:root {
  --fp-bg: var(--sz-color-window, #ece9d8);
  --fp-text: var(--sz-color-window-text, #1b1b1b);
  --fp-panel: color-mix(in srgb, var(--fp-bg) 88%, #ffffff 12%);
  --fp-border: var(--sz-color-button-shadow, #8d8d8d);
  --fp-axis: #232323;
  --fp-grid-major: rgba(0, 0, 0, 0.22);
  --fp-grid-minor: rgba(0, 0, 0, 0.09);
  --fp-canvas: #ffffff;
  --fp-func: #1769ff;
  --fp-num: #0e7a1f;
  --fp-var: #cc6a00;
  --fp-const: #8b2fb0;
  --fp-error: #c62828;
  --fp-menu: var(--sz-color-menu, #ece9d8);
  --fp-menu-text: var(--sz-color-menu-text, #1b1b1b);
  --fp-highlight: var(--sz-color-highlight, #245edb);
  --fp-highlight-text: var(--sz-color-highlight-text, #ffffff);
}

body,
html {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--fp-bg);
  color: var(--fp-text);
  font: 12px/1.35 Tahoma, "Segoe UI", sans-serif;
}

/* ── Main Grid Layout ── */

.plotter-app {
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-columns: 300px 1fr;
  grid-template-rows: auto 1fr auto;
}

/* ── Menu Bar ── */

.menu-bar {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  padding: 0;
  background: var(--fp-menu);
  border-bottom: 1px solid var(--fp-border);
  user-select: none;
  flex-shrink: 0;
  z-index: 100;
}

.menu-item {
  position: relative;
  padding: 3px 8px;
  cursor: default;
  color: var(--fp-menu-text);
}

.menu-item:hover,
.menu-item.open {
  background: var(--fp-highlight);
  color: var(--fp-highlight-text);
}

.menu-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 200px;
  background: var(--fp-menu);
  border: 1px solid var(--fp-border);
  box-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
  z-index: 1000;
  padding: 2px 0;
}

.menu-item.open > .menu-dropdown {
  display: block;
}

.menu-entry {
  padding: 4px 24px;
  cursor: default;
  color: var(--fp-menu-text);
  white-space: nowrap;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
}

.menu-entry:hover {
  background: var(--fp-highlight);
  color: var(--fp-highlight-text);
}

.menu-entry.disabled {
  color: var(--sz-color-gray-text, #808080);
  pointer-events: none;
}

.menu-entry .shortcut {
  margin-left: 24px;
  font-size: 10px;
  opacity: 0.7;
}

.menu-entry.checkbox::before,
.menu-entry.radio::before {
  content: '';
  display: inline-block;
  width: 16px;
  margin-left: -16px;
  text-align: center;
}

.menu-entry.checkbox.checked::before {
  content: '\2713';
}

.menu-entry.radio.checked::before {
  content: '\2022';
}

.menu-separator {
  height: 1px;
  background: var(--fp-border);
  margin: 2px 4px;
}

/* ── Sidebar ── */

.sidebar {
  position: relative;
  border-right: 1px solid var(--fp-border);
  background: var(--fp-panel);
  display: flex;
  flex-direction: column;
  min-width: 0;
  overflow: auto;
}

.panel {
  padding: 8px;
  border-bottom: 1px solid var(--fp-border);
}

.panel h2 {
  margin: 0;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.panel-header h2 {
  margin: 0;
}

.panel-toggle {
  cursor: pointer;
  user-select: none;
  list-style: none;
  margin-bottom: 6px;
}

.panel-toggle::-webkit-details-marker {
  display: none;
}

.panel-toggle h2 {
  display: inline;
}

.panel-toggle::before {
  content: '\25bc';
  display: inline-block;
  width: 12px;
  font-size: 8px;
  transition: transform 0.15s;
}

details:not([open]) > .panel-toggle::before {
  transform: rotate(-90deg);
}

.btn {
  border: 1px solid var(--fp-border);
  background: linear-gradient(to bottom, #fff, #d8d8d8);
  color: var(--fp-text);
  padding: 4px 8px;
  font: inherit;
  cursor: pointer;
}

.btn:active {
  transform: translateY(1px);
}

.btn-add {
  font-size: 11px;
  padding: 2px 8px;
}

/* ── Function List ── */

.function-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-height: 44vh;
  overflow: auto;
  padding-right: 2px;
}

