/* ==========================================================================
   和暦変換ナビ — デザインシステム v3（和モダン・グラフィカル・モーション）
   ========================================================================== */

:root {
  --ink: #1c1a17;
  --ink-soft: #463f37;
  --muted: #6f6a5e;
  --paper: #f4efe4;
  --paper-2: #fffdf8;
  --paper-3: #faf6ec;
  --line: #e6ddca;
  --line-2: #efe8d7;
  --ai: #1b3a5b;
  --ai-2: #27567f;
  --ai-deep: #122a40;
  --shu: #c8472b;
  --shu-2: #e0613f;
  --gold: #b08d4e;
  --sun: #c8472b;
  --sat: #2b5fa6;

  /* 元号カラー（伝統色） */
  --c-meiji: #2e6e5b;
  --c-taisho: #6b4a8a;
  --c-showa: #a8412a;
  --c-heisei: #2b5fa6;
  --c-reiwa: #c4607f;

  --radius: 16px;
  --radius-sm: 10px;
  --radius-lg: 24px;
  --shadow-sm: 0 1px 3px rgba(28,26,23,.07);
  --shadow: 0 4px 14px rgba(28,26,23,.08), 0 1px 3px rgba(28,26,23,.06);
  --shadow-lg: 0 18px 50px -12px rgba(18,42,64,.30), 0 6px 18px rgba(28,26,23,.08);
  --shadow-ai: 0 18px 44px -14px rgba(18,42,64,.55);
  --container: 980px;
  --serif: "Shippori Mincho", "Hiragino Mincho ProN", "Yu Mincho", serif;
  --sans: "Noto Sans JP", -apple-system, "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;

  /* 麻の葉パターン（淡い罫） */
  --asanoha: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='56' height='96' viewBox='0 0 56 96'%3E%3Cg fill='none' stroke='%23d9cdb0' stroke-width='1' opacity='0.5'%3E%3Cpath d='M28 0v32M28 32L0 16M28 32l28-16M28 32v32M28 64L0 48M28 64l28-16M0 16v32l28 16M56 16v32L28 64M0 48l28-16 28 16'/%3E%3C/g%3E%3C/svg%3E");
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink-soft);
  background-color: var(--paper);
  background-image:
    radial-gradient(1200px 480px at 50% -8%, rgba(27,58,91,.07), transparent 70%),
    var(--asanoha);
  line-height: 1.85;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container { width: 100%; max-width: var(--container); margin-inline: auto; padding-inline: 18px; }

a { color: var(--ai); text-decoration: none; transition: color .15s; }
a:hover { color: var(--shu); }

h1,h2,h3,h4 { font-family: var(--serif); color: var(--ink); line-height: 1.42; font-weight: 700; letter-spacing: .01em; }

img { max-width: 100%; height: auto; }

.skip-link { position: absolute; left: -9999px; background: var(--ai); color:#fff; padding:10px 16px; z-index:100; }
.skip-link:focus { left: 0; top: 0; }
:focus-visible { outline: 3px solid var(--ai); outline-offset: 2px; border-radius: 4px; }

/* ===== ヘッダー ===== */
.site-header {
  background: rgba(255,253,248,.86);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--ink); }
.brand:hover { color: var(--ink); }
.brand-mark {
  font-family: var(--serif); font-weight: 700; color:#fff;
  background: linear-gradient(145deg, var(--ai-2), var(--ai-deep));
  width: 40px; height: 40px; display: grid; place-items: center; border-radius: 11px; font-size: 17px;
  letter-spacing: -1px; box-shadow: var(--shadow-sm), inset 0 1px 0 rgba(255,255,255,.18);
}
.brand-name { font-family: var(--serif); font-weight: 700; font-size: 18px; }
.site-nav { display: flex; gap: 2px; flex-wrap: wrap; }
.site-nav a { color: var(--ink-soft); font-size: 14px; font-weight: 500; padding: 8px 13px; border-radius: 999px; position: relative; }
.site-nav a:hover { background: var(--paper-3); color: var(--ai); }

