.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}

.glass {
  border: 1px solid var(--line);
  background: var(--glass-bg);
  box-shadow: var(--shadow), var(--inner-glow);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  isolation: isolate;
}

.app-shell {
  position: relative;
  z-index: 10;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  grid-template-rows: auto minmax(0, 1fr);
  width: 100vw;
  height: 100dvh;
  gap: 10px;
  padding: max(10px, env(safe-area-inset-top)) max(10px, env(safe-area-inset-right)) max(10px, env(safe-area-inset-bottom)) max(10px, env(safe-area-inset-left));
}

.topbar {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 68px;
  padding: 10px 16px;
  border-radius: 22px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand-mark {
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  border: 1px solid var(--glass-highlight);
  border-radius: 13px;
  background:
    radial-gradient(circle at 30% 22%, rgb(255 255 255 / 85%), transparent 18%),
    linear-gradient(105deg, var(--accent-from), var(--accent-mid) 52%, var(--accent-to));
  box-shadow: 0 14px 34px var(--glass-accent-shadow), var(--inner-glow);
}

.brand strong {
  display: block;
  font-size: 15px;
  letter-spacing: -0.02em;
}

.brand small {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.topbar-start {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

.button,
.tool-button {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--glass-bg);
  color: var(--text);
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, calc(0.55 * var(--glass-reflex-light))),
    inset 0 -1px 2px rgba(0, 0, 0, calc(0.12 * var(--glass-reflex-dark))),
    0 4px 18px var(--glass-shadow);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  transition: background-color 0.35s ease, transform 0.35s cubic-bezier(0.34, 1.45, 0.64, 1),
    border-color 0.35s ease;
  cursor: pointer;
  padding: 9px 14px;
}

.button:hover,
.tool-button:hover {
  border-color: var(--accent-mid);
  transform: translateY(-1px);
  background: var(--glass-bg-hover);
}

.icon-button {
  width: 42px;
  height: 42px;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 0;
  flex: 0 0 auto;
  text-decoration: none;
  color: inherit;
}

.icon-button svg {
  width: 20px;
  height: 20px;
  display: block;
}

.icon-button--brand {
  width: auto;
  min-width: 42px;
  padding: 0 12px 0 10px;
  gap: 6px;
  line-height: 1;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.icon-button--brand span {
  display: block;
  line-height: 1;
}

.workspace {
  position: relative;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  background:
    radial-gradient(circle at 25% 20%, color-mix(in srgb, var(--accent-mid) 14%, transparent), transparent 28%),
    var(--glass-bg);
}

.canvas-stage {
  position: relative;
  width: 100%;
  height: 100%;
  min-width: 0;
  min-height: 0;
  overflow: hidden;
  border-radius: 16px;
}

#simCanvas {
  display: block;
  width: 100%;
  height: 100%;
  cursor: crosshair;
  touch-action: none;
  background: var(--sim-empty);
}

.hud {
  position: absolute;
  top: 18px;
  left: 18px;
  z-index: 2;
  padding: 10px 12px;
  border-radius: 16px;
  font-size: 12px;
  pointer-events: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.hud-row {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
}

.hud-row strong,
.hud-row .mono {
  color: var(--text);
  font-family: var(--font-mono);
  font-weight: 650;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--ok);
  box-shadow: 0 0 10px color-mix(in srgb, var(--ok) 70%, transparent);
  animation: pulse 1.6s ease-in-out infinite;
}

.status-dot.is-paused {
  background: var(--warn);
  box-shadow: 0 0 10px color-mix(in srgb, var(--warn) 70%, transparent);
  animation: none;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.45; }
}

.hint-pill {
  position: absolute;
  bottom: 18px;
  left: 18px;
  z-index: 2;
  padding: 8px 12px;
  border-radius: 14px;
  color: var(--muted);
  font-size: 12px;
  pointer-events: none;
}

.hint-pill b {
  color: var(--text);
  font-weight: 650;
}

.dock {
  min-width: 0;
  min-height: 0;
  display: flex;
}

.dock-panel {
  display: flex;
  flex-direction: column;
  width: 100%;
  min-height: 0;
  padding: 16px 8px 16px 16px;
  border-radius: var(--radius);
  overflow: hidden;
}

.dock-scroll {
  display: flex;
  flex-direction: column;
  flex: 1;
  gap: 16px;
  min-height: 0;
  padding-right: 8px;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: color-mix(in srgb, var(--accent-mid) 62%, transparent) transparent;
}

.dock-kicker {
  margin: 0 0 4px;
  font-size: 15px;
  letter-spacing: -0.02em;
}

.dock-copy {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.45;
}

.action-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 8px;
}

.tool-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 42px;
  padding: 8px 10px;
  border-radius: 16px;
  font-size: 12px;
}

.tool-button svg {
  width: 14px;
  height: 14px;
  flex: 0 0 auto;
}

.tool-button.is-active {
  border-color: var(--accent-mid);
  background: var(--glass-accent-bg);
  box-shadow: 0 8px 22px var(--glass-accent-shadow), var(--inner-glow);
}

.control {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.lab-label {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  font-size: 12px;
  color: var(--muted);
}

.lab-value {
  font-family: var(--font-mono);
  color: var(--text);
}

.check {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  min-height: 44px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--glass-bg);
  color: var(--text);
  font-size: 12px;
  cursor: pointer;
  user-select: none;
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, calc(0.55 * var(--glass-reflex-light))),
    inset 0 -1px 2px rgba(0, 0, 0, calc(0.12 * var(--glass-reflex-dark))),
    0 4px 18px var(--glass-shadow);
}

