/* ====================================================================
 * URDF Studio — Web build stylesheet.
 *
 * Loaded AFTER media/styles.css so it can override the VS Code-style
 * chrome the renderer ships with. The renderer reads its colors from
 * --vscode-* custom properties; we redefine those here so the whole
 * side panel inherits the new palette for free.
 * ==================================================================== */

:root {
  /* `color-scheme` lights up the CSS `light-dark()` function — without
     this, `light-dark()` falls back to its `light` argument. The
     theme-toggle button below switches this between `light` and `dark`
     to override prefers-color-scheme on demand. */
  color-scheme: light dark;

  /* Palette — one declaration per token using light-dark() instead of a
     duplicated @media (prefers-color-scheme: dark) block. */
  --us-bg:             light-dark(#ffffff, #131314);
  --us-bg-elevated:    light-dark(#f8f9fa, #1e1f20);
  --us-bg-subtle:      light-dark(#f1f3f4, #28292a);
  --us-surface:        light-dark(#ffffff, #1e1f20);
  --us-fg:             light-dark(#1f1f1f, #e3e3e3);
  --us-fg-muted:       light-dark(#5f6368, #9aa0a6);
  --us-fg-faint:       light-dark(#80868b, #80868b);
  --us-border:         light-dark(#e8eaed, #3c4043);
  --us-border-strong:  light-dark(#dadce0, #5f6368);
  --us-accent:         light-dark(#1a73e8, #8ab4f8);
  --us-accent-hover:   light-dark(#1967d2, #aecbfa);
  --us-accent-soft:    light-dark(rgba(26, 115, 232, 0.08), rgba(138, 180, 248, 0.12));
  --us-accent-soft-hover: light-dark(rgba(26, 115, 232, 0.14), rgba(138, 180, 248, 0.2));
  --us-on-accent:      light-dark(#ffffff, #062e6f);
  --us-success:        light-dark(#1e8e3e, #81c995);
  --us-warning:        light-dark(#f29900, #fdd663);
  --us-danger:         light-dark(#d93025, #f28b82);
  --us-shadow-sm: light-dark(
    0 1px 2px rgba(60, 64, 67, 0.08), 0 1px 3px 1px rgba(60, 64, 67, 0.05),
    0 1px 2px rgba(0, 0, 0, 0.3),     0 1px 3px 1px rgba(0, 0, 0, 0.15)
  );
  --us-shadow-md: light-dark(
    0 1px 3px rgba(60, 64, 67, 0.1),  0 4px 8px 3px rgba(60, 64, 67, 0.05),
    0 1px 3px rgba(0, 0, 0, 0.4),     0 4px 8px 3px rgba(0, 0, 0, 0.15)
  );
  --us-shadow-lg: light-dark(
    0 2px 6px rgba(60, 64, 67, 0.1),  0 8px 24px 4px rgba(60, 64, 67, 0.1),
    0 2px 6px rgba(0, 0, 0, 0.4),     0 8px 24px 4px rgba(0, 0, 0, 0.3)
  );

  /* Spacing scale (8px grid). */
  --us-space-1: 4px;
  --us-space-2: 8px;
  --us-space-3: 12px;
  --us-space-4: 16px;
  --us-space-5: 24px;
  --us-space-6: 32px;
  --us-space-8: 48px;

  /* Radii. */
  --us-radius-sm: 6px;
  --us-radius-md: 10px;
  --us-radius-lg: 16px;
  --us-radius-pill: 999px;

