/* ゴロメディカ 参考書（新しい形）：テーマの本文・一問一答・選択肢の○×（js/sankousho/render.js・drill.js）
   見た目は 2026-10-27 の案A（白地・深緑・枠線だけ。濃い塗りは使わない）。PC は「2段」（案B：左に目次と進み具合）も選べる。
   クラスは sk- を付けて app.css と分ける。 */
.sk, .sk-nav {
  --bg: #ffffff; --bg-2: #f6f8f7; --bg-3: #edf2f1;
  --fg: #131d1c; --fg-2: #46524f; --fg-3: #6a7774;
  --line: #e4e9e8; --line-2: #cdd7d5;
  --accent: #0f4f4b; --accent-soft: #edf2f1; --bar: #9fbfb8; --bar-2: #5e958a;
  --red: #d23c28; --red-soft: #fbe9e6; --marker: #fcf0b0; --gold: #b58a1e;
}
.sk {
  max-width: 860px; margin: 0 auto; padding-block: 24px 48px;
  color: var(--fg); font-family: var(--sans); font-size: 15px; line-height: 1.75;
}
.sk p { margin: 0; }
.sk [hidden] { display: none !important; }
.sk h1, .sk h2 { word-break: keep-all; }
.sk b { font-weight: 700; }
/* 強調：黄色マーカー＝3回以上出題、点線＝1〜2回出題（第101〜120回） */
.sk mark { background: linear-gradient(transparent 58%, var(--marker) 58%); color: inherit; padding: 0 1px; }
.sk u { text-decoration: none; border-bottom: 1.5px dotted var(--fg-3); }

/* テーマの中の移動：ヘッダーの下に貼りつく帯（分野へ・節・問題へ） */
.sk-nav { position: sticky; top: calc(var(--head-h) + env(safe-area-inset-top, 0px)); z-index: 20; background: color-mix(in srgb, #fff 94%, transparent); -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); font-family: var(--sans); }
.sk-nav-in { --g: 16px; box-sizing: border-box; max-width: calc(860px + 2 * var(--g)); margin-inline: auto; padding-inline: max(var(--g), env(safe-area-inset-left, 0px)); display: flex; align-items: center; gap: 4px; height: 48px; }
@media (min-width: 640px) { .sk-nav-in { --g: 24px; } }
@media (min-width: 960px) { .sk-nav-in { --g: 32px; } }
.sk-page .sk-nav { margin-inline: calc(-1 * var(--gut)); } /* 無料ページでは main.wrap の中に置くので、余白の外まで広げる */
.sk-nav-back { display: inline-flex; align-items: center; gap: 2px; flex: none; max-width: 10em; min-height: 44px; padding-right: 6px; font-size: 13px; color: var(--fg-2); text-decoration: none; }
.sk-nav-back span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sk-nav-back svg { width: 16px; height: 16px; flex: none; }
.sk-chips { flex: 1 1 auto; min-width: 0; display: flex; gap: 2px; overflow-x: auto; scrollbar-width: none; scroll-behavior: smooth; }
.sk-chips::-webkit-scrollbar { display: none; }
.sk-chip { flex: none; padding: 4px 11px; border-radius: 999px; font-size: 13px; line-height: 1.5; color: var(--fg-2); text-decoration: none; white-space: nowrap; }
.sk-chip:hover { color: var(--accent); }
.sk-chip.sk-now { background: var(--bg-3); color: var(--accent); font-weight: 700; }
.sk-toq { flex: none; margin-left: 6px; padding: 4px 12px; border: 1px solid var(--accent); border-radius: 999px; font-size: 13px; line-height: 1.5; font-weight: 700; color: var(--accent); text-decoration: none; white-space: nowrap; }
.sk-toq:hover, .sk-toq.sk-now { background: var(--bg-3); color: var(--accent); }
.sk-navst { margin-left: 8px; font-weight: 500; }
.sk-navst b { font-family: var(--num); }
@media (max-width: 600px) { .sk-nav-in { height: 46px; } .sk-nav-back { padding-right: 2px; } .sk-nav-back span { display: none; } .sk-toq { padding: 4px 10px; margin-left: 4px; } .sk-navst { margin-left: 5px; } }

