* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root,
[data-theme="dark"] {
  --bg: #1e1e2e;
  --surface: #181825;
  --overlay: #313244;
  --text: #cdd6f4;
  --subtext: #a6adc8;
  --blue: #89b4fa;
  --green: #a6e3a1;
  --red: #f38ba8;
  --yellow: #f9e2af;
  --border: #45475a;
  --tab-active: #1e1e2e;
  --tab-inactive: #11111b;
  --header-bg: #11111b;
  --preview-bg: #fff;
  --preview-placeholder-bg: #f5f5f5;
  --preview-placeholder-color: #666;
  --dialog-backdrop: rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
  --bg: #eff1f5;
  --surface: #e6e9ef;
  --overlay: #ccd0da;
  --text: #4c4f69;
  --subtext: #6c6f85;
  --blue: #1e66f5;
  --green: #40a02b;
  --red: #d20f39;
  --yellow: #df8e1d;
  --border: #bcc0cc;
  --tab-active: #eff1f5;
  --tab-inactive: #dce0e8;
  --header-bg: #dce0e8;
  --preview-bg: #fff;
  --preview-placeholder-bg: #f5f5f5;
  --preview-placeholder-color: #666;
  --dialog-backdrop: rgba(0, 0, 0, 0.3);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  height: 48px;
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

header h1 {
  font-size: 16px;
  font-weight: 600;
  color: var(--blue);
}

#view-only-badge {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--yellow);
  border: 1px solid var(--yellow);
  border-radius: 3px;
  padding: 2px 6px;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

#status {
  font-size: 13px;
  color: var(--subtext);
}

#docs-link {
  font-size: 12px;
  color: var(--subtext);
  text-decoration: none;
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 4px;
  transition: border-color 0.15s, color 0.15s;
}

#docs-link:hover {
  border-color: var(--blue);
  color: var(--text);
}

#download-group {
  position: relative;
}

#download-btn,
#upload-btn {
  padding: 5px 12px;
  background: none;
  color: var(--subtext);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 12px;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

#download-btn:hover,
#upload-btn:hover {
  border-color: var(--blue);
  color: var(--text);
}

#download-menu {
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: 4px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
  z-index: 300;
  min-width: 150px;
}

#download-menu.hidden {
  display: none;
}

#download-menu button {
  display: block;
  width: 100%;
  padding: 8px 14px;
  background: none;
  color: var(--text);
  border: none;
  font-size: 12px;
  text-align: left;
  cursor: pointer;
  transition: background 0.1s;
}

#download-menu button:hover {
  background: var(--overlay);
}

#download-menu button + button {
  border-top: 1px solid var(--border);
}

#new-session-btn {
  padding: 5px 12px;
  background: none;
  color: var(--subtext);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 12px;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

#new-session-btn:hover {
  border-color: var(--blue);
  color: var(--text);
}

#theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-size: 16px;
  cursor: pointer;
  padding: 4px 8px;
  line-height: 1;
  transition: border-color 0.15s;
}

#theme-toggle:hover {
  border-color: var(--blue);
}

#app {
  display: flex;
  flex: 1;
  overflow: hidden;
}

#editor-panel {
  display: flex;
  flex-direction: column;
  width: 50%;
  min-width: 300px;
}

#tabs-bar {
  display: flex;
  background: var(--tab-inactive);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#tabs {
  display: flex;
  overflow-x: auto;
  flex: 1;
}

.tab {
  display: flex;
  align-items: center;
  border-right: 1px solid var(--border);
}

.tab-btn {
  padding: 8px 12px;
  background: var(--tab-inactive);
  color: var(--subtext);
  border: none;
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.1s, color 0.1s;
}

.tab-btn:hover {
  background: var(--overlay);
}

.tab-btn.active {
  background: var(--tab-active);
  color: var(--text);
  border-bottom: 2px solid var(--blue);
}

.tab-btn.dirty::after {
  content: " *";
  color: var(--yellow);
}

.tab-delete {
  background: none;
  border: none;
  color: var(--subtext);
  font-size: 14px;
  cursor: pointer;
  padding: 0 6px;
  opacity: 0;
  transition: opacity 0.1s, color 0.1s;
}

.tab:hover .tab-delete {
  opacity: 1;
}

.tab-delete:hover {
  color: var(--red);
}

#new-file-btn {
  padding: 4px 12px;
  background: none;
  border: none;
  color: var(--subtext);
  font-size: 18px;
  cursor: pointer;
  flex-shrink: 0;
  transition: color 0.1s;
}

#new-file-btn:hover {
  color: var(--blue);
}

#editor-container {
  flex: 1;
  overflow: auto;
  background: var(--bg);
}

#editor-container .cm-editor {
  height: 100%;
}

#editor-container .cm-scroller {
  overflow: auto;
}

#editor-statusbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 2px 10px;
  background: var(--tab-inactive);
  border-top: 1px solid var(--border);
  font-size: 11px;
  color: var(--subtext);
  flex-shrink: 0;
  height: 26px;
}

#editor-file-info {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#editor-statusbar-right {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

#editor-statusbar-right label {
  color: var(--subtext);
  font-size: 11px;
}

.statusbar-link {
  color: var(--subtext);
  text-decoration: none;
  font-size: 11px;
  transition: color 0.15s;
}

