:root {
  /* --- Palette: Brand & Accents --- */
  --accent-primary: #8364ff;
  --accent-secondary: #ffca28;
  --accent-active-line: rgba(92, 80, 255, 0.2);
  --piano-felt-red: #800;

  /* --- Palette: Background Surfaces --- */
  --bg-app: #121212; /* Main body */
  --bg-panel: #1e1e1e; /* Dashboard, Side panels */
  --bg-panel-editor: #2d1b38; /* Purple tint for Editor Mode */
  --bg-surface-1: #1a1a1a; /* Darker elements, key sides */
  --bg-surface-2: #2a2a2a; /* Inputs, Buttons */
  --bg-surface-3: #252525; /* Secondary containers */
  --bg-surface-hover: #333333;

  /* --- Editor Specific Palette --- */
  --bg-editor-input: #3e2a4d;
  --bg-editor-input-hover: #4e3660;
  --bg-editor-contrast: rgba(0, 0, 0, 0.4);

  /* --- Palette: Piano Specifics --- */
  --bg-piano-dark: #0a0a0a;
  --bg-piano-wood: #181818;
  --piano-black-key: #111111;
  --piano-black-key-active: #000000;
  --piano-white-key: #f0f0f0;
  --piano-white-key-active: #d1d1d1;

  /* --- Palette: Text --- */
  --text-main: #e0e0e0;
  --text-muted: #888888;
  --text-dark: #555555; /* Labels on light/gray backgrounds */
  --text-inverse: #ffffff;

  /* --- Palette: Borders & Dividers --- */
  --border-subtle: #333333;
  --border-strong: #111111;
  --border-input: #555555;

  /* --- Effects --- */
  --shadow-key: rgba(0, 0, 0, 0.4);
  --shadow-depth: rgba(0, 0, 0, 0.5);
  --shadow-floating: 0 10px 40px rgba(0, 0, 0, 0.6);
  --pattern-wood: linear-gradient(
    45deg,
    rgba(0, 0, 0, 0.2) 25%,
    transparent 25%,
    transparent 50%,
    rgba(0, 0, 0, 0.2) 50%,
    rgba(0, 0, 0, 0.2) 75%,
    transparent 75%,
    transparent
  );

  /* --- Layers (Z-Index) --- */
  --z-piano-keys: 1;
  --z-piano-sharps: 2;
  --z-sticky-header: 1000;
  --z-side-panel: 2000;
  --z-modal-overlay: 3000;
}

/* =========================================
   Global & Reset
   ========================================= */
body {
  background: var(--bg-app);
  color: var(--text-main);
  font-family: "Segoe UI", system-ui, sans-serif;
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  user-select: none;
}

.icon-svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
  display: inline-block;
  vertical-align: middle;
  flex-shrink: 0;
}

/* =========================================
   UI Components: Buttons & Inputs
   ========================================= */
.wide-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0 15px;
  flex-shrink: 0;
  width: auto;
  font-size: 13px;
  font-weight: 600;
}

.control-btn {
  background: var(--bg-app);
  color: var(--text-main);
  border: 1px solid var(--border-subtle);
  min-width: 32px;
  height: 32px;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 700;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.control-btn:hover:not(:disabled) {
  background: var(--bg-surface-hover);
  border-color: var(--text-dark);
}

.control-btn:disabled {
  opacity: 0.2;
  cursor: not-allowed;
  background: transparent;
}

.control-btn.primary-action {
  background: var(--accent-primary);
  color: #fff;
  border: none;
}
.control-btn.primary-action:hover {
  filter: brightness(1.1);
}

.control-btn.danger-action {
  background: var(--piano-felt-red);
  color: #fff;
  border: none;
}
.control-btn.danger-action:hover {
  filter: brightness(1.2);
}

select,
input[type="text"],
input[type="number"] {
  background: var(--bg-surface-2);
  color: var(--text-main);
  border: 1px solid var(--border-subtle);
  padding: 6px 12px;
  border-radius: 4px;
  font-size: 13px;
  outline: none;
  transition: border-color 0.2s;
}

select {
  cursor: pointer;
}

select:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

input[type="text"]:focus,
input[type="number"]:focus {
  border-color: var(--accent-primary);
}

input[type="range"] {
  width: 80px;
  height: 4px;
  accent-color: var(--text-muted);
  cursor: pointer;
  margin: 0;
}