.function-card {
  border: 1px solid var(--fp-border);
  background: color-mix(in srgb, var(--fp-panel) 82%, #fff 18%);
  padding: 6px;
}

.function-card.selected {
  border-color: var(--fp-highlight);
  box-shadow: inset 0 0 0 1px var(--fp-highlight);
}

.function-head {
  display: grid;
  grid-template-columns: auto auto 1fr auto;
  gap: 6px;
  align-items: center;
  margin-bottom: 6px;
}

.color-input {
  width: 20px;
  height: 20px;
  padding: 0;
  border: 1px solid var(--fp-border);
  background: transparent;
}

.expr-wrap {
  position: relative;
  border: 1px solid var(--fp-border);
  background: #fff;
  min-height: 48px;
}

.expr-highlight,
.expr-input {
  font: 12px/1.35 Consolas, "Courier New", monospace;
  padding: 5px;
  white-space: pre-wrap;
  word-break: break-word;
  overflow: hidden;
}

.expr-highlight {
  margin: 0;
  color: transparent;
  min-height: 36px;
}

.expr-input {
  position: absolute;
  inset: 0;
  border: 0;
  margin: 0;
  width: 100%;
  min-height: 36px;
  resize: vertical;
  background: transparent;
  color: transparent;
  caret-color: #111;
}

.expr-input:focus {
  outline: 1px solid #3f82ff;
  outline-offset: -1px;
}

.expr-input.invalid {
  outline: 1px solid var(--fp-error);
  outline-offset: -1px;
}

.fn-token { color: var(--fp-func); }
.num-token { color: var(--fp-num); }
.var-token { color: var(--fp-var); }
.const-token { color: var(--fp-const); font-weight: bold; }
.op-token { color: var(--fp-text); }
.err-token { color: var(--fp-text); text-decoration: underline wavy var(--fp-error); }

.error-text {
  color: var(--fp-error);
  min-height: 15px;
  margin-top: 4px;
}

/* ── Reference Insert Buttons ── */

.expr-ref-buttons {
  position: absolute;
  bottom: 2px;
  right: 2px;
  display: flex;
  gap: 2px;
  z-index: 2;
}

.expr-ref-btn {
  width: 20px;
  height: 18px;
  padding: 0;
  border: 1px solid var(--fp-border);
  background: linear-gradient(to bottom, #fff, #e8e8e8);
  color: var(--fp-text);
  font: bold 11px Tahoma, sans-serif;
  cursor: pointer;
  opacity: 0.6;
  line-height: 16px;
  text-align: center;
}

.expr-ref-btn:hover {
  opacity: 1;
  border-color: var(--fp-highlight);
}

/* ── Reference Popup ── */

.ref-popup {
  position: absolute;
  z-index: 200;
  background: var(--fp-menu);
  border: 1px solid var(--fp-border);
  box-shadow: 2px 2px 6px rgba(0, 0, 0, 0.25);
  min-width: 200px;
  max-width: 280px;
  max-height: 240px;
  display: flex;
  flex-direction: column;
}

.ref-popup-title {
  padding: 4px 8px;
  font-weight: bold;
  font-size: 11px;
  border-bottom: 1px solid var(--fp-border);
  background: color-mix(in srgb, var(--fp-menu) 85%, #000 15%);
  color: var(--fp-menu-text);
}

.ref-popup-list {
  overflow: auto;
  flex: 1;
  min-height: 0;
}

.ref-popup-item {
  display: flex;
  gap: 8px;
  padding: 3px 8px;
  cursor: pointer;
  font-size: 11px;
  color: var(--fp-menu-text);
  align-items: baseline;
}

.ref-popup-item:hover {
  background: var(--fp-highlight);
  color: var(--fp-highlight-text);
}

.ref-popup-name {
  font-family: Consolas, "Courier New", monospace;
  font-weight: bold;
  min-width: 50px;
}

.ref-popup-desc {
  opacity: 0.75;
  font-size: 10px;
}

/* ── Family Controls ── */

.family-panel {
  margin-top: 6px;
  border-top: 1px solid var(--fp-border);
  padding-top: 6px;
}

.family-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}

.family-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 4px;
}

.family-grid[hidden],
.family-list-input[hidden],
.family-panel[hidden] {
  display: none;
}

