*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #111827;
  color: #e5e7eb;
  min-height: 100vh;
}

header {
  background: #1f2937;
  border-bottom: 1px solid #374151;
  padding: 16px 28px;
  display: flex;
  align-items: baseline;
  gap: 12px;
}
header h1 { font-size: 1.25rem; font-weight: 700; color: #60a5fa; letter-spacing: -0.3px; }
header p { font-size: 0.82rem; color: #6b7280; flex: 1; }
.github-link {
  color: #6b7280;
  transition: color 0.15s;
  display: flex;
  align-items: center;
  flex-shrink: 0;
}
.github-link:hover { color: #e5e7eb; }

/* ── Outer tab bar (multi-instance tabs) ── */
.outer-tab-bar {
  background: #0f172a;
  border-bottom: 1px solid #1e293b;
  padding: 8px 28px 0;
  display: flex;
  align-items: flex-end;
  gap: 4px;
  overflow-x: auto;
}
.outer-tab {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border-radius: 6px 6px 0 0;
  cursor: pointer;
  border: 1px solid #1e293b;
  border-bottom: none;
  background: #1e293b;
  color: #6b7280;
  font-size: 0.82rem;
  font-family: 'SFMono-Regular', Consolas, monospace;
  transition: background 0.15s, color 0.15s;
  user-select: none;
  max-width: 320px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.outer-tab.active {
  background: #111827;
  color: #60a5fa;
  border-color: #374151;
  font-weight: 600;
}
.outer-tab:hover:not(.active) { background: #1f2937; color: #9ca3af; }
.outer-tab-label {
  overflow: hidden;
  text-overflow: ellipsis;
}
.close-tab-btn {
  font-size: 1rem;
  line-height: 1;
  color: #4b5563;
  cursor: pointer;
  flex-shrink: 0;
  padding: 0 2px;
  border-radius: 3px;
}
.close-tab-btn:hover { color: #f87171; background: rgba(248,113,113,0.15); }
.add-tab-btn {
  padding: 7px 12px;
  border-radius: 6px 6px 0 0;
  cursor: pointer;
  border: 1px solid #1e293b;
  border-bottom: none;
  background: transparent;
  color: #4b5563;
  font-size: 0.82rem;
  transition: background 0.15s, color 0.15s;
  flex-shrink: 0;
}
.add-tab-btn:hover { background: #1f2937; color: #60a5fa; }

/* ── Outer panel container ── */
.outer-panel { display: none; }
.outer-panel.active { display: block; }

.container { max-width: 1440px; margin: 0 auto; padding: 24px 28px; }

/* ── Unified tab-nav card (scope selector on top, filtered tabs below) ── */
.tab-nav {
  background: #0f172a;
  border: 1px solid #1f2937;
  border-radius: 10px;
  padding: 10px 12px 12px;
  margin-bottom: 22px;
  position: relative;
}
/* Thin accent stripe on the left edge that shifts color by scope, giving
   an at-a-glance hint of which section is active. */
.tab-nav::before {
  content: "";
  position: absolute;
  left: 0; top: 10px; bottom: 10px;
  width: 3px;
  border-radius: 3px;
  background: #3b82f6;
  transition: background 0.2s;
}
.tab-nav[data-scope="operations"]::before { background: #a855f7; }

