--fg);
}
.tree { flex: 1; overflow: auto; padding-bottom: 8px; }
.tree-group {
  display: flex; align-items: center; gap: 4px; width: 100%; text-align: left;
  padding: 3px 8px 3px 4px; font-size: 11px; font-weight: 700; letter-spacing: 0.04em;
  text-transform: uppercase; color: var(--fg);
}
.tree-group::before {
  content: ""; width: 0; height: 0; margin: 0 4px;
  border: 4px solid transparent; border-left-color: var(--muted); border-left-width: 5px;
  transform: rotate(90deg); transition: transform 0.1s;
}
.tree-group[aria-expanded="false"]::before { transform: none; }
.tree-group[aria-expanded="false"] + .tree-items { display: none; }
.tree-item {
  display: flex; align-items: baseline; gap: 6px; width: 100%; text-align: left;
  padding: 2px 8px 2px 22px; line-height: 20px; color: var(--fg); white-space: nowrap; overflow: hidden;
}
.tree-item:hover { background: var(--hover); }
.tree-item[aria-current="true"] { background: var(--selected); color: var(--fg-strong); }
.tree-item .name { flex: none; }
.tree-item .desc { color: var(--muted); font-size: 11.5px; overflow: hidden; text-overflow: ellipsis; }
.sidebar-note {
  border-top: 1px solid var(--border); padding: 8px 14px 10px 20px; font-size: 11.5px;
  color: var(--muted); max-height: 42%; overflow: auto;
}
.sidebar-note p { margin: 0 0 8px; }
.sidebar-note b { color: var(--fg); }
.sidebar-backdrop { display: none; }

/* ---------------------------------------------------------------- the panes */

.editor-area {
  display: grid; grid-template-columns: minmax(0, var(--editor-w)) 4px minmax(0, var(--plot-w));
  min-height: 0; min-width: 0;
}
.pane { display: flex; flex-direction: column; min-width: 0; min-height: 0; background: var(--bg); }
.pane-body { flex: 1; min-height: 0; }
.tabs {
  display: flex; align-items: stretch; height: 35px; background: var(--tabs);
  border-bottom: 1px solid var(--border); flex: none;
}
.tab {
  display: inline-flex; align-items: center; gap: 6px; padding: 0 14px; font-size: 12.5px;
  color: var(--muted); border-right: 1px solid var(--border); white-space: nowrap;
}
.tab.active {
  color: var(--fg-strong); background: var(--tab-active); position: relative;
}
.tab.active::after {
  content: ""; position: absolute; left: 0; right: 0; top: 0; height: 1px; background: var(--accent);
}
.tab.active::before {
  content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 1px; background: var(--tab-active);
}
.tab-icon {
  display: inline-flex; align-items: center; justify-content: center; width: 14px; height: 14px;
  font-size: 9px; font-weight: 700; border-radius: 2px;
}
.tab-icon.yaml { background: var(--violet); color: #fff; }
.tab-icon.plot {
  background: linear-gradient(to top right, transparent 46%, var(--orange) 46%, var(--orange) 54%, transparent 54%),
    linear-gradient(to right, var(--blue) 2px, transparent 2px), linear-gradient(to top, var(--blue) 2px, transparent 2px);
  border-radius: 1px;
}
.tab-strip { display: flex; align-items: stretch; min-width: 0; overflow-x: auto; scrollbar-width: none; }
.tab-strip::-webkit-scrollbar { display: none; }
.tab-strip .tab { flex: none; }
.tab-strip .tab .swatch { width: 8px; height: 8px; border-radius: 50%; }
button.tab:hover { color: var(--fg); }
.tab-hint { align-self: center; margin-left: 10px; color: var(--muted); font-size: 11.5px; }
.tab-actions {
  margin-left: auto; display: flex; align-items: center; gap: 6px; padding: 0 8px;
}
.action {
  display: inline-flex; align-items: center; gap: 5px; padding: 3px 10px; border-radius: 4px;
  font-size: 12.5px; font-weight: 500; color: var(--fg); border: 1px solid transparent;
}
.action:hover:not(:disabled) { background: var(--hover); }
.action.primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
.action.primary:hover:not(:disabled) { background: #2369bf; }
.plot-controls label { display: inline-flex; align-items: center; gap: 4px; font-size: 12px; color: var(--muted); }
.plot-controls label.check { color: var(--fg); }
.plot-controls input[type="checkbox"] { margin: 0; accent-color: var(--accent); }

