:root {
  --bg: #0a0e14;
  --bg-elevated: #121820;
  --bg-panel: #161d28;
  --border: #243044;
  --text: #e8edf4;
  --text-muted: #7d8da6;
  --accent: #3dd6c6;
  --accent-dim: #2a9d8f;
  --accent-glow: rgba(61, 214, 198, 0.25);
  --marker: #ff8c42;
  --marker-2: #a78bfa;
  --grid: #2a3548;
  --grid-major: #3d4f66;
  --chart-bg: #0d1219;
  --danger: #f07178;
  --radius: 10px;
  --font: "DM Sans", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
}

[data-theme="light"] {
  --bg: #f4f6f9;
  --bg-elevated: #ffffff;
  --bg-panel: #ffffff;
  --border: #d8dee8;
  --text: #1a2332;
  --text-muted: #5c6b7f;
  --accent: #0d9488;
  --accent-dim: #0f766e;
  --accent-glow: rgba(13, 148, 136, 0.15);
  --marker: #ea580c;
  --marker-2: #7c3aed;
  --grid: #c5d0de;
  --grid-major: #94a3b8;
  --chart-bg: #fafbfc;
}

*, *::before, *::after { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

body {
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, var(--accent-glow), transparent),
    var(--bg);
}

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elevated);
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.brand-icon {
  width: 36px;
  height: 36px;
  color: var(--accent);
}

.brand h1 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.tagline {
  margin: 0.1rem 0 0;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.field-inline {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.field-inline input,
.field-inline select {
  width: 4.5rem;
  padding: 0.35rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg-panel);
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.78rem;
}

.field-inline select { width: auto; }

.unit { font-size: 0.72rem; color: var(--text-muted); }

.btn {
  padding: 0.45rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--accent);
  color: #0a0e14;
  font-family: var(--font);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.12s, box-shadow 0.12s, background 0.12s;
}

[data-theme="light"] .btn { color: #fff; }

.btn:hover { filter: brightness(1.08); transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn.ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn.ghost:hover { background: var(--bg-panel); }
.btn.ghost.active { border-color: var(--accent); color: var(--accent); }

.btn.sm { padding: 0.35rem 0.65rem; font-size: 0.75rem; }

.btn.icon {
  padding: 0.4rem;
  background: transparent;
  color: var(--text-muted);
  border-color: var(--border);
}

.main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr min(340px, 38vw);
  gap: 0;
  min-height: 0;
}

@media (max-width: 900px) {
  .main { grid-template-columns: 1fr; }
}

.chart-panel {
  display: flex;
  flex-direction: column;
  padding: 1rem;
  min-height: 0;
  min-width: 0;
}

.chart-wrap {
  position: relative;
  flex: 1;
  min-height: 280px;
  min-width: 0;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--chart-bg);
  box-shadow: inset 0 0 60px rgba(0,0,0,0.2);
  overflow: hidden;
}

#chart {
  position: absolute;
  display: block;
  cursor: crosshair;
  /* width/height set in JS to keep 1:1 aspect (Smith chart must be circular) */
}

.chart-hud {
  position: absolute;
  bottom: 0.6rem;
  left: 0.75rem;
  right: 0.75rem;
  display: flex;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
  pointer-events: none;
}

.chart-toolbar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 0.65rem;
  flex-wrap: wrap;
}

.toggle {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  cursor: pointer;
}

.toggle input { accent-color: var(--accent); }

.sidebar {
  border-left: 1px solid var(--border);
  background: var(--bg-elevated);
  overflow-y: auto;
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

@media (max-width: 900px) {
  .sidebar { border-left: none; border-top: 1px solid var(--border); }
}

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem;
}

.panel h2 {
  margin: 0 0 0.65rem;
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.panel h2 span { color: var(--accent); font-family: var(--mono); }

.hint {
  margin: 0 0 0.6rem;
  font-size: 0.72rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.tabs {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 0.65rem;
}

.tab {
  flex: 1;
  padding: 0.4rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
}

.tab.active {
  background: var(--accent);
  color: #0a0e14;
  border-color: var(--accent);
}

[data-theme="light"] .tab.active { color: #fff; }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.input-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
}

.input-grid label,
.tline-controls label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.input-grid input,
.tline-controls input[type="number"] {
  padding: 0.45rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.8rem;
}

.input-grid input:focus,
.tline-controls input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-glow);
}

.readouts {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.4rem 0.75rem;
  margin: 0.75rem 0 0;
  padding-top: 0.65rem;
  border-top: 1px solid var(--border);
}

.readouts.compact { margin-top: 0.5rem; }

.readouts div {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
}

.readouts dt {
  margin: 0;
  font-size: 0.68rem;
  color: var(--text-muted);
}

.readouts dd {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent);
  text-align: right;
}

.slider-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.slider-row input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
}

.slider-row input[type="number"] {
  width: 4rem;
  padding: 0.35rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.75rem;
}

.tline-controls input[type="number"]#tlineWl { width: 100%; margin-top: 0.15rem; }

.btn-row {
  display: flex;
  gap: 0.4rem;
  margin-top: 0.5rem;
}

.marker-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  max-height: 140px;
  overflow-y: auto;
}

.marker-list li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.5rem;
  border-radius: 6px;
  border: 1px solid transparent;
  font-family: var(--mono);
  font-size: 0.68rem;
  cursor: pointer;
  transition: background 0.1s, border-color 0.1s;
}

.marker-list li:hover { background: var(--bg); }
.marker-list li.active {
  border-color: var(--accent);
  background: var(--accent-glow);
}

.marker-list .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.marker-list .del {
  margin-left: auto;
  padding: 0.15rem 0.35rem;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.85rem;
  border-radius: 4px;
}

.marker-list .del:hover { color: var(--danger); background: rgba(240,113,120,0.1); }

.preset-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.35rem;
}

.preset-grid button {
  padding: 0.4rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.68rem;
  font-family: var(--mono);
  cursor: pointer;
  text-align: left;
  transition: border-color 0.1s, background 0.1s;
}

.preset-grid button:hover {
  border-color: var(--accent);
  background: var(--accent-glow);
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.5rem 1.25rem;
  border-top: 1px solid var(--border);
  font-size: 0.68rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}