/* ===== パンくず ===== */
.breadcrumbs { font-size: 12.5px; padding-top: 14px; }
.breadcrumbs ol { list-style:none; display:flex; flex-wrap:wrap; gap:6px; margin:0; padding:0; color:var(--muted); }
.breadcrumbs li { display:inline-flex; align-items:center; gap:6px; }
.breadcrumbs li + li::before { content:"›"; color:var(--line); }

.site-main { padding: 20px 0 64px; }
section { margin-block: 46px; }

/* ===== セクション見出し（朱マーカー） ===== */
.sec-title { position: relative; font-size: clamp(20px,4.6vw,26px); margin: 0 0 18px; padding-left: 16px; }
.sec-title::before {
  content:""; position:absolute; left:0; top:.18em; bottom:.18em; width:6px; border-radius:3px;
  background: linear-gradient(var(--shu), var(--shu-2));
}
.sec-sub { color: var(--muted); margin: -8px 0 18px; }

/* ===== ヒーロー ===== */
.hero {
  position: relative; margin-top: 14px;
  background:
    radial-gradient(600px 300px at 85% -10%, rgba(200,71,43,.16), transparent 60%),
    linear-gradient(160deg, var(--ai-2) 0%, var(--ai-deep) 100%);
  border-radius: var(--radius-lg); padding: 40px 26px 30px; color: #eef3f7; overflow: hidden;
  box-shadow: var(--shadow-ai);
}
.hero::before {
  content:""; position:absolute; inset:0; opacity:.10; pointer-events:none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='80' height='40' viewBox='0 0 80 40'%3E%3Cg fill='none' stroke='%23ffffff' stroke-width='1.2'%3E%3Cpath d='M0 40a20 20 0 0140 0 20 20 0 0140 0M-40 40a20 20 0 0140 0M40 40a20 20 0 0140 0'/%3E%3C/g%3E%3C/svg%3E");
}
.hero .seal {
  position:absolute; right:22px; top:22px; width:74px; height:74px; border-radius:50%;
  border:2px solid rgba(255,255,255,.45); color:#fff; display:grid; place-items:center;
  font-family:var(--serif); font-weight:700; font-size:13px; line-height:1.25; text-align:center;
  background: rgba(200,71,43,.30); backdrop-filter: blur(2px);
}
.hero h1 { color:#fff; font-size: clamp(28px,7vw,46px); margin:0 0 12px; position:relative; text-shadow:0 2px 14px rgba(0,0,0,.18); }
.hero .lead { color: rgba(238,243,247,.92); font-size: clamp(14px,3.6vw,17px); margin:0; max-width: 34em; position:relative; }
.hero .ruby { font-size:.5em; color: rgba(255,255,255,.7); display:block; letter-spacing:.3em; margin-bottom:4px; }