  /* Typography. */
  --us-font-sans: 'Google Sans', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --us-font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  /* ---- Renderer compatibility shims. The renderer's HTML uses
         var(--vscode-*) names; we alias them to our tokens. ---- */
  --vscode-font-family: var(--us-font-sans);
  --vscode-foreground: var(--us-fg);
  --vscode-editor-background: var(--us-bg);
  --vscode-editor-foreground: var(--us-fg);
  --vscode-sideBar-background: var(--us-bg-elevated);
  --vscode-panel-border: var(--us-border);
  --vscode-input-background: var(--us-surface);
  --vscode-input-foreground: var(--us-fg);
  --vscode-input-border: var(--us-border-strong);
  --vscode-button-background: var(--us-accent);
  --vscode-button-foreground: var(--us-on-accent);
  --vscode-button-hoverBackground: var(--us-accent-hover);
  --vscode-toolbar-hoverBackground: var(--us-bg-subtle);
  --vscode-list-activeSelectionBackground: var(--us-accent-soft);
  --vscode-list-hoverBackground: var(--us-bg-subtle);
  --vscode-textLink-foreground: var(--us-accent);
  --vscode-editorWidget-background: var(--us-surface);
  --vscode-errorForeground: var(--us-danger);
  --vscode-editorWarning-foreground: var(--us-warning);
  --vscode-editorInfo-foreground: var(--us-accent);
}

/* Theme override. The default `color-scheme: light dark` lets
   `light-dark()` follow the OS; pinning it forces either side. */
:root[data-theme='light'] { color-scheme: light; }
:root[data-theme='dark']  { color-scheme: dark; }
/* data-theme='system' is the default — no override needed. */

/* View Transitions API: a smooth crossfade when the theme flips. The
   transition swaps the whole page, so we pick generous timings. */
@supports (view-transition-name: root) {
  ::view-transition-old(root),
  ::view-transition-new(root) {
    animation-duration: 380ms;
    animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
  }
}

/* Respect reduced motion across the entire app. */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  width: 100%;
  margin: 0;
  overflow: hidden;
  font-family: var(--us-font-sans);
  color: var(--us-fg);
  background: var(--us-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
}

/* Subtle radial gradient backdrop — visible behind the topbar's translucent
   surface. Strong enough to give the page a sense of depth without competing
   with the 3D viewport. */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: -1;
  --backdrop-1: light-dark(rgba(26, 115, 232, 0.08), rgba(138, 180, 248, 0.07));
  --backdrop-2: light-dark(rgba(168, 67, 233, 0.05), rgba(197, 138, 248, 0.05));
  background:
    radial-gradient(1200px 600px at 8% -20%, var(--backdrop-1), transparent 60%),
    radial-gradient(900px 500px at 100% 0%, var(--backdrop-2), transparent 60%);
}

/* ===== Topbar ===== */

#topbar {
  position: relative;
  background: color-mix(in srgb, var(--us-bg) 85%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--us-border);
  z-index: 5;
}

.topbar-row {
  display: flex;
  align-items: center;
  gap: var(--us-space-3);
  /* Same fluid gutters as the renderer toolbar below so the left/right
     edges of all three rows (topbar / toolbar / subtoolbar) stay flush.
     The previous max-width: 1800px caused a ~12px offset on wide screens. */
  padding: var(--us-space-3) clamp(var(--us-space-4), 2.5vw, var(--us-space-8));
  min-height: 60px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--us-space-2);
  font-family: var(--us-font-sans);
  font-weight: 600;
  font-size: 18px;
  letter-spacing: -0.01em;
  color: var(--us-fg);
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--us-radius-sm);
  display: block;
  flex-shrink: 0;
  /* Tiny rim so the icon doesn't blend into the topbar bg. */
  box-shadow: 0 0 0 1px light-dark(rgba(0, 0, 0, 0.06), rgba(255, 255, 255, 0.08));
}

.brand-tag {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  margin-left: var(--us-space-1);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--us-accent);
  background: var(--us-accent-soft);
  border-radius: var(--us-radius-pill);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: var(--us-space-2);
  margin-left: auto;
  flex-wrap: wrap;
}

/* ===== Buttons (override styles.css) ===== */

button,
input,
select,
textarea {
  font-family: var(--us-font-sans);
  font-size: 13px;
}

#topbar button,
#topbar a.ghost-link,
#topbar select {
  height: 36px;
  padding: 0 14px;
  /* Rounded rectangle (matches dialog actions, renderer toolbar buttons,
     and the segmented theme switcher). Previous pill style felt heavy
     against the page's geometry. */
  border-radius: var(--us-radius-md);
  border: 1px solid var(--us-border-strong);
  background: var(--us-surface);
  color: var(--us-fg);
  font-weight: 500;
  letter-spacing: -0.005em;
  cursor: pointer;
  transition: background 120ms ease, border-color 120ms ease, transform 80ms ease, box-shadow 120ms ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  text-decoration: none;
}

