:root {
  --paper: #f2f0e9;
  --surface: #fff;
  --surface-soft: #f8f7f2;
  --ink: #151a18;
  --ink-soft: #66706b;
  --deep: #18382e;
  --accent: #e1c62f;
  --accent-soft: #f6efbd;
  --line: #d8d9d3;
  --line-dark: #aeb3ae;
  --white: #fff;
  --display: "Hiragino Kaku Gothic ProN", "Yu Gothic", "Noto Sans JP", sans-serif;
  --sans: "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: var(--sans); line-height: 1.85; }
a { color: inherit; text-underline-offset: .22em; }
button, input { font: inherit; }
a:focus-visible, button:focus-visible, input:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }
.skip-link { position: fixed; left: 1rem; top: -5rem; z-index: 100; padding: .7rem 1rem; color: var(--white); background: var(--ink); }
.skip-link:focus { top: 1rem; }

.preview-bar { min-height: 34px; display: flex; align-items: center; justify-content: center; gap: 1rem; padding: .35rem 1.2rem; color: var(--ink); background: var(--accent); border-bottom: 1px solid rgba(21, 26, 24, .28); font-size: .68rem; letter-spacing: .03em; }
.preview-bar strong { letter-spacing: .14em; }
.site-frame { width: min(1440px, 100%); margin: 0 auto; overflow: hidden; background: var(--surface); border-inline: 1px solid var(--line); }
.shell { width: min(1120px, calc(100% - 64px)); margin-inline: auto; }

.site-header { min-height: 74px; display: flex; align-items: center; justify-content: space-between; gap: 2rem; padding: 1rem clamp(2rem, 5vw, 5rem); border-bottom: 1px solid var(--line); background: var(--surface); }
.brand { display: inline-flex; align-items: center; gap: .72rem; text-decoration: none; }
.brand-mark { width: 34px; height: 34px; display: grid; place-items: center; color: var(--white); background: var(--deep); font-family: var(--display); font-size: .95rem; font-weight: 800; }
.brand strong, .brand small { display: block; }
.brand strong { font-size: .93rem; letter-spacing: .04em; }
.brand small { margin-top: -.08rem; color: var(--ink-soft); font-size: .53rem; letter-spacing: .12em; }
.site-header nav { display: flex; gap: 1.55rem; }
.site-header nav a { padding-block: .2rem; border-bottom: 2px solid transparent; font-size: .75rem; font-weight: 700; text-decoration: none; }
.site-header nav a:hover, .site-header nav a:focus-visible { color: var(--deep); border-bottom-color: var(--accent); }

.hero { min-height: 560px; display: grid; grid-template-columns: 1.05fr .95fr; align-items: center; gap: clamp(3rem, 7vw, 6.5rem); margin-top: 3rem; padding: clamp(3.5rem, 7vw, 6.5rem) 0; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line); }
.hero-copy { max-width: 650px; }
.eyebrow { width: fit-content; margin: 0 0 1.25rem; color: var(--deep); font-size: .63rem; font-weight: 800; letter-spacing: .16em; text-transform: uppercase; }
.eyebrow::before { content: ""; width: 25px; display: inline-block; margin-right: .7rem; border-top: 3px solid var(--accent); vertical-align: .18em; }
.hero h1, .page-hero h1, .section-heading h2, .tool-cta h2 { margin: 0; font-family: var(--display); font-weight: 800; line-height: 1.34; letter-spacing: -.035em; }
.hero h1 { font-size: clamp(2.35rem, 4.2vw, 3.85rem); }
.hero h1 span { display: block; white-space: nowrap; }
.hero h1 span:first-child { margin-bottom: .32rem; font-size: .66em; letter-spacing: .01em; }
.hero-lead { max-width: 570px; margin: 1.65rem 0 0; color: var(--ink-soft); font-size: .93rem; }

.button-row { display: flex; flex-wrap: wrap; align-items: center; gap: .85rem 1.35rem; margin-top: 2rem; }
.button { min-height: 46px; display: inline-flex; align-items: center; justify-content: center; gap: .55rem; padding: .68rem 1.05rem; border: 1px solid var(--ink); border-radius: 2px; cursor: pointer; font-size: .78rem; font-weight: 800; text-decoration: none; transition: background .16s ease, color .16s ease, border-color .16s ease; }
.button.primary { color: var(--white); background: var(--ink); }
.button.primary:hover, .button.primary:focus-visible { color: var(--ink); background: var(--accent); border-color: var(--accent); }
.button.light { color: var(--ink); border-color: var(--white); background: var(--white); }
.button.light:hover, .button.light:focus-visible { color: var(--ink); border-color: var(--accent); background: var(--accent); }
.button.text { min-height: auto; padding: .35rem 0; border-width: 0 0 1px; background: transparent; }
.button.text:hover, .button.text:focus-visible { color: var(--deep); border-bottom-color: var(--accent); }

