/* =========================================================
   SOCIAL IMPLEMENTATION — 共通パーツ（ヘッダー / フッター / 全ページ要素）
   ・全ページで読み込む（is_front_page 条件の外）。
   ・:root もグローバルセレクタ（* / html / body / a / img）も含めない。
     → 下層記事ページのスタイルを一切壊さないため。
   ・必要なCSS変数は、ヘッダー/フッター等のセレクタ自身に定義し、
     継承で配下要素にだけ効かせる（:root の代替）。
   ========================================================= */

/* --- スコープ付きCSS変数（:root の代替。配下要素へ継承される） --- */
.page-noise,
.site-header,
.mobile-menu,
.site-footer,
.page-top-button {
  --ink: #061831;
  --ink-2: #0a2349;
  --blue: #0b3f99;
  --blue-deep: #052a6c;
  --line: rgba(16, 61, 126, 0.16);
  --soft-line: rgba(4, 31, 72, 0.1);
  --mist: #f3f7fc;
  --paper: #fbfdff;
  --white: #fff;
  --muted: #778293;
  --max: 1200px;
  --header-h: 80px;
  --shadow: 0 18px 55px rgba(4, 31, 72, 0.1);
  --ease: cubic-bezier(0.2, 0.75, 0.22, 1);
}

/* --- 全ページ共通の装飾・レイアウト --- */
.page-noise {
  position: fixed;
  inset: 0;
  z-index: 1000;
  opacity: 0.035;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.95' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.45'/%3E%3C/svg%3E");
}
.layout {
  width: min(calc(100% - 56px), var(--max, 1200px));
  margin-inline: auto;
}

/* ========================= Header ========================= */
.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  padding: 0 28px;
  background: rgba(251, 253, 255, 0.72);
  border-bottom: 1px solid transparent;
  backdrop-filter: blur(18px);
  transition:
    height 0.35s var(--ease),
    background 0.35s,
    border-color 0.35s,
    box-shadow 0.35s;
}
.site-header.is-scrolled {
  height: 80px;
  background: rgba(251, 253, 255, 0.94);
  border-color: var(--soft-line);
  box-shadow: 0 10px 35px rgba(3, 25, 57, 0.06);
}
.brand {
  position: relative;
  z-index: 102;
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: 0.1em;
  white-space: nowrap;
}
.brand i {
  width: 30px;
  height: 2px;
  background: var(--blue-deep);
  transition: width 0.35s var(--ease);
}
.brand span {
  font-weight: 900;
}
.brand p {
  margin: 0;
  font-size: 14px;
  font-weight: 500;
}
.brand:hover i {
  width: 58px;
}
.desktop-nav {
  display: flex;
  align-items: center;
  gap: 42px;
  margin-left: auto;
  margin-right: 48px;
}
.desktop-nav a {
  position: relative;
  padding: 11px 3px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  transition: color 0.25s;
}
.desktop-nav a::before {
  content: "";
  position: absolute;
  inset: 4px -12px;
  z-index: -1;
  border-radius: 999px;
  background: rgba(11, 63, 153, 0.06);
  opacity: 0;
  transform: scale(0.85);
  transition:
    opacity 0.25s,
    transform 0.35s var(--ease);
}
.desktop-nav a::after {
  content: "";
  position: absolute;
  left: 3px;
  right: 3px;
  bottom: 4px;
  height: 1px;
  background: var(--blue);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease);
}
.desktop-nav a:hover,
.desktop-nav a.is-active {
  color: var(--blue);
}
.desktop-nav a:hover::before,
.desktop-nav a.is-active::before {
  opacity: 1;
  transform: scale(1);
}
.desktop-nav a:hover::after,
.desktop-nav a.is-active::after {
  transform: scaleX(1);
}

