:root {
    --bg-dark: #09090b;
    --bg-panel: #18181b;
    --border: #27272a;
    --primary: #6366f1;
    --text: #e4e4e7;
    --text-dim: #a1a1aa;
}

body { margin: 0; background: var(--bg-dark); color: var(--text); font-family: 'Inter', sans-serif; display: flex; height: 100vh; overflow: hidden; }

/* Sidebar */
.sidebar { width: 300px; background: var(--bg-panel); border-right: 1px solid var(--border); display: flex; flex-direction: column; padding: 20px; }
.brand { font-family: 'JetBrains Mono', monospace; font-weight: 700; font-size: 1.2rem; display: flex; align-items: center; gap: 10px; margin-bottom: 40px; }
.logo-square { width: 20px; height: 20px; background: var(--primary); border-radius: 4px; }

.nav-item {
    background: transparent; border: none; color: var(--text-dim);
    width: 100%; text-align: left; padding: 12px; margin-bottom: 5px;
    border-radius: 6px; cursor: pointer; font-size: 0.95rem;
    display: flex; gap: 10px; align-items: center; transition: 0.2s;
}
.nav-item:hover { background: #27272a; color: white; }
.nav-item.active { background: #2e2e32; color: white; font-weight: 600; border-left: 3px solid var(--primary); }

.sidebar-footer { margin-top: auto; font-size: 0.8rem; }
.status-ready { color: #4ade80; }
.status-working { color: #facc15; }
.status-success { color: #6366f1; }
.status-error { color: #ef4444; }

/* Main Content */
.main-content { flex: 1; position: relative; }
.tab-pane { display: none; height: 100%; }
.tab-pane.active { display: flex; }

/* Visualizer Tab Layout */
#tab-visualizer { flex-direction: row; }
.editor-panel { width: 400px; border-right: 1px solid var(--border); display: flex; flex-direction: column; background: #111; }
.panel-header { padding: 10px; background: #1f1f22; font-size: 0.8rem; color: #888; border-bottom: 1px solid var(--border); }
textarea { flex: 1; background: #000; border: none; color: #ccc; padding: 15px; font-family: 'JetBrains Mono'; resize: none; outline: none; }
.action-bar { padding: 15px; border-top: 1px solid var(--border); display: flex; gap: 10px; }
.canvas-panel { flex: 1; background-image: radial-gradient(#333 1px, transparent 1px); background-size: 20px 20px; }

/* Dataset Tab Layout */
#tab-dataset { flex-direction: column; padding: 40px; overflow-y: auto; }
.dataset-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 30px; }
.header-actions { display: flex; gap: 10px; }

/* Table */
.data-table { width: 100%; border-collapse: collapse; text-align: left; }
.data-table th { border-bottom: 1px solid var(--border); padding: 15px; color: var(--text-dim); font-size: 0.85rem; font-weight: 600; }
.data-table td { border-bottom: 1px solid #1f1f22; padding: 15px; font-size: 0.9rem; }
.mono { font-family: 'JetBrains Mono'; color: var(--primary); }
.mono-dim { font-family: 'JetBrains Mono'; color: #666; font-size: 0.8rem; }
.badge { background: #27272a; padding: 4px 8px; border-radius: 4px; font-size: 0.75rem; }

/* Buttons */
.btn { padding: 10px 16px; border-radius: 6px; border: none; cursor: pointer; font-weight: 500; font-size: 0.9rem; text-decoration: none; display: inline-block;}
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: #4f46e5; }
.btn-secondary { background: #3f3f46; color: white; }
.btn-outline { background: transparent; border: 1px solid var(--border); color: var(--text); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Modal */
.modal-overlay { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.7); display: flex; align-items: center; justify-content: center; z-index: 1000; }
.hidden { display: none; }
.modal { background: var(--bg-panel); width: 400px; padding: 30px; border-radius: 12px; border: 1px solid var(--border); }
.modal h3 { margin-top: 0; }
.modal input { width: 100%; padding: 10px; margin-bottom: 15px; background: #000; border: 1px solid var(--border); color: white; border-radius: 4px; }
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 20px; }