.hero-board { padding: 1.3rem 1.45rem 1.1rem; border: 1px solid var(--ink); background: var(--surface-soft); }
.board-head { display: flex; justify-content: space-between; padding-bottom: .9rem; border-bottom: 1px solid var(--ink); color: var(--ink-soft); font-size: .62rem; font-weight: 700; letter-spacing: .11em; }
.board-stage { display: grid; grid-template-columns: 34px 1fr auto; gap: .9rem; align-items: center; min-height: 80px; padding: .85rem .2rem; border-bottom: 1px solid var(--line); }
.board-stage > span { color: var(--ink-soft); font-size: .65rem; }
.board-stage strong, .board-stage small { display: block; }
.board-stage strong { font-size: .86rem; }
.board-stage small { margin-top: .15rem; color: var(--ink-soft); font-size: .63rem; }
.board-stage b { min-width: 30px; padding: .1rem .35rem; color: var(--ink); background: var(--accent-soft); text-align: center; font-size: .76rem; }
.board-stage.active { box-shadow: inset 4px 0 0 var(--accent); }
.hero-board > p { margin: .9rem .2rem 0; color: var(--ink-soft); font-size: .68rem; }

.section { padding-block: clamp(4.5rem, 8vw, 7rem); }
.section-heading h2 { font-size: clamp(1.75rem, 3.1vw, 2.65rem); }
.section-heading.split { display: grid; grid-template-columns: 1fr .75fr; align-items: end; gap: 4rem; }
.section-heading.split > p { max-width: 440px; margin: 0 0 .25rem; color: var(--ink-soft); font-size: .86rem; }
.principles { border-bottom: 1px solid var(--line); }
.principle-grid { display: grid; grid-template-columns: repeat(3, 1fr); margin-top: 3rem; border-top: 1px solid var(--ink); }
.principle-grid article { min-height: 220px; padding: 1.7rem 1.8rem 1.9rem 0; border-bottom: 1px solid var(--line); }
.principle-grid article + article { padding-left: 1.8rem; border-left: 1px solid var(--line); }
.principle-grid span { color: var(--deep); font-size: .66rem; font-weight: 800; }
.principle-grid h3 { margin: 2.5rem 0 .7rem; font-size: 1.05rem; }
.principle-grid p { margin: 0; color: var(--ink-soft); font-size: .8rem; }

.guide-section { background: var(--surface-soft); border-block: 1px solid var(--line); }
.guide-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin-top: 3.5rem; border-top: 1px solid var(--ink); }
.guide-card { min-height: 315px; display: flex; flex-direction: column; padding: 1.45rem 1.6rem 1.25rem; border-bottom: 1px solid var(--line); background: transparent; transition: background .16s ease; }
.guide-card + .guide-card { border-left: 1px solid var(--line); }
.guide-card:hover { background: var(--surface); }
.guide-type { color: var(--deep); font-size: .59rem; font-weight: 800; letter-spacing: .12em; }
.guide-card h3 { margin: 2.65rem 0 .8rem; font-size: clamp(1.05rem, 1.45vw, 1.3rem); line-height: 1.55; }
.guide-card h3 a { text-decoration: none; }
.guide-card h3 a:hover, .guide-card h3 a:focus-visible { text-decoration: underline; text-decoration-color: var(--accent); text-decoration-thickness: 3px; }
.guide-card p { margin: 0; color: var(--ink-soft); font-size: .78rem; }
.guide-card-footer { display: flex; justify-content: space-between; gap: 1rem; margin-top: auto; padding-top: 1.6rem; border-top: 1px solid var(--line); font-size: .66rem; }
.guide-card-footer a { color: var(--deep); font-weight: 800; text-decoration: none; }
.guide-card-footer a:hover, .guide-card-footer a:focus-visible { background: var(--accent); }
.index-grid { margin-bottom: 4rem; }
.index-grid .guide-card:nth-child(3n + 1) { border-left: 0; }

.amazon-route { display: grid; grid-template-columns: .72fr 1.28fr; gap: clamp(2.5rem, 6vw, 6rem); padding: clamp(2.5rem, 5vw, 4.5rem) 0; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line); }
.amazon-route-intro h2 { margin: 0; font-size: clamp(1.55rem, 2.7vw, 2.35rem); line-height: 1.45; letter-spacing: -.03em; }
.amazon-route-intro > p:last-child { margin: 1.35rem 0 0; color: var(--ink-soft); font-size: .8rem; }
.amazon-route-steps { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.amazon-route-steps a { display: grid; grid-template-columns: 34px 1fr auto; gap: .9rem; align-items: center; padding: .78rem .2rem; border-bottom: 1px solid var(--line); text-decoration: none; }
.amazon-route-steps a:hover, .amazon-route-steps a:focus-visible { background: var(--accent-soft); }
.amazon-route-steps span { color: var(--ink-soft); font-size: .62rem; font-weight: 700; }
.amazon-route-steps strong, .amazon-route-steps small { display: block; }
.amazon-route-steps strong { font-size: .84rem; line-height: 1.5; }
.amazon-route-steps small { margin-top: .12rem; color: var(--ink-soft); font-size: .62rem; }
.amazon-route-steps b { color: var(--deep); font-size: .62rem; white-space: nowrap; }

