/* Layout Header */
header {
  height: 52px;
  background: var(--bg-header);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
  flex-shrink: 0;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--primary);
}
.brand svg { width: 22px; height: 22px; fill: currentColor; }
.header-center { display: flex; align-items: center; gap: 0.6rem; }
.header-actions { display: flex; align-items: center; gap: 0.5rem; }

/* App Body & Sidebar */
.app-body {
  display: flex;
  flex: 1;
  overflow: hidden;
}
aside {
  width: 250px;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}
.sidebar-header {
  padding: 0.65rem 0.85rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-dim);
  background: var(--bg-sidebar);
}
.sidebar-content {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem;
}
.table-list { list-style: none; }
.table-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.45rem 0.6rem;
  border-radius: 6px;
  font-size: 0.82rem;
  cursor: pointer;
  color: var(--text-muted);
  transition: all 0.15s ease;
}
.table-item:hover { background: var(--bg-panel); color: var(--text-main); }
.table-item.active { background: var(--table-hover); color: var(--primary); font-weight: 600; }

/* Main Workspace Tabs */
main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--bg-main);
  transition: background-color 0.2s ease;
}
.tab-bar {
  display: flex;
  background: var(--bg-header);
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
  flex-shrink: 0;
  transition: background-color 0.2s ease;
}
.tab-btn {
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-muted);
  padding: 0.65rem 1rem;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  white-space: nowrap;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.tab-btn:hover { color: var(--text-main); }
.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  font-weight: 600;
  background: var(--table-hover);
}

.tab-panel {
  flex: 1;
  display: none;
  flex-direction: column;
  overflow: hidden;
}
.tab-panel.active { display: flex; }

/* SQL Console */
.editor-container {
  display: flex;
  flex-direction: column;
  height: 40%;
  border-bottom: 1px solid var(--border);
  background: var(--bg-card);
  transition: background-color 0.2s ease;
}
.editor-toolbar {
  padding: 0.45rem 1rem;
  background: var(--bg-sub);
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
}
.sql-textarea {
  flex: 1;
  width: 100%;
  background: transparent;
  color: var(--text-main);
  border: none;
  padding: 0.85rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  resize: none;
  outline: none;
  line-height: 1.5;
}

/* Query Results Table */
.results-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--bg-main);
}
.results-header {
  padding: 0.45rem 1rem;
  background: var(--bg-sub);
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: var(--text-muted);
}
.results-body {
  flex: 1;
  overflow: auto;
  padding: 0;
}
.sql-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
  text-align: left;
}
.sql-table th {
  background: var(--table-th-bg);
  color: var(--text-main);
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--border);
  border-right: 1px solid var(--border);
  position: sticky;
  top: 0;
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
}
.sql-table td {
  padding: 0.45rem 0.75rem;
  border-bottom: 1px solid var(--table-border);
  border-right: 1px solid var(--table-border);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  white-space: nowrap;
  color: var(--text-main);
}
.sql-table tr:hover { background: var(--table-hover); }

/* ER Diagram Canvas */
.er-canvas-container {
  flex: 1;
  overflow: auto;
  padding: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  align-items: flex-start;
  background: var(--bg-main);
}
.er-table-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 260px;
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}
.er-table-card-header {
  background: var(--bg-panel);
  padding: 0.5rem 0.75rem;
  font-weight: 700;
  color: var(--primary);
  font-size: 0.85rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
}
.er-field-row {
  display: flex;
  justify-content: space-between;
  padding: 0.35rem 0.75rem;
  font-size: 0.78rem;
  border-bottom: 1px solid var(--border);
  font-family: var(--font-mono);
  color: var(--text-main);
}