/* 見出し */
.sk-hd { display: flex; gap: 18px; align-items: center; }
.sk-rank { flex: none; width: 64px; height: 64px; box-sizing: border-box; border: 1.5px solid var(--accent); border-radius: 8px; color: var(--accent); display: grid; place-items: center; align-content: center; }
.sk-rank small { font-size: 11px; font-weight: 500; line-height: 1; }
.sk-rank b { font: 700 28px/1.05 var(--num); margin-top: 3px; }
.sk-ht { flex: 1 1 auto; min-width: 0; }
.sk-hd h1 { margin: 0; font-size: 30px; line-height: 1.3; letter-spacing: .03em; text-wrap: balance; }
.sk-hd .sk-sub { font-size: 14px; color: var(--fg-2); margin-top: 2px; }
/* PC のページの形（1段・2段）。狭い画面では出さない */
.sk-lay { display: none; }
@media (min-width: 1080px) {
  .sk-lay { display: inline-flex; flex: none; align-self: flex-start; padding: 2px; border: 1px solid var(--line-2); border-radius: 8px; }
  .sk-lay button { font: inherit; font-size: 12px; line-height: 1.5; padding: 3px 10px; border: 0; border-radius: 6px; background: none; color: var(--fg-2); cursor: pointer; white-space: nowrap; }
  .sk-lay button:hover { color: var(--accent); }
  .sk-lay button[aria-checked="true"] { background: var(--bg-3); color: var(--accent); font-weight: 700; }
}

/* 回ごとの出題（第101〜120回の棒。新しい10回は濃い色。数は棒に重ねない） */
.sk-freq { margin-top: 16px; display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 0 16px; align-items: end; }
.sk-freq .sk-lb { font-size: 11px; color: var(--fg-2); line-height: 1.4; padding-bottom: 18px; white-space: nowrap; }
.sk-freq .sk-lb b { font: 700 22px/1 var(--num); color: var(--fg); margin-right: 1px; }
.sk-bars { display: grid; grid-auto-flow: column; grid-auto-columns: minmax(0, 1fr); gap: 3px; align-items: end; }
.sk-bars span { display: grid; grid-template-columns: minmax(0, 1fr); justify-items: stretch; text-align: center; font-family: var(--num); } /* 回の数字は棒の幅を広げずにはみ出す */
.sk-bars b { display: none; }
.sk-bars i { display: block; background: var(--bar); border-radius: 1px 1px 0 0; }
.sk-bars .sk-nw i { background: var(--bar-2); }
.sk-bars i.sk-z { height: 2px !important; background: var(--line); }
.sk-bars small { display: flex; justify-content: center; white-space: nowrap; font-size: 11px; color: var(--fg-3); padding-top: 3px; }
.sk-bars small:not(.sk-k5) { color: transparent; }
.sk-bars span:first-child small { justify-content: flex-start; }
.sk-bars span:last-child small { justify-content: flex-end; }
@media (max-width: 479px) { .sk-bars { gap: 2px; } .sk-bars small { font-size: 10px; } }
.sk-legend { margin-top: 8px; display: flex; flex-wrap: wrap; gap: 4px 18px; font-size: 12px; color: var(--fg-2); }

.sk-first { margin-top: 20px; padding: 16px 22px 18px; background: var(--bg-2); border-radius: 10px; }
.sk-first .sk-lb { font-size: 13px; font-weight: 700; color: var(--accent); }
.sk-first ol { margin: 6px 0 0; padding-left: 1.4em; display: grid; gap: 2px; }
.sk-first li { font-size: 15.5px; line-height: 1.75; }
.sk-first li::marker { color: var(--accent); font-family: var(--num); font-weight: 700; }

/* 参考書の節 */
.sk-rs { margin-top: 30px; }
.sk-rs h2 { margin: 0 0 10px; font-size: 19px; line-height: 1.5; color: var(--accent); }
.sk-rs p { margin-top: 8px; }
.sk-rs ul.sk-li { margin: 6px 0 0; padding-left: 1.1em; }
.sk-rs ul.sk-li li + li { margin-top: 2px; }
.sk-tbl { overflow-x: auto; }
.sk table { border-collapse: collapse; width: 100%; font-size: 14px; line-height: 1.6; }
.sk th, .sk td { border: 0; border-bottom: 1px solid var(--line); padding: 9px 12px; text-align: left; vertical-align: top; }
.sk thead th { font-size: 12px; font-weight: 500; color: var(--fg-2); border-bottom-color: var(--line-2); }
.sk tbody th { font-weight: 700; white-space: nowrap; }
.sk-c3 th:first-child { width: 22%; }

