/* 2026-09-28: CTA原文・開閉構造を保持。背景は勉強方法CTAと同じ #355951 に全体で統一。 */
body.grade3-reading main > section#textbook-guide[data-cta-design="study"] { padding: 0; background: #355951; border: 0; }
#textbook-guide[data-cta-design="study"] > .public-container.article-shell { width: 100%; max-width: none; }
.grade3-reading #textbook-guide[data-cta-design="study"] :is(.grade3-offer, .grade3-offer-product) { padding: 0; border: 0; border-radius: 0; background: transparent; color: #dce9e0; }
#textbook-guide[data-cta-design="study"] .grade3-compact-head { padding: 40px 0; background: #355951; }
#textbook-guide[data-cta-design="study"] :is(.grade3-compact-width, .grade3-compact-body) { width: min(800px, calc(100% - 44px)); margin-inline: auto; }
#textbook-guide[data-cta-design="study"] .grade3-compact-body { padding: 32px 0 48px; }
#textbook-guide[data-cta-design="study"] .grade3-cta-brand { margin: 0 0 18px; color: #fff; font-family: Georgia, serif; font-size: 32px; font-weight: 400; line-height: 1.2; letter-spacing: -.03em; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-product h2 { margin: 0; color: #fff; font-size: clamp(24px, 2.35vw, 32px); line-height: 1.65; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-product p { margin: 0 0 16px; color: #dce9e0; font-size: 15px; line-height: 2; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-product strong { color: #fff; }
#textbook-guide[data-cta-design="study"] .grade3-compact-intro { margin: 0 0 32px; border: 0; background: transparent; }
#textbook-guide[data-cta-design="study"] .grade3-compact-intro > summary { display: inline-flex; gap: 20px; align-items: center; padding: 8px 0; color: #f1e4b7; font-size: 14px; font-weight: 700; list-style: none; cursor: pointer; }
#textbook-guide[data-cta-design="study"] .grade3-compact-intro-copy { padding-top: 16px; }
#textbook-guide[data-cta-design="study"] summary::-webkit-details-marker { display: none; }
#textbook-guide[data-cta-design="study"] :is(.grade3-compact-intro, .grade3-compact-feature) > summary::after { content: '+'; flex: 0 0 24px; text-align: center; color: #c3d9cc; font-size: 23px; font-weight: 400; }
#textbook-guide[data-cta-design="study"] :is(.grade3-compact-intro, .grade3-compact-feature)[open] > summary::after { content: '−'; }
#textbook-guide[data-cta-design="study"] .grade3-offer-comparison { width: 100%; margin: 0; background: transparent; color: #dce9e0; font-size: 14px; }
#textbook-guide[data-cta-design="study"] .grade3-offer-comparison caption { color: #fff; font-size: 16px; padding-bottom: 14px; }
#textbook-guide[data-cta-design="study"] .grade3-offer-comparison :is(th, td) { padding: 15px 18px; border: 0; border-bottom: 1px solid #ffffff35; background: transparent; color: #dce9e0; }
#textbook-guide[data-cta-design="study"] .grade3-offer-comparison thead th { background: #ffffff08; color: #fff; font-size: 12px; }
#textbook-guide[data-cta-design="study"] .grade3-offer-comparison tbody th { color: #fff; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plans { display: block; padding: 0; margin: 40px 0 0; border: 0; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan { display: flex; flex-direction: column; min-width: 0; padding: 32px 0; border: 0; border-top: 1px solid #ffffff35; border-radius: 0; background: transparent; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan:last-child { padding-bottom: 0; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan h3 { margin: 0 0 16px; color: #fff; font-size: 23px; line-height: 1.7; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-button { align-self: flex-start; width: auto; max-width: 100%; min-height: 44px; margin: 0 0 24px; padding: 12px 18px; border-radius: 6px; background: #f1e4b7; color: #213e34; font-size: 14px; line-height: 1.8; text-decoration: none; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-button:hover { background: #fff0c3; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-feature { margin: 0; padding: 0; border: 0; border-bottom: 1px solid #ffffff35; border-radius: 0; background: transparent; }
#textbook-guide[data-cta-design="study"] .grade3-compact-feature > summary { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 18px 0; list-style: none; cursor: pointer; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-feature h4 { margin: 0; padding: 0; border: 0; color: #fff; font-size: 16px; line-height: 1.8; }
#textbook-guide[data-cta-design="study"] .grade3-compact-feature h4 span { white-space: normal; }
#textbook-guide[data-cta-design="study"] .grade3-compact-answer { max-width: 720px; padding: 0 28px 8px 0; }
#textbook-guide[data-cta-design="study"] summary:hover { color: #fff; background: #ffffff08; }
#textbook-guide[data-cta-design="study"] :is(a, summary):focus-visible { outline: 3px solid #f1e4b7; outline-offset: 4px; }
@media (max-width: 600px) {
  #textbook-guide[data-cta-design="study"] .grade3-compact-head { padding: 30px 0; }
  #textbook-guide[data-cta-design="study"] .grade3-compact-body { padding: 26px 0 32px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-product p { font-size: 14px; }
  #textbook-guide[data-cta-design="study"] .grade3-offer-comparison :is(th, td) { padding: 12px 9px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan h3 { font-size: 21px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-button { font-size: 13px; padding: 12px 14px; gap: 12px; }
  #textbook-guide[data-cta-design="study"] .grade3-compact-answer { padding-right: 0; }
  #textbook-guide[data-cta-design="study"] .grade3-compact-feature > summary { gap: 12px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-feature h4 { font-size: 15px; }
}
@media print {
  #textbook-guide[data-cta-design="study"] details:not([open]) > :not(summary) { display: block !important; }
}