#editor { overflow: hidden; }
.cm-editor { height: 100%; font-size: 13px; background: var(--bg) !important; }
.cm-editor.cm-focused { outline: none; }
.cm-editor .cm-gutters { background: var(--bg) !important; border-right: 0 !important; color: var(--muted) !important; }
.cm-editor .cm-activeLineGutter { background: var(--hover) !important; }
.cm-editor .cm-activeLine { background: color-mix(in srgb, var(--hover) 55%, transparent) !important; }
.cm-editor .cm-content { padding: 6px 0; }
.cm-editor .cm-scroller { line-height: 1.5; }
.error {
  flex: none; padding: 6px 12px; font-size: 12px; border-top: 1px solid var(--border);
  background: var(--error-bg); color: var(--error-fg); white-space: pre-wrap; word-break: break-word;
  max-height: 30%; overflow: auto;
}
.error::before { content: "⨯ "; font-weight: 700; }

.plot-body { display: flex; flex-direction: column; }
.plot-toolbar {
  flex: none; display: flex; align-items: center; gap: 8px 14px; padding: 5px 10px 0 14px; flex-wrap: wrap;
}
.caption {
  flex: 1; min-width: 0; font-size: 12px; color: var(--muted);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.plot-controls { display: flex; align-items: center; gap: 10px; margin-left: auto; }
#plot { flex: 1; min-height: 0; width: 100%; }
#plot[hidden], .plot-controls[hidden] { display: none; }
.tab-icon.chain {
  background: linear-gradient(var(--blue), var(--blue)) left center / 5px 5px no-repeat,
    linear-gradient(var(--muted), var(--muted)) center / 6px 1.5px no-repeat,
    linear-gradient(var(--orange), var(--orange)) right center / 5px 5px no-repeat;
}
.tab-icon.scope { border-radius: 50%; border: 1.5px solid var(--green); background: radial-gradient(var(--green) 28%, transparent 32%); }

/* the chain: the blocks on one horizontal line, the scopes hung under their arrow */
.chain {
  --block-h: 58px;
  flex: 1; min-height: 0; overflow: auto; padding: 18px 16px;
  display: flex; flex-wrap: nowrap; align-items: flex-start;
}
.chain[hidden] { display: none; }
.chain-block {
  flex: none; display: flex; flex-direction: column; justify-content: center; gap: 1px;
  min-height: var(--block-h); padding: 6px 10px; min-width: 92px; max-width: 200px; border-radius: 6px;
  border: 1px solid var(--input-border); background: var(--side); color: var(--fg); cursor: default;
}
.chain-block.scope { min-height: 0; border-color: var(--green); border-style: dashed; background: var(--bg); }
.chain-kind { font-weight: 600; font-size: 12.5px; color: var(--fg-strong); white-space: nowrap; }
.chain-block.scope .chain-kind { color: var(--green); font-size: 11.5px; }
.chain-label { font-size: 11.5px; color: var(--accent); white-space: nowrap; }
.chain-param {
  font-family: "SF Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 11px;
  color: var(--muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 100%;
}
.chain-param span { color: var(--fg); }
.chain-link { flex: none; display: flex; flex-direction: column; align-items: center; min-width: 34px; }
.chain-link.tapped { padding: 0 8px; }
.chain-arrow { align-self: stretch; height: var(--block-h); position: relative; min-width: 34px; }
.chain-arrow::before { content: ""; position: absolute; left: 3px; right: 6px; top: calc(50% - 0.5px); height: 1px; background: var(--muted); }
.chain-arrow::after {
  content: ""; position: absolute; right: 2px; top: calc(50% - 4px); border: 4px solid transparent;
  border-left: 6px solid var(--muted); border-right: 0;
}
/* the stem from the arrow down to the scopes */
.chain-taps { display: flex; flex-direction: column; align-items: center; gap: 6px; position: relative; padding-top: 14px; }
.chain-link:not(.tapped) .chain-taps { display: none; }
.chain-taps::before {
  content: ""; position: absolute; top: calc(var(--block-h) / -2); left: 50%; height: calc(var(--block-h) / 2 + 14px);
  border-left: 1px dashed var(--green);
}

