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

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  min-height: 100vh;
  /* Tooltips and hover transforms may poke past the viewport edge;
     clip (not hidden) kills the phantom horizontal scrollbar without
     creating a scroll container. */
  overflow-x: clip;
  transition: var(--transition-theme);
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

/* ── Header ── */
.site-header {
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  padding: var(--space-md) var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  transition: var(--transition-theme);
}

.site-logo {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.site-logo span { color: var(--accent); }

.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.site-nav {
  display: flex;
  gap: var(--space-lg);
  list-style: none;
}

.site-nav a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s;
}

.site-nav a:hover,
.site-nav a.active { color: var(--text-primary); }

/* ── Theme Toggle ── */
.theme-toggle {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 20px;
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 1rem;
  height: 32px;
  width: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  flex-shrink: 0;
}

.theme-toggle:hover {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent);
}

/* ── Footer ── */
.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  padding: var(--space-xl);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-top: var(--space-2xl);
  transition: var(--transition-theme);
}

.site-footer a { color: var(--text-muted); }
.site-footer a:hover { color: var(--accent); }

/* ── Shared Controls ── */
.control-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  position: relative;
}

.control-group label {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.control-group select,
.control-group input[type="number"] {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  padding: var(--space-sm) var(--space-md);
  width: 100%;
  cursor: pointer;
  transition: border-color 0.15s, background 0.25s, color 0.25s;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%239898b8' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
}

[data-theme="light"] .control-group select,
[data-theme="light"] .control-group input[type="number"] {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%2344446e' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
}

.control-group select:hover,
.control-group select:focus,
.control-group input[type="number"]:hover,
.control-group input[type="number"]:focus {
  border-color: var(--accent);
  outline: none;
}

.control-group input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
  cursor: pointer;
  height: 4px;
}

.control-group input[type="color"] {
  width: 100%;
  height: 40px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-elevated);
  cursor: pointer;
  padding: 2px;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 500;
  padding: var(--space-sm) var(--space-md);
  transition: background 0.15s, transform 0.1s, color 0.15s;
  white-space: nowrap;
  position: relative;
}

.btn:active { transform: scale(0.97); }

/* `hidden` must beat the display:inline-flex above */
.btn[hidden] { display: none; }

/* Screen-reader-only text (page h1 on the visualizer) */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); color: #fff; }

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent-hover); }

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover { color: var(--text-primary); }

/* ── Tooltip System ── */
[data-tooltip] { position: relative; }

[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--tooltip-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  box-shadow: 0 4px 16px var(--shadow);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.72rem;
  font-weight: 400;
  line-height: 1.45;
  padding: 6px 10px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  transition-delay: 0s;
  z-index: 300;
  width: 200px;
  white-space: normal;
  text-align: center;
  text-transform: none;
  letter-spacing: 0;
}

[data-tooltip]:hover::after {
  opacity: 1;
  transition-delay: 0.35s;
}

/* Tooltip arrow */
[data-tooltip]::before {
  content: '';
  position: absolute;
  top: calc(100% + 2px);
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-bottom-color: var(--border);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  transition-delay: 0s;
  z-index: 301;
}

[data-tooltip]:hover::before {
  opacity: 1;
  transition-delay: 0.35s;
}

/* Tooltip positioned to the right (for sidebar controls) */
[data-tooltip-pos="right"]::after {
  top: 50%;
  left: calc(100% + 10px);
  transform: translateY(-50%);
}

[data-tooltip-pos="right"]::before {
  top: 50%;
  left: calc(100% + 4px);
  transform: translateY(-50%);
  border-bottom-color: transparent;
  border-right-color: var(--border);
}

/* Tooltip positioned above */
[data-tooltip-pos="above"]::after {
  top: auto;
  bottom: calc(100% + 8px);
}

[data-tooltip-pos="above"]::before {
  top: auto;
  bottom: calc(100% + 2px);
  border-bottom-color: transparent;
  border-top-color: var(--border);
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .site-header { padding: var(--space-sm) var(--space-md); }
  .site-nav { gap: var(--space-md); }
  .header-right { gap: var(--space-md); }
}

@media (max-width: 600px) {
  /* Wrap logo onto its own row, nav fills the row below */
  .site-header {
    flex-wrap: wrap;
    row-gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
  }

  .site-logo { flex: 0 0 auto; }

  .header-right {
    width: 100%;
    gap: var(--space-sm);
    justify-content: space-between;
  }

  /* The <nav> flex child must be allowed to shrink so the ul can scroll */
  .header-right nav { flex: 1; min-width: 0; }

  /* Horizontal-scroll nav — no wrapping, no overflow clipping the page */
  .site-nav {
    flex: 1;
    gap: var(--space-sm);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: 2px;
  }
  .site-nav::-webkit-scrollbar { display: none; }
  .site-nav a {
    font-size: 0.8rem;
    white-space: nowrap;
  }
}

/* ── Minimum touch targets ── */
@media (hover: none) and (pointer: coarse) {
  .btn { min-height: 44px; padding: var(--space-sm) var(--space-md); }
  .theme-toggle { width: 44px; height: 44px; }
  .ring-tab { min-height: 44px; }
  /* Suppress tooltips on touch — they never fire on hover anyway */
  [data-tooltip]::after,
  [data-tooltip]::before { display: none; }
}