.sk-flow { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; }
.sk-flow li { min-width: 0; padding: 10px 12px; border: 1px solid var(--line-2); border-radius: 8px; line-height: 1.5; }
.sk-flow b { display: block; font-size: 14px; color: var(--accent); }
.sk-flow span { display: block; font-size: 13px; color: var(--fg-2); }
@media (max-width: 600px) {
  .sk-flow { grid-template-columns: minmax(0, 1fr); gap: 6px; }
  .sk-flow li { padding: 8px 12px; }
  .sk-flow b { display: inline; margin-right: 8px; } .sk-flow span { display: inline; }
}
.sk-note { margin-top: 12px; padding: 10px 16px; border-left: 3px solid var(--accent); background: var(--bg-2); font-size: 14px; }
.sk-note .sk-lb { font-weight: 700; font-size: 13px; color: var(--accent); }

/* 問題：段階（基礎・標準を埋めたら応用） */
.sk-drill { margin-top: 40px; }
.sk-lvbar { display: flex; align-items: center; gap: 12px; border-bottom: 1px solid var(--line-2); }
.sk-lvs { display: flex; gap: 28px; }
.sk-lvb { font: inherit; display: inline-flex; align-items: baseline; gap: 8px; padding: 10px 2px; margin-bottom: -1px; border: 0; border-bottom: 2.5px solid transparent; background: none; color: var(--fg-2); cursor: pointer; }
.sk-lvb b { font-size: 15px; font-weight: 500; line-height: 1.4; display: inline-flex; align-items: center; gap: 5px; }
.sk-lvb small { font-size: 12px; color: var(--fg-3); }
.sk-lvb:hover { color: var(--accent); }
.sk-lvb[aria-selected="true"] { border-bottom-color: var(--accent); color: var(--accent); }
.sk-lvb[aria-selected="true"] b { font-weight: 700; }
.sk-lk { display: inline-flex; } .sk-lk svg { width: 11px; height: 13px; }
.sk-lvst { margin-left: auto; font-size: 13px; color: var(--fg-2); white-space: nowrap; }
.sk-lvst b { font: 700 15px/1 var(--num); color: var(--fg); }
@media (max-width: 479px) { .sk-lvs { gap: 20px; } .sk-lvb small { display: none; } }
.sk-drill[data-lv="b"] [data-lvl="a"], .sk-drill[data-lv="a"] [data-lvl="b"] { display: none; }
.sk-lock { margin-top: 14px; padding: 16px 18px; background: var(--bg-2); border-radius: 10px; font-size: 14px; color: var(--fg-2); }
.sk-lock b { font: 700 15px/1 var(--num); color: var(--fg); }
.sk-lock .sk-back { margin-left: 10px; font-size: 13px; }
.sk-qa { margin-top: 18px; }
.sk-qh { margin: 0 0 4px; font-size: 17px; line-height: 1.5; color: var(--fg); display: flex; align-items: center; flex-wrap: wrap; gap: 6px 10px; }
/* 見出しの右：習得数と最終演習日 */
.sk-stat { margin-left: auto; display: flex; flex-wrap: wrap; justify-content: flex-end; align-items: baseline; gap: 0 12px; font-size: 12.5px; font-weight: 500; color: var(--fg-2); }
.sk-stat b { font: 700 16px/1 var(--num); color: var(--accent); margin-right: 1px; }
.sk-stat .sk-d { color: var(--fg-3); }
.sk-tools { display: flex; justify-content: flex-end; gap: 6px; margin: 0 0 4px; }
.sk-tg { font: inherit; font-size: 13px; line-height: 1.4; padding: 4px 12px; border: 1px solid var(--line-2); border-radius: 999px; background: var(--bg); color: var(--accent); cursor: pointer; white-space: nowrap; }
.sk-tg:hover { border-color: var(--accent); }
.sk-tg[aria-pressed="true"] { background: var(--bg-3); border-color: var(--accent); font-weight: 700; }