/* =========================================
   Layout: Dashboard / Header
   ========================================= */
.piano-sticky-wrapper {
  position: sticky;
  top: -180px;
  z-index: var(--z-sticky-header);
  width: 100%;
  box-shadow: 0 10px 30px var(--shadow-depth);
}

.piano-assembly {
  display: flex;
  flex-direction: column;
  background: var(--bg-piano-dark);
}

.dashboard {
  background: var(--bg-panel);
  height: 60px;
  padding: 0 30px;
  display: flex;
  gap: 10px;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-subtle);
}

.left-controls,
.right-controls {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.separator {
  width: 1px;
  height: 24px;
  background: var(--border-subtle);
}

.song-selection {
  display: flex;
  gap: 10px;
}

.song-picker {
  width: 200px;
  font-weight: 600;
  text-overflow: ellipsis;
}

.checkbox-controls {
  display: flex;
  gap: 10px;
}

.toggle-container {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  cursor: pointer;
  text-transform: uppercase;
}

.toggle-container input {
  accent-color: var(--accent-primary);
  cursor: pointer;
}

.playback-controls {
  display: flex;
  gap: 10px;
}

.settings-wrapper {
  position: relative;
  display: inline-block;
}

.settings-dropdown {
  position: absolute;
  top: 120%;
  left: 0;
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 15px;
  width: 300px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  z-index: 4000;

  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.2s ease;
}

.settings-dropdown.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.setting-row {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 5px;
}

.setting-label {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
}

.setting-label span {
  font-family: monospace;
  color: var(--text-main);
  cursor: pointer;
}

.separator-horizontal {
  width: 100%;
  height: 1px;
  background: var(--border-subtle);
  margin: 10px 0;
}

.settings-dropdown input[type="range"] {
  width: 100%;
}

.tempo-control {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-surface-2);
  padding: 0 10px;
  height: 32px;
  border-radius: 4px;
  border: 1px solid var(--border-subtle);
}

#sideVolumeValue,
#sideTempoValue,
#sideNoteLengthValue,
#volumeValue,
#tempoValue,
#noteLengthValue {
  font-size: 11px;
  font-family: monospace;
  color: var(--text-muted);
  cursor: pointer;
}

#sideVolumeValue:hover,
#sideTempoValue:hover,
#sideNoteLengthValue:hover,
#volumeValue:hover,
#tempoValue:hover,
#noteLengthValue:hover {
  color: var(--text-main);
  text-decoration: underline;
}

/* =========================================
   Dashboard Bindings Group
   ========================================= */
.dashboard-bindings-group {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 2px;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
  background: var(--bg-app);
}

.dashboard-bindings-group:hover {
  background: var(--bg-surface-hover);
}

.bindings-icon {
  margin: 0 6px;
  color: var(--text-main);
  display: flex;
  align-items: center;
}

.dashboard-bindings-group .mini-key {
  width: 24px;
  height: 24px;
  flex: 0 0 auto;
}

/* =========================================
   Component: Piano Visuals
   ========================================= */
.piano-body {
  display: flex;
  width: 100%;
  height: 260px;
  background: var(--bg-piano-dark);
  position: relative;
}

.piano-shadow {
  width: 100%;
  height: 8px;
  background: var(--bg-piano-dark);
  background-image: var(--pattern-wood);
  background-size: 4px 4px;
}

.cheek-block {
  flex-grow: 1;
  background: var(--bg-piano-wood);
  background-image: var(--pattern-wood);
  background-size: 4px 4px;
  border-bottom: 1px solid var(--border-strong);
  box-shadow: inset 0 0 20px var(--shadow-depth);
}

.piano-frame {
  width: 100%;
  max-width: 1400px;
  min-width: 1000px;
  position: relative;
  display: flex;
  flex-direction: column;
}

.fallboard {
  height: 20px;
  background-color: var(--border-strong);
}

.keys-wrapper {
  position: relative;
  flex-grow: 1;
  background: var(--border-strong);
  overflow: hidden;
  border-top: 4px solid var(--piano-felt-red);
}

/* --- Piano Keys --- */
.key {
  position: absolute;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  padding-bottom: 12px;
  box-sizing: border-box;
  transition:
    background 0.05s,
    transform 0.05s;
  user-select: none;
}

