/* 水面と葉っぱ。画面いっぱいのキャンバスの上に、半透明のパネルを重ねる */

:root {
  --glass: rgba(10, 24, 20, 0.58);
  --glass-border: rgba(255, 255, 255, 0.14);
  --text: #eef6f1;
  --muted: #b3c9bd;
  --primary: #6fe0a8;
  --primary-ink: #06140d;
  --font: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans",
    "BIZ UDPGothic", Meiryo, system-ui, -apple-system, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: #0b1a17;
  color: var(--text);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
}

canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  cursor: crosshair;
}

.bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: max(12px, env(safe-area-inset-top)) 16px 0;
  pointer-events: none;
}

.home {
  pointer-events: auto;
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--glass);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}
.home:hover { background: rgba(10, 24, 20, 0.75); }
.home:focus-visible, button:focus-visible, input:focus-visible + span, summary:focus-visible, input[type="range"]:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.fps {
  font: 12px/1 ui-monospace, SFMono-Regular, Consolas, monospace;
  color: var(--muted);
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(10, 24, 20, 0.4);
}
.fps:empty { display: none; }

.panel {
  position: fixed;
  left: 16px;
  bottom: max(16px, env(safe-area-inset-bottom));
  width: min(340px, calc(100vw - 32px));
  max-height: calc(100vh - 90px);
  overflow: auto;
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: 16px;
  backdrop-filter: blur(14px) saturate(1.2);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.panel__toggle {
  display: none;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: none;
  border: 0;
  color: var(--text);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
.panel__toggle svg { width: 20px; height: 20px; transition: transform 0.2s; transform: rotate(180deg); }
.panel.is-closed .panel__toggle svg { transform: none; }

.panel__body { padding: 16px 18px 18px; }

h1 {
  margin: 0 0 6px;
  font-size: 18px;
  letter-spacing: 0.02em;
}

.lead {
  margin: 0 0 14px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.ctrl {
  display: grid;
  grid-template-columns: 6.5em 1fr;
  align-items: center;
  gap: 10px;
  margin: 8px 0;
  font-size: 13px;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--primary);
}

.seg {
  border: 0;
  margin: 12px 0 0;
  padding: 0;
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  align-items: center;
}
.seg legend {
  float: left;
  width: 6.5em;
  font-size: 13px;
  padding: 0;
  margin-right: 10px;
}
.seg label { position: relative; }
.seg input { position: absolute; opacity: 0; inset: 0; margin: 0; cursor: pointer; }
.seg span {
  display: block;
  padding: 6px 10px;
  font-size: 12px;
  border-radius: 999px;
  border: 1px solid var(--glass-border);
  color: var(--muted);
}
.seg input:checked + span {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--primary-ink);
  font-weight: 700;
}

.btns { display: flex; gap: 8px; margin-top: 14px; }

button {
  font: inherit;
  cursor: pointer;
}
.btns button {
  flex: 1;
  padding: 9px 12px;
  font-size: 13px;
  font-weight: 700;
  border-radius: 10px;
  border: 1px solid var(--primary);
  background: var(--primary);
  color: var(--primary-ink);
}
.btns button:hover { filter: brightness(1.08); }
.btns .ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--glass-border);
}

.how {
  margin-top: 14px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--muted);
}
.how summary {
  cursor: pointer;
  color: var(--text);
  font-weight: 700;
  font-size: 13px;
}
.how ul { margin: 8px 0 0; padding-left: 1.2em; }
.how li { margin: 4px 0; }
.how b { color: var(--text); }

.fallback {
  position: fixed;
  inset: 0;
  display: grid;
  place-content: center;
  padding: 24px;
  text-align: center;
  line-height: 1.8;
  background: #0b1a17;
}
.fallback[hidden] { display: none; }
.fallback a { color: var(--primary); }

@media (max-width: 640px) {
  .panel { left: 8px; right: 8px; width: auto; bottom: max(8px, env(safe-area-inset-bottom)); }
  .panel__toggle { display: flex; }
  .panel__body { padding-top: 0; }
  .panel__body h1 { display: none; }
  .panel.is-closed .panel__body { display: none; }
}