/* ===== ガラス調カード（ツール） ===== */
.tool {
  background: linear-gradient(180deg, var(--paper-2), var(--paper-3));
  border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-lg); padding: 22px;
  position: relative; margin-top: -26px; z-index: 2;
}
.tool::before {
  content:""; position:absolute; left:0; right:0; top:0; height:4px; border-radius:var(--radius) var(--radius) 0 0;
  background: linear-gradient(90deg, var(--ai), var(--shu));
}
.tool .tabs { display:flex; gap:6px; margin-bottom:18px; background:var(--paper); padding:5px; border-radius:999px; position:relative; }
.tool .tabs button {
  flex:1; border:0; background:transparent; padding:11px 8px; border-radius:999px; cursor:pointer;
  font-family:var(--sans); font-weight:700; font-size:14px; color:var(--muted); transition:color .2s; position:relative; z-index:1;
}
.tool .tabs button[aria-selected="true"] { color:#fff; }
.tool .tabs button[aria-selected="true"]::before {
  content:""; position:absolute; inset:0; z-index:-1; border-radius:999px;
  background: linear-gradient(145deg, var(--ai-2), var(--ai-deep)); box-shadow: var(--shadow-sm);
  animation: pop .25s ease;
}
.field-row { display:flex; gap:12px; align-items:flex-end; flex-wrap:wrap; }
.field { display:flex; flex-direction:column; gap:7px; }
.field label { font-size:12.5px; color:var(--muted); font-weight:600; letter-spacing:.02em; }
select, input[type="number"], input[type="text"], input[type="email"], textarea {
  font-family:var(--sans); font-size:16px; padding:13px 15px; border:1.5px solid var(--line);
  border-radius:var(--radius-sm); background:#fff; color:var(--ink); min-height:50px; transition:border-color .15s, box-shadow .15s;
}
select:focus, input:focus, textarea:focus { border-color:var(--ai); outline:none; box-shadow:0 0 0 4px rgba(27,58,91,.13); }
.btn {
  display:inline-flex; align-items:center; justify-content:center; gap:8px;
  background: linear-gradient(145deg, var(--shu-2), var(--shu)); color:#fff; border:0; border-radius:var(--radius-sm);
  padding:14px 26px; font-family:var(--sans); font-weight:700; font-size:16px; cursor:pointer; min-height:50px;
  box-shadow: 0 8px 20px -8px rgba(200,71,43,.6); transition: transform .12s, box-shadow .12s, filter .12s;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 14px 26px -8px rgba(200,71,43,.6); color:#fff; }
.btn:active { transform: translateY(0); }
.btn-ghost { background:transparent; color:var(--ai); border:1.5px solid var(--ai); box-shadow:none; }
.btn-ghost:hover { background:var(--ai); color:#fff; }

/* 変換結果 */
.tool-result {
  margin-top:18px; font-family:var(--serif); font-size:clamp(20px,5.4vw,30px); color:var(--ink);
  background: var(--paper-3); border:1px dashed var(--line); border-radius:var(--radius-sm);
  padding:18px; text-align:center; min-height: 70px; display:flex; align-items:center; justify-content:center;
  transition: background .2s;
}
.tool-result.has { background: linear-gradient(180deg, #fff, var(--paper-3)); border-style:solid; animation: pop .3s ease; }
.tool-result strong { color:var(--shu); font-size:1.16em; }
.tool-result.empty { color:var(--muted); font-family:var(--sans); font-size:14px; }

/* ===== 即答カード（AEO） ===== */
.answer {
  position:relative; background: linear-gradient(180deg, var(--paper-2), #fff);
  border:1px solid var(--line); border-radius: var(--radius); padding: 22px 24px 22px 28px;
  box-shadow: var(--shadow); overflow:hidden;
}
.answer::before { content:""; position:absolute; left:0; top:0; bottom:0; width:6px; background:linear-gradient(var(--shu),var(--shu-2)); }
.answer .a-label { font-size:12px; color:var(--shu); font-weight:700; letter-spacing:.12em; margin:0 0 6px; text-transform:uppercase; }
.answer .a-main { font-family:var(--serif); font-size:clamp(22px,5.4vw,32px); color:var(--ink); font-weight:700; margin:0; }
.answer .a-main strong { color:var(--shu); }
.answer .a-sub { margin:10px 0 0; font-size:14px; color:var(--muted); }

/* ===== 変換式カード ===== */
.formula-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(220px,1fr)); gap:14px; }
.fcard {
  background:var(--paper-2); border:1px solid var(--line); border-radius:var(--radius-sm);
  padding:16px 18px; box-shadow:var(--shadow-sm); position:relative; overflow:hidden;
  transition: transform .15s, box-shadow .15s;
}
.fcard:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.fcard::after { content:""; position:absolute; right:-20px; bottom:-20px; width:70px; height:70px; border-radius:50%; background:var(--era,#ccc); opacity:.08; }
.fcard .era-chip {
  display:inline-flex; align-items:center; gap:6px; font-family:var(--serif); font-weight:700; color:#fff;
  background:var(--era,#888); padding:4px 14px; border-radius:999px; font-size:16px; box-shadow:var(--shadow-sm);
}
.fcard .f-add { font-family:var(--serif); font-size:26px; color:var(--ink); margin:12px 0 4px; }
.fcard .f-add b { color:var(--shu); }
.fcard .f-ex { font-size:13px; color:var(--muted); }

