/* ==========================================================
   common.css — 全ページ共通：リセット・基本要素・共通UI・ヘッダー/ナビ/フッター
   並び順：ベース → 768px以下 → 480px以下
   ========================================================== */

/* ---------- ベース ---------- */
:root {
  --ink: #141b2b;
  --ink-2: #1a2336;
  --night: #0e1320;
  --moss: #1e2c27;
  --paper: #efe9dc;
  --muted: #aab0bf;
  --lamp: #e3a857;
  --line: rgba(239, 233, 220, .2);

  --font-serif: "Shippori Mincho", "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", "Noto Serif JP", "Noto Serif CJK JP", serif;
  --font-sans: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic Medium", "Yu Gothic", "Noto Sans JP", "Noto Sans CJK JP", Meiryo, sans-serif;

  --gutter: clamp(1.25rem, 5vw, 4.5rem);
  --header-h: 4.5rem;
  --maxw: 76rem;
  --ease: cubic-bezier(.2, .7, .2, 1);
}

*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-h);
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.95;
  letter-spacing: .04em;
  word-break: auto-phrase;
  overflow-wrap: anywhere;
}
body.is-nav-open { overflow: hidden; }

h1, h2, h3, p, ul, ol, dl, dd, figure { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, iframe { display: block; max-width: 100%; }
img { height: auto; }
a { color: inherit; text-underline-offset: .25em; }
address { font-style: normal; }
small { font-size: .8125rem; }
button { font: inherit; color: inherit; }

:focus-visible { outline: 2px solid var(--lamp); outline-offset: 3px; }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0; border: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

.skip-link {
  position: fixed; top: .75rem; left: .75rem; z-index: 100;
  padding: .7rem 1.2rem;
  background: var(--lamp); color: var(--ink); font-weight: 700;
  transform: translateY(-200%);
}
.skip-link:focus { transform: none; }

/* 共通レイアウト */
.section { padding: clamp(5rem, 11vw, 9rem) var(--gutter); }
.section__inner { max-width: var(--maxw); margin-inline: auto; }
/* 子ページなど、固定ヘッダーの下から始まるmain用 */
.main--offset { padding-top: var(--header-h); }

.section-title {
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: clamp(1.75rem, 3.2vw, 2.5rem);
  line-height: 1.6;
  letter-spacing: .14em;
  text-wrap: balance;
}
.section-lead { margin-top: 1.25rem; max-width: 40em; color: var(--muted); }

/* ボタン */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 3.25rem; padding: .7em 2em;
  border: 1px solid var(--lamp); border-radius: 2px;
  background: var(--lamp); color: var(--ink);
  font-weight: 700; letter-spacing: .14em; text-decoration: none;
  transition: background-color .25s, color .25s, border-color .25s;
}
.btn:hover { background: transparent; color: var(--lamp); }
.btn--ghost { background: transparent; color: var(--paper); border-color: var(--line); }
.btn--ghost:hover { border-color: var(--lamp); color: var(--lamp); }
.btn--sm { min-height: 2.5rem; padding: .35em 1.3em; font-size: .875rem; }

/* ヘッダー（is-solid：ファーストビューのない子ページ用に常時ベタ背景） */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  transition: background-color .3s, box-shadow .3s;
}
.site-header.is-scrolled,
.site-header.is-solid { background: rgba(14, 19, 32, .92); backdrop-filter: blur(8px); }
.site-header__inner {
  display: flex; align-items: center; gap: 1.5rem;
  height: var(--header-h); padding-inline: var(--gutter);
}
.logo {
  position: relative; z-index: 2; margin-right: auto;
  font-family: var(--font-serif); font-size: 1.25rem; letter-spacing: .22em;
  text-decoration: none;
}
.logo img { height: 2.25rem; width: auto; }
.nav { position: relative; z-index: 1; }
.nav ul { display: flex; gap: 2rem; }
.nav a {
  display: inline-block; padding: .4rem 0;
  font-size: .9375rem; letter-spacing: .12em; text-decoration: none;
  background: linear-gradient(var(--lamp), var(--lamp)) left bottom / 0 1px no-repeat;
  transition: background-size .35s var(--ease);
}
.nav a:hover { background-size: 100% 1px; }
.header-cta { position: relative; z-index: 2; }