/* 一問一答：左に番号と習得の□、右に「答えを見る」。答えは問いの下に赤で */
ol.sk-qs { list-style: none; margin: 0; padding: 0; }
.sk-q { display: grid; grid-template-columns: 44px minmax(0, 1fr) 120px; gap: 0 12px; align-items: start; padding: 14px 0; border-bottom: 1px solid var(--line); scroll-margin-top: calc(var(--head-h) + 64px); }
.sk-q .sk-no { grid-column: 1; grid-row: 1 / span 4; display: grid; justify-items: center; gap: 4px; }
.sk-q .sk-no b { font: 700 12.5px/1.7 var(--num); color: var(--accent); }
.sk-ck { width: 18px; height: 18px; box-sizing: border-box; border: 1.5px solid var(--fg-3); border-radius: 3px; background: var(--bg); padding: 0; cursor: pointer; display: grid; place-items: center; }
.sk-ck[aria-pressed="true"], .sk-ck.sk-on { background: var(--accent); border-color: var(--accent); }
.sk-ck[aria-pressed="true"]::after, .sk-ck.sk-on::after { content: ""; width: 5px; height: 9px; border: solid #fff; border-width: 0 2px 2px 0; transform: translateY(-1px) rotate(45deg); }
.sk-ck.sk-ng { border-color: var(--red); background: var(--red-soft); color: var(--red); font: 700 12px/1 var(--sans); }
.sk-ck.sk-ng::after { content: "×"; }
.sk-q .sk-qq { grid-column: 2; grid-row: 1; font-weight: 500; font-size: 15.5px; line-height: 1.75; }
.sk-cnt { white-space: nowrap; }
.sk-st { font-size: 12px; letter-spacing: 0; color: var(--gold); margin-left: 6px; white-space: nowrap; }
.sk-st i { font-style: normal; color: #d6dcda; }
.sk-hs { display: inline-flex; align-items: center; height: 20px; padding: 0 8px; margin-left: 6px; vertical-align: 2px; border: 1px solid var(--line-2); border-radius: 999px; font-size: 11px; font-weight: 500; line-height: 1; color: var(--fg-2); white-space: nowrap; }
.sk-q .sk-an { display: contents; }
.sk-see { grid-column: 3; grid-row: 1; width: 100%; height: 36px; padding: 0 12px; border: 1px solid var(--accent); border-radius: 8px; background: var(--bg); color: var(--accent); font: 700 13px/1 var(--sans); letter-spacing: .04em; cursor: pointer; white-space: nowrap; }
.sk-see:hover { background: var(--bg-3); }
.sk-q .sk-at { grid-column: 2; grid-row: 2; margin-top: 6px; color: var(--red); font-weight: 700; font-size: 16px; line-height: 1.6; cursor: pointer; }
.sk-q:not(.sk-open) .sk-at, .sk-q.sk-open .sk-see { display: none; }
.sk-kh { display: none; }
/* 答えを見たあと：PC は右に「Enter 習得済みにして次へ」（js/sankousho/drill.js） */
@media (hover: hover) and (pointer: fine) {
  .sk-q.sk-cur.sk-open:not(.sk-done) .sk-kh { grid-column: 3; grid-row: 1; display: flex; flex-wrap: wrap; align-items: center; gap: 4px 6px; padding-top: 6px; font-size: 11px; line-height: 1.5; color: var(--fg-3); }
  .sk-kh kbd { padding: 1px 5px; border: 1px solid var(--line-2); border-bottom-width: 2px; border-radius: 4px; font: 500 10px/1.4 var(--sans); color: var(--fg-2); }
}
.sk-q .sk-ex { grid-column: 2; grid-row: 3; margin-top: 2px; font-size: 14px; line-height: 1.7; color: var(--fg-2); }
.sk-q .sk-meta { grid-column: 2; grid-row: 4; margin-top: 6px; display: flex; flex-wrap: wrap; gap: 2px 10px; align-items: baseline; font-size: 12px; }
.sk-ids a { font-family: var(--num); font-size: 12px; color: var(--fg-2); text-decoration: none; border-bottom: 1px dotted var(--line-2); margin-right: 8px; white-space: nowrap; }
.sk-ids a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.sk-ids .sk-nol { font-family: var(--num); font-size: 12px; color: var(--fg-3); margin-right: 8px; white-space: nowrap; }
.sk-back { font: inherit; font-size: 12px; color: var(--accent); background: none; border: 0; padding: 0; cursor: pointer; white-space: nowrap; }
.sk-q:not(.sk-open) .sk-ex { display: none; }
.sk-only .sk-q.sk-done { display: none; }