.tool-cta { display: grid; grid-template-columns: 1fr .75fr; gap: 5rem; align-items: center; margin-block: 5rem; padding: clamp(2.8rem, 6vw, 5rem); color: var(--white); background: var(--deep); border-top: 7px solid var(--accent); }
.tool-cta .eyebrow { color: var(--white); }
.tool-cta h2 { font-size: clamp(1.75rem, 3vw, 2.6rem); }
.tool-cta > div:last-child p { color: #ced9d3; }

.page-main { padding-bottom: 7rem; }
.page-hero { max-width: 920px; margin-top: 3rem; padding: clamp(3rem, 7vw, 5.5rem) 0; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line); }
.page-hero h1 { font-size: clamp(1.9rem, 3.8vw, 3.2rem); }
.page-hero > p:last-child { max-width: 680px; margin: 1.4rem 0 0; color: var(--ink-soft); font-size: .9rem; }
.editorial-box { padding: 1.2rem 1.3rem; border-left: 5px solid var(--deep); background: var(--surface-soft); }
.editorial-box strong { font-size: .88rem; }
.editorial-box p { margin: .35rem 0 0; color: var(--ink-soft); font-size: .78rem; }
.editorial-box.warning { border-left-color: var(--accent); background: #fbf8e8; }
.article-early-cta { margin: 1.25rem 0 0; }
.article-early-cta small { display: block; margin-top: .65rem; color: var(--ink-soft); font-size: .68rem; line-height: 1.7; }

.article { padding-bottom: 8rem; }
.article-header { max-width: 960px; margin-top: 3rem; padding: clamp(2.7rem, 5vw, 4.5rem) 0 3rem; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line); }
.article-header h1 { margin: 0; font-size: clamp(1.75rem, 2.4vw, 2.25rem); line-height: 1.48; letter-spacing: -.025em; }
.article-header h1 br { display: none; }
.article-header h1 .phrase-keep { white-space: nowrap; }
.article-lead { max-width: 790px; margin: 1.4rem 0 1rem; color: var(--ink-soft); font-size: .94rem; }
.article-meta { display: flex; flex-wrap: wrap; gap: .45rem 1.2rem; margin-top: 1.4rem; color: var(--ink-soft); font-size: .66rem; }
.article-meta span + span::before { content: "/"; margin-right: 1.2rem; color: var(--line-dark); }
.article-layout { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: clamp(2.5rem, 6vw, 6rem); align-items: start; margin-top: 2.2rem; }
.article-layout > * { min-width: 0; max-width: 100%; }
.article-body .seller-comparison { width: 100%; min-width: 0; max-width: 100%; overflow-x: auto; }
.article-body { max-width: 760px; }
.article-body section { margin-top: 3.2rem; padding-top: 1.9rem; border-top: 1px solid var(--line); }
.article-body h2 { margin: 0 0 1.15rem; font-size: clamp(1.2rem, 2vw, 1.55rem); line-height: 1.6; }
.article-body p { color: #343d39; font-size: .91rem; }
.article-side { position: sticky; top: 2rem; }
.side-card { padding: 1.45rem; color: var(--white); background: var(--deep); border-top: 5px solid var(--accent); }
.side-card > span { color: var(--accent); font-size: .59rem; font-weight: 800; letter-spacing: .14em; }
.side-card strong { display: block; margin-top: 1.35rem; font-size: 1.08rem; line-height: 1.6; }
.side-card p { color: #c8d5cf; font-size: .76rem; }
.side-card .button { width: 100%; margin-top: .6rem; color: var(--ink); background: var(--white); border-color: var(--white); }
.side-card .button:hover, .side-card .button:focus-visible { background: var(--accent); border-color: var(--accent); }

