:root {
  color-scheme: dark;
  --rkb-night: #07101d;
  --rkb-night-soft: #0b1930;
  --rkb-panel: #112543;
  --rkb-orange: #ff6a2a;
  --rkb-gold: #ffb262;
  --rkb-cream: #fff8ed;
  --rkb-mist: #bdc9dc;
  --rkb-line: rgba(255, 255, 255, 0.14);
  --rkb-wrap: min(1120px, calc(100% - 40px));
  --rkb-reading: 720px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--rkb-night); }
body {
  margin: 0;
  overflow-x: hidden;
  background: var(--rkb-night);
  color: var(--rkb-cream);
  font: 400 17px/1.76 Inter, "Noto Sans", "Noto Sans JP", "Noto Sans KR", "Noto Sans SC", "Hiragino Sans", "Yu Gothic", Meiryo, "Apple SD Gothic Neo", "Malgun Gothic", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-wrap: anywhere;
}

body::selection { background: var(--rkb-orange); color: #fff; }
a { color: inherit; text-underline-offset: 0.2em; }
a:focus-visible { outline: 3px solid var(--rkb-gold); outline-offset: 4px; border-radius: 5px; }
.rkb-wrap { width: var(--rkb-wrap); margin-inline: auto; }
.rkb-skip {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 16px;
  padding: 10px 14px;
  border-radius: 10px;
  background: #fff;
  color: var(--rkb-night);
  transform: translateY(-170%);
}
.rkb-skip:focus { transform: none; }

.rkb-header {
  position: relative;
  z-index: 40;
  border-bottom: 1px solid var(--rkb-line);
  background: rgba(7, 16, 29, 0.92);
  backdrop-filter: blur(12px);
}
.rkb-nav { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.rkb-brand { display: inline-flex; align-items: center; gap: 11px; text-decoration: none; font: 700 22px/1 Fredoka, Inter, sans-serif; }
.rkb-brand img { border-radius: 11px; box-shadow: 0 8px 22px rgba(0, 0, 0, 0.35); }
.rkb-nav-actions { display: flex; align-items: center; justify-content: flex-end; gap: 16px; min-width: 0; }
.rkb-back { color: #dce5f2; font-size: 14px; font-weight: 700; text-decoration: none; }
.rkb-back::before { content: "←"; margin-right: 8px; color: var(--rkb-gold); }
.rkb-sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.rkb-language { position: relative; flex: 0 0 auto; }
.rkb-language summary { display: flex; align-items: center; gap: 8px; min-height: 42px; padding: 9px 12px; border: 1px solid rgba(255, 178, 98, 0.32); border-radius: 13px; background: rgba(255, 255, 255, 0.05); color: #fff; font-size: 13px; font-weight: 700; cursor: pointer; list-style: none; }
.rkb-language summary::-webkit-details-marker { display: none; }
.rkb-language summary:focus-visible, .rkb-language a:focus-visible { outline: 3px solid var(--rkb-gold); outline-offset: 3px; }
.rkb-language[open] summary { border-color: var(--rkb-gold); background: rgba(255, 178, 98, 0.1); }
.rkb-language nav { position: absolute; z-index: 30; top: calc(100% + 8px); right: 0; width: 220px; padding: 6px; border: 1px solid var(--rkb-line); border-radius: 16px; background: #101c30; box-shadow: 0 22px 55px rgba(0, 0, 0, 0.46); }
.rkb-language ul { display: grid; gap: 2px; margin: 0; padding: 0; list-style: none; }
.rkb-language a { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 42px; padding: 9px 10px; border-radius: 10px; color: #dce5f2; font-size: 13px; font-weight: 600; text-decoration: none; }
.rkb-language a:hover, .rkb-language a[aria-current="page"] { background: rgba(255, 178, 98, 0.11); color: #fff; }

