/* ─── Reset & base ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b22;
  --border:    #30363d;
  --text:      #c9d1d9;
  --muted:     #8b949e;
  --accent:    #58a6ff;
  --radius:    8px;

  /* Token type palette */
  --c-word:        #3fb950;
  --c-pipe:        #ff7b72;
  --c-and:         #ffa657;
  --c-or:          #ffa657;
  --c-semicolon:   #d2a8ff;
  --c-ampersand:   #d2a8ff;
  --c-newline:     #79c0ff;
  --c-redir-in:    #56d364;
  --c-redir-out:   #56d364;
  --c-redir-app:   #56d364;
  --c-heredoc:     #56d364;
  --c-redir-dup:   #56d364;
  --c-paren:       #f778ba;
  --c-eof:         #6e7681;
  --c-error:       #f85149;

  /* AST node type palette */
  --c-node-command:    #3fb950;
  --c-node-pipe:       #ff7b72;
  --c-node-and:        #ffa657;
  --c-node-or:         #d2a8ff;
  --c-node-sequence:   #79c0ff;
  --c-node-subshell:   #f778ba;
  --c-node-block:      #56d364;
  --c-node-background: #ffd866;
}

html { font-size: 15px; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, sans-serif;
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ─── Header ────────────────────────────────────────────────────── */
header {
  padding: .75rem 1.5rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: baseline;
  gap: 1rem;
  background: var(--surface);
  flex-shrink: 0;
}
.logo { font-size: 1.3rem; font-weight: 700; letter-spacing: .04em; }
.logo span { color: var(--accent); }
.subtitle { color: var(--muted); font-size: .85rem; }

/* ─── Layout ────────────────────────────────────────────────────── */
main {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ─── Sidebar ───────────────────────────────────────────────────── */
#sidebar {
  width: 240px;
  min-width: 180px;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  background: var(--surface);
  flex-shrink: 0;
}
#sidebar h2 {
  padding: .75rem 1rem;
  font-size: .8rem;
  text-transform: uppercase;
  letter-spacing: .1em;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
}
#session-list {
  flex: 1;
  overflow-y: auto;
  padding: .5rem 0;
}
.session-item {
  padding: .55rem 1rem;
  cursor: pointer;
  border-left: 3px solid transparent;
  font-size: .82rem;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: background .15s, color .15s, border-color .15s;
}
.session-item:hover { background: rgba(88,166,255,.08); color: var(--text); }
.session-item.active {
  border-left-color: var(--accent);
  background: rgba(88,166,255,.12);
  color: var(--accent);
}
.session-item .badge {
  display: inline-block;
  font-size: .6rem;
  padding: .1rem .35rem;
  border-radius: 3px;
  margin-left: .4rem;
  vertical-align: middle;
}
.badge-tok { background: rgba(63,185,80,.2); color: #3fb950; }
.badge-ast { background: rgba(88,166,255,.2); color: #58a6ff; }
.hint { padding: .75rem 1rem; color: var(--muted); font-size: .8rem; }
.sidebar-footer {
  border-top: 1px solid var(--border);
  padding: .75rem 1rem;
}
.load-btn {
  display: block;
  background: rgba(88,166,255,.12);
  color: var(--accent);
  border: 1px solid rgba(88,166,255,.3);
  border-radius: var(--radius);
  padding: .5rem .75rem;
  font-size: .82rem;
  cursor: pointer;
  text-align: center;
  transition: background .15s;
}
.load-btn:hover { background: rgba(88,166,255,.22); }

/* ─── Main panel ────────────────────────────────────────────────── */
#panel {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.welcome {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: 1rem;
  text-align: center;
  line-height: 1.8;
}

/* ─── Viz container ─────────────────────────────────────────────── */
#viz-container { flex-direction: column; gap: 1.2rem; }

#input-display {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: .75rem 1rem;
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: .95rem;
  color: var(--text);
  word-break: break-all;
}
#input-display::before {
  content: '$ ';
  color: var(--accent);
  font-weight: 700;
}

