*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --split: 50;
  --sidebar-width: 240px;
  --toolbar-height: 48px;

  --brand: #007acc;
  --accent: #007acc;
  --success: #2da44e;
  --success-hover: #2c974b;
  --primary: #0e639c;
  --primary-hover: #1177bb;

  --bg: #1e1e1e;
  --surface: #252526;
  --surface-raised: #2d2d2d;
  --surface-hover: #3c3c3c;
  --border: #3c3c3c;
  --text: #cccccc;
  --text-muted: #858585;

  --active-bg: #094771;
  --error-bg: #5a1d1d;
  --error-text: #f48771;

  --radius: 6px;
  --radius-sm: 4px;
  --shadow-toolbar: 0 1px 0 rgba(0, 0, 0, 0.3);
  --shadow-popover: 0 8px 24px rgba(0, 0, 0, 0.45);
}

[hidden] {
  display: none !important;
}

body.is-logged-in .btn-login {
  display: none !important;
}

body.is-logged-out .user-menu {
  display: none !important;
}

html,
body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, sans-serif;
  font-size: 14px;
}

button:focus-visible,
select:focus-visible,
a:focus-visible,
.pane-resizer:focus-visible,
.mobile-tab:focus-visible,
.icon-btn:focus-visible,
.user-menu-trigger:focus-visible,
.menu-item:focus-visible,
.brand-link:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: var(--toolbar-height);
  padding: 0 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-toolbar);
  flex-shrink: 0;
  flex-wrap: wrap;
}

.toolbar .spacer {
  flex: 1;
  min-width: 8px;
}

.toolbar-brand {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
  border-radius: var(--radius-sm);
  padding: 4px 6px;
  margin: -4px -6px;
  transition: color 0.15s;
}

.brand-link:hover {
  color: #fff;
}

.brand-logo {
  color: var(--brand);
  flex-shrink: 0;
}

.brand-name {
  white-space: nowrap;
}

.toolbar-center {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.toolbar-group {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.toolbar-divider {
  width: 1px;
  align-self: stretch;
  margin: 8px 0;
  background: var(--border);
  flex-shrink: 0;
}

.icon-btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--text);
  min-width: 32px;
  height: 32px;
  padding: 0 8px;
  font: inherit;
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.icon-btn:hover {
  background: var(--surface-hover);
  border-color: var(--accent);
}

.toolbar button,
.toolbar a.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--text);
  padding: 7px 14px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background 0.15s, border-color 0.15s;
}

.toolbar button:hover,
.toolbar a.btn:hover {
  background: var(--surface-hover);
  border-color: var(--accent);
}

.toolbar button.primary {
  background: var(--primary);
  border-color: var(--accent);
  color: #fff;
  font-weight: 600;
}

.toolbar button.primary:hover:not(:disabled) {
  background: var(--primary-hover);
}

.toolbar button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-icon-text {
  padding: 7px 10px;
}

.btn-icon-text svg {
  flex-shrink: 0;
  opacity: 0.85;
}

.btn-icon-text span {
  font-size: 13px;
}

.btn-login {
  appearance: none;
  border: 1px solid transparent;
  background: var(--success);
  color: #fff;
  padding: 8px 14px;
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: background 0.15s;
}

.btn-login:hover {
  background: var(--success-hover);
}

.layout-select-wrap {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-muted);
}

.layout-select-wrap select {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--text);
  padding: 7px 10px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background 0.15s, border-color 0.15s;
}

.layout-select-wrap select:hover {
  background: var(--surface-hover);
  border-color: var(--accent);
}

.save-group {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

#btn-save-help {
  min-width: 28px;
  padding: 7px 8px;
  justify-content: center;
  font-weight: 600;
  color: var(--text-muted);
}

#btn-save-help:hover,
#btn-save-help.active {
  color: var(--text);
  border-color: var(--accent);
}

