/* けいさん帖 ― 家計の計算ノート
   紙（方眼）＋ボールペンの藍＋蛍光ペンの黄。カテゴリはノートのインデックスタブの色。 */
:root {
  --paper: #FBFCFD;
  --grid: #E6ECF3;
  --sheet: #FFFFFF;
  --ink: #1B2A41;
  --ink-2: #4A5A72;
  --ink-3: #7B889B;
  --rule: #D9E1EB;
  --pen: #2B4C9B;
  --pen-soft: #EAF0FA;
  --marker: #FFE27A;
  --stamp: #C8463D;
  --cat: var(--pen);
  --r-sm: 6px;
  --r-md: 10px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #121822; --grid: #1B2330; --sheet: #182130; --ink: #E7ECF3; --ink-2: #B4C0D0; --ink-3: #8794A7;
    --rule: #2A3546; --pen: #8FB0F2; --pen-soft: #1E2A40; --marker: #7A6620; --stamp: #F08A7F;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #121822; --grid: #1B2330; --sheet: #182130; --ink: #E7ECF3; --ink-2: #B4C0D0; --ink-3: #8794A7;
  --rule: #2A3546; --pen: #8FB0F2; --pen-soft: #1E2A40; --marker: #7A6620; --stamp: #F08A7F;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; color: var(--ink); background-color: var(--paper);
  font-family: "Zen Kaku Gothic New", "Hiragino Sans", "Yu Gothic", system-ui, sans-serif;
  font-size: 16px; line-height: 1.85; font-feature-settings: "palt" 0;
  font-variant-numeric: tabular-nums;
}
a { color: var(--pen); text-underline-offset: 3px; }
:focus-visible { outline: 3px solid var(--pen); outline-offset: 2px; border-radius: 4px; }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 16px; }
main.wrap { padding-bottom: 24px; }

/* ===== ヘッダー：ロゴ＋検索、下にインデックスタブ ===== */
.site-header { background: var(--sheet); border-bottom: 1px solid var(--rule); position: sticky; top: 0; z-index: 10; }
.site-header .wrap { max-width: 1040px; }
.head-row { display: flex; align-items: center; gap: 16px; height: 58px; }
.logo { display: flex; align-items: center; gap: 8px; color: var(--ink); text-decoration: none; font-weight: 900; font-size: 1.2rem; letter-spacing: .06em; white-space: nowrap; }
.logo b { color: var(--pen); font-weight: 900; }
.logo-mark { width: 20px; height: 24px; border-radius: 3px; background: var(--pen); position: relative; flex: none; }
.logo-mark::after { content: ""; position: absolute; left: 4px; right: 4px; bottom: 5px; height: 6px; background: var(--marker); border-radius: 1px; }
.head-search { margin-left: auto; flex: 0 1 280px; }
.head-search input { min-height: 38px; padding: 6px 12px; font-size: .88rem; border-radius: 999px; }
.tabs { border-top: 1px solid var(--rule); }
.tabs-row { display: flex; gap: 4px; overflow-x: auto; scrollbar-width: none; padding-top: 8px; }
.tabs-row::-webkit-scrollbar { display: none; }
@media (max-width: 1040px) { .tabs-row { -webkit-mask-image: linear-gradient(90deg, #000 88%, transparent); mask-image: linear-gradient(90deg, #000 88%, transparent); padding-right: 32px; } }
.tabs a {
  flex: none; color: var(--ink-2); text-decoration: none; font-size: .84rem; font-weight: 500;
  padding: 6px 10px 7px; border-radius: 8px 8px 0 0; border: 1px solid transparent; border-bottom: 0;
  position: relative; top: 1px;
}
.tabs a::before { content: ""; display: inline-block; width: 8px; height: 8px; border-radius: 2px; background: var(--cat); margin-right: 6px; vertical-align: 1px; }
.tabs a:hover { color: var(--ink); background: var(--paper); }
.tabs a[aria-current] { color: var(--ink); background: var(--paper); border-color: var(--rule); font-weight: 700; }

/* ===== 見出しまわり ===== */
h1 { font-size: 1.75rem; line-height: 1.4; font-weight: 900; margin: 0 0 8px; letter-spacing: .02em; }
h2 { font-size: 1.22rem; line-height: 1.5; font-weight: 700; margin: 44px 0 12px; }
h3 { font-size: 1.04rem; font-weight: 700; margin: 26px 0 8px; }
.page-head { padding: 22px 0 18px; border-left: 4px solid var(--cat); padding-left: 16px; margin: 20px 0 20px; }
.crumbs { font-size: .8rem; color: var(--ink-3); margin: 0 0 6px; }
.crumbs a { color: var(--ink-3); }
.crumbs span { margin: 0 6px; }
.lead { color: var(--ink-2); margin: 0; max-width: 40em; }