.white-key {
  background: var(--piano-white-key);
  width: calc(100% / 36 + 1px);
  height: calc(100% - 2px);
  border-bottom: 4px solid var(--border-subtle);
  border-radius: 0 0 6px 6px;
  z-index: var(--z-piano-keys);
  box-shadow: inset 0 0 4px var(--shadow-key);
}

.black-key {
  background: var(--piano-black-key);
  height: 60%;
  border-radius: 0 0 4px 4px;
  z-index: var(--z-piano-sharps);
  border: 1px solid var(--border-strong);
  border-bottom: 3px solid var(--border-subtle);
  box-shadow:
    4px 0px 4px var(--shadow-key),
    -4px 0px 4px var(--shadow-key),
    0px 2px 4px var(--shadow-key);
}

.white-key.active {
  background: var(--piano-white-key-active);
  transform: translateY(2px);
  box-shadow: inset 0 -2px 5px var(--shadow-key);
  border-bottom: none;
}

.black-key.active {
  background: var(--piano-black-key-active);
  height: calc(60% + 2px);
  border-bottom: 1px solid var(--border-subtle);
  box-shadow:
    4px 0px 4px var(--shadow-key),
    -4px 0px 4px var(--shadow-key);
}

/* --- Note Labels --- */
.hide-notes .note-name,
.hide-hints .key-hint {
  display: none;
}

.note-name {
  font-size: 11px;
  font-weight: 700;
  margin-bottom: 2px;
  color: var(--text-dark);
}

.key-hint {
  font-size: 10px;
  font-weight: 600;
  color: var(--accent-primary);
  opacity: 0.9;
}

.black-key .note-name {
  color: var(--text-muted);
}
.black-key .key-hint {
  color: var(--accent-secondary);
}

/* =========================================
   Component: Sheet Music Display (Book)
   ========================================= */
.app-container {
  max-width: 1000px;
  margin: 40px auto;
  padding: 0 20px;
  position: relative;
}

.sheet-display {
  background: var(--bg-panel);
  border-radius: 8px;
  padding: 30px;
  border: 1px solid var(--border-subtle);
  min-height: 500px;
  transition: background-color 0.3s ease;
}

/* --- Editor Mode Variant --- */
.app-container.editor-mode .sheet-display {
  background: var(--bg-panel-editor);
  border-color: var(--accent-primary);
}

.sheet-header {
  display: flex;
  gap: 15px;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 15px;
}

.sheet-info {
  width: 100%;
}

.sheet-info h2 {
  margin: 0;
  color: var(--accent-secondary);
  overflow-wrap: anywhere;
}

/* Container for Title and Edit Button to prevent overlap/deletion */
.title-row {
  display: flex;
  gap: 15px;
  justify-content: space-between;
  margin-bottom: 5px;
}

.sheet-meta {
  font-size: 13px;
  color: var(--text-muted);
  font-family: monospace;
}

/* Pagination Controls */
.sheet-controls {
  display: flex;
  align-items: center;
  gap: 10px;
  border-radius: 4px;
  border: 1px solid var(--border-subtle);
}

/* Editor Pagination Colors */
.app-container.editor-mode .sheet-controls {
  border-color: var(--accent-primary);
}

/* Tint all general buttons inside the editor */
.app-container.editor-mode .sheet-display .control-btn,
.app-container.editor-mode .sheet-controls .control-btn {
  background: var(--bg-editor-input);
  border-color: var(--border-subtle);
}

/* Hover state for those buttons */
.app-container.editor-mode .sheet-display .control-btn:hover:not(:disabled),
.app-container.editor-mode .sheet-controls .control-btn:hover:not(:disabled) {
  background: var(--bg-editor-input-hover);
  border-color: var(--accent-primary);
}

/* Preserve Primary/Danger colors if they have the specific class */
.app-container.editor-mode .control-btn.primary-action {
  background: var(--accent-primary);
}
.app-container.editor-mode .control-btn.primary-action:hover {
  background: var(--accent-primary);
  filter: brightness(1.1);
}

.app-container.editor-mode .control-btn.danger-action {
  background: var(--piano-felt-red);
}
.app-container.editor-mode .control-btn.danger-action:hover {
  background: var(--piano-felt-red);
  filter: brightness(1.2);
}

