:root {
  color-scheme: light dark;
  --stage-bg: #f4f2ee;
  --panel-bg: #ffffff;
  --text: #1d1c1a;
  --muted: #6b6760;
  --border: #d9d5cc;
  --accent: #2f5fd0;
  --accent-text: #ffffff;
  --shape-fill: rgba(47, 95, 208, 0.28);
  --corner: #d0602f;
  --hand-left: #2f5fd0;
  --hand-right: #b8326b;
  --error: #b42318;
}

@media (prefers-color-scheme: dark) {
  :root {
    --stage-bg: #161616;
    --panel-bg: #232322;
    --text: #ecebe8;
    --muted: #a19d95;
    --border: #3a3936;
    --accent: #7ea2ff;
    --accent-text: #0d1424;
    --shape-fill: rgba(126, 162, 255, 0.3);
    --corner: #ff9a62;
    --hand-left: #7ea2ff;
    --hand-right: #f07aa9;
    --error: #ff8a80;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: var(--stage-bg);
  color: var(--text);
  font: 16px/1.4 system-ui, -apple-system, "Segoe UI", sans-serif;
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
  overscroll-behavior: none;
}

#stage {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
  display: block;
}

button, select, .file-btn {
  font: inherit;
  color: var(--text);
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  min-height: 44px;
  cursor: pointer;
}
button:focus-visible, select:focus-visible, input:focus-visible, .file-btn:focus-within {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

#topbar {
  position: fixed;
  top: max(12px, env(safe-area-inset-top));
  left: max(12px, env(safe-area-inset-left));
  right: max(12px, env(safe-area-inset-right));
  display: flex;
  gap: 8px;
  pointer-events: none;
  z-index: 2;
}
#topbar button { pointer-events: auto; }
#show-btn { margin-left: auto; }
#show-btn[aria-pressed="true"] { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }

#backdrop {
  position: fixed;
  inset: 0;
  z-index: 3;
  touch-action: none;
}

#menu {
  position: fixed;
  top: calc(max(12px, env(safe-area-inset-top)) + 52px);
  left: max(12px, env(safe-area-inset-left));
  width: min(340px, calc(100vw - 24px));
  max-height: calc(100dvh - 90px);
  overflow-y: auto;
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 14px 16px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.18);
  z-index: 4;
  user-select: text;
}
#menu[hidden], #backdrop[hidden], #start[hidden] { display: none; }
#menu h2 {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin: 4px 0 8px;
}
#menu h2:not(:first-child) { margin-top: 18px; }

.shape-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(92px, 1fr));
  gap: 6px;
  margin-bottom: 8px;
}
.shape-list button[aria-pressed="true"] { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }

.file-btn {
  display: block;
  text-align: center;
  position: relative;
}
.file-btn input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
  width: 100%;
}

.hint { font-size: 13px; color: var(--muted); margin: 6px 0 0; }

.row {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
}
.row select, .row input[type="range"] { margin-left: auto; }
.row input[type="range"] { width: 140px; }
.row input[type="checkbox"] { width: 20px; height: 20px; }
kbd {
  font: 12px ui-monospace, monospace;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0 5px;
  color: var(--muted);
}

.status { font-size: 13px; color: var(--muted); margin: 10px 0 0; min-height: 1.4em; }
.status.error { color: var(--error); }

#start {
  position: fixed;
  inset: 0;
  z-index: 5;
  display: grid;
  place-items: center;
  padding: 16px;
  background: color-mix(in srgb, var(--stage-bg) 85%, transparent);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
#start .card {
  max-width: 480px;
  max-height: calc(100dvh - 32px);
  overflow-y: auto;
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 20px 22px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.18);
}
#start h1 { margin: 0 0 8px; font-size: 24px; }
#start ul { padding-left: 20px; margin: 8px 0; }
#start li { margin: 4px 0; }
#start-btn {
  margin-top: 8px;
  width: 100%;
  background: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
  font-weight: 600;
}