/* 元号ごとの色 */
.e-meiji{--era:var(--c-meiji)} .e-taisho{--era:var(--c-taisho)} .e-showa{--era:var(--c-showa)}
.e-heisei{--era:var(--c-heisei)} .e-reiwa{--era:var(--c-reiwa)}

/* テーブル内など、詰まった場所向けの控えめな元号表示（色ドット＋濃い文字） */
.era-name { display:inline-flex; align-items:center; gap:9px; font-family:var(--serif); font-weight:700; color:var(--ink); white-space:nowrap; }
.era-name::before { content:""; width:11px; height:11px; border-radius:3px; background:var(--era,#888); flex:0 0 auto; box-shadow:0 0 0 2px color-mix(in srgb, var(--era,#888) 22%, transparent); }
.era-name:hover { color:var(--era,var(--ai)); }

/* 元号カード（大きな元号名＋色バー。一覧向け） */
.era-card { position:relative; border-top:4px solid var(--era,#888); padding-top:18px; }
.era-card .ec-head { display:flex; align-items:baseline; gap:10px; flex-wrap:wrap; margin-bottom:2px; }
.era-card .ec-name { font-family:var(--serif); font-weight:700; font-size:30px; line-height:1.15; color:var(--era,var(--ink)); letter-spacing:.02em; }
.era-card .ec-kana { font-size:12.5px; color:var(--muted); }
.era-card .ec-period { display:block; font-size:13.5px; color:var(--ink); font-weight:700; margin:2px 0 8px; }
.era-card .ec-sum { font-size:13px; color:var(--muted); line-height:1.7; display:block; }
.era-card::before { display:none; } /* 共通カードの上部グラデは元号バーと重なるため無効化 */
.era-card::after { content:"→"; position:absolute; right:16px; top:14px; color:var(--era,#888); font-weight:700; opacity:0; transform:translateX(-4px); transition:opacity .2s, transform .2s; }
.era-card:hover::after { opacity:1; transform:none; }

/* ===== 元号タイムライン ===== */
.timeline { position:relative; padding: 8px 0; }
.tl-track { display:flex; gap:4px; border-radius:999px; overflow:hidden; box-shadow:var(--shadow-sm); }
.tl-seg { padding:14px 10px; color:#fff; text-align:center; font-family:var(--serif); font-weight:700; position:relative; min-width:0; }
.tl-seg .tl-name { font-size:clamp(13px,3.2vw,17px); white-space:nowrap; }
.tl-seg .tl-yr { display:block; font-family:var(--sans); font-weight:500; font-size:10.5px; opacity:.9; margin-top:2px; }
.tl-seg:hover { filter:brightness(1.08); }

/* ===== カードグリッド（関連リンク） ===== */
.card-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(160px,1fr)); gap:14px; }
.card {
  position:relative; background:var(--paper-2); border:1px solid var(--line); border-radius:var(--radius-sm);
  padding:18px 16px; box-shadow:var(--shadow-sm); color:var(--ink-soft);
  transition:transform .14s, box-shadow .14s, border-color .14s; overflow:hidden; display:block;
}
.card::before { content:""; position:absolute; left:0; top:0; right:0; height:3px; background:linear-gradient(90deg,var(--ai),var(--shu)); transform:scaleX(0); transform-origin:left; transition:transform .25s; }
.card:hover { transform:translateY(-4px); box-shadow:var(--shadow); color:var(--ink-soft); border-color:var(--line-2); }
.card:hover::before { transform:scaleX(1); }
.card .c-ico { font-size:22px; display:block; margin-bottom:6px; }
.card .c-title { font-family:var(--serif); font-weight:700; color:var(--ink); display:block; margin-bottom:3px; }
.card .c-sub { font-size:12.5px; color:var(--muted); display:block; }

