/* ── Theme Variables ─────────────────────────────────── */
:root, [data-theme="dark"] {
  --bg-body: #111827; --bg-card: #1f2937; --bg-control: #111827;
  --border: #374151; --text-primary: #d1d5db; --text-secondary: #9ca3af;
  --text-muted: #6b7280; --text-dim: #4b5563;
  --accent: #60a5fa; --accent-bg: #60a5fa; --accent-text: #111827;
  --input-bg: #1f2937; --select-bg: #1f2937;
}
[data-theme="light"] {
  --bg-body: #f8fafc; --bg-card: #ffffff; --bg-control: #f1f5f9;
  --border: #e2e8f0; --text-primary: #0f172a; --text-secondary: #475569;
  --text-muted: #94a3b8; --text-dim: #cbd5e1;
  --accent: #2563eb; --accent-bg: #2563eb; --accent-text: #ffffff;
  --input-bg: #ffffff; --select-bg: #ffffff;
}

/* ── Light theme overrides for inline-styled elements ─ */
[data-theme="light"] body { background: var(--bg-body) !important; color: var(--text-primary) !important; }
[data-theme="light"] .header { background: var(--bg-card) !important; border-color: var(--border) !important; }
[data-theme="light"] .controls { background: var(--bg-card) !important; }
[data-theme="light"] .control-group { background: var(--bg-control) !important; }
[data-theme="light"] .control-group h3 { color: var(--text-muted) !important; }
[data-theme="light"] .header p { color: var(--text-secondary) !important; }
[data-theme="light"] .plot { background: var(--bg-card) !important; }
[data-theme="light"] .info-box { background: var(--bg-control) !important; color: var(--text-secondary) !important; }
[data-theme="light"] .info-box code { color: var(--accent) !important; }
[data-theme="light"] label { color: var(--text-primary) !important; }
[data-theme="light"] label span.val { color: var(--accent) !important; }
[data-theme="light"] input[type=range] { accent-color: var(--accent) !important; }
[data-theme="light"] select { background: var(--select-bg) !important; color: var(--text-primary) !important; border-color: var(--border) !important; }
[data-theme="light"] .toggle-group button { background: var(--bg-control) !important; color: var(--text-secondary) !important; border-color: var(--border) !important; }
[data-theme="light"] .toggle-group button.active { background: var(--accent-bg) !important; color: var(--accent-text) !important; border-color: var(--accent) !important; }
[data-theme="light"] .metric { border-color: var(--border) !important; }
[data-theme="light"] .metric .label { color: var(--text-secondary) !important; }
[data-theme="light"] .metric .value { color: var(--accent) !important; }
[data-theme="light"] .status { color: var(--text-secondary) !important; }
[data-theme="light"] .status.warn { color: #d97706 !important; }
[data-theme="light"] .status.bad { color: #dc2626 !important; }
[data-theme="light"] .status.ok { color: #16a34a !important; }
[data-theme="light"] button { color: var(--text-primary) !important; }
[data-theme="light"] input[type=number] { background: var(--input-bg) !important; color: var(--text-primary) !important; border-color: var(--border) !important; }

/* ── Index page light overrides ───────────────────────── */
[data-theme="light"] .course { background: var(--bg-card) !important; }
[data-theme="light"] .course-header { border-color: var(--border) !important; }
[data-theme="light"] .course-header .ref { color: var(--text-muted) !important; }
[data-theme="light"] .demos { background: var(--border) !important; }
[data-theme="light"] .demo-link { background: var(--bg-card) !important; color: var(--text-primary) !important; }
[data-theme="light"] .demo-link:hover { background: #f1f5f9 !important; }
[data-theme="light"] .demo-link .num { color: var(--text-muted) !important; }
[data-theme="light"] .demo-link .arrow { color: var(--text-muted) !important; }
[data-theme="light"] .footer { color: var(--text-muted) !important; }

/* ── Header layout (back + title + toggle) ────────────── */
.header { display: flex !important; align-items: center !important; gap: 1rem !important; }
.back-link {
  color: var(--text-muted); text-decoration: none; font-size: 1.1rem;
  padding: 0.3rem 0.5rem; border-radius: 6px; line-height: 1;
  transition: color 0.15s, background 0.15s;
}
.back-link:hover { color: var(--accent); background: rgba(96,165,250,0.1); }
.header-title { flex: 1; }
.theme-toggle {
  background: none; border: 1px solid var(--border); color: var(--text-secondary);
  width: 2.2rem; height: 2.2rem; border-radius: 8px; cursor: pointer;
  font-size: 1rem; display: flex; align-items: center; justify-content: center;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); background: rgba(96,165,250,0.08); }

