:root {
  font-family: Inter, 'Segoe UI', 'Microsoft YaHei', sans-serif;
  color: #263644;
  background: #f5f6f8;
  font-size: 14px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  overflow: hidden;
}

button,
input,
select {
  font: inherit;
}

button,
select {
  cursor: pointer;
}

button {
  border: 1px solid #dce2e8;
  border-radius: 8px;
  background: #fff;
  color: #354555;
  padding: 8px 11px;
}

button:hover {
  background: #f0f4f7;
}

button:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 3px solid #a6bce2;
  outline-offset: 2px;
}

header {
  position: relative;
  z-index: 2;
  background: #ffffffed;
  border-bottom: 1px solid #edf0f3;
  padding: 10px 16px;
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 0;
}

select {
  max-width: 180px;
  padding: 8px;
  border: 1px solid #dce2e8;
  border-radius: 8px;
  background: #fff;
}

#status {
  font-size: 12px;
  color: #647484;
}

#viewport {
  position: absolute;
  inset: 58px 0 0;
  overflow: hidden;
  background: #fff;
  touch-action: none;
  cursor: grab;
  user-select: none;
  -webkit-user-select: none;
}

#viewport.dragging {
  cursor: grabbing;
}

svg {
  width: 100%;
  height: 100%;
  display: block;
}

.node {
  cursor: pointer;
  outline: none;
}

.node text {
  pointer-events: none;
  user-select: none;
  -webkit-user-select: none;
}

.edge {
  fill: none;
  stroke-width: 1.6;
  opacity: 0.85;
}

.box {
  stroke: none;
}

.toggle {
  fill: #fff;
  stroke: #c3cdd6;
  stroke-width: 1;
}

.zoom {
  position: absolute;
  bottom: 12px;
  right: 16px;
  display: flex;
  align-items: center;
  gap: 5px;
  background: white;
  border: 1px solid #dce2e8;
  padding: 5px;
  border-radius: 10px;
}

.zoom button {
  border: 0;
  padding: 7px 10px;
}

#zoomLabel {
  min-width: 49px;
  text-align: center;
  font-size: 12px;
}

#empty {
  position: absolute;
  left: 50%;
  top: 45%;
  transform: translate(-50%, -50%);
  max-width: 520px;
  width: 85%;
  background: #fff;
  padding: 28px;
  border: 1px solid #dce2e8;
  border-radius: 14px;
  line-height: 1.8;
}

#error {
  color: #b45309;
}

@media (max-width: 700px) {
  header {
    padding: 12px;
  }
}

#nodeEditor {
  position: absolute;
  z-index: 5;
  padding: 0;
  margin: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  transform-origin: 0 0;
  cursor: text;
  touch-action: auto;
}

#nodeEditor[hidden] {
  display: none;
}

#nodeText {
  user-select: text;
  -webkit-user-select: text;
  display: block;
  width: 100%;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  outline: none;
  background: transparent;
  box-shadow: none;
  resize: none;
  overflow: hidden;
  color: #333333;
  caret-color: #333333;
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  font-weight: 700;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

#nodeText:focus-visible {
  outline: none;
}

#nodeText:disabled {
  opacity: 1;
  -webkit-text-fill-color: #333333;
}

#editError {
  color: #ad3b24;
  font:
    12px/1.4 'Segoe UI',
    'Microsoft YaHei',
    sans-serif;
  margin-top: 4px;
  background: #fff;
}

#editError:empty {
  display: none;
}

.toggle-control {
  cursor: pointer;
  opacity: 0;
}

.node:hover .toggle-control,
.node:focus-within .toggle-control,
.toggle-control.is-collapsed {
  opacity: 1;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.toolbar button,
.toolbar select,
.toolbar input {
  font-size: 13px;
}

.toolbar button {
  padding: 7px 9px;
}

#fileInfo {
  position: absolute;
  left: 20px;
  bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  max-width: calc(100% - 230px);
  padding: 5px 8px;
  border-radius: 6px;
  background: #ffffffeb;
  pointer-events: none;
}