.sheet-controls .icon-svg {
  width: 20px;
  height: 20px;
}

#pageIndicator {
  font-size: 12px;
  font-weight: 600;
  font-family: monospace;
  color: var(--text-muted);
  min-width: 50px;
  text-align: center;
}

/* Dual Page Layout */
.sheet-content {
  display: flex;
  gap: 30px;
  width: 100%;
}

.sheet-divider {
  width: 1px;
  background: var(--border-subtle);
  align-self: stretch;
}

.sheet-page-container {
  flex: 1;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-main);
  min-width: 0;
}

/* Sheet Line Styling (Read Mode) */
.sheet-line {
  display: block;
  padding: 0 4px;
  border-radius: 2px;
  min-height: 1.6em;
  cursor: pointer;
  transition: background-color 0.1s;
}

.sheet-line:hover {
  background-color: rgba(255, 255, 255, 0.05);
}

.sheet-line.active-line {
  background-color: var(--accent-active-line);
  color: var(--text-inverse);
  box-shadow: -4px 0 0 var(--accent-primary);
}

/* --- Editor Specific Styles --- */
.editor-toolbar {
  display: flex;
  gap: 10px;
  margin-bottom: 15px;
  flex-wrap: wrap;
}

.editor-inputs-row {
  display: flex;
  gap: 15px;
  margin-bottom: 15px;
  width: 100%;
}

.editor-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
}

/* Tint editor top inputs */
.editor-group input,
.editor-group select {
  background: var(--bg-editor-input);
}
.editor-group input:focus,
.editor-group select:focus {
  background: var(--bg-editor-input-hover);
}

.editor-label {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 4px;
}

.page-textarea {
  width: 100%;
  height: 500px;
  background: rgba(0, 0, 0, 0.2);
  border: 1px solid transparent;
  color: var(--text-main);
  font-family: "Consolas", "Monaco", monospace;
  font-size: 14px;
  line-height: 1.6;
  resize: none;
  padding: 10px;
  border-radius: 4px;
  outline: none;
  transition: all 0.2s;
  box-sizing: border-box;
  color-scheme: dark;
}

.page-textarea:focus {
  background: rgba(0, 0, 0, 0.3);
  border-color: var(--accent-primary);
}

/* =========================================
   Component: Floating Side Panel
   ========================================= */
.side-panel-track {
  position: absolute;
  top: 0;
  right: -180px;
  bottom: 0;
  width: 150px;
}

.side-panel {
  position: sticky;
  top: 160px;
  width: 150px;
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  box-shadow: var(--shadow-floating);
  z-index: var(--z-side-panel);

  opacity: 0;
  transform: translateX(30px);
  pointer-events: none;
  transition:
    opacity 0.4s ease,
    transform 0.4s ease-in-out;
}

.side-panel.visible {
  opacity: 1;
  transform: translateX(0);
  pointer-events: auto;
}

.side-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.side-label {
  font-size: 10px;
  font-weight: 800;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.side-row {
  display: flex;
  gap: 10px;
}

.side-row .control-btn {
  flex: 1;
}

.side-select {
  width: 100%;
  background: var(--bg-surface-2);
  color: var(--text-main);
  border: 1px solid var(--border-subtle);
  padding: 5px;
  font-size: 11px;
  border-radius: 4px;
}

.toggle-container.mini {
  font-size: 10px;
  margin-top: 5px;
}

#sideVolumeSlider,
#sideTempoSlider,
#sideNoteLengthSlider {
  width: 100%;
}

/* Mini Rebinder in Side Panel */
.side-group.clickable {
  cursor: pointer;
  transition: opacity 0.2s;
}

.mini-rebinder {
  display: flex;
  flex-direction: column;
  gap: 2px;
  transition: all 0.2s;
  background: var(--bg-app);
  padding: 2px;
  border-radius: 4px;
}

.mini-rebinder:hover {
  background: var(--bg-surface-hover);
}

.mini-row {
  display: flex;
  gap: 2px;
  height: 24px;
}

.mini-key {
  flex: 1;
  background: var(--bg-surface-2);
  border: 1px solid var(--bg-app);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2px;
  font-family: monospace;
  font-size: 10px;
  font-weight: 700;
  color: var(--text-muted);
  overflow: hidden;
  position: relative;
  box-shadow:
    inset 0 2px 0 rgba(255, 255, 255, 0.1),
    inset 0 -2px 0 var(--accent-active-line);
}