.tab-scope-bar {
  display: flex;
  gap: 6px;
  padding: 0 0 10px;
  margin-bottom: 10px;
  border-bottom: 1px solid #1f2937;
  align-items: center;
}
.tab-scope-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 6px;
  cursor: pointer;
  background: transparent;
  color: #6b7280;
  border: 1px solid transparent;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.4px;
  text-transform: uppercase;
  user-select: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.tab-scope-btn.active {
  background: #1e3a5f;
  color: #93c5fd;
  border-color: #3b82f6;
}
.tab-scope-btn[data-scope="operations"].active {
  background: #3b1e5f;
  color: #c4b5fd;
  border-color: #a855f7;
}
.tab-scope-btn:hover:not(.active) {
  background: #1f2937;
  color: #d1d5db;
}
.tab-scope-icon { font-size: 0.8rem; opacity: 0.8; }
.tab-scope-count {
  display: inline-flex;
  justify-content: center;
  min-width: 18px;
  padding: 1px 5px;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.06);
  color: #9ca3af;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0;
}
.tab-scope-btn.active .tab-scope-count { background: rgba(147, 197, 253, 0.18); color: #bfdbfe; }
.tab-scope-btn[data-scope="operations"].active .tab-scope-count {
  background: rgba(196, 181, 253, 0.18); color: #ddd6fe;
}

/* Scope-based filtering: only show tabs whose data-scope matches the tab-bar.
   One rule per scope — add a new line when you add a new scope. */
.tab-bar[data-scope="basics"]     .tab:not([data-scope="basics"])     { display: none; }
.tab-bar[data-scope="operations"] .tab:not([data-scope="operations"]) { display: none; }

/* ── Inner tabs (Layout / TV Layout switcher) ── */
.tab-bar { display: flex; flex-wrap: wrap; gap: 6px; margin: 0; }
.tab {
  padding: 7px 18px;
  border-radius: 6px;
  cursor: pointer;
  border: 1px solid #374151;
  background: #1f2937;
  color: #9ca3af;
  font-size: 0.88rem;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  user-select: none;
  white-space: nowrap;
}
.tab.active { background: #1e3a5f; color: #60a5fa; border-color: #3b82f6; font-weight: 600; }
.tab[data-scope="operations"].active { background: #3b1e5f; color: #c4b5fd; border-color: #a855f7; }
.tab:hover:not(.active) { background: #283548; color: #d1d5db; }

/* ── Panel layout ── */
.panel { display: none; gap: 22px; align-items: flex-start; }
.panel.active { display: flex; flex-wrap: wrap; }

/* ── Controls ── */
.controls {
  background: #1f2937;
  border: 1px solid #374151;
  border-radius: 10px;
  padding: 20px;
  flex: 0 0 300px;
  min-width: 280px;
}
.controls h2 { font-size: 0.9rem; font-weight: 600; color: #93c5fd; margin-bottom: 18px; text-transform: uppercase; letter-spacing: 0.5px; }

.form-group { margin-bottom: 14px; }
label { display: block; font-size: 0.76rem; color: #9ca3af; margin-bottom: 5px; letter-spacing: 0.3px; }
input[type="text"] {
  width: 100%;
  background: #111827;
  border: 1px solid #374151;
  border-radius: 5px;
  padding: 7px 10px;
  color: #f3f4f6;
  font-family: 'SFMono-Regular', Consolas, monospace;
  font-size: 0.85rem;
  transition: border-color 0.15s;
}
input[type="text"]:focus { outline: none; border-color: #3b82f6; }

textarea {
  width: 100%;
  background: #111827;
  border: 1px solid #374151;
  border-radius: 5px;
  padding: 7px 10px;
  color: #f3f4f6;
  font-family: 'SFMono-Regular', Consolas, monospace;
  font-size: 0.85rem;
  transition: border-color 0.15s;
  resize: vertical;
  line-height: 1.5;
}
textarea:focus { outline: none; border-color: #3b82f6; }

.btn {
  background: #1e3a5f;
  color: #93c5fd;
  border: 1px solid #3b82f6;
  border-radius: 5px;
  padding: 8px 14px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: background 0.15s, color 0.15s;
}
.btn:hover { background: #3b82f6; color: #fff; }
.btn.active { background: #3b82f6; color: #fff; border-color: #60a5fa; }
.btn-render { width: 100%; margin-top: 4px; padding: 9px; font-weight: 600; }

