:root {
  color-scheme: dark light;
  --bg-color: #1a1c23;
  --card-bg: #24262d;
  --text-main: #e2e8f0;
  --text-sub: #94a3b8;
  --primary: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --line: #383b45;

  /* キャンバス描画用(app.jsがgetComputedStyleで読む) */
  --fg: var(--text-main);
  --muted: var(--text-sub);
  --point: var(--primary);
  --point-selected: var(--danger);
}

:root[data-theme="light"] {
  --bg-color: #f4f5f7;
  --card-bg: #ffffff;
  --text-main: #1a1c23;
  --text-sub: #5b6472;
  --line: #dfe2e7;
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg-color: #f4f5f7;
    --card-bg: #ffffff;
    --text-main: #1a1c23;
    --text-sub: #5b6472;
    --line: #dfe2e7;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Helvetica Neue', Arial, "Hiragino Kaku Gothic ProN", sans-serif;
  color: var(--text-main);
  background: var(--bg-color);
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 15px;
}

header { margin-bottom: 1.25rem; }

h1 {
  font-size: 1.25rem;
  margin: 0;
  padding-left: 12px;
  border-left: 4px solid var(--primary);
}

main {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.15);
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: end;
}

.controls label {
  display: flex;
  flex-direction: column;
  font-size: 0.8rem;
  color: var(--text-sub);
  gap: 0.3rem;
}

.controls .grow { flex-grow: 1; min-width: 160px; }

.hint-inline { font-size: 0.75rem; }

.controls input, .controls select {
  font-size: 0.95rem;
  padding: 0.4rem 0.5rem;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--bg-color);
  color: var(--text-main);
}

button {
  font-size: 0.9rem;
  font-weight: bold;
  padding: 0.6rem 1rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

button:disabled { opacity: 0.4; cursor: not-allowed; }
button:not(:disabled):hover { opacity: 0.9; }

.btn-primary { background: var(--primary); color: #04241a; }

.btn-danger {
  background: rgba(239, 68, 68, 0.15);
  color: var(--danger);
  border: 1px solid var(--danger);
}

.hint { color: var(--text-sub); font-size: 0.85rem; margin: 0.5rem 0 0; }

.canvas-wrap {
  width: 100%;
  margin-top: 0.75rem;
}

canvas {
  display: block;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  touch-action: none;
}

.graph-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: 0.75rem;
}

#status { min-height: 1.2em; font-size: 0.9rem; }