/* ── Fullscreen button (same style as theme-toggle) ──── */
.fullscreen-toggle {
  background: none; border: 1px solid var(--border); color: var(--text-secondary);
  width: 2.2rem; height: 2.2rem; border-radius: 8px; cursor: pointer;
  font-size: 1rem; display: flex; align-items: center; justify-content: center;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}
.fullscreen-toggle:hover { color: var(--accent); border-color: var(--accent); background: rgba(96,165,250,0.08); }

/* ── Per-plot focus controls ───────────────────────── */
.plot {
  position: relative;
  min-width: 0;
  min-height: 0;
}

.plot-focus-btn {
  position: absolute;
  top: 0.7rem;
  right: 0.7rem;
  z-index: 20;
  width: 2rem;
  height: 2rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(17, 24, 39, 0.72);
  color: #f8fafc;
  cursor: pointer;
  opacity: 0.72;
  backdrop-filter: blur(10px);
  transition: opacity 0.15s, transform 0.15s, border-color 0.15s, background 0.15s;
}

.plot:hover .plot-focus-btn,
.plot-focus-btn:focus-visible {
  opacity: 1;
}

.plot-focus-btn:hover {
  transform: translateY(-1px);
  border-color: var(--accent);
  background: rgba(37, 99, 235, 0.86);
}

.plot-focus-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.plots.plot-focus-active {
  grid-template-columns: 1fr !important;
  grid-template-rows: 1fr !important;
}

.plots.plot-focus-active .plot {
  display: none !important;
}

.plots.plot-focus-active .plot.plot-focus-target {
  display: block !important;
  min-height: calc(100vh - 125px);
  height: calc(100vh - 125px) !important;
}

/* ── Fullscreen mode ─────────────────────────────────── */
.container.fs-active { grid-template-columns: 1fr !important; }
.container.fs-active .controls { display: none !important; }
.container.fs-active .plots { grid-template-columns: 1fr 1fr !important; height: calc(100vh - 60px) !important; }
.container.fs-active .plots.plot-focus-active { grid-template-columns: 1fr !important; }
.container.fs-active .plots.plot-focus-active .plot.plot-focus-target {
  min-height: calc(100vh - 90px);
  height: calc(100vh - 90px) !important;
}

/* ── Mobile layout (<768px) ──────────────────────────── */
@media (max-width: 768px) {
  .header { padding: 0.6rem 0.8rem !important; gap: 0.5rem !important; }
  .header h1 { font-size: 0.95rem !important; }
  .header p { display: none !important; }

  .container {
    grid-template-columns: 1fr !important;
    grid-template-rows: auto 1fr !important;
    height: auto !important;
    min-height: 100vh;
  }

  /* Collapsible controls: collapsed by default on mobile */
  .controls {
    max-height: 0; overflow: hidden;
    border-right: none !important; border-bottom: 1px solid var(--border) !important;
    padding: 0 1.2rem !important;
    transition: max-height 0.3s ease, padding 0.3s ease;
  }
  .controls.mobile-open {
    max-height: 80vh; overflow-y: auto;
    padding: 1rem 1.2rem !important;
  }

  .plots {
    grid-template-columns: 1fr !important;
    grid-template-rows: auto !important;
    height: auto !important;
    padding: 0.5rem !important;
    gap: 0.4rem !important;
  }
  .plot { min-height: 280px; height: 44vh; }
  .plot-focus-btn {
    top: 0.55rem;
    right: 0.55rem;
    width: 1.9rem;
    height: 1.9rem;
  }
  .plots.plot-focus-active .plot.plot-focus-target {
    min-height: calc(100vh - 110px);
    height: calc(100vh - 110px) !important;
  }

  /* Index page */
  .hero h1 { font-size: 1.3rem; }
  .hero .stats { gap: 1rem; }
  .courses { grid-template-columns: 1fr !important; padding: 0 1rem; }
}

/* ── Mobile controls toggle button ─────────────────── */
.mobile-controls-toggle {
  display: none;
}
@media (max-width: 768px) {
  .mobile-controls-toggle {
    display: flex; align-items: center; justify-content: center;
    background: none; border: 1px solid var(--border); color: var(--text-secondary);
    width: 2.2rem; height: 2.2rem; border-radius: 8px; cursor: pointer;
    font-size: 1rem;
    transition: color 0.15s, border-color 0.15s, background 0.15s;
  }
  .mobile-controls-toggle:hover { color: var(--accent); border-color: var(--accent); background: rgba(96,165,250,0.08); }
}