:root {
  --bg: #f5f6f8;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --text: #1c222c;
  --muted: #667085;
  --line: #e2e5ea;
  --brand: #3b5bdb;
  --brand-contrast: #ffffff;
  --best-bg: #fff3c4;
  --best-text: #6b4e00;
  --pos: #0b7a43;
  --neg: #c92a2a;
  --warn-bg: #fff4e5;
  --warn-line: #f5b25b;
  --tag-bg: #eef0f4;
  --shadow: 0 1px 2px rgb(16 24 40 / 6%);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1217;
    --surface: #171b22;
    --surface-2: #1e232c;
    --text: #e7eaf0;
    --muted: #9aa3b2;
    --line: #2b313b;
    --brand: #7b93ff;
    --brand-contrast: #0f1217;
    --best-bg: #3d3210;
    --best-text: #ffd966;
    --pos: #3ecf8e;
    --neg: #ff7b7b;
    --warn-bg: #3a2a12;
    --warn-line: #9a6a24;
    --tag-bg: #262c36;
    --shadow: none;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic UI", Meiryo, sans-serif;
  font-size: 15px;
  line-height: 1.6;
}

a { color: var(--brand); }

.inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 16px;
}

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ヘッダー */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  padding: 20px 0 16px;
  margin-bottom: 16px;
}
.site-title {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: .02em;
}
.site-title a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: inherit;
  text-decoration: none;
}
.logo-mark { width: 1.3em; height: 1.3em; flex: none; }
.logo-bg { fill: var(--brand); }
.logo-ring { fill: none; stroke: #fff; stroke-opacity: .45; stroke-width: 1.5; }
.logo-sweep { fill: #fff; fill-opacity: .3; }
.logo-beam { stroke: #fff; stroke-width: 2; stroke-linecap: round; }
.logo-blip { fill: #ffd43b; }
.meta {
  margin: 8px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 12px;
  font-size: 13px;
  color: var(--muted);
}
.updated { color: var(--text); font-weight: 600; }

/* ページの見出しと説明 */
.page-title { font-size: 20px; line-height: 1.4; margin: 16px 0 6px; }
.lead { margin: 0 0 12px; color: var(--muted); font-size: 14px; }
.lead strong { color: var(--text); }
.section-title { font-size: 16px; margin: 24px 0 8px; }
.breadcrumb { font-size: 12px; color: var(--muted); margin: 4px 0 8px; }
.breadcrumb a { color: var(--muted); }

/* お知らせ（取得エラーなど） */
.alert {
  background: var(--warn-bg);
  border: 1px solid var(--warn-line);
  border-radius: 8px;
  padding: 8px 12px;
  margin-bottom: 12px;
  font-size: 13px;
}

/* 絞り込み・並び替え */
.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 16px;
  margin-bottom: 8px;
}
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text);
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 13px;
  text-decoration: none;
}
.chip:hover { border-color: var(--brand); }
.chip[aria-current="page"] {
  background: var(--brand);
  border-color: var(--brand);
  color: var(--brand-contrast);
  font-weight: 600;
}
.sort { display: flex; align-items: center; gap: 6px; font-size: 13px; color: var(--muted); }
.sort select {
  font: inherit;
  font-size: 13px;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 4px 6px;
}
.count { margin: 0 0 6px; font-size: 12px; color: var(--muted); }

/* 比較表。表の中だけをスクロールさせ、見出し行と商品名の列を固定する */
.table-wrap {
  overflow: auto;
  max-height: 80vh;
  max-height: 80dvh;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 10px;
  box-shadow: var(--shadow);
}
.price-table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
  font-variant-numeric: tabular-nums;
}
.price-table th,
.price-table td {
  padding: 8px 10px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  vertical-align: middle;
}
.price-table thead th {
  position: sticky;
  top: 0;
  z-index: 2;
  background: var(--surface-2);
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  white-space: nowrap;
  text-align: right;
}
.price-table thead th:first-child { text-align: left; }
.price-table thead th a { color: inherit; }
.price-table .col-name {
  position: sticky;
  left: 0;
  z-index: 1;
  min-width: 16em;
  max-width: 25em;
  text-align: left;
  font-weight: 400;
  border-right: 1px solid var(--line);
}
.price-table thead .col-name { z-index: 3; }

.name-wrap { display: flex; align-items: center; gap: 10px; }
.thumb {
  flex: none;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 6px;
  /* 商品画像は白背景のものが多いので、ダークモードでも白い台紙に載せる */
  background: #fff;
}
.thumb img { display: block; width: 100%; height: 100%; object-fit: contain; }
.thumb-empty { background: var(--surface-2); }
.thumb--large { width: 112px; height: 112px; border-radius: 10px; }