.popover {
  border-radius: var(--radius);
  box-shadow: var(--shadow-popover);
}

.save-help-popover {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  z-index: 200;
  width: min(420px, calc(100vw - 24px));
  padding: 14px 16px;
  background: var(--surface);
  border: 1px solid var(--accent);
  font-size: 13px;
  line-height: 1.5;
}

.save-help-popover[hidden],
.user-menu-popover[hidden] {
  display: none;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  background: rgba(0, 0, 0, 0.55);
}

.modal-backdrop[hidden] {
  display: none;
}

.name-dialog {
  width: min(400px, 100%);
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--accent);
  font-size: 13px;
  line-height: 1.5;
}

.name-dialog-title {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}

.name-dialog-hint {
  margin: 0 0 12px;
  color: var(--text-muted);
  font-size: 12px;
}

.name-dialog-input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  font: inherit;
  font-size: 13px;
}

.name-dialog-input:focus {
  outline: none;
  border-color: var(--accent);
}

.name-dialog-error {
  margin: 8px 0 0;
  color: var(--error-text);
  font-size: 12px;
}

.name-dialog-error[hidden] {
  display: none;
}

.name-dialog-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 16px;
}

.name-dialog-btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--text);
  padding: 6px 14px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background 0.15s, border-color 0.15s;
}

.name-dialog-btn:hover {
  background: var(--surface-hover);
}

.name-dialog-btn.primary {
  background: var(--primary);
  border-color: var(--accent);
  color: #fff;
}

.name-dialog-btn.primary:hover {
  background: var(--primary-hover);
}

.name-dialog-btn.name-dialog-overwrite {
  border-color: var(--error-text);
  color: var(--error-text);
}

.name-dialog-btn.name-dialog-overwrite:hover {
  background: var(--error-bg);
}

.save-help-popover p {
  margin: 0 0 8px;
  color: var(--text);
}

.save-help-popover p:last-child {
  margin-bottom: 0;
}

.save-help-popover .hint {
  color: var(--text-muted);
  font-size: 12px;
}

.save-help-path {
  display: block;
  margin: 8px 0;
  padding: 8px 10px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-family: 'Cascadia Code', 'Consolas', monospace;
  font-size: 12px;
  color: var(--text);
  word-break: break-all;
}

.save-help-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.save-help-actions a,
.save-help-actions button {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--accent);
  padding: 4px 10px;
  font: inherit;
  font-size: 12px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s;
}

.save-help-actions a:hover,
.save-help-actions button:hover {
  background: var(--surface-hover);
  border-color: var(--accent);
}

.user-menu {
  position: relative;
}

.user-menu-trigger {
  appearance: none;
  border: 1px solid transparent;
  background: transparent;
  color: var(--text);
  padding: 4px 8px 4px 4px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  border-radius: var(--radius);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: background 0.15s, border-color 0.15s;
}

.user-menu-trigger:hover,
.user-menu-trigger.active {
  background: var(--surface-raised);
  border-color: var(--border);
}

.user-menu-trigger img {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1px solid var(--border);
}

.user-menu-name {
  max-width: 120px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.user-menu-chevron {
  color: var(--text-muted);
  flex-shrink: 0;
}

.user-menu-popover {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  z-index: 200;
  min-width: 180px;
  padding: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
}

.menu-item {
  appearance: none;
  border: none;
  background: transparent;
  color: var(--text);
  width: 100%;
  padding: 8px 10px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 10px;
  text-align: left;
  transition: background 0.15s;
}

.menu-item:hover {
  background: var(--surface-hover);
}

.menu-item svg {
  color: var(--text-muted);
  flex-shrink: 0;
}

.share-url {
  font-size: 12px;
  color: var(--text-muted);
  max-width: 200px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.main {
  display: flex;
  flex: 1;
  min-height: 0;
  position: relative;
}