/* 選択肢の○× */
.sk-oxs { margin-top: 30px; }
ol.sk-ox { list-style: none; margin: 0; padding: 0; }
.sk-oxg { margin: 14px 0 0; font-size: 12px; font-weight: 700; color: var(--fg-2); }
.sk-o { display: grid; grid-template-columns: 44px minmax(0, 1fr) auto; gap: 0 12px; align-items: start; padding: 12px 0; border-bottom: 1px solid var(--line); }
.sk-o .sk-n { grid-column: 1; grid-row: 1; font: 700 13px/1.75 var(--num); color: var(--accent); text-align: center; }
.sk-o .sk-ck { grid-column: 1; grid-row: 2; justify-self: center; margin-top: 4px; cursor: default; }
.sk-o .sk-s { grid-column: 2; grid-row: 1 / span 2; font-size: 15px; line-height: 1.75; }
.sk-o .sk-ids { margin-left: 8px; }
.sk-kk { display: inline-flex; align-items: center; height: 20px; padding: 0 8px; margin-left: 6px; vertical-align: 2px; border: 1px solid var(--red); border-radius: 999px; font-size: 11px; font-weight: 500; line-height: 1; color: var(--red); white-space: nowrap; }
.sk-o .sk-pick { grid-column: 3; grid-row: 1 / span 2; align-self: center; display: flex; gap: 8px; }
.sk-o .sk-pick button { width: 44px; height: 36px; padding: 0; border: 1px solid var(--line-2); border-radius: 8px; background: var(--bg); color: var(--fg-2); font: 400 18px/1 var(--sans); cursor: pointer; }
.sk-o .sk-pick button:hover { border-color: var(--accent); color: var(--accent); }
.sk-o .sk-r { grid-column: 2 / 4; grid-row: 3; margin-top: 4px; font-size: 14px; line-height: 1.7; color: var(--fg-2); display: none; }
.sk-o .sk-r b { margin-right: 8px; } .sk-o .sk-r .sk-ok { color: var(--accent); } .sk-o .sk-r .sk-ng { color: var(--red); }
.sk-o.sk-done .sk-r { display: block; }
.sk-o.sk-done .sk-pick button { cursor: default; color: var(--line-2); border-color: var(--line); }
.sk-o.sk-done .sk-pick button.sk-right { border: 1.5px solid var(--red); color: var(--red); }
.sk-o.sk-done .sk-pick button.sk-wrong { background: var(--bg-2); border-color: var(--line-2); color: var(--fg-2); }
.sk-o .sk-again { font: inherit; font-size: 12px; color: var(--accent); background: none; border: 0; padding: 0; margin-left: 8px; cursor: pointer; }
.sk-oxl.sk-only .sk-o.sk-skip, .sk-oxl.sk-only .sk-g:not(:has(.sk-o:not(.sk-skip))) { display: none; }

.sk-flash { animation: sk-fl 1.4s ease-out; }
@keyframes sk-fl { 0% { background: color-mix(in srgb, var(--marker) 55%, transparent); } 100% { background: transparent; } }
@media (max-width: 479px) { .sk-hd { gap: 12px; } .sk-hd h1 { font-size: 23px; } .sk-hd .sk-sub { font-size: 13px; } .sk-rank { width: 50px; height: 50px; } .sk-rank small { font-size: 10px; } .sk-rank b { font-size: 22px; } .sk table { font-size: 13.5px; } .sk th, .sk td { padding: 8px; } }