#fileInfo[hidden] {
  display: none;
}

.file-label {
  display: flex;
  align-items: center;
  gap: 6px;
  min-width: 0;
}

#fileName {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: #53616d;
  font-size: 13px;
  font-weight: 600;
}

#count,
#storageStatus {
  color: #71808c;
  font-size: 12px;
  white-space: nowrap;
  flex: none;
}

button:disabled {
  opacity: 0.35;
  cursor: default;
}

#shortcuts {
  margin-left: auto;
  border-radius: 50%;
  width: 38px;
  height: 38px;
  font-size: 21px;
  font-weight: 600;
  padding: 0;
  flex: none;
}

#shortcutHelp {
  width: 450px;
  max-width: calc(100vw - 28px);
  padding: 20px;
  border: 1px solid #e0e5ea;
  border-radius: 12px;
  color: #354555;
  background: #fff;
}

#shortcutHelp::backdrop {
  background: #16293930;
}

.help-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  gap: 8px;
}

#closeHelp {
  border: 0;
  display: grid;
  place-items: center;
  flex: none;
  width: 28px;
  height: 28px;
  font-size: 20px;
  line-height: 1;
  padding: 0;
}

#shortcutHelp table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

#shortcutHelp td {
  padding: 9px 0;
  border-bottom: 1px solid #f0f2f5;
}

#shortcutHelp td:last-child {
  text-align: right;
}

kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 22px;
  min-height: 22px;
  vertical-align: middle;
  box-sizing: border-box;
  font:
    12px/18px 'Segoe UI',
    sans-serif;
  background: #f4f6f8;
  border-radius: 4px;
  padding: 2px 5px;
}

#nodeMenu {
  position: fixed;
  z-index: 20;
  width: 190px;
  padding: 5px;
  background: #fff;
  border: 1px solid #e3e7eb;
  border-radius: 9px;
  box-shadow: 0 5px 22px #18324718;
}

#nodeMenu[hidden],
#nodeMenu [hidden] {
  display: none;
}

#nodeMenu:focus {
  outline: none;
}

#nodeMenu button {
  display: block;
  width: 100%;
  border: 0;
  background: transparent;
  border-radius: 5px;
  text-align: left;
  padding: 9px 12px;
  font-size: 13px;
  color: #354555;
}

#nodeMenu button:not(:disabled):hover,
#nodeMenu button:focus-visible {
  background: #f1f4f7;
  outline: none;
}

#nodeMenu button:disabled {
  opacity: 0.35;
}

.menu-separator {
  height: 1px;
  background: #edf0f3;
  margin: 4px 6px;
}

#nodeMenu .menu-delete {
  color: #ac4040;
}

.node.is-selected > .box {
  stroke: var(--branch-color, #333333);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
}

.node.drop-target > .box {
  stroke: var(--branch-color, #333333);
  stroke-width: 3;
  vector-effect: non-scaling-stroke;
}

.node.drop-invalid > .box {
  stroke: #ce5555;
  stroke-width: 3;
  vector-effect: non-scaling-stroke;
}

.node.drag-source {
  opacity: 0.35;
}

#selectionRect {
  position: absolute;
  pointer-events: none;
  z-index: 4;
  border: 1px solid #648dcb;
  background: #648dcb18;
}

#selectionRect[hidden],
#dropHint[hidden] {
  display: none;
}

#dropHint {
  position: absolute;
  pointer-events: none;
  z-index: 6;
  padding: 5px 9px;
  border-radius: 6px;
  background: #eef7f2;
  color: #267150;
  font-size: 12px;
  white-space: nowrap;
}

#dropHint[data-mode='swap'] {
  background: #fff7df;
  color: #8a6a1f;
}

#dropHint[data-mode='child'],
#dropHint[data-mode='detach'] {
  background: #eef7f2;
  color: #267150;
}