#topbar button:hover,
#topbar a.ghost-link:hover {
  background: var(--us-bg-subtle);
  border-color: var(--us-border-strong);
}

#topbar button:active {
  transform: scale(0.98);
}

#topbar button.primary {
  background: var(--us-accent);
  color: var(--us-on-accent);
  border-color: transparent;
  box-shadow: 0 1px 2px rgba(26, 115, 232, 0.18), 0 1px 3px 1px rgba(26, 115, 232, 0.1);
}

#topbar button.primary:hover {
  background: var(--us-accent-hover);
  box-shadow: 0 2px 4px rgba(26, 115, 232, 0.25), 0 2px 6px 2px rgba(26, 115, 232, 0.12);
}

#topbar button.primary:disabled {
  background: var(--us-bg-subtle);
  color: var(--us-fg-faint);
  cursor: not-allowed;
  box-shadow: none;
}

#topbar button.ghost {
  background: transparent;
  border-color: transparent;
  color: var(--us-fg-muted);
}

#topbar button.ghost:hover {
  background: var(--us-bg-subtle);
  color: var(--us-fg);
}

/* Icon-only buttons (Settings, Help). Match the height (36px) of the
   adjacent labelled buttons but use a larger glyph so the ⚙ and ?
   carry the same visual weight as text-bearing siblings. */
#help-btn,
#settings-btn {
  width: 40px;
  padding: 0;
  font-size: 20px;
  font-weight: 500;
  line-height: 1;
  justify-content: center;
}

#file-select {
  min-width: 240px;
  max-width: 380px;
  padding-right: 32px;
  background-image: linear-gradient(45deg, transparent 50%, var(--us-fg-muted) 50%),
    linear-gradient(135deg, var(--us-fg-muted) 50%, transparent 50%);
  background-position:
    calc(100% - 14px) 50%,
    calc(100% - 9px) 50%;
  background-size: 5px 5px;
  background-repeat: no-repeat;
  appearance: none;
  -webkit-appearance: none;
}

#file-select:disabled {
  color: var(--us-fg-faint);
  cursor: not-allowed;
}

.topbar-status {
  padding: 8px var(--us-space-5) 10px;
  font-size: 12.5px;
  color: var(--us-fg-muted);
  border-top: 1px solid var(--us-border);
  background: var(--us-bg-elevated);
}

.topbar-status[data-kind='error'] {
  color: var(--us-danger);
}

.topbar-status[data-kind='progress'] {
  color: var(--us-accent);
}

/* ===== Renderer chrome overrides =====
   The renderer ships its own toolbar/subtoolbar/side panel from styles.css.
   We refine spacing, rounded corners, and hover states. */

#app {
  position: relative;
  height: 100%;
  width: 100%;
  overflow: hidden;
}

#app .shell {
  height: 100%;
  background: var(--us-bg);
}

#app .toolbar,
#app .subtoolbar {
  border-bottom: 1px solid var(--us-border);
  background: color-mix(in srgb, var(--us-bg-elevated) 60%, transparent);
  /* Scale gutters with viewport so the toolbar doesn't look orphaned on
     ultra-wide screens, but stays compact on a laptop. */
  padding: 10px clamp(var(--us-space-4), 2.5vw, var(--us-space-8));
  gap: 12px;
}

#app .toolbar button,
#app .subtoolbar button,
#app .toolbar select,
#app .subtoolbar select {
  height: 32px;
  padding: 0 12px;
  border-radius: var(--us-radius-sm);
  border: 1px solid var(--us-border);
  background: var(--us-surface);
  color: var(--us-fg);
  font-weight: 500;
  cursor: pointer;
  transition: background 100ms ease, border-color 100ms ease;
}