.sidebar-backdrop {
  position: fixed;
  inset: var(--toolbar-height) 0 22px 0;
  z-index: 150;
  background: rgba(0, 0, 0, 0.45);
}

.sidebar-backdrop[hidden] {
  display: none;
}

.sidebar {
  width: 0;
  overflow: hidden;
  background: var(--surface);
  border-right: none;
  display: none;
  flex-direction: column;
  flex-shrink: 0;
  transition: width 0.2s ease;
}

.sidebar.visible {
  display: flex;
}

body.sidebar-open .sidebar.visible {
  width: var(--sidebar-width);
  border-right: 1px solid var(--border);
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px 10px 10px 12px;
  border-bottom: 1px solid var(--border);
  min-width: var(--sidebar-width);
}

.sidebar-header h3 {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  white-space: nowrap;
}

.sidebar-new-btn {
  min-width: 28px;
  height: 28px;
  font-size: 20px;
  font-weight: 400;
  color: var(--accent);
}

.sidebar-new-btn:hover {
  color: #fff;
  background: var(--primary);
  border-color: var(--accent);
}

.diagram-list {
  list-style: none;
  margin: 0;
  padding: 6px;
  overflow-y: auto;
  flex: 1;
  min-width: var(--sidebar-width);
}

.diagram-list-item {
  display: flex;
  align-items: center;
  gap: 2px;
}

.diagram-list-item .diagram-item-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  min-width: 0;
  text-align: left;
  padding: 8px 10px;
  border: none;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background 0.15s;
}

.context-menu {
  position: fixed;
  z-index: 300;
  min-width: 140px;
  padding: 4px;
  background: var(--surface);
  border: 1px solid var(--border);
}

.context-menu[hidden] {
  display: none;
}

.context-menu button {
  display: block;
  width: 100%;
  padding: 8px 12px;
  border: none;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 13px;
  text-align: left;
  cursor: pointer;
  border-radius: var(--radius-sm);
}

.context-menu button:hover {
  background: var(--surface-hover);
  color: var(--accent);
}

.context-menu-separator {
  height: 1px;
  margin: 4px 8px;
  background: var(--border);
}

.context-menu-danger {
  color: var(--error-text);
}

.context-menu-danger:hover {
  background: var(--error-bg);
  color: var(--error-text);
}

.diagram-item-icon {
  color: var(--text-muted);
  font-size: 10px;
  flex-shrink: 0;
}

.diagram-item-label {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.diagram-list-item .diagram-item-btn:hover {
  background: var(--surface-hover);
}

.diagram-list-item .diagram-item-btn.active {
  background: var(--active-bg);
  color: #fff;
}

.diagram-list-item .diagram-item-btn.active .diagram-item-icon {
  color: var(--accent);
}

.workbench-area {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-width: 0;
  min-height: 0;
}

.mobile-tabs {
  display: none;
  flex-shrink: 0;
  gap: 0;
  padding: 0 12px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.mobile-tab {
  appearance: none;
  border: none;
  border-bottom: 2px solid transparent;
  background: transparent;
  color: var(--text-muted);
  padding: 10px 16px;
  font: inherit;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}

.mobile-tab:hover {
  color: var(--text);
}

.mobile-tab.active {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.workbench {
  display: flex;
  flex: 1;
  min-width: 0;
  min-height: 0;
}

.pane {
  display: flex;
  flex-direction: column;
  min-height: 0;
  min-width: 0;
}

.pane-source {
  flex: 0 0 calc(var(--split) * 1%);
  border-right: 1px solid var(--border);
}

.pane-preview {
  flex: 1;
}

.pane-resizer {
  flex-shrink: 0;
  width: 4px;
  margin: 0 -2px;
  cursor: col-resize;
  background: transparent;
  position: relative;
  z-index: 1;
  transition: background 0.15s;
}