/* 2段（PC で選んだとき、広い画面だけ）：左に目次（読んだ節は●）と問題の進み具合、次のテーマ */
.sk-side { display: none; }
@media (min-width: 1080px) {
  .sk.sk-2col { max-width: 1056px; display: grid; grid-template-columns: 250px minmax(0, 760px); column-gap: 46px; align-items: start; }
  .sk.sk-2col > .sk-side { display: block; position: sticky; top: calc(var(--head-h) + 20px); max-height: calc(100vh - var(--head-h) - 40px); overflow-y: auto; overscroll-behavior: contain; padding: 4px 2px 8px 0; }
  .sk.sk-2col .sk-rank { display: none; }
  .sk-nav.sk-2col { display: none; }
  .sk.sk-2col ~ .rt-act, .sk.sk-2col ~ .rt-pn, .sk.sk-2col ~ .sk-more { margin-left: 296px; max-width: 760px; }
}
.sk-side { font-size: 14px; line-height: 1.6; }
.sk-side .sk-side-back { font-size: 13px; color: var(--fg-2); text-decoration: none; }
.sk-side .sk-side-back:hover { color: var(--accent); }
.sk-side .sk-side-rk { margin-top: 14px; font-size: 12px; color: var(--fg-3); }
.sk-side .sk-side-rk b { font-family: var(--num); font-weight: 700; }
.sk-side .sk-side-t { margin-bottom: 14px; font-size: 17px; font-weight: 700; line-height: 1.45; }
.sk-side .sk-side-h { margin-bottom: 4px; font-size: 12px; font-weight: 700; color: var(--fg-3); }
.sk-side .sk-toc + .sk-side-h { margin-top: 22px; margin-bottom: 8px; }
.sk-toc { list-style: none; margin: 0; padding: 0; }
.sk-toc a { display: flex; align-items: center; gap: 10px; padding: 7px 12px; border-radius: 6px; font-size: 14px; line-height: 1.5; color: var(--fg-2); text-decoration: none; }
.sk-toc a:hover { color: var(--accent); }
.sk-toc a.sk-now { background: var(--bg-3); color: var(--accent); font-weight: 700; }
.sk-dot { flex: none; width: 8px; height: 8px; box-sizing: border-box; border: 1.5px solid var(--bar); border-radius: 50%; }
.sk-toc a.sk-read .sk-dot { background: var(--accent); border-color: var(--accent); }
.sk-card { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 6px 8px; align-items: center; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px; color: var(--fg); text-decoration: none; }
.sk-card + .sk-card { margin-top: 8px; }
.sk-card:hover { border-color: var(--accent); color: var(--fg); }
.sk-cn { font: 500 13px/1 var(--num); color: var(--fg-2); }
.sk-cn b { color: var(--fg); }
.sk-pb { grid-column: 1 / -1; display: block; height: 6px; border-radius: 3px; background: var(--bg-3); overflow: hidden; }
.sk-pb i { display: block; width: 0; height: 100%; background: var(--accent); }
.sk-side .sk-side-note { margin: 10px 2px 0; font-size: 12px; color: var(--fg-3); }
.sk-side .sk-side-next { margin-top: 24px; padding-top: 14px; border-top: 1px solid var(--line); font-size: 13px; }
.sk-side-next span { display: block; color: var(--fg-3); }
.sk-side-next a { font-weight: 700; color: var(--accent); text-decoration: none; }

