:root{
  --bg: #071026;
  --card-bg: #081428;
  --panel-border: #0f2b3a;
  --text: #e6eef6;
  --muted: #98a4b3;
  --accent: #4aa3e0;
  --accent-strong: #7ad3b7;
  --mono-bg: #06101a;
  --danger: #e06b6b;
  --radius: 12px;
  --pad: 12px;
  --gap: 12px;
  --max-width: 1280px;
  --font-sans: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Menlo", "Courier New", monospace;
}

*{box-sizing:border-box}
html,body{height:100%;margin:0}
body{
  background: radial-gradient(900px 300px at 8% 8%, rgba(74,163,224,0.04), transparent 8%),
              linear-gradient(180deg, var(--bg), #041025 120%);
  color:var(--text);
  font-family:var(--font-sans);
  padding:20px;
  display:flex;
  justify-content:center;
  -webkit-font-smoothing:antialiased;
}

.app{
  width:100%;
  max-width:var(--max-width);
  display:flex;
  flex-direction:column;
  gap:16px;
}

/* TOPBAR */
.topbar{
  display:flex;
  flex-direction:row;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:10px;
  border-radius:var(--radius);
  background:linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));
  border:1px solid var(--panel-border);
  box-shadow: 0 6px 18px rgba(2,8,20,0.45);
}

/* Home button */
.home-btn{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:8px 12px;
  background: linear-gradient(180deg, #6fc0ff, #4aa3e0);
  color: #022831;
  border-radius:10px;
  font-weight:700;
  text-decoration:none;
  box-shadow: 0 6px 14px rgba(30,120,160,0.12);
  line-height:1;
  border:0;
}
.home-btn:hover{ transform:translateY(-2px); box-shadow:0 10px 20px rgba(30,120,160,0.12) }

.branding h1{ margin:0; font-size:1.05rem }
.branding .subtitle{ color:var(--muted); font-size:0.88rem }

.top-controls{
  display:flex;
  gap:10px;
  align-items:center;
  flex-wrap:wrap;
  justify-content:flex-end;
}

.control-group{ display:flex; flex-direction:column; gap:6px; min-width:120px }
.control-group label{ color:var(--muted); font-size:0.85rem }
.control-group select, .control-group input{
  padding:8px 10px;
  border-radius:8px;
  border:1px solid var(--panel-border);
  background:var(--mono-bg);
  color:var(--text);
  min-width:110px;
  font-size:0.92rem;
}
.control-group.mini{ min-width:90px; max-width:160px }

.btn-group { display:flex; gap:8px; align-items:center; margin-left:6px }
button{ padding:8px 12px; border-radius:8px; border:0; cursor:pointer; font-weight:700; font-size:0.92rem }
button.primary{ color:white; background: linear-gradient(180deg,var(--accent), #3a8fc0); box-shadow:0 6px 12px rgba(10,50,80,0.25); }
button.ghost{ background:transparent; color:var(--accent); border:1px solid rgba(74,163,224,0.12); box-shadow:none; }

.status{ color:var(--muted); font-size:0.9rem }

/* MAIN content: 3 columns */
.content.three-col{
  display:grid;
  grid-template-columns: 1fr 1fr 360px;
  gap:var(--gap);
  align-items:start;
}

/* panes */
.pane{ padding:var(--pad); border-radius:12px; background:linear-gradient(180deg, rgba(255,255,255,0.01), var(--card-bg)); border:1px solid var(--panel-border); box-shadow:0 6px 18px rgba(0,0,0,0.35); }

.input-pane{ min-height:420px; display:flex; flex-direction:column; gap:8px; }
.preview-pane{ min-height:420px; display:flex; flex-direction:column; gap:8px; }
.cols-pane{ min-height:420px; display:flex; flex-direction:column; gap:8px; }

/* pane title */
.pane-title{ font-weight:700; color:var(--accent); margin-bottom:6px }

/* textarea */
.big-textarea{
  width:100%;
  min-height:320px;
  resize:vertical;
  padding:12px;
  border-radius:8px;
  border:1px solid var(--panel-border);
  background:var(--mono-bg);
  color:var(--text);
  font-family:var(--font-mono);
  font-size:0.95rem;
  line-height:1.4;
  outline:none;
}

/* table preview */
.table-wrapper{
  width:100%;
  min-height:320px;
  border-radius:8px;
  border:1px dashed rgba(255,255,255,0.03);
  background:linear-gradient(180deg, rgba(255,255,255,0.01), rgba(255,255,255,0.02));
  padding:8px;
  overflow:auto;
}
.table-wrapper .empty-state{ color:var(--muted); padding:28px; text-align:center }

.table-preview{ width:100%; border-collapse:collapse; font-family:var(--font-mono); font-size:0.92rem }
.table-preview thead th{ position:sticky; top:0; background:rgba(0,0,0,0.2); color:var(--accent); font-weight:700; padding:8px; text-align:left; border-bottom:1px solid rgba(255,255,255,0.03) }
.table-preview tbody td{ padding:6px 8px; border-bottom:1px solid rgba(255,255,255,0.02); color:var(--text); white-space:nowrap; overflow:hidden; text-overflow:ellipsis; max-width:240px; }

/* Columns list */
.columns-list{ display:flex; flex-direction:column; gap:6px; max-height:260px; overflow:auto }
.col-item{ display:flex; align-items:center; gap:8px; padding:6px; border-radius:8px; background:linear-gradient(180deg, rgba(255,255,255,0.005), transparent); border:1px solid rgba(255,255,255,0.02) }
.col-item label{ font-size:0.92rem; color:var(--text); }
.col-item input[type="checkbox"]{ width:18px; height:18px }

.small-muted{ color:var(--muted); font-size:0.85rem }

/* subtle separators for clarity */
.input-pane { border-right: 1px solid rgba(255,255,255,0.02); }
.preview-pane { border-right: 1px solid rgba(255,255,255,0.02); }

/* Responsive: collapse to single column on small screens */
@media (max-width:1100px){
  .content.three-col{ grid-template-columns: 1fr; }
  .input-pane, .preview-pane, .cols-pane { min-height:240px; }
  .table-preview tbody td{ white-space:normal; }
}