.rkb-hero {
  position: relative;
  overflow: hidden;
  padding: 88px 0 0;
  background: radial-gradient(circle at 76% 18%, rgba(255, 106, 42, 0.24), transparent 28%), radial-gradient(circle at 10% 28%, rgba(45, 102, 178, 0.2), transparent 31%), linear-gradient(150deg, #050a13 4%, #0a1528 58%, #24130f 100%);
}
.rkb-stars {
  position: absolute;
  inset: 0;
  opacity: 0.38;
  pointer-events: none;
  background-image: radial-gradient(circle, rgba(255, 255, 255, 0.82) 0 1px, transparent 1.3px), radial-gradient(circle, rgba(255, 178, 98, 0.74) 0 1px, transparent 1.4px);
  background-position: 14px 28px, 70px 76px;
  background-size: 136px 136px, 211px 211px;
}
.rkb-hero-inner { position: relative; }
.rkb-kicker { margin: 0 0 12px; color: var(--rkb-gold); font-size: 12px; font-weight: 800; letter-spacing: 0.15em; text-transform: uppercase; }
.rkb-hero h1 {
  max-width: 960px;
  margin: 0;
  font: 700 clamp(44px, 6.2vw, 80px)/0.98 Fredoka, Inter, sans-serif;
  letter-spacing: -0.04em;
  text-wrap: balance;
}
.rkb-deck { max-width: 760px; margin: 26px 0 0; color: #d4deeb; font-size: clamp(18px, 2vw, 21px); line-height: 1.62; }
.rkb-store-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 16px; margin: 28px 0 38px; }
.rkb-app-store { display: inline-flex; flex: 0 0 auto; border-radius: 9px; }
.rkb-app-store img { display: block; width: 180px; height: 60px; }
.rkb-app-store:hover { transform: translateY(-2px); }
.rkb-google-play { display: inline-flex; flex: 0 0 auto; align-items: center; border-radius: 9px; }
.rkb-google-play img { display: block; width: 180px; height: auto; }
.rkb-google-play:hover { transform: translateY(-2px); }
.rkb-primary-action { display: inline-flex; align-items: center; min-height: 54px; padding: 13px 20px; border-radius: 12px; background: var(--rkb-orange); color: var(--rkb-night); font-weight: 800; text-decoration: none; }
.rkb-primary-action:hover { background: #ff7d45; }
.rkb-meta { display: inline-flex; flex-wrap: wrap; gap: 3px 7px; }
.rkb-cover { position: relative; margin: 0; aspect-ratio: 1200 / 630; overflow: hidden; border: 1px solid rgba(255, 255, 255, 0.17); border-radius: 30px 30px 0 0; background: var(--rkb-panel); box-shadow: 0 28px 70px rgba(0, 0, 0, 0.42); }
.rkb-cover img { display: block; width: 100%; height: 100%; object-fit: cover; object-position: center; }

.rkb-article-layout { display: grid; grid-template-columns: minmax(170px, 230px) minmax(0, var(--rkb-reading)); justify-content: center; gap: 70px; padding-block: 74px 110px; }
.rkb-reading-column { min-width: 0; }
.rkb-toc { position: sticky; top: 24px; align-self: start; padding: 20px; border: 1px solid var(--rkb-line); border-radius: 18px; background: rgba(17, 37, 67, 0.62); }
.rkb-toc h2 { margin: 0 0 13px; color: var(--rkb-gold); font-size: 12px; letter-spacing: 0.12em; text-transform: uppercase; }
.rkb-toc ul { display: grid; gap: 9px; margin: 0; padding: 0; list-style: none; color: #c8d3e2; font-size: 13px; line-height: 1.45; }
.rkb-toc a { text-decoration-color: rgba(255, 178, 98, 0.45); }

.rkb-answer { margin-bottom: 44px; padding: 26px 28px; border: 1px solid rgba(255, 178, 98, 0.34); border-radius: 20px; background: linear-gradient(135deg, rgba(255, 106, 42, 0.12), rgba(17, 37, 67, 0.8)); }
.rkb-answer p:last-child { margin: 0; font-size: 19px; line-height: 1.62; }
.rkb-prose { color: #e3e9f2; }
.rkb-prose h2, .rkb-prose h3 { scroll-margin-top: 24px; color: var(--rkb-cream); font-family: Fredoka, Inter, sans-serif; line-height: 1.14; text-wrap: balance; }
.rkb-prose h2 { margin: 64px 0 20px; font-size: clamp(30px, 4vw, 42px); letter-spacing: -0.025em; }
.rkb-prose h3 { margin: 38px 0 14px; font-size: 25px; }
.rkb-prose p, .rkb-prose ul, .rkb-prose ol, .rkb-prose blockquote { margin: 0 0 25px; }
.rkb-prose a { color: #ffc28c; font-weight: 600; }
.rkb-prose blockquote { padding: 18px 22px; border-left: 4px solid var(--rkb-orange); border-radius: 0 14px 14px 0; background: rgba(255, 255, 255, 0.05); color: #d5deeb; }
.rkb-prose table { display: block; width: 100%; max-width: 100%; margin: 30px 0; overflow-x: auto; border-collapse: collapse; white-space: nowrap; scrollbar-color: var(--rkb-orange) var(--rkb-night-soft); }
.rkb-prose th, .rkb-prose td { padding: 12px 15px; border: 1px solid rgba(255, 255, 255, 0.16); text-align: left; }
.rkb-prose th { background: rgba(255, 255, 255, 0.09); color: var(--rkb-cream); }
.rkb-prose code { padding: 0.15em 0.35em; border-radius: 5px; background: rgba(255, 255, 255, 0.09); font-size: 0.9em; }