/* 折り返し：文の切れ目（かなのあと・句読点のあと・かっこの前）でだけ折り返す。印（wbr）は読み込み時に入れる */
.sk { word-break: keep-all; overflow-wrap: anywhere; line-break: strict; }
.sk th { overflow-wrap: normal; }
/* 表示の設定 */
.sk-lvnote { margin-top: 10px; font-size: 13.5px; line-height: 1.65; color: var(--fg-2); }
.sk-prefs { margin-top: 2px; font-size: 13px; color: var(--fg-2); }
.sk-prefs summary { width: max-content; margin-left: auto; padding: 4px 0; list-style: none; color: var(--accent); cursor: pointer; }
.sk-prefs summary::-webkit-details-marker { display: none; }
.sk-prefs summary::after { content: ""; display: inline-block; width: 6px; height: 6px; margin: 0 2px 2px 7px; border: solid currentColor; border-width: 0 1.5px 1.5px 0; transform: rotate(45deg); }
.sk-prefs[open] summary::after { transform: translateY(3px) rotate(-135deg); }
.sk-prefs label { display: flex; gap: 10px; align-items: flex-start; margin-top: 6px; padding: 10px 14px; background: var(--bg-2); border-radius: 4px; line-height: 1.6; cursor: pointer; }
.sk-prefs input { flex: none; width: 17px; height: 17px; margin: 2px 0 0; accent-color: var(--accent); }
/* スマホ：表は画面の幅いっぱいに。一問一答は「答えを見る」を番号の横に、○×のボタンは文の下に大きく */
@media (max-width: 600px) {
  .sk { padding-top: 18px; }
  .sk-first { padding: 14px 16px; }
  .sk-first li { font-size: 15px; }
  .sk-rs { margin-top: 24px; }
  .sk-rs h2 { font-size: 17px; }
  .sk-tbl { margin-inline: -16px; }
  .sk-tbl th:first-child, .sk-tbl td:first-child { padding-left: 16px; }
  .sk-tbl th:last-child, .sk-tbl td:last-child { padding-right: 16px; }
  .sk-tbl tr > :only-child { padding-inline: 16px; }
  .sk table.sk-kv, .sk-kv tbody, .sk-kv tr, .sk-kv th, .sk-kv td { display: block; }
  .sk-kv tr { border-top: 1px solid var(--line); }
  .sk-kv tr:last-child { border-bottom: 1px solid var(--line); }
  .sk-kv th, .sk-kv td, .sk-tbl .sk-kv th:first-child, .sk-tbl .sk-kv td:last-child { border: 0; padding-inline: 16px; }
  .sk-kv th { padding-block: 9px 0; white-space: normal; color: var(--accent); }
  .sk-tbl .sk-kv th:first-child { width: auto; } /* 見出しを上に積むので、横並びのときの幅（22%）を外す */
  .sk-kv td { padding-block: 2px 10px; }
  .sk-drill { margin-top: 32px; }
  .sk-q { grid-template-columns: 30px minmax(0, 1fr) auto; column-gap: 10px; padding: 12px 0; }
  .sk-q .sk-qq { grid-column: 2 / 4; font-size: 15px; }
  .sk-q .sk-meta { grid-column: 2; grid-row: 2; align-self: center; margin-top: 8px; }
  .sk-see { grid-column: 3; grid-row: 2; width: auto; height: 38px; margin-top: 8px; padding: 0 16px; }
  .sk-q .sk-at { grid-column: 2 / 4; }
  .sk-q .sk-ex { grid-column: 2 / 4; font-size: 13.5px; }
  .sk-q.sk-open .sk-meta { grid-column: 2 / 4; grid-row: 4; }
  .sk-o { grid-template-columns: 24px minmax(0, 1fr); column-gap: 8px; }
  .sk-o .sk-n { text-align: left; }
  .sk-o .sk-ck { justify-self: start; margin-top: 2px; }
  .sk-o .sk-s { font-size: 14.5px; }
  .sk-o .sk-pick { grid-column: 2; grid-row: 3; justify-self: end; margin-top: 8px; }
  .sk-o .sk-pick button { width: 64px; height: 40px; }
  .sk-o .sk-r { grid-column: 2; grid-row: 4; }
  .sk-tg { padding: 6px 12px; }
  .sk-q.sk-cur.sk-open:not(.sk-done) .sk-kh { display: none; }
}

/* 無料ページ（/sankousho/…）：ほかのテーマ・一覧 */
.sk-more { max-width: 860px; margin: 8px auto 56px; padding: 16px 18px; background: var(--bg-2); font-size: 14px; }
.sk-more-h { font-weight: 700; color: var(--accent); margin: 0 0 6px; }
.sk-more ul { margin: 0; padding-left: 1.2em; display: grid; gap: 2px; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
.sk-more a { color: var(--accent); }
.sk-more-cta { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 18px; margin: 14px 0 0; }
.sk-more-cta .btn { color: var(--on-accent); }
.sk-idx h1 { font-size: 28px; margin: 0; }
.sk-idx > .sk-sub { margin-top: 4px; font-size: 14px; color: var(--fg-2); }
.sk-idx-f { margin-top: 22px; }
.sk-idx-f h2 { font-size: 17px; color: var(--accent); padding-bottom: 4px; border-bottom: 1px solid var(--line-2); margin: 0 0 6px; }
.sk-idx-f ol { list-style: none; margin: 0; padding: 0; display: grid; gap: 0 18px; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.sk-idx-f a { display: grid; padding: 8px 0; border-bottom: 1px solid var(--line); color: var(--fg); text-decoration: none; }
.sk-idx-f a b { font-size: 15.5px; color: var(--accent); }
.sk-idx-f a span { font-size: 12.5px; color: var(--fg-2); }

/* 無料ページ（/sankousho/…）のヘッダーはアプリと同じ（js/header.js・app.css の .hd-cta） */