:root {
  --bg: #fafdf8;
  --text: #1f2a1f;
  --accent: #2e7d32;
  --card: rgba(230, 255, 230, 0.5);
  --border: #cfe3cf;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121a12;
    --text: #e4efe4;
    --accent: #7ccf80;
    --card: rgba(60, 100, 60, 0.35);
    --border: #2f4a2f;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.9;
}

.page {
  max-width: 48rem;
  margin: 0 auto;
  padding: 2rem 1rem 3rem;
}

h1 {
  font-size: 2rem;
  margin: 0 0 1rem;
  color: var(--accent);
}

h2 {
  font-size: 1.4rem;
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.3rem;
  border-bottom: 2px solid var(--border);
}

a {
  color: var(--accent);
}

pre {
  overflow-x: auto;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
}

details.md-doc {
  margin: 1rem 0;
  border: 1px solid var(--border);
  border-radius: 1rem;
  padding: 0.5rem 1rem;
}

details.md-doc > summary {
  cursor: pointer;
  font-weight: bold;
}

.md-source {
  white-space: pre-wrap;
  border: none;
  padding: 0;
}

.md-body {
  padding: 1.5rem;
  margin: 0.5rem 0;
  background: var(--card);
  border-radius: 1.5rem;
  overflow-wrap: anywhere;
}

.md-error {
  color: #c62828;
}

label {
  display: block;
  font-weight: bold;
}

textarea {
  display: block;
  width: 100%;
  margin: 0.5rem 0;
  font: inherit;
}

.page-footer {
  text-align: center;
  padding: 1rem;
  border-top: 1px solid var(--border);
}

/* ---- 動的な見た目 ---- */
html {
  scroll-behavior: smooth;
}

body {
  background-image: radial-gradient(circle at 15% 0%, var(--card), transparent 45%),
    radial-gradient(circle at 90% 30%, var(--card), transparent 40%);
  background-attachment: fixed;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  z-index: 10;
}

/* .reveal はJSが付けるクラス。JSが無ければ全部そのまま見える */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

h1 {
  background: linear-gradient(90deg, var(--accent), #66bb6a, var(--accent));
  background-size: 200% auto;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: shine 6s linear infinite;
}

@keyframes shine {
  to {
    background-position: 200% center;
  }
}

details.md-doc {
  transition: box-shadow 0.3s ease, transform 0.3s ease;
}

details.md-doc:hover {
  box-shadow: 0 6px 20px rgba(46, 125, 50, 0.18);
  transform: translateY(-2px);
}

details.md-doc[open] .md-body {
  animation: unfold 0.4s ease;
}

@keyframes unfold {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
}

button {
  padding: 0.5rem 1.5rem;
  border: none;
  border-radius: 999px;
  background: var(--accent);
  color: var(--bg);
  font: inherit;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(46, 125, 50, 0.35);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  h1,
  details.md-doc[open] .md-body {
    animation: none;
  }

  .reveal,
  details.md-doc,
  button {
    transition: none;
  }
}