#dropHint.invalid {
  background: #fff1f1;
  color: #a43c3c;
}

#dragGhost {
  pointer-events: none;
  opacity: 0.75;
}

#dragActions {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 16px;
  z-index: 7;
  pointer-events: none;
}

#dragActions[hidden] {
  display: none;
}

.drop-zone {
  width: 150px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border: 1.5px dashed #aeb8c2;
  border-radius: 12px;
  background: #fffffff2;
  color: #687582;
  font-size: 14px;
  font-weight: 600;
  box-shadow: 0 3px 16px #23394c0b;
}

.drop-zone svg {
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.drop-zone.is-active {
  border-style: solid;
  background: #edf1f5;
  border-color: #788b9c;
  color: #40566a;
}

.drop-zone.delete {
  border-color: #d99b96;
  color: #b95048;
}

.drop-zone.delete.is-active {
  background: #fce8e6;
  border-color: #c8554b;
  color: #b1372d;
}

@media (max-width: 700px) {
  #fileInfo {
    left: 12px;
    bottom: 14px;
    max-width: calc(100% - 205px);
    flex-direction: column;
    align-items: flex-start;
    gap: 3px;
  }
  .file-label {
    max-width: 100%;
    gap: 6px;
  }
  #dragActions {
    bottom: 70px;
    gap: 10px;
  }
  .drop-zone {
    width: 130px;
    height: 56px;
  }
}

.back-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: none;
  width: 34px;
  height: 34px;
  margin-right: 4px;
  border: 1px solid #dce2e8;
  border-radius: 8px;
  background: #fff;
  color: #444;
  text-decoration: none;
}
.back-link:hover {
  background: #f0f4f7;
  color: #222;
  text-decoration: none;
}
.back-link svg {
  width: 18px;
  height: 18px;
  display: block;
}
.back-link:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 2px;
}
@media (max-width: 600px) {
  header {
    padding: 8px;
  }
  .toolbar {
    gap: 5px;
  }
  .toolbar button,
  .toolbar select {
    padding: 7px 8px;
    font-size: 12px;
  }
  #branches {
    max-width: 120px;
  }
}

#storageStatus {
  font-weight: 400;
  pointer-events: auto;
  border: 0;
  border-radius: 0;
  padding: 0;
  background: none;
  cursor: default;
  opacity: 1;
}
#storageStatus:not(:disabled) {
  cursor: pointer;
}
#storageStatus:not(:disabled):hover {
  text-decoration: underline;
}

#save {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 90px;
  min-width: 90px;
  max-width: 90px;
  flex: 0 0 90px;
}
#saveLabel {
  display: inline-block;
  width: 3em;
  text-align: center;
  white-space: nowrap;
}
.save-icon {
  display: block;
  width: 16px;
  height: 16px;
  flex: 0 0 16px;
}
.save-icon svg {
  display: none;
  width: 16px;
  height: 16px;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}
#save[data-state='dirty'] .save-dirty,
#save[data-state='saving'] .save-busy,
#save[data-state='saved'] .save-done,
#save[data-state='error'] .save-error {
  display: block;
}
#save[data-state='saved'] {
  opacity: 1;
  cursor: default;
  color: #286344;
  background: #edf7f0;
  border-color: #c4ddcc;
}
#save[data-state='saved'] .save-done {
  stroke-width: 2.5;
}
#save[data-state='saving'] {
  opacity: 1;
  color: #647484;
}
#save[data-state='error'] {
  color: #9a5a21;
  border-color: #dfc9b6;
  background: #fff9f3;
}
.save-busy {
  stroke-dasharray: 36 15;
  animation: save-spin 0.85s linear infinite;
}
@keyframes save-spin {
  to {
    transform: rotate(360deg);
  }
}
@media (prefers-reduced-motion: reduce) {
  .save-busy {
    animation: none;
  }
}