.rkb-experience { display: grid; grid-template-columns: minmax(0, 1fr) minmax(150px, 220px); align-items: center; gap: 32px; margin: 70px 0 40px; padding: 34px; overflow: hidden; border: 1px solid var(--rkb-line); border-radius: 26px; background: linear-gradient(145deg, #132c50, #291812); }
.rkb-experience h2 { margin: 0 0 15px; font: 600 33px/1.08 Fredoka, Inter, sans-serif; }
.rkb-experience-copy > p:not(.rkb-kicker) { margin: 0; color: #d5dfec; font-size: 15px; }
.rkb-experience-visual { align-self: end; margin: -10px 0 0; }
.rkb-experience-visual img { display: block; width: 100%; height: auto; border: 1px solid rgba(255, 255, 255, 0.16); border-radius: 24px; box-shadow: 0 24px 50px rgba(0, 0, 0, 0.45); }
.rkb-secondary-action { display: inline-flex; margin-top: 22px; color: #fff; font-weight: 800; }
.rkb-related { margin-top: 70px; padding-top: 38px; border-top: 1px solid var(--rkb-line); }
.rkb-related > h2 { margin: 0 0 24px; font: 600 34px/1.1 Fredoka, Inter, sans-serif; }
.rkb-related-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.rkb-related-grid article { padding: 22px; border: 1px solid var(--rkb-line); border-radius: 18px; background: var(--rkb-night-soft); }
.rkb-related-grid h3 { margin: 0; font: 600 20px/1.3 Fredoka, Inter, sans-serif; }
.rkb-related-grid a { color: var(--rkb-cream); text-decoration-color: rgba(255, 178, 98, 0.5); }

.rkb-footer { border-top: 1px solid var(--rkb-line); color: #9baac0; font-size: 13px; }
.rkb-footer .rkb-wrap { display: flex; justify-content: space-between; gap: 24px; padding-block: 28px; }
.rkb-footer-credit { display: inline-flex; flex-wrap: wrap; gap: 3px 7px; }

.rkb-index-hero { position: relative; overflow: hidden; padding: 80px 0 62px; background: radial-gradient(circle at 82% 12%, rgba(255, 106, 42, 0.24), transparent 28%), radial-gradient(circle at 12% 72%, rgba(45, 102, 178, 0.2), transparent 30%), linear-gradient(150deg, #050a13 4%, #0a1528 58%, #24130f 100%); }
.rkb-index-hero-inner { position: relative; }
.rkb-index-hero h1 { max-width: 900px; margin: 0; font: 700 clamp(46px, 6.4vw, 82px)/0.98 Fredoka, Inter, sans-serif; letter-spacing: -0.04em; text-wrap: balance; }
.rkb-index-hero-inner > p:not(.rkb-kicker) { max-width: 750px; margin: 26px 0 0; color: #d4deeb; font-size: clamp(18px, 2vw, 21px); }
.rkb-category-guide { margin-top: 36px; }
.rkb-category-guide h2 { margin: 0 0 14px; color: var(--rkb-gold); font-size: 12px; letter-spacing: 0.13em; text-transform: uppercase; }
.rkb-category-guide ul { display: flex; flex-wrap: wrap; gap: 9px; margin: 0; padding: 0; list-style: none; }
.rkb-category-guide li { padding: 8px 12px; border: 1px solid var(--rkb-line); border-radius: 999px; background: rgba(255, 255, 255, 0.05); color: #dce5f2; font-size: 13px; font-weight: 700; }
.rkb-index-content { padding-block: 72px 96px; }
.rkb-index-listings-label { margin: 0 0 16px; }
.rkb-index-sections { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); grid-auto-rows: auto; align-items: stretch; gap: 24px; }
.rkb-index-sections > section { display: flex; flex-direction: column; min-width: 0; }
.rkb-index-sections > .rkb-index-section-single { align-self: start; }
.rkb-index-section-heading { min-height: 52px; margin-bottom: 18px; }
.rkb-index-section-heading h2, .rkb-index-empty h2 { margin: 0; font: 600 clamp(27px, 2.6vw, 36px)/1.08 Fredoka, Inter, sans-serif; }
.rkb-index-section-heading h2 { min-height: 2.16em; }
.rkb-index-grid { display: grid; flex: 1; grid-template-columns: minmax(0, 1fr); grid-auto-rows: 1fr; gap: 18px; }
.rkb-index-card { display: flex; flex-direction: column; min-width: 0; overflow: hidden; border: 1px solid var(--rkb-line); border-radius: 22px; background: linear-gradient(145deg, rgba(17, 37, 67, 0.96), rgba(9, 24, 43, 0.96)); box-shadow: 0 20px 50px rgba(0, 0, 0, 0.22); }
.rkb-index-card-image { display: block; aspect-ratio: 1200 / 630; overflow: hidden; background: var(--rkb-panel); }
.rkb-index-card-image img { display: block; width: 100%; height: 100%; object-fit: cover; transition: transform 0.25s ease; }
.rkb-index-card:hover .rkb-index-card-image img { transform: scale(1.02); }
.rkb-index-card-body { display: flex; flex: 1; flex-direction: column; min-height: 340px; padding: 22px; }
.rkb-index-card h3 { margin: 0; font: 600 clamp(22px, 2.3vw, 28px)/1.1 Fredoka, Inter, sans-serif; text-wrap: balance; }
.rkb-index-card h3 a { text-decoration: none; }
.rkb-index-card-body > p:not(.rkb-kicker) { margin: 14px 0 20px; color: var(--rkb-mist); font-size: 14px; line-height: 1.6; }
.rkb-index-card-meta { display: flex; flex-wrap: wrap; gap: 8px 16px; margin-top: auto; color: #9fb0c6; font-size: 12px; }
.rkb-index-read { display: inline-flex; align-items: center; gap: 8px; align-self: flex-end; margin: 22px 0 0 auto; color: #ffc28c; font-weight: 800; text-decoration: none; }
.rkb-index-read:hover { color: var(--rkb-cream); }
.rkb-index-empty { max-width: 680px; margin-inline: auto; padding: 54px 32px; border: 1px solid var(--rkb-line); border-radius: 26px; background: rgba(17, 37, 67, 0.62); text-align: center; }
.rkb-index-empty img { border-radius: 17px; box-shadow: 0 14px 35px rgba(0, 0, 0, 0.32); }
.rkb-index-empty h2 { margin-top: 22px; }
.rkb-index-empty p { margin: 16px auto 0; color: var(--rkb-mist); }