/* ---------------------------------------------------------------- the sashes */

.sash { background: var(--border); position: relative; z-index: 2; }
.sash::after { content: ""; position: absolute; inset: -3px; }
.sash-vertical { cursor: col-resize; }
.sash-horizontal { cursor: row-resize; }
.sash:hover, .sash.dragging { background: var(--accent); transition: background 0.15s 0.2s; }

/* ---------------------------------------------------------------- the terminal */

.panel { display: flex; flex-direction: column; min-height: 0; background: var(--terminal-bg); }
.panel-tabs { background: var(--terminal-bg); }
.panel-tabs .tab { border-right: 0; text-transform: uppercase; font-size: 11px; letter-spacing: 0.06em; padding: 0 12px 0 18px; }
.panel-tabs .tab.active { background: transparent; }
.panel-tabs .tab.active::after { top: auto; bottom: -1px; }
.panel-tabs .tab.active::before { display: none; }
.terminal {
  flex: 1; margin: 0; padding: 6px 18px; overflow: auto; font-size: 12px; line-height: 1.5;
  color: var(--terminal-fg); white-space: pre; tab-size: 4;
}
.terminal .ok { color: var(--green); }
.terminal .fail { color: var(--red); font-weight: 600; }
.terminal .dim { color: var(--muted); }
.terminal .err { color: var(--error-fg); }
.terminal .prompt { color: var(--accent); }

/* ---------------------------------------------------------------- the status bar */

.statusbar {
  display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 0 10px;
  background: var(--status-bg); color: var(--status-fg); font-size: 12px;
  user-select: none; -webkit-user-select: none;
}
.status { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.status.running::before {
  content: ""; display: inline-block; width: 9px; height: 9px; margin-right: 6px;
  border-radius: 50%; border: 2px solid var(--status-fg); border-top-color: transparent;
  animation: spin 0.8s linear infinite; vertical-align: -1px;
}
@keyframes spin { to { transform: rotate(360deg); } }
.status-right { display: flex; gap: 14px; white-space: nowrap; }
.status-item:empty { display: none; }

/* ---------------------------------------------------------------- phones and tablets */

@media (max-width: 900px) {
  /* the page still fits the screen: the editor, the plot and the terminal are stacked,
     each with its share of the height and its own scrolling, the page itself never moves */
  .workbench {
    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: minmax(0, 3fr) minmax(0, 1fr);
    grid-template-areas: "main" "panel";
  }
  .explorer-toggle { display: inline-flex; }
  .sidebar {
    position: fixed; top: 36px; bottom: 0; left: 0; width: min(320px, 86vw); z-index: 20;
    transform: translateX(-100%); transition: transform 0.18s ease-out; box-shadow: none;
  }
  .sidebar.open { transform: none; box-shadow: var(--shadow); }
  .sidebar-backdrop { display: block; position: fixed; inset: 36px 0 0; z-index: 19; background: rgba(0, 0, 0, 0.3); }
  .sidebar-backdrop[hidden] { display: none; }
  .title-links a:not(:last-of-type) { display: none; }
  .title-center { display: none; }
  .page-name, .title-sep { display: none; }
  .editor-area { grid-template-columns: minmax(0, 1fr); grid-template-rows: minmax(0, 1fr) minmax(0, 1fr); }
  .sash { display: none; }
  .plot-pane { border-top: 1px solid var(--border); }
  .panel { border-top: 1px solid var(--border); }
  .terminal { white-space: pre-wrap; word-break: break-word; padding: 6px 12px; }
  .status-right .status-item:not(#engine) { display: none; }
  select { max-width: 110px; }
  #share { font-size: 0; gap: 0; padding: 3px 7px; } /* the icon alone on a phone */
}