.comp-result-box {
  display: none;
  margin: 8px 0;
  padding: 8px 10px;
  background: #111827;
  border: 1px solid #1e3a5f;
  border-radius: 5px;
  font-family: 'SFMono-Regular', Consolas, monospace;
  font-size: 0.8rem;
  color: #93c5fd;
  word-break: break-all;
}
.comp-result-box.visible { display: block; }

.error-msg {
  color: #f87171;
  font-size: 0.78rem;
  margin-top: 6px;
  display: none;
  background: #2d1b1b;
  border: 1px solid #7f1d1d;
  border-radius: 4px;
  padding: 6px 8px;
}
.warning-msg {
  color: #fbbf24;
  font-size: 0.78rem;
  margin-top: 6px;
  display: none;
  background: #2a231a;
  border: 1px solid #78590d;
  border-radius: 4px;
  padding: 6px 8px;
  line-height: 1.4;
}

/* ── Presets ── */
.presets { margin-top: 20px; border-top: 1px solid #374151; padding-top: 16px; }
.presets h3 { font-size: 0.76rem; color: #6b7280; margin-bottom: 10px; text-transform: uppercase; letter-spacing: 0.5px; }
.preset-list { display: flex; flex-direction: column; gap: 5px; }
.preset-btn {
  text-align: left;
  font-size: 0.78rem;
  padding: 5px 9px;
  border-color: #374151;
  color: #9ca3af;
  font-family: 'SFMono-Regular', Consolas, monospace;
  background: #111827;
}
.preset-btn:hover { background: #1f2937; color: #e5e7eb; border-color: #60a5fa; }

/* ── Hint ── */
.hint {
  margin-top: 18px;
  border-top: 1px solid #374151;
  padding-top: 14px;
  font-size: 0.76rem;
  color: #6b7280;
  line-height: 1.6;
}
.hint code {
  background: #111827;
  padding: 1px 5px;
  border-radius: 3px;
  font-family: 'SFMono-Regular', Consolas, monospace;
  color: #a5b4fc;
}

/* ── Visualization ── */
.visualization { flex: 1; min-width: 360px; }
.viz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}
.viz-title { font-size: 0.82rem; color: #9ca3af; font-family: 'SFMono-Regular', Consolas, monospace; }
.viz-box {
  background: #fff;
  border: 1px solid #374151;
  border-radius: 10px;
  padding: 20px;
  overflow: auto;
}

/* ── Legend ── */
.legend {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.legend-item {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 0.75rem;
  color: #9ca3af;
  background: #1f2937;
  border: 1px solid #374151;
  border-radius: 4px;
  padding: 3px 7px;
}
.legend-swatch {
  width: 12px;
  height: 12px;
  border-radius: 2px;
  border: 1px solid rgba(0,0,0,0.3);
  flex-shrink: 0;
}

/* ── Composition results 2x2 grid ── */
.comp-results {
  flex: 1;
  min-width: 360px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.comp-viz-item { min-width: 0; }
.comp-viz-item .viz-box { padding: 10px; }
.comp-viz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}
.comp-viz-label {
  font-size: 0.82rem;
  color: #9ca3af;
  font-family: 'SFMono-Regular', Consolas, monospace;
}
.mode-btn-group { display: inline-flex; gap: 1px; }
.mode-btn {
  font-size: 0.7rem;
  padding: 2px 8px;
  background: #1f2937;
  color: #9ca3af;
  border: 1px solid #374151;
  cursor: pointer;
  font-family: 'SFMono-Regular', Consolas, monospace;
  transition: background 0.15s, color 0.15s;
}
.mode-btn:first-child { border-radius: 4px 0 0 4px; }
.mode-btn:last-child { border-radius: 0 4px 4px 0; }
.mode-btn:not(:first-child):not(:last-child) { border-radius: 0; }
.mode-btn:hover { background: #1e3a5f; color: #93c5fd; border-color: #3b82f6; }
.mode-btn.active { background: #1e3a5f; color: #60a5fa; border-color: #3b82f6; font-weight: 600; }