/* Read-only touch viewing; retain the original layout and control sizes. */
.touch-ui #new,
.touch-ui #save,
.touch-ui #saveAs,
.touch-ui #undo,
.touch-ui #redo,
.touch-ui #export,
.touch-ui #shortcuts {
  display: none;
}
.touch-ui .node {
  cursor: grab;
}
.touch-ui .toggle-control {
  display: none;
}
.touch-ui #svg {
  -webkit-touch-callout: none;
}

.shortcut-platform {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr;
  flex: none;
  width: 96px;
  height: 28px;
  padding: 2px;
  margin-left: auto;
  border: 1px solid #e0e5ea;
  border-radius: 8px;
  background: #f1f3f5;
}
.shortcut-platform::before {
  content: '';
  position: absolute;
  top: 2px;
  bottom: 2px;
  left: 2px;
  width: calc(50% - 2px);
  border-radius: 5px;
  background: #fff;
  box-shadow: 0 1px 3px #00000012;
  transition: transform 0.16s ease;
}
.shortcut-platform[data-platform='mac']::before {
  transform: translateX(100%);
}
.shortcut-platform label {
  position: relative;
  margin: 0;
  cursor: pointer;
  text-align: center;
}
.shortcut-platform label span {
  display: block;
  padding: 2px 6px;
  font-size: 12px;
  line-height: 18px;
  color: #71808c;
}
.shortcut-platform input:checked + span {
  color: #354555;
  font-weight: 600;
}
.shortcut-platform input:focus-visible + span {
  outline: 2px solid currentColor;
  outline-offset: 1px;
  border-radius: 5px;
}
@media (prefers-reduced-motion: reduce) {
  .shortcut-platform::before {
    transition: none;
  }
}

.app-notice {
  position: fixed;
  right: 20px;
  bottom: 76px;
  z-index: 40;
  width: 360px;
  max-width: calc(100vw - 32px);
  padding: 16px;
  border: 1px solid #e1cdbf;
  border-radius: 12px;
  background: #fffaf6;
  box-shadow: 0 8px 28px #00000014;
  color: #4c3b30;
}
.app-notice[hidden],
#noticeActions[hidden] {
  display: none;
}
.notice-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
#noticeClose {
  border: 0;
  background: transparent;
  padding: 0;
  width: 24px;
  height: 24px;
  font-size: 20px;
  line-height: 1;
  color: inherit;
}
#noticeMessage {
  margin: 9px 0 14px;
  font-size: 13px;
  line-height: 1.65;
  overflow-wrap: anywhere;
}
#noticeActions,
.confirm-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
}
#noticeActions button {
  font-size: 12px;
  padding: 6px 10px;
}
#appConfirm {
  width: 380px;
  max-width: calc(100vw - 32px);
  padding: 22px;
  border: 1px solid #dce2e8;
  border-radius: 12px;
  background: #fff;
  color: #354555;
  box-shadow: 0 12px 36px #0002;
}
#appConfirm::backdrop {
  background: #16293945;
}
#confirmMessage {
  font-size: 14px;
  line-height: 1.75;
  margin: 12px 0 22px;
}
#confirmAccept {
  background: #354555;
  border-color: #354555;
  color: #fff;
}
.touch-ui #noticeActions {
  display: none;
}

/* Fixed geometry avoids platform-specific key glyphs and emoji rendering. */
.shortcut-key-icon {
  display: block;
  width: 16px;
  height: 16px;
  min-width: 16px;
  flex: 0 0 16px;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.toolbar-icon {
  display: block;
  width: 18px;
  height: 18px;
  min-width: 18px;
  flex: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}
#undo,
#redo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
#shortcutTitle:focus {
  outline: none;
}

#insertMarker {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 12;
}
#insertMarker[hidden] {
  display: none;
}
#insertMarker svg {
  display: block;
  width: 100%;
  height: 100%;
  overflow: visible;
}
#insertPath {
  fill: none;
  stroke: #526f84;
  stroke-width: 2;
  stroke-dasharray: 6 5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
#dropHint[data-mode='insert'] {
  border-color: #8fa5b5;
  background: #f1f5f8;
  color: #405b70;
}