@media (max-width: 900px) {
  .rkb-article-layout { grid-template-columns: minmax(0, var(--rkb-reading)); gap: 34px; }
  .rkb-toc { position: static; }
  .rkb-index-sections { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 42px 20px; }
  .rkb-index-section-heading { min-height: 0; }
}

@media (min-width: 681px) and (max-width: 900px) {
  .rkb-index-sections > section:last-child:nth-child(odd) { grid-column: 1 / -1; justify-self: center; width: calc((100% - 20px) / 2); }
}

@media (max-width: 680px) {
  :root { --rkb-wrap: min(100% - 28px, 1120px); }
  body { font-size: 16px; line-height: 1.72; }
  .rkb-nav { min-height: 66px; }
  .rkb-brand { font-size: 20px; }
  .rkb-brand img { width: 38px; height: 38px; }
  .rkb-brand span { display: none; }
  .rkb-nav-actions { gap: 8px; }
  .rkb-back { max-width: 92px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; text-align: right; }
  .rkb-language summary { max-width: 126px; }
  .rkb-language summary > span:nth-child(2) { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .rkb-language nav { position: fixed; top: 72px; right: 14px; left: 14px; width: auto; }
  .rkb-hero { padding-top: 62px; }
  .rkb-hero h1 { font-size: clamp(39px, 11.2vw, 58px); }
  .rkb-cover { margin-inline: -14px; border-radius: 20px 20px 0 0; }
  .rkb-article-layout { padding-block: 48px 76px; }
  .rkb-answer { padding: 22px; }
  .rkb-answer p:last-child { font-size: 17px; }
  .rkb-prose h2 { margin-top: 52px; }
  .rkb-experience { grid-template-columns: 1fr; padding: 25px; }
  .rkb-experience-visual { width: min(72%, 220px); margin: 4px auto 0; }
  .rkb-store-actions { gap: 10px; }
  .rkb-related-grid { grid-template-columns: 1fr; }
  .rkb-index-hero { padding: 70px 0 60px; }
  .rkb-index-page .rkb-back { display: none; }
  .rkb-index-hero h1 { font-size: clamp(40px, 11.5vw, 58px); }
  .rkb-index-content { padding-block: 64px 80px; }
  .rkb-index-sections { grid-template-columns: 1fr; grid-auto-rows: auto; align-items: start; gap: 46px; }
  .rkb-index-section-heading h2 { min-height: 0; }
  .rkb-index-grid { flex: none; grid-auto-rows: auto; }
  .rkb-index-card-body { min-height: 0; padding: 24px; }
  .rkb-index-empty { padding: 40px 22px; }
  .rkb-footer .rkb-wrap { flex-direction: column; gap: 5px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .rkb-app-store:hover { transform: none; }
}