/* ===== 本文 ===== */
.prose { max-width: 44em; }
.prose h2 { font-size:22px; margin:38px 0 14px; padding-left:14px; position:relative; }
.prose h2::before { content:""; position:absolute; left:0; top:.2em; bottom:.2em; width:5px; border-radius:3px; background:linear-gradient(var(--ai),var(--ai-2)); }
.prose h3 { font-size:18px; margin:26px 0 8px; }
.prose p { margin:13px 0; }
.prose ul, .prose ol { padding-left:1.3em; }
.prose li { margin:6px 0; }
.prose strong { color:var(--ink); }
.prose .lead { font-size:1.04em; }

/* リスト（チェック風） */
ul.ticks { list-style:none; padding:0; }
ul.ticks li { position:relative; padding-left:30px; margin:10px 0; }
ul.ticks li::before {
  content:""; position:absolute; left:0; top:.45em; width:18px; height:18px; border-radius:50%;
  background:radial-gradient(circle at 50%, var(--shu) 38%, transparent 40%), rgba(200,71,43,.12);
}

/* ===== 注記・式 ===== */
.note { background: linear-gradient(180deg,#f5f0e3,#efe8d7); border:1px solid var(--line); border-radius:var(--radius-sm); padding:14px 18px; font-size:13.5px; color:var(--muted); }
.formula-badge { font-family:var(--serif); background:linear-gradient(145deg,var(--ai-2),var(--ai-deep)); color:#fff; padding:10px 18px; border-radius:999px; display:inline-block; font-size:1.05em; box-shadow:var(--shadow-sm); }

/* ===== テーブル ===== */
.table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; border-radius:var(--radius-sm); border:1px solid var(--line); box-shadow:var(--shadow-sm); background:var(--paper-2); }
table.data { width:100%; border-collapse:collapse; font-size:15px; }
table.data caption { font-family:var(--serif); font-weight:700; color:var(--ink); padding:14px; font-size:17px; }
table.data th, table.data td { padding:12px 14px; text-align:center; border-bottom:1px solid var(--line-2); }
table.data thead th { background:linear-gradient(180deg,var(--ai-2),var(--ai)); color:#fff; font-weight:700; position:sticky; top:0; }
table.data tbody tr { transition:background .12s; }
table.data tbody tr:nth-child(even) { background:var(--paper-3); }
table.data tbody tr:hover { background:#f3ece0; }
table.data a { font-weight:700; }
table.data th[scope="row"] { background:var(--paper-3); color:var(--ink); }

/* カレンダー */
table.cal { width:100%; border-collapse:collapse; background:var(--paper-2); }
table.cal caption { font-family:var(--serif); font-weight:700; color:var(--ink); padding:8px; font-size:16px; }
table.cal th, table.cal td { padding:7px 4px; text-align:center; border:1px solid var(--line-2); font-size:14px; }
table.cal th { background:var(--paper-3); font-weight:500; }
td.sun, .dow-sun { color:var(--sun); } td.sat, .dow-sat { color:var(--sat); }
td.holiday { background:#fdecea; color:var(--sun); font-weight:700; }

/* ===== FAQ ===== */
.faq details {
  background:var(--paper-2); border:1px solid var(--line); border-radius:var(--radius-sm);
  padding:2px 18px; margin:12px 0; box-shadow:var(--shadow-sm); transition:box-shadow .15s, border-color .15s;
}
.faq details[open] { box-shadow:var(--shadow); border-color:var(--line-2); }
.faq summary { font-family:var(--serif); font-weight:700; color:var(--ink); cursor:pointer; padding:15px 0; list-style:none; display:flex; justify-content:space-between; align-items:center; gap:12px; }
.faq summary::-webkit-details-marker { display:none; }
.faq summary::after { content:"＋"; color:#fff; background:var(--ai); width:24px; height:24px; border-radius:50%; display:grid; place-items:center; font-size:14px; flex:0 0 auto; transition:transform .25s, background .2s; }
.faq details[open] summary::after { content:"−"; background:var(--shu); transform:rotate(180deg); }
.faq details p { margin:0 0 16px; color:var(--ink-soft); animation: fadeUp .3s ease; }