#app .toolbar button:hover,
#app .subtoolbar button:hover,
#app .toolbar select:hover,
#app .subtoolbar select:hover {
  background: var(--us-bg-subtle);
}

#app .toolbar button.primary {
  background: var(--us-accent);
  color: var(--us-on-accent);
  border-color: transparent;
}

#app .toolbar button.primary:hover {
  background: var(--us-accent-hover);
}

#app .toolbar label,
#app .subtoolbar label {
  font-size: 12.5px;
  color: var(--us-fg-muted);
}

/* Scale the side panel with the viewport. On a laptop (1280–1600px) it
   stays near the renderer's default 360–390px. On a 1080p or 1440p
   monitor it grows to ~420–460px. On a 4K display it caps at 520px so
   the viewport stays the centre of attention. */
#app .workspace {
  grid-template-columns: minmax(0, 1fr) clamp(340px, 24vw, 520px);
}

#app .side {
  border-left: 1px solid var(--us-border);
  background: var(--us-bg-elevated);
  /* Match the new row height of .tabs (40px) below. */
  /* Slightly taller than the renderer's default so the new tab font /
     padding (see #app .tab below) gets enough headroom and the active
     underline floats a few pixels below the text. */
  grid-template-rows: 48px minmax(0, 1fr);
}

#app .tabs {
  border-bottom: 1px solid var(--us-border);
  background: var(--us-bg-elevated);
}

#app .tab {
  position: relative;
  background: transparent;
  border: none;
  border-radius: 0;
  color: var(--us-fg-muted);
  font-weight: 500;
  /* Bumped from 13px so labels read clearly against the 48px row. */
  font-size: 14px;
  /* Asymmetric vertical padding leaves a clear 6px gap between the
     label baseline and the underline. */
  padding: 14px 16px 12px;
  cursor: pointer;
  transition: color 120ms ease;
}

#app .tab:hover {
  color: var(--us-fg);
  background: transparent;
}

#app .tab.active {
  color: var(--us-accent);
}

#app .tab.active::after {
  content: '';
  position: absolute;
  left: 12px;
  right: 12px;
  /* Float the underline a few pixels above the row border instead of
     hugging the text. Visually balances the typography. */
  bottom: 4px;
  height: 2px;
  background: var(--us-accent);
  border-radius: 2px;
}

/* More breathing room inside the side panels at higher resolutions. */
#app .panel {
  padding: clamp(12px, 1vw, 18px) clamp(14px, 1.2vw, 22px);
}

/* Metric tiles (Links / Joints / Movable counts). Bigger numbers on
   wide screens, with a subtle elevation. */
#app .summary {
  gap: 10px;
  margin-bottom: 14px;
}

#app .metric {
  padding: 12px 14px;
  border-radius: var(--us-radius-md);
  background: var(--us-surface);
  box-shadow: var(--us-shadow-sm);
  text-align: center;
}

#app .metric b {
  font-size: clamp(20px, 1.4vw, 26px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--us-fg);
}

#app .metric span {
  font-size: 11.5px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--us-fg-muted);
}

/* Xacro-args + details cards. */
#app .xacro-args,
#app details {
  border-radius: var(--us-radius-md);
  border-color: var(--us-border);
  background: var(--us-surface);
  box-shadow: var(--us-shadow-sm);
}

#app details {
  margin-bottom: 10px;
}

#app summary {
  padding: 10px 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--us-fg);
  user-select: none;
}

#app summary:hover {
  background: var(--us-bg-subtle);
  border-radius: var(--us-radius-md) var(--us-radius-md) 0 0;
}

#app .detail-body {
  padding: 4px 12px 12px;
  gap: 10px;
}

/* Joint row: give the joint name a bit more room and the slider some
   real estate when we have it. Font scales lightly. */
#app .joint-row {
  grid-template-columns: minmax(110px, 1fr) minmax(120px, 1.8fr) 84px;
  font-size: clamp(12px, 0.9vw, 13.5px);
  gap: 12px;
}

#app .joint-row .joint-name {
  font-weight: 500;
  color: var(--us-fg);
}

#app .joint-row input[type='range'] {
  height: 24px;
  background: transparent;
}