.menu-button {
  position: relative;
  z-index: 102;
  width: 34px;
  height: 30px;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
  transition: opacity 0.2s ease;
}
.menu-button span {
  position: absolute;
  left: 2px;
  width: 29px;
  height: 2px;
  background: var(--ink);
  transition:
    transform 0.4s var(--ease),
    top 0.4s var(--ease),
    opacity 0.25s;
}
.menu-button span:nth-child(1) {
  top: 6px;
}
.menu-button span:nth-child(2) {
  top: 14px;
  width: 22px;
}
.menu-button span:nth-child(3) {
  top: 22px;
}
.menu-button:hover span:nth-child(2) {
  width: 29px;
}
.menu-button.is-open span:nth-child(1) {
  top: 14px;
  transform: rotate(45deg);
}
.menu-button.is-open span:nth-child(2) {
  opacity: 0;
  transform: translateX(10px);
}
.menu-button.is-open span:nth-child(3) {
  top: 14px;
  transform: rotate(-45deg);
}
.menu-button.is-open {
  opacity: 0;
  pointer-events: none;
}

.mobile-menu {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  /* .brand が z-index:102 のため 101 だとヘッダーのサイト名・キャッチコピーが
     メニューパネルの上に突き抜けていた。brand より上に重ねて解消（2026-08-04） */
  z-index: 103;
  visibility: hidden;
  pointer-events: none;
  transition: visibility 0.28s ease-in-out;
}
.mobile-menu.is-open {
  visibility: visible;
  pointer-events: auto;
}
.mobile-menu__scrim {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  border: 0;
  background: rgba(0, 0, 0, 0.42);
  opacity: 0;
  cursor: pointer;
  transition: opacity 0.28s ease-in-out;
}
.mobile-menu__panel {
  position: fixed;
  top: 0;
  right: 0;
  display: flex;
  flex-direction: column;
  width: 360px;
  max-width: 100%;
  height: 100vh;
  overflow-y: auto;
  padding-top: 82px;
  background: #ffffff;
  box-shadow: -16px 0 42px rgba(0, 0, 0, 0.16);
  transform: translateX(100%);
  transition: transform 0.28s ease-in-out;
  -webkit-overflow-scrolling: touch;
}
.mobile-menu.is-open .mobile-menu__scrim {
  opacity: 1;
}
.mobile-menu.is-open .mobile-menu__panel {
  transform: translateX(0);
}
.mobile-menu__close {
  position: absolute;
  top: 22px;
  right: 22px;
  width: 52px;
  height: 52px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: #ffffff;
  cursor: pointer;
  transition:
    border-color 0.25s ease,
    transform 0.25s ease;
}
.mobile-menu__close:hover {
  border-color: rgba(6, 24, 49, 0.34);
  transform: rotate(90deg);
}
.mobile-menu__close span,
.mobile-menu__close span::before {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 28px;
  height: 2px;
  background: var(--ink);
  content: "";
}
.mobile-menu__close span {
  transform: translate(-50%, -50%) rotate(45deg);
}
.mobile-menu__close span::before {
  transform: translate(-50%, -50%) rotate(90deg);
}
.mobile-menu__close:focus-visible,
.mobile-menu__nav a:focus-visible,
.mobile-menu__scrim:focus-visible {
  outline: 3px solid rgba(11, 63, 153, 0.35);
  outline-offset: 4px;
}
.mobile-menu__nav {
  display: flex;
  flex-direction: column;
  gap: 0;
  padding: 0 0 56px;
  border-top: 1px solid #e5e7eb;
}
.mobile-menu__nav a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  min-height: 60px;
  padding: 0 26px;
  border-bottom: 1px solid #e5e7eb;
  color: #061831;
  font-family:
    "Noto Sans JP", "Yu Gothic", "Hiragino Kaku Gothic ProN", sans-serif;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0;
  opacity: 0;
  transform: translateY(18px);
  transition:
    color 0.25s ease,
    opacity 0.4s ease,
    transform 0.4s ease;
}
.mobile-menu.is-open .mobile-menu__nav a {
  opacity: 1;
  transform: translateY(0);
}
.mobile-menu.is-open .mobile-menu__nav a:nth-child(1) {
  transition-delay: 0.08s;
}
.mobile-menu.is-open .mobile-menu__nav a:nth-child(2) {
  transition-delay: 0.14s;
}
.mobile-menu.is-open .mobile-menu__nav a:nth-child(3) {
  transition-delay: 0.2s;
}
.mobile-menu.is-open .mobile-menu__nav a:nth-child(4) {
  transition-delay: 0.26s;
}
.mobile-menu.is-open .mobile-menu__nav a:nth-child(5) {
  transition-delay: 0.32s;
}
.mobile-menu__nav a span {
  display: none;
}
.mobile-menu__nav a:hover,
.mobile-menu__nav a.is-active {
  color: var(--blue);
  background: #f8fafc;
}