/* ===== トップ ===== */
.hero { padding: 40px 0 8px; }
.hero h1 { font-size: clamp(2rem, 7vw, 3.1rem); line-height: 1.25; letter-spacing: .03em; margin-bottom: 14px; }
.hero-lead { color: var(--ink-2); max-width: 36em; margin: 0 0 22px; }
.search input { min-height: 56px; font-size: 1.05rem; padding: 12px 18px; border-radius: 14px; border: 2px solid var(--ink); background: var(--sheet); }
.search input:focus { outline: none; box-shadow: 0 0 0 4px var(--pen-soft); border-color: var(--pen); }
.search-empty { color: var(--ink-2); margin: 10px 2px 0; }
.pops { margin: 34px 0 8px; }
.pops-title { font-size: 1rem; color: var(--ink-2); margin: 0 0 12px; font-weight: 700; }
.pop-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.pop {
  display: flex; flex-direction: column; gap: 4px; text-decoration: none; color: var(--ink);
  background: var(--sheet); border: 1px solid var(--rule); border-top: 4px solid var(--cat); border-radius: var(--r-sm);
  padding: 12px 14px 14px;
}
.pop:hover { border-color: var(--cat); }
.pop-cat { font-size: .74rem; color: var(--cat); font-weight: 700; }
.pop strong { font-size: 1.02rem; line-height: 1.45; }
.pop-ex { font-size: .82rem; color: var(--ink-2); line-height: 1.5; }

/* ===== 目次（ツール一覧） ===== */
.index-cats { margin-top: 8px; }
.toc-cat { margin: 36px 0 0; }
.toc-cat h2 { display: flex; align-items: baseline; gap: 10px; margin: 0 0 6px; font-size: 1.15rem; padding-bottom: 8px; border-bottom: 2px solid var(--cat); }
.toc-cat h2 a { color: var(--ink); text-decoration: none; }
.toc-cat h2 a:hover { color: var(--cat); }
.toc-cat h2::before { content: ""; width: 10px; height: 10px; border-radius: 2px; background: var(--cat); flex: none; align-self: center; }
.count { font-size: .78rem; color: var(--ink-3); font-weight: 500; }
.count::after { content: "ページ"; }
.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-list li a {
  display: flex; align-items: baseline; gap: 10px; padding: 11px 2px; text-decoration: none; color: var(--ink);
  border-bottom: 1px solid var(--rule);
}
.toc-list .t { font-weight: 700; flex: none; }
.toc-list .leader { flex: 1 1 24px; border-bottom: 2px dotted var(--rule); transform: translateY(-5px); min-width: 24px; }
.toc-list .d { color: var(--ink-2); font-size: .88rem; text-align: right; flex: 0 1 auto; }
.toc-list a:hover .t { color: var(--cat); }
.toc-list a:hover .leader { border-color: var(--cat); }
.kind { font-style: normal; font-size: .7rem; font-weight: 700; color: var(--cat); border: 1px solid currentColor; border-radius: 4px; padding: 0 5px; margin-left: 8px; vertical-align: 2px; }
.toc-cat.solo { margin-top: 0; }
.more { margin-top: 40px; }
.more h2 { font-size: 1.05rem; margin: 0 0 4px; }