#app .joint-row input[type='number'] {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

/* The joint-filter (search box) at the top of the joints panel. */
#app .joint-filter {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  margin-bottom: 12px;
  padding: 8px 10px;
  border-radius: var(--us-radius-md);
  background: var(--us-bg-subtle);
}

#app .joint-filter input[type='search'] {
  width: 100%;
  height: 32px;
  padding: 0 12px;
  border-radius: var(--us-radius-sm);
  border: 1px solid var(--us-border);
  background: var(--us-surface);
}

#app .joint-filter input[type='search']:focus {
  outline: none;
  border-color: var(--us-accent);
  box-shadow: 0 0 0 3px var(--us-accent-soft);
}

#app .joint-filter label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--us-fg-muted);
  white-space: nowrap;
}

/* Inspector grid — looks better with a bit more vertical air. */
#app .inspector-grid {
  grid-template-columns: clamp(96px, 7vw, 132px) minmax(0, 1fr);
  gap: 8px 14px;
  font-size: 13px;
}

#app .inspector-grid .value {
  color: var(--us-fg);
}

/* HUD over the 3D viewport — refined glass card. */
#app .hud {
  left: 14px;
  bottom: 14px;
  padding: 8px 14px;
  border-radius: var(--us-radius-pill);
  background: color-mix(in srgb, var(--us-surface) 78%, transparent);
  border-color: color-mix(in srgb, var(--us-border-strong) 40%, transparent);
  backdrop-filter: blur(10px) saturate(180%);
  font-size: 12.5px;
  color: var(--us-fg-muted);
  box-shadow: var(--us-shadow-sm);
}

/* Link tree — the Links tab. */
#app .panel.tree {
  font-size: clamp(12px, 0.9vw, 13.5px);
}

/* Checks panel — keep the diagnostic list legible. */
#app #panel-checks ul,
#app #panel-checks ol {
  padding-left: 20px;
}

#app #panel-checks li {
  margin: 6px 0;
  font-size: 13px;
}

#app #panel-checks code {
  font-family: var(--us-font-mono);
  font-size: 0.88em;
  background: var(--us-bg-subtle);
  padding: 1px 5px;
  border-radius: 4px;
}

#app input[type='range'] {
  accent-color: var(--us-accent);
}

#app input[type='number'],
#app input[type='text'],
#app input[type='search'] {
  border-radius: var(--us-radius-sm);
  border: 1px solid var(--us-border);
  background: var(--us-surface);
  padding: 6px 10px;
  font-family: var(--us-font-mono);
  font-size: 12.5px;
}

#app input[type='number']:focus,
#app input[type='text']:focus,
#app input[type='search']:focus {
  outline: none;
  border-color: var(--us-accent);
  box-shadow: 0 0 0 3px var(--us-accent-soft);
}

#app .hud {
  background: color-mix(in srgb, var(--us-surface) 80%, transparent);
  backdrop-filter: blur(6px);
  border: 1px solid var(--us-border);
  border-radius: var(--us-radius-md);
  padding: 8px 14px;
  font-size: 12.5px;
  color: var(--us-fg-muted);
  box-shadow: var(--us-shadow-sm);
}

/* ===== Settings dialog ===== */

dialog#settings-dialog {
  border: none;
  border-radius: var(--us-radius-lg);
  padding: 0;
  width: min(560px, 92vw);
  background: var(--us-surface);
  color: var(--us-fg);
  box-shadow: var(--us-shadow-lg);
}

dialog#settings-dialog::backdrop {
  background: rgba(15, 17, 21, 0.45);
  backdrop-filter: blur(2px);
}

dialog#settings-dialog form {
  display: flex;
  flex-direction: column;
  gap: var(--us-space-3);
  padding: var(--us-space-5) var(--us-space-6);
}

dialog#settings-dialog h3 {
  margin: 0 0 var(--us-space-2);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

dialog#settings-dialog label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 12.5px;
  font-weight: 500;
  color: var(--us-fg-muted);
}

dialog#settings-dialog textarea,
dialog#settings-dialog input,
dialog#settings-dialog select {
  font-family: var(--us-font-mono);
  font-size: 12.5px;
  padding: 8px 10px;
  background: var(--us-bg-elevated);
  color: var(--us-fg);
  border: 1px solid var(--us-border);
  border-radius: var(--us-radius-sm);
  resize: vertical;
}

dialog#settings-dialog textarea:focus,
dialog#settings-dialog input:focus,
dialog#settings-dialog select:focus {
  outline: none;
  border-color: var(--us-accent);
  box-shadow: 0 0 0 3px var(--us-accent-soft);
}

