/* =============================================================
   Serenavi — mobile styles
   style.css（PC用）の上に重ねるスマホ専用レイヤー。
   - 768px 以下でのみレイアウトを上書き（PC表示は一切変更しない）
   - セレクタは style.css と同じ詳細度に合わせ、後読みの本ファイルで上書き
   - カラー変数・SVGスプライトは style.css / index.html のものを流用
   ============================================================= */

/* スマホ専用UI（ハンバーガー・DLボタン）は PC では非表示 */
.nav-toggle,
.m-cta {
  display: none;
}

@media (max-width: 768px) {
  /* -----------------------------------------------------------
     レイアウト共通
     ----------------------------------------------------------- */
  .container {
    width: 100%;
  }

  /* -----------------------------------------------------------
     ヘッダー / ハンバーガーメニュー
     ----------------------------------------------------------- */
  header {
    position: sticky;
    top: 0;
    z-index: 20;
    padding: 1.2rem 1.8rem;
    background: rgb(255 255 255 / 92%);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid rgb(7 29 69 / 8%);
  }

  header a img {
    width: 150px;
  }

  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    width: 28px;
    height: 20px;
    padding: 0;
  }

  .nav-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--c-navy);
    border-radius: 2px;
    transition: transform 0.3s, opacity 0.3s;
  }

  .nav-toggle.is-open span:nth-child(1) {
    transform: translateY(9px) rotate(45deg);
  }
  .nav-toggle.is-open span:nth-child(2) {
    opacity: 0;
  }
  .nav-toggle.is-open span:nth-child(3) {
    transform: translateY(-9px) rotate(-45deg);
  }

  /* ドロップダウン */
  header nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 19;
    max-height: 0;
    overflow: hidden;
    background: var(--c-white);
    box-shadow: 0 12px 24px rgb(7 29 69 / 12%);
    transition: max-height 0.32s ease;
  }

  header nav.is-open {
    max-height: 200px;
  }

  header nav ul {
    display: block;
  }

  header nav ul li a {
    display: block;
    padding: 1.6rem 2rem;
    font-weight: 700;
    border-top: 1px solid rgb(7 29 69 / 6%);
  }

  header nav ul li:first-child a {
    border-top: none;
  }

  /* -----------------------------------------------------------
     ヒーロー（main-visual）：重ね配置 → 縦積みへ
     ----------------------------------------------------------- */
  main #main-visual {
    padding: 3.2rem 2rem 3.6rem;
    text-align: center;
    background: linear-gradient(180deg, #f3faff 0%, #eaf4ff 100%);
  }

  main #main-visual::before {
    display: none;
  }

  main #main-visual .background-image {
    display: none;
  }

  main #main-visual .main-copy {
    position: static;
    margin-bottom: 2.4rem;
  }

  main #main-visual .main-copy h1 {
    margin-bottom: 1.6rem;
    font-size: 2.8rem;
  }

  main #main-visual .main-copy p {
    font-size: 1.4rem;
    line-height: 1.9;
  }

  main #main-visual .app-image {
    position: static;
    display: block;
    width: 56%;
    max-width: 220px;
    margin: 0 auto 2.8rem;
    filter: drop-shadow(0 16px 30px rgb(7 29 69 / 18%));
  }

  /* 特徴3つ：横並び → カード縦積み */
  main #main-visual > ul {
    position: static;
    width: 100%;
    grid-template-columns: 1fr;
    gap: 1.2rem;
  }

  main #main-visual > ul li {
    display: grid;
    grid-template-columns: 4.8rem 1fr;
    column-gap: 1.4rem;
    align-items: center;
    padding: 1.4rem 1.6rem;
    text-align: left;
    background: var(--c-white);
    border-radius: 12px;
    box-shadow: 0 6px 16px rgb(7 29 69 / 8%);
  }

  main #main-visual > ul li + li {
    border-left: none;
  }

  main #main-visual > ul li svg {
    grid-row: 1 / span 3;
    align-self: center;
    width: 4.8rem;
    height: 4.8rem;
    margin: 0;
    padding: 1rem;
    border-radius: 12px;
    background: var(--c-blue-soft);
  }

  main #main-visual > ul li b {
    grid-column: 2;
    white-space: normal;
  }

  main #main-visual > ul li p {
    grid-column: 2;
    white-space: normal;
  }

  /* -----------------------------------------------------------
     機能セクション
     ----------------------------------------------------------- */
  main #function {
    display: block;
    margin-top: 0;
    padding: 4rem 2rem;
    scroll-margin-top: 6rem;
  }

  main #function h2 {
    margin: 0 auto 2.8rem;
    font-size: 2.2rem;
  }

  main #function .images {
    gap: 1.2rem;
    margin-bottom: 2.8rem;
  }

  main #function ul {
    gap: 1.2rem;
  }

  main #function li {
    grid-template-columns: 3.2rem 5.2rem 1fr;
    column-gap: 1.2rem;
    padding: 1.2rem 1.4rem;
  }

  main #function li::before {
    width: 3.2rem;
    height: 3.2rem;
    font-size: 1.4rem;
  }

  main #function .material-symbols-rounded {
    width: 5.2rem;
    height: 5.2rem;
    font-size: 3rem;
  }

  main #function b {
    font-size: 1.6rem;
  }

  main #function .core-image {
    margin-top: 2rem;
  }

  /* -----------------------------------------------------------
     安全セクション
     ----------------------------------------------------------- */
  main #safety {
    padding: 0 0 3.2rem;
    scroll-margin-top: 6rem;
  }

  main #slogan {
    margin: 0 2rem 3.2rem;
    padding: 3.2rem 2.4rem;
    border-radius: 16px;
    text-align: center;
    background:
      linear-gradient(160deg, rgb(0 70 155 / 96%) 0%, rgb(0 97 210 / 95%) 100%),
      url('./images/bg.png') center / cover no-repeat;
  }

  main #slogan h3 {
    font-size: 2rem;
  }

  main #slogan p {
    font-size: 1.3rem;
  }

  main #safety .content::before {
    margin-bottom: 2.8rem;
    font-size: 2.2rem;
  }

  main #safety .content ul {
    grid-template-columns: 1fr;
    gap: 1.6rem;
    padding: 0 2rem;
  }

  main #safety .content li {
    grid-template-columns: 5.6rem minmax(0, 1fr);
  }

  main #safety .content svg {
    width: 5.6rem;
    height: 5.6rem;
  }

  main #safety .content b {
    font-size: 1.7rem;
  }

  main #safety .content p {
    font-size: 1.25rem;
    white-space: normal;
  }

  /* -----------------------------------------------------------
     ダウンロードボタン
     ----------------------------------------------------------- */
  .m-cta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.8rem;
    width: calc(100% - 4rem);
    margin: 0 2rem 1.2rem;
    padding: 1.4rem;
    border-radius: 12px;
    color: var(--c-white);
    background: var(--c-blue);
    font-size: 1.6rem;
    font-weight: 800;
    text-decoration: none;
    box-shadow: 0 10px 24px rgb(11 114 223 / 35%);
  }

  .m-cta .material-symbols-rounded {
    font-size: 2.2rem;
  }

  /* -----------------------------------------------------------
     フッター
     ----------------------------------------------------------- */
  footer {
    flex-direction: column;
    gap: 1.2rem;
    margin-top: 1.6rem;
    padding: 3.2rem 2rem 4rem;
  }

  footer img {
    width: 11rem;
  }

  footer p {
    font-size: 1.4rem;
  }
}