.mini-key.wide {
  flex: 1.5;
}
.mini-key.wider {
  flex: 2;
}

.mini-key.dynamic {
  flex-direction: row;
  justify-content: space-evenly;
  padding: 0 1px;
}

.mini-key span {
  transition: color 0.2s;
}

.color-muted {
  color: var(--text-muted);
}
.color-active {
  color: var(--accent-secondary);
}

.mini-key.static {
  opacity: 0.5;
  font-size: 9px;
}

@media (max-width: 1510px) {
  .side-panel.visible {
    display: none;
  }
}

/* =========================================
   Component: Modals
   ========================================= */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: var(--z-modal-overlay);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
  backdrop-filter: blur(2px);
}

.modal-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-window {
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  max-width: 90%;
  padding: 24px;
  box-shadow: 0 20px 50px var(--shadow-depth);
  transform: translateY(20px);
  transition: transform 0.2s ease-in-out;
}

.modal-overlay.open .modal-window {
  transform: translateY(0);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 15px;
}

.modal-header h2 {
  margin: 0;
  color: var(--accent-secondary);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.5px;
}

/* =========================================
   Component: Key Re-binder (3D Keycaps)
   ========================================= */
.rebinder-container {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  padding: 20px 0;
  margin: 0 auto;
  width: fit-content;
}

.rebinder-row {
  display: flex;
  background: var(--border-strong);
  padding: 3px;
  gap: 3px;
  margin-top: -3px;
  border-radius: 4px;
}
.rebinder-row:first-child {
  margin-top: 0;
}

.keycap {
  width: 130px;
  height: 130px;
  position: relative;
  display: grid;
  grid-template-columns: 19px 1fr 19px;
  grid-template-rows: 8px 1fr 30px;
}

/* Key Base (The "Skirt") */
.keycap::before {
  content: "";
  grid-column: 1 / -1;
  grid-row: 1 / -1;
  background: var(--bg-surface-2);
  border-style: solid;
  border-width: 10px 22px 30px 22px;
  border-color: var(--border-subtle) var(--bg-surface-2) var(--bg-surface-1);
  border-radius: 3px;
}

/* Key Top Face (The "Scoop") */
.keycap::after {
  content: "";
  grid-column: 2;
  grid-row: 2;
  border: 2px solid var(--text-dark);
  border-bottom: none;
  border-radius: 4px;
  background: linear-gradient(
    to right,
    var(--bg-panel),
    transparent,
    transparent,
    var(--bg-panel)
  );
}

.no-scoop::after {
  background: none;
}

.keycap-label-row,
.keycap-input-area {
  z-index: 2;
  grid-column: 2;
  grid-row: 2;
  position: relative;
}

.keycap-label-row {
  display: flex;
  justify-content: space-around;
  padding: 8px 4px 0;
}

.muted-keycap-label,
.keycap-label {
  font-size: 24px;
  font-weight: 600;
  color: var(--text-main);
  font-family: "Segoe UI", sans-serif;
  text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.8);
}

.muted-keycap-label {
  color: var(--text-muted);
}

.keycap-input-area {
  display: flex;
  gap: 6px;
  width: 100%;
  align-items: flex-end;
  padding: 0 8px 8px 8px;
  box-sizing: border-box;
  align-self: flex-end;
}

.input-group {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex: 1;
  gap: 2px;
}

input[type="text"].bind-input {
  width: 100%;
  background: var(--bg-app);
  border: 1px solid var(--border-subtle);
  border-radius: 3px;
  color: var(--accent-secondary);
  text-align: center;
  font-size: 13px;
  font-weight: 700;
  padding: 3px 0;
  font-family: monospace;
  outline: none;
  transition: all 0.2s;
  box-shadow: inset 0 1px 3px var(--shadow-depth);
}

input[type="text"].bind-input:focus {
  background: var(--bg-surface-hover);
  border-color: var(--text-dark);
}

.input-sublabel {
  font-size: 8px;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  font-weight: 800;
}

.modal-footer-hint {
  margin-top: 25px;
  font-size: 11px;
  color: var(--text-muted);
  text-align: center;
  border-top: 1px solid var(--border-subtle);
  padding-top: 15px;
}