.pane-resizer::after {
  content: '';
  position: absolute;
  inset: 0 -2px;
}

.pane-resizer:hover,
.pane-resizer.is-active,
.pane-resizer:focus-visible {
  background: var(--accent);
}

body.is-resizing {
  cursor: col-resize;
  user-select: none;
}

body.is-resizing * {
  cursor: col-resize !important;
}

.pane-header {
  padding: 8px 12px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  flex-shrink: 0;
}

.editor-root {
  flex: 1;
  min-height: 0;
  overflow: hidden;
}

.editor-root .cm-editor {
  height: 100%;
}

.preview-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}

.preview-controls {
  display: flex;
  align-items: center;
  gap: 4px;
  text-transform: none;
  letter-spacing: normal;
}

.preview-controls button {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-raised);
  color: var(--text);
  min-width: 26px;
  padding: 3px 7px;
  font: inherit;
  font-size: 12px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background 0.15s, border-color 0.15s;
}

.preview-controls button:hover:not(:disabled) {
  background: var(--surface-hover);
  border-color: var(--accent);
}

.preview-controls button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.zoom-label {
  min-width: 40px;
  text-align: center;
  font-size: 11px;
  color: var(--text-muted);
}

#preview.preview-viewport {
  flex: 1;
  overflow: hidden;
  position: relative;
  background: var(--bg);
  cursor: grab;
  touch-action: none;
}

#preview.preview-viewport.is-panning {
  cursor: grabbing;
}

#preview.preview-viewport.preview-disabled {
  cursor: default;
}

#preview-canvas {
  transform-origin: 0 0;
  will-change: transform;
}

.preview-error {
  position: absolute;
  inset: 24px;
  color: var(--error-text);
  font-family: 'Cascadia Code', 'Consolas', monospace;
  font-size: 12px;
  white-space: pre-wrap;
  overflow: auto;
}

.status {
  flex-shrink: 0;
  padding: 4px 14px;
  background: var(--surface);
  color: var(--text-muted);
  font-size: 12px;
  border-top: 1px solid var(--border);
  min-height: 22px;
  display: none;
}

.status.visible {
  display: block;
  background: var(--accent);
  color: #fff;
}

.status.error {
  background: var(--error-bg);
  color: var(--error-text);
}

@media (max-width: 768px) {
  .toolbar {
    padding: 0 10px;
    gap: 8px;
  }

  .toolbar-divider {
    display: none;
  }

  .toolbar-center {
    order: 3;
    width: 100%;
    flex-basis: 100%;
  }

  .brand-name {
    display: none;
  }

  .btn-icon-text span {
    display: none;
  }

  .btn-icon-text {
    padding: 7px 9px;
  }

  .user-menu-name {
    display: none;
  }

  .user-menu-trigger {
    padding: 4px;
  }

  .toolbar-secondary .share-url {
    display: none;
  }

  .layout-select-wrap {
    font-size: 0;
  }

  .layout-select-wrap select {
    font-size: 13px;
  }

  .mobile-tabs {
    display: flex;
  }

  .pane-resizer {
    display: none;
  }

  .workbench {
    position: relative;
  }

  .pane-source,
  .pane-preview {
    flex: 1;
    border-right: none;
  }

  body.tab-source .pane-preview {
    display: none;
  }

  body.tab-preview .pane-source {
    display: none;
  }

  .sidebar.visible {
    position: fixed;
    top: var(--toolbar-height);
    left: 0;
    bottom: 22px;
    z-index: 200;
    width: var(--sidebar-width);
    transform: translateX(-100%);
    transition: transform 0.2s ease;
    border-right: 1px solid var(--border);
    box-shadow: var(--shadow-popover);
  }

  body.sidebar-open .sidebar.visible {
    transform: translateX(0);
  }

}

@media (max-width: 480px) {
  .btn-login span {
    display: none;
  }

  .btn-login {
    padding: 8px 10px;
  }

  .btn-login svg {
    width: 18px;
    height: 18px;
  }
}