/* 2026-09-28: 勉強方法CTAに合わせ、PCの①②③を横3列、スマホを縦積みにする。原文と開閉は保持。 */
@media (min-width: 801px) {
  #textbook-guide[data-cta-design="study"] .grade3-compact-body { width: min(1060px, calc(100% - 60px)); }
  #textbook-guide[data-cta-design="study"] .grade3-compact-body > :is(p, .grade3-compact-intro, .grade3-offer-comparison) { max-width: 800px; margin-inline: auto; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plans { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; align-items: start; border-top: 1px solid #ffffff35; padding-top: 30px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan { padding: 0 26px; border-top: 0; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan + .grade3-offer-plan { border-left: 1px solid #ffffff35; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan h3 { font-size: 21px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-button { padding: 12px; font-size: 13px; }
}

/* 冒頭は常時表示、プラン説明は開閉式のCTA: 大見出しと段落ごとの小見出しを区別し、原文を読み進めやすくする。 */
#textbook-guide[data-cta-design="study"] .grade3-compact-intro-copy { padding-top: 8px; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-intro-subtitle { margin: 26px 0 10px; color: #fff; font-size: 19px; line-height: 1.7; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-feature { padding: 0; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-feature h4 { margin: 0; padding: 0; border: 0; font-size: 16px; }
#textbook-guide[data-cta-design="study"] .grade3-compact-answer { max-width: none; padding: 8px 0 24px; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-answer h5 { margin: 24px 0 10px; color: #f1e4b7; font-size: 16px; font-weight: 700; line-height: 1.8; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-answer h5:first-child { margin-top: 0; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-answer p { font-size: 14px; line-height: 1.95; margin-bottom: 0; }
@media (max-width: 800px) {
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-feature h4 { font-size: 16px; }
}

/* CTA導入の左端をタイトル・本文と揃え、タイトル直下の文章としてつなげる。 */
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-body > p.grade3-offer-article-intro { max-width: 800px; margin: 0 auto 16px; }
#textbook-guide[data-cta-design="study"] .grade3-compact-head { padding-bottom: 16px; }
#textbook-guide[data-cta-design="study"] .grade3-compact-body { padding-top: 8px; }

/* 2026-09-28: 原文を保持し、ブランド横のタイトルと金色の中見出しで導入の階層を明確にする。 */
#textbook-guide[data-cta-design="study"] .grade3-compact-head .grade3-compact-width { display: flex; align-items: center; gap: 28px; padding-bottom: 24px; border-bottom: 1px solid #e7cf914d; }
#textbook-guide[data-cta-design="study"] .grade3-cta-brand { flex: 0 0 auto; margin: 0; color: #f1e4b7; font-size: 38px; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-product h2 { padding-left: 28px; border-left: 1px solid #e7cf9170; font-size: clamp(22px, 2.1vw, 28px); line-height: 1.65; }
#textbook-guide[data-cta-design="study"] .grade3-compact-head { padding-bottom: 20px; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-intro-subtitle { display: flex; align-items: center; gap: 14px; margin: 32px 0 14px; color: #f1e4b7; font-size: 21px; letter-spacing: .02em; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-intro-subtitle::before { content: ''; flex: 0 0 22px; height: 2px; background: #e7cf91; }
.grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-intro-copy > p { padding-left: 36px; }
@media (max-width: 600px) {
  #textbook-guide[data-cta-design="study"] .grade3-compact-head .grade3-compact-width { gap: 14px; padding-bottom: 20px; }
  #textbook-guide[data-cta-design="study"] .grade3-cta-brand { font-size: 27px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-product h2 { padding-left: 14px; font-size: 19px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-intro-subtitle { gap: 10px; font-size: 18px; align-items: baseline; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-intro-subtitle::before { flex-basis: 14px; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-compact-intro-copy > p { padding-left: 24px; }
}

/* スマホでは最初のプラン前の線を省き、プラン間のみ画面幅の太い線で区切る。 */
@media (max-width: 800px) {
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan { border-top: 0; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan + .grade3-offer-plan { position: relative; }
  .grade3-reading #textbook-guide[data-cta-design="study"] .grade3-offer-plan + .grade3-offer-plan::before { content: ''; position: absolute; top: 0; left: -22px; right: -22px; height: 2px; background: #b6d0c280; }
}