.product { display: block; font-weight: 600; font-size: 14px; line-height: 1.4; color: var(--text); text-decoration: none; }
a.product:hover { text-decoration: underline; }
.sub { display: block; font-size: 11px; color: var(--muted); font-weight: 400; margin-top: 2px; }
.tag {
  display: inline-block;
  background: var(--tag-bg);
  border-radius: 4px;
  padding: 0 5px;
  margin-left: 4px;
  font-size: 10px;
  color: var(--muted);
}

.num { text-align: right; white-space: nowrap; }
.col-best { font-weight: 700; font-size: 15px; }
.profit.pos { color: var(--pos); font-weight: 600; }
.profit.neg { color: var(--neg); font-weight: 600; }
.none { color: var(--muted); }

.shop a { color: var(--text); text-decoration: none; }
.shop a:hover { text-decoration: underline; }
.shop.is-best { background: var(--best-bg); }
.shop.is-best a { color: var(--best-text); font-weight: 700; }
.shop.is-stale a { color: var(--muted); font-style: italic; }
.warn-mark { color: var(--neg); margin-left: 2px; }

.group th {
  background: var(--surface-2);
  font-size: 13px;
  font-weight: 700;
  text-align: left;
  padding-top: 10px;
  padding-bottom: 6px;
}
.group th span { position: sticky; left: 10px; }
.group th a { color: inherit; text-decoration: none; }
.group th a:hover { text-decoration: underline; }

/* 商品ページ */
.item-summary {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  margin-top: 8px;
}
.item-heading .page-title { margin-top: 0; }
.item-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin: 10px 0 12px;
}
.item-facts dt { font-size: 12px; color: var(--muted); }
.item-facts dd { margin: 0; font-size: 16px; font-weight: 600; font-variant-numeric: tabular-nums; }
.item-facts .col-best { font-size: 20px; }
.table-wrap--auto { max-height: none; }
.shop-table {
  border-collapse: collapse;
  width: 100%;
  font-variant-numeric: tabular-nums;
}
.shop-table th, .shop-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--line);
  text-align: left;
}
.shop-table thead th { background: var(--surface-2); font-size: 12px; color: var(--muted); font-weight: 600; }
.shop-table .num { text-align: right; }
.shop-table .price a { color: var(--text); font-weight: 600; }
.shop-table tr.is-best td, .shop-table tr.is-best th { background: var(--best-bg); }
.shop-table tr.is-best .price a { color: var(--best-text); font-weight: 700; }
.shop-table tr.is-stale .price a { color: var(--muted); font-style: italic; }
.shop-table .diff { color: var(--muted); font-size: 13px; }
.shop-table tr.none th, .shop-table tr.none td { color: var(--muted); }
.related { list-style: none; padding: 0; margin: 0 0 12px; }
.related li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}
.related-price { color: var(--muted); white-space: nowrap; font-variant-numeric: tabular-nums; }

tbody tr:not(.group):hover td,
tbody tr:not(.group):hover th { background: var(--surface-2); }
tbody tr:not(.group):hover td.is-best { background: var(--best-bg); }

.empty { text-align: center; color: var(--muted); padding: 24px; }

/* 注意書き・フッター */
.notes {
  margin: 24px 0 8px;
  font-size: 13px;
  color: var(--muted);
}
.notes h2 { font-size: 14px; color: var(--text); margin: 0 0 6px; }
.notes ul { margin: 0; padding-left: 1.2em; }
.sources a { margin-right: 10px; }
.site-footer {
  margin-top: 24px;
  padding: 16px 0 32px;
  font-size: 12px;
  color: var(--muted);
}
.site-footer p { margin: 0 0 8px; }
/* Yahoo!のクレジット表記は色や大きさを変えてはいけないので、ブラウザ標準の見た目に戻す */
.yahoo-credit { font-size: 15px; }
.yahoo-credit a { color: revert; }

.not-found { padding: 64px 16px; text-align: center; }
.not-found h1 { font-size: 22px; }

@media (max-width: 600px) {
  body { font-size: 14px; }
  .site-title { font-size: 19px; }
  .price-table th, .price-table td { padding: 7px 8px; }
  .price-table .col-name { min-width: 12.5em; max-width: 13.5em; }
  .name-wrap { gap: 8px; }
  .thumb { width: 34px; height: 34px; }
  .thumb--large { width: 80px; height: 80px; }
  .product { font-size: 13px; }
  .col-best { font-size: 14px; }
  .page-title { font-size: 18px; }
  .item-summary { gap: 12px; }
}