.dialog-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--us-space-2);
  margin-top: var(--us-space-3);
}

.dialog-actions button {
  height: 36px;
  padding: 0 18px;
  border-radius: var(--us-radius-pill);
  border: 1px solid var(--us-border-strong);
  background: var(--us-surface);
  color: var(--us-fg);
  font-weight: 500;
  cursor: pointer;
}

.dialog-actions button.primary {
  background: var(--us-accent);
  border-color: transparent;
  color: var(--us-on-accent);
}

.dialog-actions button:hover {
  background: var(--us-bg-subtle);
}

.dialog-actions button.primary:hover {
  background: var(--us-accent-hover);
}

/* ===== Onboarding tour ===== */

dialog.onboarding {
  border: none;
  border-radius: var(--us-radius-lg);
  padding: 0;
  width: min(560px, 92vw);
  background: var(--us-surface);
  color: var(--us-fg);
  box-shadow: var(--us-shadow-lg);
  overflow: hidden;
}

dialog.onboarding::backdrop {
  background: rgba(15, 17, 21, 0.5);
  backdrop-filter: blur(4px);
}

.onboarding-card {
  padding: var(--us-space-6) var(--us-space-6) var(--us-space-5);
  position: relative;
}

.onboarding-step {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--us-accent);
  margin-bottom: 10px;
  font-weight: 600;
}

.onboarding-card h2 {
  margin: 0 0 var(--us-space-3);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.onboarding-card p {
  margin: 0 0 var(--us-space-3);
  font-size: 14.5px;
  line-height: 1.6;
  color: var(--us-fg);
}

.onboarding-card p code {
  font-family: var(--us-font-mono);
  font-size: 12.5px;
  background: var(--us-bg-subtle);
  border-radius: var(--us-radius-sm);
  padding: 2px 6px;
}

.onboarding-card a {
  color: var(--us-accent);
  text-decoration: none;
  font-weight: 500;
}

.onboarding-card a:hover {
  text-decoration: underline;
}

.onboarding-hint {
  font-size: 13px;
  color: var(--us-fg-muted);
  background: var(--us-bg-elevated);
  border-radius: var(--us-radius-md);
  padding: 12px 14px;
  margin-top: var(--us-space-3);
  border-left: 3px solid var(--us-accent);
}

.onboarding-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--us-space-3);
  margin-top: var(--us-space-5);
  padding-top: var(--us-space-4);
  border-top: 1px solid var(--us-border);
}

.onboarding-dots {
  display: flex;
  gap: 8px;
}

.onboarding-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--us-border-strong);
  cursor: pointer;
  transition: background 120ms ease, transform 120ms ease;
  border: none;
  padding: 0;
}

.onboarding-dot:hover {
  background: var(--us-fg-muted);
}

.onboarding-dot.active {
  background: var(--us-accent);
  transform: scale(1.15);
}

.onboarding-actions {
  display: flex;
  gap: var(--us-space-2);
}

.onboarding-actions button {
  height: 36px;
  padding: 0 18px;
  border-radius: var(--us-radius-pill);
  border: 1px solid var(--us-border-strong);
  background: var(--us-surface);
  color: var(--us-fg);
  font-weight: 500;
  font-size: 13px;
  cursor: pointer;
  transition: background 120ms ease, border-color 120ms ease;
}