.statusbar-link:hover {
  color: var(--blue);
}

.statusbar-sep {
  width: 1px;
  height: 12px;
  background: var(--border);
}

#editor-statusbar #editor-theme {
  padding: 1px 4px;
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 3px;
  font-size: 11px;
  cursor: pointer;
}

#editor-statusbar #editor-theme:focus {
  outline: none;
  border-color: var(--blue);
}

#divider {
  width: 4px;
  background: var(--border);
  cursor: col-resize;
  flex-shrink: 0;
}

#divider:hover {
  background: var(--blue);
}

#preview-panel {
  flex: 1;
  min-width: 300px;
  position: relative;
  background: var(--preview-bg);
}

#preview-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--preview-placeholder-color);
  font-size: 15px;
  background: var(--preview-placeholder-bg);
}

#preview-frame {
  width: 100%;
  height: 100%;
  border: none;
  display: none;
}

#preview-frame.visible {
  display: block;
}

/* New file dialog */
#new-file-dialog {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--dialog-backdrop);
  z-index: 200;
}

#new-file-dialog.hidden {
  display: none;
}

.dialog-content {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
  min-width: 360px;
}

.dialog-content h3 {
  font-size: 15px;
  margin-bottom: 12px;
  color: var(--text);
}

#new-file-help {
  font-size: 12px;
  line-height: 1.6;
  color: var(--subtext);
  margin-bottom: 14px;
  padding: 8px 10px;
  background: var(--bg);
  border-radius: 4px;
  border: 1px solid var(--border);
}

#new-file-help code {
  font-size: 11px;
  background: var(--overlay);
  padding: 1px 4px;
  border-radius: 3px;
}

#new-file-help a {
  color: var(--blue);
}

.dialog-row {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}

.dialog-row select,
.dialog-row input {
  padding: 6px 10px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 13px;
}

.dialog-row select {
  width: 130px;
}

.dialog-row input {
  flex: 1;
}

.dialog-row input:focus,
.dialog-row select:focus {
  outline: none;
  border-color: var(--blue);
}

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

.dialog-actions button {
  padding: 6px 16px;
  border-radius: 4px;
  font-size: 13px;
  cursor: pointer;
  border: 1px solid var(--border);
  background: var(--overlay);
  color: var(--text);
  transition: border-color 0.15s;
}

.dialog-actions button:hover {
  border-color: var(--blue);
}

#new-file-add {
  background: var(--blue) !important;
  color: #fff !important;
  border-color: var(--blue) !important;
}

[data-theme="dark"] #new-file-add {
  color: var(--header-bg) !important;
}

/* Mobile panel toggle - hidden on desktop */
#mobile-panel-toggle {
  display: none;
  background: var(--tab-inactive);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#mobile-panel-toggle button {
  flex: 1;
  padding: 8px;
  background: var(--tab-inactive);
  color: var(--subtext);
  border: none;
  border-bottom: 2px solid transparent;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}

#mobile-panel-toggle button.active {
  color: var(--text);
  border-bottom-color: var(--blue);
}

/* Responsive - mobile */
@media (max-width: 768px) {
  header {
    padding: 0 8px;
    height: 44px;
    flex-wrap: nowrap;
  }

  header h1 {
    font-size: 14px;
  }

  .header-right {
    gap: 4px;
  }

  #status {
    display: none;
  }

  #docs-link,
  #download-btn,
  #upload-btn,
  #new-session-btn {
    padding: 4px 8px;
    font-size: 11px;
  }

  #mobile-panel-toggle {
    display: flex;
  }

  #app {
    flex-direction: column;
    overflow: hidden;
    min-height: 0;
  }

  #editor-panel {
    width: 100% !important;
    min-width: 0;
  }

  #divider {
    display: none;
  }

  #preview-panel {
    min-width: 0;
  }

  #app.show-preview #editor-panel {
    display: none;
  }

  #app.show-preview #preview-panel {
    display: flex;
    flex-direction: column;
    flex: 1;
  }

  #app:not(.show-preview) #preview-panel {
    display: none;
  }

  #app:not(.show-preview) #editor-panel {
    flex: 1;
    overflow: hidden;
  }

  #editor-container {
    min-height: 0;
  }

  #editor-statusbar {
    gap: 4px;
  }

  #editor-statusbar-right label {
    display: none;
  }

  .statusbar-link {
    font-size: 10px;
  }

  .dialog-content {
    min-width: 0;
    width: calc(100vw - 32px);
    max-width: 400px;
  }

  .dialog-row {
    flex-direction: column;
  }

  .dialog-row select {
    width: 100%;
  }

  .tab-btn {
    padding: 6px 10px;
    font-size: 12px;
  }
}

/* Output panel */
#output-panel {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  max-height: 200px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  z-index: 100;
  display: flex;
  flex-direction: column;
}

#output-panel.hidden {
  display: none;
}

#output-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 12px;
  background: var(--overlay);
  font-size: 13px;
  font-weight: 600;
  flex-shrink: 0;
}

#output-header button {
  background: none;
  border: none;
  color: var(--text);
  font-size: 18px;
  cursor: pointer;
  padding: 0 4px;
}

#output-content {
  padding: 8px 12px;
  font-family: "Fira Code", "Cascadia Code", "JetBrains Mono", monospace;
  font-size: 12px;
  overflow: auto;
  flex: 1;
  color: var(--subtext);
  white-space: pre-wrap;
  word-break: break-all;
}