/* ===== 計算フォーム（方眼の紙） ===== */
.tool {
  background-color: var(--sheet);
  background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 20px 20px; background-position: -1px -1px;
  border: 1px solid var(--rule); border-radius: var(--r-md); padding: 22px 20px 20px;
}
.field { margin-bottom: 16px; }
.field label { display: block; font-weight: 700; font-size: .92rem; margin-bottom: 6px; }
.hint { font-weight: 400; color: var(--ink-3); font-size: .8rem; }
p.hint { margin: 6px 0 0; }
.row { display: flex; gap: 12px; flex-wrap: wrap; }
.row > .field { flex: 1 1 180px; }
input, select {
  width: 100%; font: inherit; color: var(--ink); background: var(--sheet);
  padding: 10px 12px; min-height: 48px; border: 1.5px solid #C3CEDB; border-radius: var(--r-sm);
  font-variant-numeric: tabular-nums;
}
input:focus, select:focus { outline: none; border-color: var(--pen); box-shadow: 0 0 0 3px var(--pen-soft); }
input[type="checkbox"], input[type="radio"] { width: auto; min-height: 0; accent-color: var(--pen); }
.inline { display: flex; align-items: center; gap: 8px; }
.unit { color: var(--ink-2); white-space: nowrap; font-size: .92rem; }
.radios { display: flex; gap: 8px; flex-wrap: wrap; }
.radios label {
  display: inline-flex; align-items: center; gap: 6px; margin: 0; padding: 9px 14px; font-weight: 500;
  border: 1.5px solid #C3CEDB; border-radius: var(--r-sm); background: var(--sheet); cursor: pointer;
}
.radios label:has(input:checked) { border-color: var(--pen); background: var(--pen-soft); color: var(--ink); font-weight: 700; }
.btn {
  display: block; width: 100%; margin-top: 8px; padding: 15px; border: 0; border-radius: var(--r-sm); cursor: pointer;
  background: var(--pen); color: #fff; font: inherit; font-weight: 700; font-size: 1.08rem; letter-spacing: .1em;
  box-shadow: 0 3px 0 #1C3473;
}
.btn:active { transform: translateY(2px); box-shadow: 0 1px 0 #1C3473; }
.debt { border: 1.5px dashed #C3CEDB; border-radius: var(--r-sm); padding: 12px 14px 0; margin: 0 0 14px; background: var(--sheet); }
.debt legend { font-weight: 700; padding: 0 6px; }
.debt .row > .field { flex: 1 1 120px; }

/* ===== 計算結果（帳簿＋蛍光ペン） ===== */
.result { display: none; margin-top: 20px; background: var(--sheet); border: 1px solid var(--rule); border-radius: var(--r-sm); padding: 18px 18px 14px; }
.result.show { display: block; animation: written .35s ease-out; }
@keyframes written { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { .result.show { animation: none; } }
.result .big {
  font-size: 2rem; font-weight: 900; line-height: 1.35; word-break: break-all; display: inline;
  background: linear-gradient(transparent 58%, var(--marker) 58%, var(--marker) 92%, transparent 92%);
  padding: 0 2px; -webkit-box-decoration-break: clone; box-decoration-break: clone;
}
.result .big small { font-size: .95rem; font-weight: 700; color: var(--ink-2); margin-left: 4px; }
.result small.label { display: block; font-size: .85rem; font-weight: 700; color: var(--ink-2); line-height: 1.6; margin: 0 0 2px; }
.result .big + p, .result .big + dl { margin-top: 12px; }
.result > p { margin: 10px 0 0; }
.result dl { display: grid; grid-template-columns: minmax(0, 1fr) auto; margin: 12px 0 0; }
.result dt, .result dd { padding: 8px 0; border-bottom: 1px dotted #C3CEDB; }
.result dt { color: var(--ink-2); padding-right: 12px; }
.result dd { margin: 0; font-weight: 700; text-align: right; white-space: nowrap; }
.result dt .hint { display: block; line-height: 1.5; }
.result h3 { font-size: .98rem; margin: 20px 0 0; padding-top: 14px; border-top: 2px solid var(--ink); }
.result table { font-size: .84rem; }
.result th, .result td { padding: 6px 8px; }
.result td:first-child, .result th:first-child { white-space: nowrap; }
.result .note { font-size: .78rem; color: var(--ink-3); margin-top: 12px; line-height: 1.7; }
.error { color: var(--stamp); font-weight: 700; margin: 0; }
.bar { display: flex; height: 22px; border-radius: 4px; overflow: hidden; margin: 14px 0 6px; background: var(--grid); }
.bar span { display: block; height: 100%; }
.bar-legend { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: .78rem; color: var(--ink-2); margin: 0; padding: 0; list-style: none; }
.bar-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; margin-right: 5px; vertical-align: -1px; }