/* ─── Tabs ──────────────────────────────────────────────────────── */
#tab-bar {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--border);
}
.tab {
  padding: .55rem 1.2rem;
  font-size: .85rem;
  font-family: inherit;
  font-weight: 600;
  background: none;
  border: none;
  color: var(--muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: color .15s, border-color .15s;
}
.tab:hover { color: var(--text); }
.tab.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}
.tab.disabled {
  opacity: .35;
  cursor: not-allowed;
}
.tab-pane { display: none; flex-direction: column; gap: 1.2rem; }
.tab-pane.active { display: flex; }

/* ─── Token strip ───────────────────────────────────────────────── */
#token-strip {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  align-items: center;
}

.token-chip {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  padding: .35rem .65rem;
  border-radius: 6px;
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: .82rem;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform .12s, box-shadow .12s, border-color .12s;
  user-select: none;
  position: relative;
}
.token-chip:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 16px rgba(0,0,0,.45);
  border-color: rgba(255,255,255,.25);
}
.token-chip.selected {
  border-color: #fff;
  box-shadow: 0 0 0 3px rgba(255,255,255,.2);
}
.chip-value {
  font-weight: 600;
  font-size: .88rem;
}
.chip-type {
  font-size: .65rem;
  opacity: .75;
  margin-top: .15rem;
  letter-spacing: .02em;
}

/* ─── Arc toolbar ───────────────────────────────────────────────── */
#arc-toolbar, #ast-toolbar {
  display: flex;
  gap: .5rem;
  justify-content: flex-end;
}
.toolbar-btn {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .3rem .75rem;
  border-radius: 6px;
  font-size: .78rem;
  font-family: inherit;
  cursor: pointer;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--muted);
  transition: background .15s, color .15s, border-color .15s;
}
.toolbar-btn:hover { color: var(--text); border-color: #555; }
.toolbar-btn.active {
  background: rgba(88,166,255,.12);
  color: var(--accent);
  border-color: rgba(88,166,255,.4);
}
.btn-icon { font-size: 1rem; line-height: 1; }

/* ─── Legend ────────────────────────────────────────────────────── */
#legend {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem .9rem;
  padding: .6rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.legend-item {
  display: flex;
  align-items: center;
  gap: .4rem;
  font-size: .75rem;
  color: var(--muted);
  cursor: pointer;
  transition: color .15s;
}
.legend-item:hover { color: var(--text); }
.legend-swatch {
  width: 10px; height: 10px;
  border-radius: 3px;
  flex-shrink: 0;
}

/* ─── Arc diagram ───────────────────────────────────────────────── */
#arc-diagram {
  width: 100%;
  height: 140px;
  overflow: visible;
  display: block;
}
.arc-path {
  fill: none;
  stroke-width: 2;
  opacity: .5;
  transition: opacity .2s, stroke-width .2s;
}
.arc-path:hover, .arc-path.hi { opacity: 1; stroke-width: 3; }
.arc-node { cursor: pointer; }
.arc-label {
  font-family: 'Fira Code', monospace;
  font-size: 11px;
  fill: var(--muted);
  text-anchor: middle;
  user-select: none;
}

/* ─── Detail panel (tokens) ────────────────────────────────────── */
#detail-panel {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
}
#detail-close {
  position: absolute;
  top: .6rem; right: .8rem;
  background: none;
  border: none;
  color: var(--muted);
  cursor: pointer;
  font-size: 1rem;
}
#detail-close:hover { color: var(--text); }
#detail-type {
  font-size: .95rem;
  margin-bottom: .6rem;
  font-family: 'Fira Code', monospace;
}
#detail-table { border-collapse: collapse; font-size: .82rem; width: 100%; }
#detail-table td {
  padding: .3rem .6rem;
  border-bottom: 1px solid var(--border);
}
#detail-table td:first-child { color: var(--muted); width: 120px; }

/* ─── AST container ────────────────────────────────────────────── */
#ast-container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  position: relative;
  min-height: 400px;
  height: 500px;
  resize: vertical;
}
#ast-svg {
  width: 100%;
  height: 100%;
  display: block;
  cursor: grab;
}
#ast-svg:active { cursor: grabbing; }

/* AST tree nodes */
.ast-link {
  fill: none;
  stroke: var(--border);
  stroke-width: 2;
  transition: stroke .2s;
}
.ast-link.highlighted {
  stroke: var(--accent);
  stroke-width: 3;
}