.check:hover {
  border-color: var(--accent-mid);
  background: var(--glass-bg-hover);
}

.check:has(input:checked) {
  border-color: var(--accent-mid);
}

.check input {
  appearance: none;
  width: 18px;
  height: 18px;
  margin: 0;
  flex: 0 0 auto;
  border: 1.5px solid var(--line);
  border-radius: 6px;
  background: var(--glass-bg);
  cursor: pointer;
  display: grid;
  place-items: center;
}

.check input:checked {
  border-color: var(--accent-mid);
  background: linear-gradient(105deg, var(--accent-from), var(--accent-mid) 50%, var(--accent-to));
}

.check input:checked::after {
  content: "";
  width: 9px;
  height: 5px;
  border: solid #1d1d1f;
  border-width: 0 0 2px 2px;
  transform: translateY(-1px) rotate(-45deg);
}

.legend {
  margin-top: auto;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 12px;
  color: var(--muted);
}

.legend strong {
  color: var(--text);
  font-weight: 650;
}

.legend-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex: 0 0 auto;
}

.legend-dot--attract { background: #6366f1; box-shadow: 0 0 8px #6366f1; }
.legend-dot--repel { background: #f59e0b; box-shadow: 0 0 8px #f59e0b; }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  background: transparent;
  margin: 6px 0 0;
}

input[type="range"]:focus {
  outline: none;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 5px;
  background: color-mix(in srgb, var(--text) 12%, transparent);
  border-radius: 10px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  margin-top: -6px;
  border-radius: 50%;
  border: 2px solid var(--page-bg);
  background: linear-gradient(105deg, var(--accent-from), var(--accent-to));
  box-shadow: 0 0 12px var(--glass-accent-shadow);
  cursor: pointer;
}

input[type="range"]::-moz-range-track {
  height: 5px;
  background: color-mix(in srgb, var(--text) 12%, transparent);
  border-radius: 10px;
  border: none;
}

input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border: none;
  border-radius: 50%;
  background: linear-gradient(105deg, var(--accent-from), var(--accent-to));
  cursor: pointer;
}

.theme-switcher {
  position: relative;
  display: inline-flex;
  align-items: center;
  margin: 0;
  padding: 0.3rem;
  min-width: 0;
  min-inline-size: auto;
  flex: 0 0 auto;
  border: none;
  border-radius: 9999px;
  background: var(--switcher-track);
  backdrop-filter: blur(22px) saturate(var(--glass-saturation));
  -webkit-backdrop-filter: blur(22px) saturate(var(--glass-saturation));
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, calc(0.55 * var(--glass-reflex-light))),
    inset 0 -1px 2px rgba(0, 0, 0, calc(0.12 * var(--glass-reflex-dark))),
    0 4px 18px var(--glass-shadow);
}

.theme-switcher::after {
  content: "";
  position: absolute;
  top: 0.3rem;
  left: 0.3rem;
  width: 2.35rem;
  height: 2.35rem;
  border-radius: 50%;
  background: var(--switcher-thumb);
  box-shadow:
    inset 0 1px 2px rgba(255, 255, 255, calc(0.65 * var(--glass-reflex-light))),
    0 2px 10px rgba(0, 0, 0, calc(0.12 * var(--glass-reflex-dark)));
  transition: transform 0.5s cubic-bezier(0.34, 1.45, 0.64, 1);
  pointer-events: none;
  z-index: 0;
}

.theme-switcher:has(.theme-switcher__input[data-option="2"]:checked)::after {
  transform: translateX(2.35rem);
}

.theme-switcher__option {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.35rem;
  height: 2.35rem;
  cursor: pointer;
  border-radius: 50%;
}

.theme-switcher__input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
  pointer-events: none;
}

.theme-switcher__icon {
  width: 1.15rem;
  height: 1.15rem;
  color: var(--switcher-icon);
  transition: color 0.35s ease, transform 0.35s cubic-bezier(0.34, 1.45, 0.64, 1);
}

.theme-switcher:has(.theme-switcher__input[data-option="1"]:checked)
  .theme-switcher__option:first-of-type
  .theme-switcher__icon,
.theme-switcher:has(.theme-switcher__input[data-option="2"]:checked)
  .theme-switcher__option:last-of-type
  .theme-switcher__icon {
  color: var(--switcher-icon-active);
  transform: scale(1.08);
}

@media (max-width: 860px) {
  .app-shell {
    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: auto minmax(0, 1fr) auto;
  }

  .dock {
    max-height: 42vh;
  }

  .hint-pill {
    display: none;
  }
}

@media (max-width: 720px) {
  .topbar {
    min-height: 56px;
    padding: 8px 10px;
    gap: 10px;
  }

  .brand small {
    display: none;
  }

  .icon-button {
    width: 36px;
    height: 36px;
  }

  .icon-button--brand {
    width: auto;
    min-width: 36px;
    height: 36px;
  }

  .theme-switcher {
    padding: 0.22rem;
  }

  .theme-switcher::after,
  .theme-switcher__option {
    width: 2rem;
    height: 2rem;
  }

  .theme-switcher:has(.theme-switcher__input[data-option="2"]:checked)::after {
    transform: translateX(2rem);
  }
}

@media (max-width: 520px) {
  .tool-button span {
    display: none;
  }
}