.family-grid label {
  font-size: 10px;
  color: color-mix(in srgb, var(--fp-text) 70%, transparent);
}

.family-grid input,
.family-list-input,
.mode-select {
  width: 100%;
  box-sizing: border-box;
  font: inherit;
  border: 1px solid var(--fp-border);
}

/* ── Analysis Panel ── */

.analysis-panel {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.analysis-panel[open] {
  overflow: auto;
}

.analysis-status {
  font-size: 11px;
  color: color-mix(in srgb, var(--fp-text) 70%, transparent);
}

.analysis-body {
  margin-top: 6px;
  overflow: auto;
  min-height: 0;
}

.analysis-group {
  margin-bottom: 8px;
}

.analysis-group b {
  display: block;
}

/* ── Legend ── */

.legend-body {
  max-height: 140px;
  overflow: auto;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.legend-entry {
  display: grid;
  grid-template-columns: 12px 1fr;
  gap: 6px;
  align-items: center;
  font-family: Consolas, "Courier New", monospace;
  font-size: 11px;
}

.legend-swatch {
  width: 12px;
  height: 12px;
  border: 1px solid var(--fp-border);
  box-sizing: border-box;
}

.legend-entry.disabled {
  opacity: 0.45;
}

/* ── Canvas Area ── */

.canvas-host {
  position: relative;
  min-width: 0;
  background: var(--fp-canvas);
}

#plotCanvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* ── Tooltips & Autocomplete ── */

.trace-tooltip,
.autocomplete,
.fn-tooltip {
  position: absolute;
  z-index: 10;
  background: #ffffe1;
  border: 1px solid #696969;
  padding: 4px 6px;
  font: 11px Tahoma, sans-serif;
  pointer-events: none;
  max-width: 260px;
}

.autocomplete {
  pointer-events: auto;
  padding: 2px;
  min-width: 220px;
}

.ac-item {
  padding: 3px 6px;
  cursor: pointer;
  display: flex;
  gap: 10px;
  align-items: baseline;
}

.ac-name {
  font-family: Consolas, "Courier New", monospace;
  font-weight: bold;
  min-width: 60px;
}

.ac-desc {
  font-size: 10px;
  opacity: 0.7;
}

.ac-item.active,
.ac-item:hover {
  background: #245edb;
  color: #fff;
}

.ac-item.active .ac-desc,
.ac-item:hover .ac-desc {
  opacity: 1;
}

/* ── Status Bar ── */

.status-bar {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 2px 8px;
  background: var(--fp-panel);
  border-top: 1px solid var(--fp-border);
  font-size: 11px;
  color: color-mix(in srgb, var(--fp-text) 80%, transparent);
  user-select: none;
  flex-shrink: 0;
}

.status-bar span {
  white-space: nowrap;
}

.status-spacer {
  flex: 1;
}

/* ── Dark Mode ── */

body.dark {
  --fp-bg: #1b1f24;
  --fp-text: #e4e4e4;
  --fp-panel: #252a31;
  --fp-border: #4d5562;
  --fp-axis: #d2d5db;
  --fp-grid-major: rgba(210, 213, 219, 0.35);
  --fp-grid-minor: rgba(210, 213, 219, 0.15);
  --fp-canvas: #13161a;
  --fp-menu: #252a31;
  --fp-menu-text: #e4e4e4;
}

body.dark .expr-wrap {
  background: #101216;
}

body.dark .expr-input {
  caret-color: #f6f6f6;
}

body.dark .expr-ref-btn {
  background: linear-gradient(to bottom, #3a3f47, #2a2f36);
  color: #e4e4e4;
}

body.dark .btn {
  background: linear-gradient(to bottom, #3a3f47, #2a2f36);
  color: #e4e4e4;
}

body.dark .trace-tooltip,
body.dark .fn-tooltip {
  background: #2a2f36;
  border-color: #4d5562;
  color: #e4e4e4;
}

body.dark .autocomplete {
  background: #2a2f36;
  border-color: #4d5562;
  color: #e4e4e4;
}

/* ── Responsive ── */

@media (max-width: 900px) {
  .plotter-app {
    grid-template-columns: 1fr;
    grid-template-rows: auto 48% 1fr auto;
  }

  .sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--fp-border);
  }

  .function-list {
    max-height: 20vh;
  }
}