/* ===== 広告枠 ===== */
.ad-slot { min-height:100px; margin:30px 0; display:grid; place-items:center; color:var(--line); border:1px dashed var(--line); border-radius:var(--radius-sm); font-size:12px; }

/* ===== フッター ===== */
.site-footer { position:relative; background:linear-gradient(180deg,var(--ai),var(--ai-deep)); color:#cdd6df; padding:40px 0 30px; margin-top:50px; }
.site-footer::before { content:""; position:absolute; top:0; left:0; right:0; height:4px; background:linear-gradient(90deg,var(--shu),var(--gold),var(--shu)); }
.footer-brand { display:flex; align-items:center; justify-content:center; gap:10px; margin-bottom:16px; }
.footer-brand .brand-mark { width:34px; height:34px; font-size:15px; }
.footer-brand span { font-family:var(--serif); color:#fff; font-weight:700; }
.footer-nav { display:flex; flex-wrap:wrap; gap:8px 20px; justify-content:center; margin-bottom:16px; }
.footer-nav a { color:#dde6ee; font-size:14px; }
.footer-nav a:hover { color:#fff; }
.copyright { text-align:center; font-size:12.5px; color:#90a3b3; margin:0; }

/* ===== ユーティリティ ===== */
.text-center { text-align:center; }
.mt-0{margin-top:0}.mb-0{margin-bottom:0}
.muted { color:var(--muted); }
.tag { display:inline-block; background:var(--paper-2); border:1px solid var(--line); border-radius:999px; padding:4px 14px; font-size:12.5px; color:var(--muted); }
.stat-row { display:grid; grid-template-columns:repeat(auto-fit,minmax(120px,1fr)); gap:12px; }
.stat { background:var(--paper-2); border:1px solid var(--line); border-radius:var(--radius-sm); padding:16px; text-align:center; box-shadow:var(--shadow-sm); }
.stat .s-val { font-family:var(--serif); font-size:clamp(22px,5vw,30px); color:var(--ai); font-weight:700; display:block; }
.stat .s-lbl { font-size:12px; color:var(--muted); }

/* ===== アニメーション ===== */
@keyframes fadeUp { from{opacity:0;transform:translateY(16px)} to{opacity:1;transform:none} }
@keyframes pop { from{transform:scale(.96);opacity:.4} to{transform:scale(1);opacity:1} }
@keyframes floaty { 0%,100%{transform:translateY(0)} 50%{transform:translateY(-6px)} }
@keyframes shimmer { from{background-position:-200% 0} to{background-position:200% 0} }

html.js .reveal { opacity:0; transform:translateY(22px); transition:opacity .6s cubic-bezier(.2,.7,.2,1), transform .6s cubic-bezier(.2,.7,.2,1); }
html.js .reveal.in { opacity:1; transform:none; }
.reveal.d1{transition-delay:.06s}.reveal.d2{transition-delay:.12s}.reveal.d3{transition-delay:.18s}.reveal.d4{transition-delay:.24s}

/* ===== レスポンシブ ===== */
@media (min-width:600px){ body{font-size:17px} .field.grow{flex:1} }
@media (max-width:560px){
  .site-nav a{ padding:7px 9px; font-size:12.5px; }
  .brand-name{ font-size:16px; }
  .hero{ padding:32px 20px 26px; }
  .hero .seal{ width:60px; height:60px; font-size:11px; top:16px; right:16px; }
  .tool{ padding:18px; }
  section{ margin-block:38px; }
}
@media (max-width:380px){ .brand-name{ display:none; } }

@media (prefers-reduced-motion: reduce){
  *{ scroll-behavior:auto !important; animation:none !important; transition:none !important; }
  .reveal{ opacity:1 !important; transform:none !important; }
}