.onboarding-actions button:hover {
  background: var(--us-bg-subtle);
}

.onboarding-actions button.primary {
  background: var(--us-accent);
  color: var(--us-on-accent);
  border-color: transparent;
  box-shadow: 0 1px 2px rgba(26, 115, 232, 0.18), 0 1px 3px 1px rgba(26, 115, 232, 0.1);
}

.onboarding-actions button.primary:hover {
  background: var(--us-accent-hover);
}

.onboarding-actions button.ghost {
  background: transparent;
  border-color: transparent;
  color: var(--us-fg-muted);
}

.onboarding-actions button.ghost:hover {
  background: var(--us-bg-subtle);
  color: var(--us-fg);
}

.onboarding-actions button[disabled] {
  opacity: 0.35;
  cursor: not-allowed;
}

/* ===== Toast (bottom error / warning bubbles) ===== */

#toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 1000;
  pointer-events: none;
  max-width: min(420px, calc(100vw - 48px));
}

.toast {
  display: grid;
  grid-template-columns: 22px 1fr auto;
  gap: 10px;
  align-items: start;
  padding: 12px 14px 12px 14px;
  border-radius: var(--us-radius-md);
  border: 1px solid var(--us-border);
  background: var(--us-surface);
  color: var(--us-fg);
  box-shadow: var(--us-shadow-lg);
  font-size: 13.5px;
  line-height: 1.5;
  pointer-events: auto;
  transform: translateY(12px);
  opacity: 0;
  transition: transform 220ms cubic-bezier(0.2, 0, 0.2, 1), opacity 200ms ease;
}

.toast.toast-entered {
  transform: translateY(0);
  opacity: 1;
}

.toast.toast-leaving {
  transform: translateY(8px);
  opacity: 0;
}

.toast-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 1px;
}

.toast-error .toast-icon {
  color: var(--us-danger);
}

.toast-warning .toast-icon {
  color: var(--us-warning);
}

.toast-info .toast-icon {
  color: var(--us-accent);
}

.toast-error {
  border-left: 3px solid var(--us-danger);
}

.toast-warning {
  border-left: 3px solid var(--us-warning);
}

.toast-info {
  border-left: 3px solid var(--us-accent);
}

.toast-body {
  min-width: 0;
}

.toast-message {
  font-weight: 500;
  color: var(--us-fg);
  word-wrap: break-word;
}

.toast-detail {
  margin-top: 4px;
  font-size: 12.5px;
  color: var(--us-fg-muted);
  word-wrap: break-word;
  font-family: var(--us-font-mono);
  max-height: 6em;
  overflow-y: auto;
}

.toast-close {
  width: 22px;
  height: 22px;
  padding: 0;
  border: none;
  background: transparent;
  color: var(--us-fg-faint);
  border-radius: 50%;
  cursor: pointer;
  font-size: 18px;
  line-height: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background 120ms ease, color 120ms ease;
}

.toast-close:hover {
  background: var(--us-bg-subtle);
  color: var(--us-fg);
}

/* ===== Theme switcher (segmented control) ===== */

.theme-mount {
  display: inline-flex;
  align-items: center;
}

.theme-switcher {
  display: inline-flex;
  align-items: center;
  height: 36px;
  padding: 3px;
  border: 1px solid var(--us-border-strong);
  border-radius: var(--us-radius-md);
  background: var(--us-bg-elevated);
  gap: 2px;
  position: relative;
}

.theme-switcher-btn {
  /* Override the topbar pill rule above — segmented buttons sit inside
     a rounded container, share its inner radius. */
  appearance: none;
  height: 28px !important;
  min-width: 36px;
  padding: 0 8px !important;
  border: 1px solid transparent !important;
  border-radius: calc(var(--us-radius-md) - 4px) !important;
  background: transparent !important;
  color: var(--us-fg-muted) !important;
  font-size: 14px;
  line-height: 1;
  cursor: pointer;
  transition: background 140ms ease, color 140ms ease, transform 100ms ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.theme-switcher-btn:hover {
  background: var(--us-bg-subtle) !important;
  color: var(--us-fg) !important;
}

