:root {
  --bg: #1a1a2e;
  --bg2: #16213e;
  --bg3: #0f3460;
  --surface: #1e2a45;
  --surface2: #243050;
  --border: #2e3f6f;
  --text: #e0e6f0;
  --text-muted: #7a8aaa;
  --accent: #4f9cf9;
  --accent-hover: #3a7ed4;
  --success: #4ade80;
  --error: #f87171;
  --warning: #fbbf24;
  --radius: 8px;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  --font-ui: 'Inter', system-ui, sans-serif;
}

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

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 14px;
  line-height: 1.5;
}

/* ── Layout ── */
#app { display: flex; height: 100vh; overflow: hidden; }

#sidebar {
  width: 220px;
  min-width: 220px;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

#main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* ── Sidebar ── */
.sidebar-logo {
  padding: 20px 16px 12px;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid var(--border);
}

.sidebar-logo svg { flex-shrink: 0; }

.sidebar-logo-text {
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.3px;
}

.sidebar-logo-text span {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 11px;
  display: block;
  letter-spacing: 0;
}

.sidebar-section {
  padding: 12px 0 4px;
}

.sidebar-section-label {
  padding: 0 16px 6px;
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-muted);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 16px;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 13px;
  border-left: 3px solid transparent;
  transition: all 0.15s;
  user-select: none;
}

.nav-item:hover {
  background: var(--surface);
  color: var(--text);
}

.nav-item.active {
  background: var(--surface);
  color: var(--accent);
  border-left-color: var(--accent);
}

.nav-item svg { flex-shrink: 0; opacity: 0.7; }
.nav-item.active svg { opacity: 1; }

/* ── Tool Panel ── */
.tool-panel {
  display: none;
  flex: 1;
  flex-direction: column;
  overflow: hidden;
}
.tool-panel.active { display: flex; }

.tool-header {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  background: var(--bg2);
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.tool-header h1 {
  font-size: 17px;
  font-weight: 600;
  color: var(--text);
}

.tool-header p {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 2px;
}

.tool-body {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* ── Two-panel editor layout ── */
.editor-panes {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  overflow: hidden;
}

.editor-pane {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-right: 1px solid var(--border);
}
.editor-pane:last-child { border-right: none; }

.pane-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  flex-wrap: wrap;
}

.pane-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-right: auto;
}

.pane-textarea {
  flex: 1;
  background: var(--bg);
  border: none;
  outline: none;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  padding: 16px;
  resize: none;
  overflow-y: auto;
}

.pane-output {
  flex: 1;
  background: var(--bg);
  overflow-y: auto;
  padding: 16px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
}

.pane-output.error { color: var(--error); }
.pane-output.success { color: var(--success); }

/* ── Single-panel layout (JSON formatter etc) ── */
.tool-body.single-col {
  flex-direction: column;
  padding: 20px 24px;
  overflow-y: auto;
  gap: 16px;
}

.tool-body.single-col .editor-panes {
  flex: none;
  grid-template-columns: 1fr 1fr;
  height: 100%;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text);
  font-size: 12px;
  font-family: var(--font-ui);
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}
.btn:hover { background: var(--bg3); border-color: var(--accent); color: var(--accent); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; }
.btn.primary:hover { background: var(--accent-hover); }
.btn.danger { border-color: var(--error); color: var(--error); }
.btn.danger:hover { background: #2a1a1a; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ── Select ── */
select {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 5px 28px 5px 10px;
  border-radius: var(--radius);
  font-size: 12px;
  font-family: var(--font-ui);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%237a8aaa' stroke-width='2'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
}
select:hover { border-color: var(--accent); }

/* ── Status badge ── */
.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 8px;
  border-radius: 12px;
  font-size: 11px;
  font-weight: 600;
}
.status-badge.ok { background: #0d2a1a; color: var(--success); }
.status-badge.err { background: #2a0d0d; color: var(--error); }
.status-badge.info { background: #0d1a2a; color: var(--accent); }

/* ── Streaming indicator ── */
.streaming-dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse 1s infinite;
  margin-left: 4px;
  vertical-align: middle;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

/* ── Code convert toolbar middle button ── */
.convert-middle {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 16px;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  border-left: 1px solid var(--border);
  min-width: 80px;
}

/* ── Tabs inside a tool ── */
.subtabs {
  display: flex;
  gap: 2px;
  padding: 0 12px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.subtab {
  padding: 8px 14px;
  font-size: 12px;
  cursor: pointer;
  color: var(--text-muted);
  border-bottom: 2px solid transparent;
  transition: all 0.15s;
}
.subtab:hover { color: var(--text); }
.subtab.active { color: var(--accent); border-bottom-color: var(--accent); }

.subtab-panel { display: none; }
.subtab-panel.active { display: flex; flex: 1; overflow: hidden; }

/* ── Options row ── */
.options-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  flex-wrap: wrap;
}

.option-label {
  font-size: 11px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

input[type="checkbox"] {
  accent-color: var(--accent);
  width: 14px;
  height: 14px;
  cursor: pointer;
}

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

/* ── Responsive ── */
@media (max-width: 900px) {
  #sidebar { width: 48px; min-width: 48px; }
  .sidebar-logo-text, .sidebar-section-label, .nav-item span { display: none; }
  .nav-item { justify-content: center; padding: 10px; }
  .editor-panes { grid-template-columns: 1fr; grid-template-rows: 1fr 1fr; }
}