/* ===== 本文 ===== */
.content { max-width: 720px; }
.content h2 { padding-bottom: 6px; border-bottom: 1px solid var(--rule); }
.content h2::before { content: ""; display: inline-block; width: 6px; height: 1.1em; background: var(--cat); margin-right: 10px; vertical-align: -3px; border-radius: 1px; }
.content p, .content li { color: var(--ink); }
.content ul, .content ol { padding-left: 1.4em; }
.content li { margin: 4px 0; }
.content strong { background: linear-gradient(transparent 68%, var(--marker) 68%); }
.table-scroll { overflow-x: auto; margin: 12px 0; }
table { width: 100%; border-collapse: collapse; background: var(--sheet); font-size: .9rem; }
th, td { border: 1px solid var(--rule); padding: 8px 10px; text-align: left; vertical-align: top; }
th { background: var(--pen-soft); font-weight: 700; }
td { font-variant-numeric: tabular-nums; }
.formula { background: var(--sheet); border: 1.5px solid var(--ink); border-radius: var(--r-sm); padding: 12px 16px; font-weight: 700; line-height: 1.9; }
.note { font-size: .82rem; color: var(--ink-3); }
.point { background: var(--pen-soft); border-radius: var(--r-sm); padding: 14px 18px; margin: 16px 0; }
.point ol, .point ul { margin: 6px 0 0; }
.warn { border-left: 4px solid var(--stamp); background: var(--sheet); padding: 12px 16px; border-radius: 0 var(--r-sm) var(--r-sm) 0; margin: 16px 0; }
.checklist { list-style: none; padding-left: 0 !important; }
.checklist li { padding: 9px 0 9px 32px; position: relative; border-bottom: 1px dashed var(--rule); margin: 0; }
.checklist li::before { content: ""; position: absolute; left: 3px; top: 14px; width: 16px; height: 16px; border: 2px solid var(--cat); border-radius: 3px; }
.faq details { border-bottom: 1px solid var(--rule); padding: 12px 0; }
.faq summary { font-weight: 700; cursor: pointer; list-style: none; padding-left: 30px; position: relative; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "Q"; position: absolute; left: 0; top: 0; width: 22px; height: 22px; border-radius: 4px; background: var(--ink); color: var(--paper); font-size: .8rem; text-align: center; line-height: 22px; }
.faq details[open] summary { color: var(--pen); }
.faq details p { margin: 8px 0 0 30px; color: var(--ink-2); }
.toc { background: var(--sheet); border: 1px solid var(--rule); border-left: 4px solid var(--cat); border-radius: 0 var(--r-sm) var(--r-sm) 0; padding: 14px 20px; }
.toc-title { margin: 0; font-weight: 700; }
.toc ol { margin: 6px 0 0; padding-left: 1.4em; }
.toc li { margin: 2px 0; }
.city-links { padding-left: 1.2em; }
.city-links li { margin: 6px 0; }
.updated { font-size: .78rem; color: var(--ink-3); margin-top: 32px; }
.ad-slot { margin: 24px 0; }

/* ===== フッター ===== */
.site-footer { margin-top: 64px; border-top: 1px solid var(--rule); background: var(--sheet); padding: 28px 0 32px; font-size: .85rem; color: var(--ink-2); }
.foot-logo { font-weight: 900; font-size: 1.05rem; color: var(--ink); margin: 0; letter-spacing: .06em; }
.foot-logo b { color: var(--pen); }
.foot-desc { margin: 4px 0 14px; }
.foot-links a { color: var(--ink-2); margin-right: 18px; }
.foot-copy { color: var(--ink-3); margin: 14px 0 0; font-size: .78rem; }

/* ===== スマホ ===== */
@media (max-width: 720px) {
  .pop-grid { grid-template-columns: 1fr 1fr; }
  .toc-list li a { flex-wrap: wrap; gap: 2px 10px; }
  .toc-list .leader { display: none; }
  .toc-list .t { flex: 1 1 100%; }
  .toc-list .d { text-align: left; flex: 1 1 100%; font-size: .84rem; }
}
@media (max-width: 520px) {
  .head-search { display: none; }
  .pop-grid { grid-template-columns: 1fr; gap: 8px; }
  .pop { flex-direction: row; flex-wrap: wrap; align-items: baseline; column-gap: 10px; border-top-width: 1px; border-left: 4px solid var(--cat); padding: 10px 12px; }
  .pop-cat { display: none; }
  .pop-ex { flex: 1 1 100%; }
  h1 { font-size: 1.45rem; }
  .hero { padding-top: 28px; }
  .result .big { font-size: 1.6rem; }
  .tool { padding: 18px 14px 16px; }
  .pop strong { font-size: .95rem; }
}
.form-embed { background: var(--sheet); border: 1px solid var(--rule); border-radius: var(--r-md); overflow: hidden; margin: 16px 0; }
.form-embed iframe { display: block; width: 100%; height: 980px; border: 0; }
@media (max-width: 520px) { .form-embed iframe { height: 1100px; } }