.ast-node { cursor: pointer; }

.ast-node-rect {
  rx: 8;
  ry: 8;
  stroke-width: 2;
  transition: filter .15s, stroke-width .15s;
}
.ast-node:hover .ast-node-rect {
  filter: brightness(1.3) drop-shadow(0 0 8px rgba(255,255,255,.2));
  stroke-width: 3;
}
.ast-node.selected .ast-node-rect {
  stroke: #fff;
  stroke-width: 3;
  filter: drop-shadow(0 0 12px rgba(255,255,255,.25));
}

.ast-node-label {
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: 12px;
  fill: #fff;
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
  font-weight: 600;
}
.ast-node-sublabel {
  font-family: 'Fira Code', 'Cascadia Code', monospace;
  font-size: 10px;
  fill: rgba(255,255,255,.7);
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
}

.ast-collapse-icon {
  font-family: 'Fira Code', monospace;
  font-size: 10px;
  fill: rgba(255,255,255,.6);
  text-anchor: middle;
  dominant-baseline: central;
  pointer-events: none;
}

/* ─── AST detail panel ─────────────────────────────────────────── */
#ast-detail {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
}
#ast-detail-close {
  position: absolute;
  top: .6rem; right: .8rem;
  background: none;
  border: none;
  color: var(--muted);
  cursor: pointer;
  font-size: 1rem;
}
#ast-detail-close:hover { color: var(--text); }
#ast-detail-type {
  font-size: .95rem;
  margin-bottom: .6rem;
  font-family: 'Fira Code', monospace;
}
#ast-detail-body {
  font-size: .82rem;
}
#ast-detail-body table {
  border-collapse: collapse;
  width: 100%;
}
#ast-detail-body td {
  padding: .3rem .6rem;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
#ast-detail-body td:first-child {
  color: var(--muted);
  width: 120px;
  white-space: nowrap;
}
#ast-detail-body code {
  background: rgba(255,255,255,.06);
  padding: .15rem .4rem;
  border-radius: 4px;
  font-size: .8rem;
}
#ast-detail-body .redir-list {
  list-style: none;
  padding: 0;
}
#ast-detail-body .redir-list li {
  padding: .2rem 0;
  font-family: 'Fira Code', monospace;
  font-size: .8rem;
}
#ast-detail-body .redir-op { color: var(--c-redir-out); font-weight: 600; }
#ast-detail-body .redir-fd { color: var(--muted); }
#ast-detail-body .redir-target { color: var(--c-word); }

/* AST legend */
#ast-pane .ast-legend {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem .9rem;
  padding: .6rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

/* ─── Settings modal ───────────────────────────────────────────── */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.6);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
}
.modal-overlay[hidden] { display: none; }
.modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  width: 480px;
  max-width: 92vw;
  max-height: 85vh;
  overflow-y: auto;
  box-shadow: 0 16px 48px rgba(0,0,0,.5);
  animation: modal-in .2s ease-out;
}
@keyframes modal-in {
  from { opacity: 0; transform: scale(.95) translateY(8px); }
  to   { opacity: 1; transform: none; }
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.2rem;
  border-bottom: 1px solid var(--border);
}
.modal-header h2 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
}
.modal-close {
  background: none;
  border: none;
  color: var(--muted);
  font-size: 1.1rem;
  cursor: pointer;
  padding: .2rem .4rem;
  border-radius: 4px;
  transition: background .15s, color .15s;
}
.modal-close:hover {
  background: rgba(255,255,255,.08);
  color: var(--text);
}
.modal-body {
  padding: 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 1.4rem;
}
.setting-group {
  display: flex;
  flex-direction: column;
  gap: .5rem;
}
.setting-label {
  font-size: .78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--muted);
}
.setting-options {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
}
.setting-chip {
  padding: .35rem .8rem;
  border-radius: 6px;
  font-size: .8rem;
  font-family: inherit;
  cursor: pointer;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--muted);
  transition: background .15s, color .15s, border-color .15s;
}
.setting-chip:hover {
  color: var(--text);
  border-color: #555;
}
.setting-chip.active {
  background: rgba(88,166,255,.15);
  color: var(--accent);
  border-color: rgba(88,166,255,.5);
}
/* Curve preview */
#curve-preview {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  display: block;
}
#curve-preview .preview-path {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
}
#curve-preview .preview-dot {
  fill: var(--accent);
}

/* ─── Scrollbar ─────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }