/* ---------- Tokens ---------- */
:root {
  --bg: #07090f;
  --bg-2: #0c1019;
  --panel: #0f1422;
  --panel-2: #131a2c;
  --border: rgba(148, 163, 184, 0.12);
  --border-strong: rgba(148, 163, 184, 0.22);
  --text: #e6ebf3;
  --muted: #94a3b8;
  --accent: #5eead4;
  --accent-2: #38bdf8;
  --accent-warm: #f472b6;
  --danger: #f87171;
  --shadow-lg: 0 30px 80px -20px rgba(0, 0, 0, 0.6);

  --radius-md: 10px;
  --radius-lg: 14px;

  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Inter, Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  font-family: var(--font);
  font-size: 14px;
  color: var(--text);
  background:
    radial-gradient(1200px 700px at 80% -10%, rgba(56,189,248,0.08), transparent 60%),
    radial-gradient(900px 600px at -10% 110%, rgba(244,114,182,0.06), transparent 60%),
    var(--bg);
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

button { font-family: inherit; font-size: inherit; color: inherit; cursor: pointer; }
.hidden { display: none !important; }
.muted { color: var(--muted); }
.small { font-size: 12px; }
.mono { font-family: var(--font-mono); }

/* ---------- Topbar ---------- */
.topbar {
  position: fixed; inset: 0 0 auto 0;
  display: flex; align-items: center; justify-content: space-between;
  height: 56px; padding: 0 18px;
  background: linear-gradient(180deg, rgba(15,20,34,0.85), rgba(15,20,34,0.55));
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 5;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand .logo { width: 28px; height: 28px; filter: drop-shadow(0 0 8px rgba(94,234,212,0.25)); }
.brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-text h1 { margin: 0; font-size: 15px; font-weight: 600; letter-spacing: 0.2px; }
.brand-text span { font-size: 11px; color: var(--muted); letter-spacing: 0.4px; text-transform: lowercase; }

.topbar-actions { display: flex; gap: 6px; }
.ghost {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 10px; border-radius: 8px;
  background: transparent; color: var(--muted);
  border: 1px solid transparent; text-decoration: none;
  transition: background .15s ease, color .15s ease, border-color .15s ease;
}
.ghost:hover { background: rgba(148,163,184,0.08); color: var(--text); border-color: var(--border); }

/* ---------- Layout ---------- */
.layout {
  position: absolute; inset: 56px 0 0 0;
  display: grid;
  grid-template-columns: 320px 1fr;
  min-height: 0;
}

/* ---------- Side panel ---------- */
.panel {
  background: linear-gradient(180deg, var(--panel), var(--bg-2));
  border-right: 1px solid var(--border);
  overflow-y: auto;
  overflow-x: hidden;
  padding: 16px 14px 32px;
  scrollbar-width: thin;
  scrollbar-color: rgba(148,163,184,0.25) transparent;
}
.panel::-webkit-scrollbar { width: 8px; }
.panel::-webkit-scrollbar-thumb { background: rgba(148,163,184,0.18); border-radius: 4px; }
.panel::-webkit-scrollbar-thumb:hover { background: rgba(148,163,184,0.32); }

.panel-section { margin-bottom: 18px; padding-bottom: 14px; border-bottom: 1px solid var(--border); }
.panel-section:last-child { border-bottom: none; padding-bottom: 0; }
.panel-section h2 {
  margin: 0 0 8px; font-size: 11px; font-weight: 600;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted);
}
.panel-section p { margin: 0 0 10px; }

/* Dropzone */
.dropzone {
  border: 1.5px dashed var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 18px 14px;
  text-align: center;
  background: rgba(148,163,184,0.03);
  color: var(--muted);
  cursor: pointer;
  transition: background .15s ease, border-color .15s ease, color .15s ease, transform .15s ease;
  display: flex; flex-direction: column; align-items: center; gap: 6px;
}
.dropzone:hover { color: var(--text); background: rgba(94,234,212,0.05); border-color: rgba(94,234,212,0.4); }
.dropzone.drag-over { background: rgba(94,234,212,0.08); border-color: var(--accent); color: var(--text); transform: scale(1.01); }
.dz-title { font-weight: 600; color: var(--text); margin-top: 4px; }
.dz-sub { font-size: 12px; }
.link { background: none; border: none; color: var(--accent); padding: 0; font-weight: 600; cursor: pointer; }
.link:hover { text-decoration: underline; }

.samples { margin-top: 12px; }
.sample-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; margin-top: 8px; }
.chip {
  border: 1px solid var(--border);
  background: rgba(148,163,184,0.04);
  color: var(--text);
  padding: 7px 10px;
  border-radius: 8px;
  font-size: 12px;
  text-align: center;
  transition: background .15s ease, border-color .15s ease, color .15s ease;
}
.chip:hover { background: rgba(94,234,212,0.08); border-color: rgba(94,234,212,0.35); color: var(--accent); }
.chip.active { background: rgba(94,234,212,0.12); border-color: var(--accent); color: var(--accent); }

.data-summary {
  margin-top: 14px; padding: 10px 12px; border-radius: 10px;
  background: rgba(56,189,248,0.04); border: 1px solid rgba(56,189,248,0.12);
}
.row { display: flex; justify-content: space-between; align-items: center; gap: 8px; padding: 3px 0; }
.row .label { color: var(--muted); font-size: 12px; }
.row .value { font-weight: 600; font-size: 13px; }

/* Fields */
.field { display: flex; flex-direction: column; gap: 6px; margin-bottom: 12px; }
.field > span:first-child {
  display: flex; justify-content: space-between; align-items: baseline;
  font-size: 12px; font-weight: 500; color: var(--text);
}
.field em { font-style: normal; color: var(--accent); font-variant-numeric: tabular-nums; font-size: 12px; }
.field .hint { font-size: 11px; color: var(--muted); }
.field select {
  appearance: none;
  background-color: var(--panel-2);
  background-image: linear-gradient(45deg, transparent 50%, var(--muted) 50%), linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position: calc(100% - 14px) center, calc(100% - 9px) center;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 7px 28px 7px 10px;
  border-radius: 8px;
  font-size: 13px;
}
.field select:focus { outline: none; border-color: var(--accent); }

/* Range slider */
input[type="range"] {
  -webkit-appearance: none; appearance: none;
  height: 4px; border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  outline: none;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px; height: 14px; border-radius: 50%;
  background: #fff; border: 2px solid var(--accent);
  box-shadow: 0 0 0 4px rgba(94,234,212,0.12);
  transition: box-shadow .15s ease;
}
input[type="range"]::-webkit-slider-thumb:hover { box-shadow: 0 0 0 6px rgba(94,234,212,0.18); }
input[type="range"]::-moz-range-thumb {
  width: 14px; height: 14px; border-radius: 50%;
  background: #fff; border: 2px solid var(--accent);
}

.checkbox { display: flex; align-items: center; gap: 8px; font-size: 13px; cursor: pointer; margin: 6px 0 12px; }
.checkbox input { accent-color: var(--accent); }

.primary {
  width: 100%;
  padding: 9px 12px;
  border-radius: 9px;
  border: 1px solid rgba(94,234,212,0.4);
  background: linear-gradient(180deg, rgba(94,234,212,0.18), rgba(56,189,248,0.18));
  color: var(--text);
  font-weight: 600;
  letter-spacing: 0.2px;
  transition: background .15s ease, border-color .15s ease, transform .05s ease;
}
.primary:hover { background: linear-gradient(180deg, rgba(94,234,212,0.28), rgba(56,189,248,0.28)); border-color: var(--accent); }
.primary:active { transform: translateY(1px); }
.primary:disabled { opacity: 0.5; cursor: not-allowed; }

.status .row .value { font-family: var(--font-mono); font-size: 12px; }

/* ---------- Canvas area ---------- */
.canvas-wrap {
  position: relative; min-height: 0; overflow: hidden;
  background:
    radial-gradient(1200px 700px at 70% 30%, rgba(56,189,248,0.08), transparent 60%),
    radial-gradient(900px 600px at 30% 80%, rgba(244,114,182,0.06), transparent 60%),
    var(--bg);
}
#graph { position: absolute; inset: 0; }
#graph canvas { display: block; }

/* Empty state */
.overlay-empty {
  position: absolute; inset: 0;
  display: grid; place-items: center;
  pointer-events: none;
  padding: 24px;
  z-index: 2;
}
.empty-card {
  position: relative;
  max-width: 520px;
  text-align: center;
  padding: 32px;
  border-radius: 18px;
  border: 1px solid var(--border);
  background: rgba(15,20,34,0.55);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  box-shadow: var(--shadow-lg);
  pointer-events: auto;
}
.empty-glow {
  position: absolute; inset: -1px; z-index: -1; border-radius: 18px;
  background: conic-gradient(from 0deg, rgba(94,234,212,0.25), rgba(56,189,248,0.0), rgba(244,114,182,0.25), rgba(94,234,212,0.25));
  filter: blur(28px); opacity: 0.6;
  animation: spin 12s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.empty-card h2 { margin: 0 0 10px; font-size: 22px; letter-spacing: -0.2px; }
.empty-card p { margin: 0 0 18px; color: var(--muted); line-height: 1.55; }
.hints { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; font-size: 12px; color: var(--muted); }
.hints kbd {
  display: inline-block; padding: 1px 6px; margin-right: 4px;
  background: rgba(148,163,184,0.1);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--font-mono); font-size: 11px; color: var(--text);
}

/* Progress overlay */
.overlay-progress {
  position: absolute; top: 14px; left: 50%; transform: translateX(-50%);
  display: flex; align-items: center; gap: 10px;
  padding: 8px 14px;
  background: rgba(15,20,34,0.85);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 12px;
  color: var(--muted);
  z-index: 3;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.spinner {
  width: 14px; height: 14px;
  border: 2px solid rgba(94,234,212,0.25);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

/* Tooltip */
.overlay-tooltip {
  position: absolute;
  pointer-events: none;
  background: rgba(15,20,34,0.95);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 12px;
  z-index: 4;
  min-width: 180px;
  box-shadow: 0 12px 30px -10px rgba(0,0,0,0.6);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.overlay-tooltip .tt-title { font-weight: 600; margin-bottom: 4px; }
.overlay-tooltip .tt-row { display: flex; justify-content: space-between; gap: 12px; color: var(--muted); }
.overlay-tooltip .tt-row b { color: var(--text); font-weight: 500; font-family: var(--font-mono); font-size: 11px; }

/* Legend */
.legend {
  position: absolute; bottom: 16px; left: 16px; z-index: 3;
  padding: 10px 12px; border-radius: 10px;
  background: rgba(15,20,34,0.85);
  border: 1px solid var(--border);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  width: 180px;
}
.legend-title { font-size: 11px; color: var(--muted); margin-bottom: 6px; text-transform: uppercase; letter-spacing: 0.08em; }
.legend-bar { height: 8px; border-radius: 4px; }
.legend-ticks { display: flex; justify-content: space-between; font-size: 11px; color: var(--muted); margin-top: 4px; font-family: var(--font-mono); }

/* Dialog */
.dialog {
  border: none; padding: 0; border-radius: 16px;
  background: var(--panel); color: var(--text);
  max-width: 540px; width: calc(100% - 32px);
  box-shadow: var(--shadow-lg);
}
.dialog::backdrop { background: rgba(7,9,15,0.7); backdrop-filter: blur(4px); }
.dialog article { padding: 24px 28px; }
.dialog h2 { margin: 0 0 12px; font-size: 18px; }
.dialog p { color: var(--muted); line-height: 1.55; margin: 0 0 10px; }
.dialog ol { padding-left: 20px; color: var(--muted); line-height: 1.6; }
.dialog ol strong { color: var(--text); }
.dialog-actions { display: flex; justify-content: flex-end; margin-top: 18px; }
.dialog-actions .primary { width: auto; padding: 8px 18px; }

@media (max-width: 880px) {
  .layout { grid-template-columns: 1fr; grid-template-rows: minmax(0, 45%) 1fr; }
  .panel { border-right: none; border-bottom: 1px solid var(--border); }
}