#insertStart,
#insertEnd {
  fill: #526f84;
}

#branchColorDialog {
  width: 320px;
  max-width: calc(100vw - 32px);
  padding: 22px;
  border: 1px solid #dce2e8;
  border-radius: 12px;
  color: #354555;
  background: #fff;
  box-shadow: 0 12px 36px #0002;
}
#branchColorDialog::backdrop {
  background: #16293930;
}
#colorSwatches {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 10px;
  margin: 18px 0;
}
#colorSwatches button {
  width: 30px;
  height: 30px;
  padding: 0;
  border: 2px solid #fff;
  border-radius: 50%;
  box-shadow: 0 0 0 1px #dce2e8;
  justify-self: center;
}
#colorSwatches button[aria-pressed='true'] {
  outline: 2px solid #354555;
  outline-offset: 2px;
}
.color-rgb {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}
.color-rgb label {
  display: grid;
  gap: 5px;
  font-size: 12px;
  color: #71808c;
}
.color-rgb input {
  width: 100%;
  min-width: 0;
  height: 36px;
  padding: 6px 8px;
  box-sizing: border-box;
  border: 1px solid #dce2e8;
  border-radius: 7px;
  background: #fff;
  color: #354555;
  font-size: 13px;
  font-family: inherit;
}
.color-rgb input:focus-visible {
  outline: 2px solid #8fa5b5;
  outline-offset: 1px;
}
.color-preview {
  display: flex;
  align-items: center;
  gap: 9px;
  margin: 16px 0;
  font-size: 13px;
}
#colorPreview {
  width: 24px;
  height: 24px;
  border-radius: 6px;
  border: 1px solid #0002;
}
#colorError {
  font-size: 12px;
  color: #a43c3c;
  margin: 0 0 12px;
}
#colorError:empty {
  display: none;
}

#reset {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

#fileDropOverlay {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  place-items: center;
  pointer-events: none;
  background: #f5f9fce8;
  backdrop-filter: blur(3px);
  -webkit-backdrop-filter: blur(3px);
}
#fileDropOverlay::before {
  content: '';
  position: absolute;
  inset: 24px;
  border: 2px dashed #8ba7bb;
  border-radius: 20px;
  z-index: -1;
}
#fileDropOverlay[hidden] {
  display: none;
}
.file-drop-card {
  display: flex;
  align-items: center;
  flex-direction: column;
  gap: 14px;
  padding: 32px 40px;
  max-width: calc(100vw - 64px);
  text-align: center;
  border: 1px solid #e3eaf0;
  border-radius: 18px;
  background: #fff;
  box-shadow: 0 12px 40px #28445b12;
  color: #354555;
}
.file-drop-icon {
  display: grid;
  place-items: center;
  width: 72px;
  height: 72px;
  border-radius: 20px;
  background: #edf4f9;
  color: #527f9f;
}
.file-drop-icon svg {
  width: 40px;
  height: 40px;
  stroke: currentColor;
  stroke-width: 2.1;
  stroke-linecap: round;
  stroke-linejoin: round;
}
#fileDropTitle {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.5;
}
.file-drop-formats {
  font-size: 13px;
  letter-spacing: 0.3px;
  color: #7b8b99;
}
#fileDropOverlay[data-blocked='true'] {
  background: #fbf8f4ed;
}
#fileDropOverlay[data-blocked='true']::before {
  border-color: #c4b39f;
}
#fileDropOverlay[data-blocked='true'] .file-drop-icon {
  background: #f6f1ea;
  color: #96764f;
}

.app-notice[data-placement='center'] {
  top: 50%;
  left: 50%;
  right: auto;
  bottom: auto;
  transform: translate(-50%, -50%);
  width: 400px;
  padding: 20px;
  box-shadow: 0 14px 48px #25394b24;
}