.theme-switcher-btn[data-active='true'] {
  background: var(--us-surface) !important;
  color: var(--us-fg) !important;
  box-shadow: var(--us-shadow-sm);
  /* View Transitions: name the active pill so it tweens between
     segments when the user picks a new mode. */
  view-transition-name: theme-pill;
}

@supports (view-transition-name: theme-pill) {
  ::view-transition-old(theme-pill),
  ::view-transition-new(theme-pill) {
    animation-duration: 220ms;
  }
}

/* ===== @starting-style: pure-CSS entrance animations =====
   Each rule pairs a `transition` on the steady state with a
   `@starting-style` block that defines the from-state. The element
   animates from the @starting-style value to the steady-state value
   when first connected to the DOM (toast) or when the dialog goes
   from closed → open. Replaces JS-driven `.toast-entered` class. */

.toast {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 220ms cubic-bezier(0.2, 0, 0.2, 1),
              transform 220ms cubic-bezier(0.2, 0, 0.2, 1);
}

@starting-style {
  .toast {
    opacity: 0;
    transform: translateY(12px);
  }
}

.toast-leaving {
  opacity: 0;
  transform: translateY(8px);
}

/* Dialogs animate in and out symmetrically.
   - The closed state (no [open]) carries the hidden values (opacity 0,
     translated down). That state is what the dialog tweens TO when
     close() is called.
   - The [open] state carries the visible values.
   - @starting-style copies the hidden state for the opening transition.
   - allow-discrete on `display` + `overlay` keeps the dialog rendered
     during the close animation; without these two, the dialog would
     vanish instantly and the transition would never play, which is the
     "laggy" behaviour the previous rule produced. */
dialog.onboarding,
dialog#settings-dialog {
  opacity: 0;
  transform: translateY(10px) scale(0.985);
  transition: opacity 180ms cubic-bezier(0.2, 0, 0.2, 1),
              transform 180ms cubic-bezier(0.2, 0, 0.2, 1),
              overlay   180ms allow-discrete,
              display   180ms allow-discrete;
}

dialog.onboarding[open],
dialog#settings-dialog[open] {
  opacity: 1;
  transform: translateY(0) scale(1);
}

@starting-style {
  dialog.onboarding[open],
  dialog#settings-dialog[open] {
    opacity: 0;
    transform: translateY(10px) scale(0.985);
  }
}

dialog.onboarding::backdrop,
dialog#settings-dialog::backdrop {
  background: rgba(15, 17, 21, 0);
  backdrop-filter: blur(0);
  transition: background 180ms ease,
              backdrop-filter 180ms ease,
              display 180ms allow-discrete;
}

dialog.onboarding[open]::backdrop,
dialog#settings-dialog[open]::backdrop {
  background: rgba(15, 17, 21, 0.5);
  backdrop-filter: blur(4px);
  opacity: 1;
}

@starting-style {
  dialog.onboarding[open]::backdrop,
  dialog#settings-dialog[open]::backdrop {
    background: rgba(15, 17, 21, 0);
    backdrop-filter: blur(0);
  }
}

/* ===== Container queries — side panel re-stacks at narrow widths ===== */

#app .side {
  container-type: inline-size;
  container-name: side;
}

@container side (max-width: 360px) {
  #app .joint-row {
    /* When the side panel is genuinely narrow (typically because the
       user pulled the workspace toward a portrait layout), stack the
       slider beneath the label so the numeric input doesn't get
       crushed. */
    grid-template-columns: minmax(0, 1fr) 72px;
    grid-template-areas:
      'name input'
      'slider slider';
    row-gap: 4px;
  }
  #app .joint-row .joint-name { grid-area: name; }
  #app .joint-row input[type='number'] { grid-area: input; }
  #app .joint-row input[type='range'] { grid-area: slider; }
}

/* ===== Responsive niceties ===== */

@media (max-width: 720px) {
  .topbar-row {
    flex-wrap: wrap;
    padding: var(--us-space-3);
    gap: var(--us-space-2);
  }
  .topbar-actions {
    flex-basis: 100%;
    margin-left: 0;
  }
  #file-select {
    min-width: 0;
    flex: 1;
  }
}