.nav-toggle {
  display: none; position: relative; z-index: 2;
  width: 2.75rem; height: 2.75rem; padding: 0;
  background: none; border: 0; cursor: pointer;
}
.nav-toggle__bar,
.nav-toggle__bar::before,
.nav-toggle__bar::after {
  position: absolute; left: 50%; width: 1.4rem; height: 2px;
  background: currentColor; transition: transform .3s var(--ease), opacity .2s;
}
.nav-toggle__bar { top: 50%; margin: -1px 0 0 -.7rem; }
.nav-toggle__bar::before, .nav-toggle__bar::after { content: ""; left: 0; }
.nav-toggle__bar::before { top: -.45rem; }
.nav-toggle__bar::after { top: .45rem; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar::before { transform: translateY(.45rem) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar::after { transform: translateY(-.45rem) rotate(-45deg); }

/* フッター */
.site-footer { background: var(--night); padding: 4rem var(--gutter) 2rem; }
.site-footer__inner {
  max-width: var(--maxw); margin-inline: auto;
  display: flex; justify-content: space-between; gap: 3rem; flex-wrap: wrap;
}
.site-footer__name { font-family: var(--font-serif); font-size: 1.5rem; letter-spacing: .2em; margin-bottom: 1rem; }
.site-footer address { color: var(--muted); font-size: .9375rem; line-height: 1.9; }
.site-footer address p + p { margin-top: .5rem; }
.site-footer__nav { display: flex; flex-wrap: wrap; gap: .25rem 2rem; max-width: 26rem; }
.site-footer__nav a { display: inline-block; padding: .35rem 0; font-size: .9375rem; text-decoration: none; }
.site-footer__nav a:hover { color: var(--lamp); }
.site-footer__copy { max-width: var(--maxw); margin: 3.5rem auto 0; padding-top: 1.5rem; border-top: 1px solid var(--line); color: var(--muted); }

/* ---------- 768px以下（タブレット） ---------- */
@media screen and (max-width: 768px) {
  :root { --header-h: 4rem; }
  body { font-size: .9375rem; }

  .site-header__inner { gap: .75rem; }
  .nav-toggle { display: block; }
  .nav {
    position: fixed; inset: 0; z-index: 1;
    display: flex; align-items: center; justify-content: center;
    background: var(--night);
    opacity: 0; visibility: hidden;
    transition: opacity .3s, visibility 0s .3s;
  }
  .nav.is-open { opacity: 1; visibility: visible; transition-delay: 0s; }
  .nav ul { flex-direction: column; align-items: center; gap: 1rem; }
  .nav a { padding: .6rem 1rem; font-size: 1.25rem; letter-spacing: .2em; }

  /* JS無効時はナビを通常表示 */
  html:not(.js) .nav-toggle { display: none; }
  html:not(.js) .nav { position: static; opacity: 1; visibility: visible; background: none; }
  html:not(.js) .nav ul { flex-direction: row; flex-wrap: wrap; gap: .25rem 1rem; }
  html:not(.js) .nav a { font-size: .8125rem; padding: .3rem 0; }
  html:not(.js) .site-header { position: absolute; background: var(--night); }
  html:not(.js) .site-header__inner { height: auto; padding-block: .75rem; flex-wrap: wrap; }

  .site-footer { padding-top: 3rem; }
  .site-footer__inner { flex-direction: column; gap: 2rem; }
}

/* ---------- 480px以下（スマートフォン） ---------- */
@media screen and (max-width: 480px) {
  :root { --gutter: 1.25rem; }
  .section { padding-block: 4.5rem; }
  .section-title { letter-spacing: .1em; }
  .logo { font-size: 1.0625rem; letter-spacing: .16em; }
  .btn { width: 100%; min-height: 3.5rem; }
  .btn--sm { width: auto; min-height: 2.5rem; }
  .site-footer__nav { gap: .25rem 1.5rem; }
}

/* ---------- 動きを減らす設定 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
}