.playground {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  padding: 1rem;
  height: calc(100vh - 52px);
  overflow: hidden;
}

.panel-left {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-height: 0;
}

.panel-right {
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow-y: auto;
}

/* Editor */
.editor-section {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
}

.editor-toolbar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-bottom: none;
  border-radius: 6px 6px 0 0;
}

.editor-toolbar label {
  font-size: 0.85rem;
  color: var(--text-dim);
}

.editor-toolbar select {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.25rem 0.5rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 4px;
  cursor: pointer;
}

.editor-container {
  flex: 1;
  min-height: 0;
  border: 1px solid var(--border);
  border-radius: 0 0 6px 6px;
  overflow: hidden;
}

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

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

/* Controls */
.controls {
  display: flex;
  gap: 0.5rem;
  flex-shrink: 0;
}

.btn {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.btn:hover:not(:disabled) {
  border-color: var(--accent);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: var(--bg);
  border-color: var(--accent);
  font-weight: 600;
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-dim);
  border-color: var(--accent-dim);
}

/* Error panel */
.error-panel {
  background: rgba(248, 113, 113, 0.15);
  border: 1px solid var(--error);
  border-radius: 4px;
  padding: 0.5rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--error);
  white-space: pre-wrap;
  flex-shrink: 0;
}

/* State viewer */
.state-viewer {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.state-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--text-dim);
  font-size: 0.95rem;
}

.state-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.75rem;
}

.state-section h3 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-dim);
  margin-bottom: 0.5rem;
}

/* Register table */
.reg-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.reg-table th {
  text-align: left;
  font-weight: 600;
  color: var(--text-dim);
  padding: 0.25rem 0.5rem;
  border-bottom: 1px solid var(--border);
}

.reg-table td {
  padding: 0.25rem 0.5rem;
  border-bottom: 1px solid var(--border);
}

.reg-table .changed {
  color: var(--changed);
  font-weight: 600;
}

/* Status grid */
.status-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.status-item {
  display: flex;
  justify-content: space-between;
  padding: 0.25rem 0.5rem;
  background: var(--bg);
  border-radius: 4px;
}

.status-label {
  color: var(--text-dim);
}

.status-value {
  font-weight: 600;
}

/* Flags */
.flags {
  display: flex;
  gap: 0.5rem;
}

.flag {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 0.25rem 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-dim);
}

.flag.active {
  color: var(--changed);
  border-color: var(--changed);
  font-weight: 600;
}

/* Hex dump */
.hex-dump {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  line-height: 1.6;
  word-break: break-all;
}

.hex-byte {
  display: inline-block;
  width: 2ch;
  text-align: center;
  margin-right: 0.25ch;
  color: var(--text-dim);
}

.hex-byte.nonzero {
  color: var(--text);
}

@media (max-width: 768px) {
  .playground {
    grid-template-columns: 1fr;
    height: auto;
  }

  .panel-left {
    min-height: 50vh;
  }
}