/* ===================== Page Top Button ===================== */
.page-top-button {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 20;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  border-radius: 50%;
  border: 1px solid rgba(15, 23, 42, 0.12);
  background: #ffffff;
  color: #0b3f99;
  font: 700 13px/1 "Barlow Condensed", sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  cursor: pointer;
  box-shadow: 0 20px 48px rgba(15, 23, 42, 0.18);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease;
}
.page-top-button.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.page-top-button:hover,
.page-top-button:focus-visible {
  transform: translateY(-4px);
}

/* ========================= Footer ========================= */
.site-footer {
  margin-top: 55px;
  padding: 55px 0;
  color: #fff;
  background: var(--ink);
}
.site-footer .layout {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}
.site-footer strong {
  font-size: 20px;
  letter-spacing: 0.1em;
}
.site-footer p {
  margin: 14px 0 0;
  color: rgba(255, 255, 255, 0.55);
  font-size: 12px;
  letter-spacing: 0.14em;
}
.site-footer__links {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}
.site-footer__links a {
  color: #fff;
  opacity: 0.8;
  font:
    600 12px/1 "Barlow Condensed",
    sans-serif;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.site-footer__links a:hover,
.site-footer__links a:focus-visible {
  opacity: 1;
}
.site-footer__copyright {
  color: rgba(255, 255, 255, 0.65);
  font-size: 12px;
  letter-spacing: 0.12em;
  white-space: nowrap;
}

/* ========================= Responsive ========================= */
@media (max-width: 1180px) {
  .desktop-nav {
    gap: 27px;
    margin-right: 35px;
  }
}
@media (max-width: 980px) {
  .layout {
    width: min(calc(100% - 44px), var(--max, 1200px));
  }
  .site-header {
    height: 80px;
    padding-inline: 23px;
    justify-content: space-between;
  }
  .brand {
    font-size: 15px;
    gap: 3px;
  }
  .desktop-nav {
    display: none;
  }
  .menu-button {
    display: inline-flex;
    margin-left: auto;
  }
}
@media (min-width: 681px) and (max-width: 980px) {
  .layout {
    width: min(calc(100% - 44px), var(--max, 1200px));
  }
  .site-header {
    height: 80px;
    padding-inline: 36px;
    background: transparent;
    backdrop-filter: none;
  }
  .brand {
    font-size: 16px;
    gap: 3px;
  }
  .desktop-nav {
    display: flex;
    gap: 18px;
    margin-right: 22px;
  }
  .desktop-nav a {
    padding: 9px 2px;
    font-size: 10px;
  }
  .menu-button {
    margin-left: 0;
    transform: scale(0.82);
    transform-origin: right center;
  }
}
@media (max-width: 680px) {
  .layout {
    width: min(calc(100% - 32px), var(--max, 1200px));
  }
  .site-header {
    height: 80px;
    padding-inline: 16px;
  }
  .site-header.is-scrolled {
    height: 80px;
  }
  .brand {
    font-size: 13px;
    letter-spacing: 0.07em;
  }
  .menu-button {
    transform: scale(0.85);
    transform-origin: right center;
  }
  .mobile-menu__panel {
    width: min(100vw, 360px);
    padding-top: 82px;
  }
  .mobile-menu__close {
    top: 22px;
    right: 22px;
  }
  .mobile-menu__nav a {
    min-height: 60px;
    padding-inline: 24px;
    font-size: 16px;
  }
  .site-footer {
    padding-top: 72px;
    padding-bottom: 76px;
  }
  .site-footer .layout {
    display: block;
    gap: 20px;
  }
  .site-footer a {
    display: inline-block;
    margin-top: 30px;
  }
}