:root {
  --purple: #8c78b5;
  --purple-light: #f3effa;
  --purple-border: #e5dcef;
  --yellow: #fff0b5;
  --text: #494252;
  --muted: #81798b;
  --white: #ffffff;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  margin: 0;
  background: var(--white);
  color: var(--text);
  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Yu Gothic",
    "Hiragino Kaku Gothic ProN",
    Meiryo,
    sans-serif;
  font-size: 15px;
  line-height: 1.9;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ヘッダー */

.header {
  padding: 18px 24px;
  border-bottom: 1px solid var(--purple-border);
  background: var(--white);
}

.site-title {
  display: block;
  max-width: 900px;
  margin: 0 auto;
  color: var(--purple);
  font-size: 16px;
  font-weight: 700;
}

/* メインビジュアル */

.hero {
  padding: 90px 20px 95px;
  background: var(--purple-light);
  text-align: center;
}

.hero-label {
  margin: 0 0 20px;
  color: var(--purple);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.2em;
}

.hero h1 {
  margin: 0;
  color: var(--purple);
  font-size: clamp(30px, 5vw, 46px);
  font-weight: 700;
  line-height: 1.7;
}

.hero-description {
  margin: 22px 0 30px;
  font-size: 14px;
}

.button {
  display: inline-block;
  padding: 12px 32px;
  border: 1px solid var(--purple);
  border-radius: 6px;
  background: var(--purple);
  color: var(--white);
  font-size: 14px;
  font-weight: 700;
  transition: opacity 0.2s;
}

.button:hover {
  opacity: 0.8;
}

/* 各セクション */

.section {
  padding: 65px 24px;
  border-bottom: 1px solid var(--purple-border);
}

.section h2 {
  max-width: 800px;
  margin: 0 auto 30px;
  padding: 0 0 12px;
  border-bottom: 3px solid var(--yellow);
  color: var(--purple);
  font-size: 23px;
  font-weight: 700;
}

.content {
  max-width: 800px;
  margin: 0 auto;
}

.content p {
  margin: 0 0 22px;
}

.content p:last-child {
  margin-bottom: 0;
}

.description {
  margin-bottom: 25px !important;
}

.small-text {
  margin-top: 15px !important;
  color: var(--muted);
  font-size: 12px;
}

.text-link {
  color: var(--purple);
  font-size: 14px;
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ブラウザゲーム */

.game-container {
  width: 100%;
  overflow: hidden;
  border: 1px solid var(--purple-border);
  border-radius: 6px;
  background: var(--purple-light);
}

.game-container iframe {
  display: block;
  width: 100%;
  height: min(65vw, 600px);
  min-height: 320px;
  border: 0;
}

/* ダウンロード */

.download-list {
  display: grid;
  gap: 12px;
}

.download-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 15px;
  padding: 18px 20px;
  border: 1px solid var(--purple-border);
  border-radius: 6px;
  background: #fbf9ff;
  transition: background 0.2s;
}

.download-link span:first-child {
  font-weight: 700;
}

.download-link span:last-child {
  color: var(--purple);
  font-size: 13px;
  white-space: nowrap;
}

.download-link:hover {
  background: var(--yellow);
}

/* ガイドライン */

.rule-label {
  display: block;
  margin-bottom: 5px;
  color: var(--purple);
  font-weight: 700;
}

/* フッター */

.footer {
  padding: 25px 20px;
  background: var(--purple-light);
  color: var(--purple);
  font-size: 13px;
  text-align: center;
}

.footer p {
  margin: 0;
}

/* スマートフォン */

@media (max-width: 600px) {
  .header {
    padding: 14px 18px;
  }

  .site-title {
    font-size: 14px;
  }

  .hero {
    padding: 65px 18px 70px;
  }

  .section {
    padding: 45px 18px;
  }

  .section h2 {
    font-size: 20px;
  }

  .game-container iframe {
    height: 65vh;
    min-height: 300px;
  }

  .download-link {
    padding: 15px;
  }
}

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

  *,
  *::before,
  *::after {
    transition: none !important;
  }
}