.metric-row { display: grid; grid-template-columns: repeat(3, 1fr); margin: 2rem 0; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line); }
.metric-row div { padding: 1rem; }
.metric-row div + div { border-left: 1px solid var(--line); }
.metric-row strong, .metric-row span { display: block; }
.metric-row strong { font-size: .8rem; }
.metric-row span { margin-top: .3rem; color: var(--ink-soft); font-size: .67rem; }
.check-steps { margin: 1.5rem 0 0; padding: 0; list-style: none; counter-reset: steps; border-top: 1px solid var(--ink); }
.check-steps li { display: grid; grid-template-columns: minmax(130px, .45fr) 1fr; gap: 1.5rem; padding: .9rem 0; border-bottom: 1px solid var(--line); counter-increment: steps; }
.check-steps strong::before { content: counter(steps, decimal-leading-zero) " / "; color: var(--deep); font-size: .62rem; }
.check-steps span { color: var(--ink-soft); font-size: .79rem; }
.decision-table { display: grid; border-top: 1px solid var(--ink); }
.decision-table > div { display: grid; grid-template-columns: .6fr 1fr; gap: 1.5rem; padding: .9rem 0; border-bottom: 1px solid var(--line); }
.decision-table span { color: var(--ink-soft); font-size: .79rem; }
.decision-table .table-head { color: var(--deep); background: transparent; font-size: .62rem; font-weight: 800; letter-spacing: .08em; }
.plain-list { padding-left: 1.2rem; }
.plain-list li { padding: .35rem 0; color: #343d39; }
.source-note { padding: 1.5rem !important; border: 1px solid var(--line) !important; background: var(--surface-soft); }
.source-note h2 { font-size: 1.1rem; }
.source-note ul { margin: .8rem 0 0; padding-left: 1.2rem; }
.source-note a { color: var(--deep); font-size: .78rem; font-weight: 700; }

.tools-page { padding-bottom: 8rem; }
.interactive-card { display: grid; grid-template-columns: .7fr 1.3fr; gap: 3rem; margin-bottom: 2rem; padding: clamp(1.5rem, 4vw, 3.5rem) 0; border-top: 1px solid var(--ink); border-bottom: 1px solid var(--line); }
.tool-intro > span { color: var(--deep); font-size: .62rem; font-weight: 800; letter-spacing: .14em; }
.tool-intro h2 { margin: 1rem 0; font-size: clamp(1.4rem, 2.7vw, 2.1rem); }
.tool-intro p { color: var(--ink-soft); font-size: .8rem; }
.tool-form fieldset { margin: 0 0 1.5rem; padding: 0; border: 0; }
.tool-form legend { margin-bottom: .8rem; font-weight: 800; }
.tool-form label { display: inline-flex; margin: 0 .4rem .5rem 0; }
.tool-form input { position: absolute; opacity: 0; pointer-events: none; }
.tool-form label span { padding: .55rem .8rem; border: 1px solid var(--line-dark); border-radius: 2px; cursor: pointer; background: var(--white); font-size: .75rem; }
.tool-form input:checked + span { color: var(--white); border-color: var(--deep); background: var(--deep); }
.tool-form input:focus-visible + span { outline: 3px solid var(--accent); outline-offset: 2px; }
.tool-result { grid-column: 1 / -1; min-height: 90px; padding: 1.35rem; border-left: 5px solid var(--accent); background: var(--surface-soft); }
.tool-result h3 { margin: 0 0 1rem; }
.result-columns { display: grid; grid-template-columns: 1fr 1fr; border-top: 1px solid var(--ink); }
.result-columns div { padding: 1rem 0; border-bottom: 1px solid var(--line); }
.result-columns div + div { padding-left: 1rem; border-left: 1px solid var(--line); }
.result-columns strong { display: block; margin-bottom: .5rem; color: var(--deep); font-size: .68rem; }
.result-columns ul { margin: 0; padding-left: 1.1rem; font-size: .79rem; }

.legal { max-width: 880px; }
.legal .page-hero { padding-bottom: 3rem; }
.legal > section { margin-top: 3.5rem; padding-top: 2rem; border-top: 1px solid var(--line); }
.legal h2 { font-size: 1.35rem; }
.legal p { color: #343d39; }
.disclosure-statement { padding: 1.5rem !important; border: 1px solid var(--ink) !important; border-left: 5px solid var(--accent) !important; background: var(--surface-soft); }
.disclosure-statement p { margin: 0; color: var(--ink); font-size: 1.05rem; font-weight: 700; }

.site-footer { display: grid; grid-template-columns: 1fr auto; gap: 2rem 4rem; padding: clamp(3rem, 6vw, 5rem) clamp(2rem, 6vw, 6rem); color: #d5dfda; background: #101916; border-top: 7px solid var(--accent); }
.footer-brand { margin: 0; color: var(--white); font-size: 1.05rem; font-weight: 800; }
.site-footer p:not(.footer-brand) { max-width: 500px; margin: .5rem 0 0; font-size: .74rem; }
.footer-links { display: flex; flex-direction: column; gap: .5rem; }
.footer-links a { font-size: .72rem; text-decoration: none; }
.footer-links a:hover, .footer-links a:focus-visible { color: var(--accent); }
.site-footer > small { grid-column: 1 / -1; padding-top: 1.5rem; border-top: 1px solid #35413c; color: #87958e; font-size: .61rem; }

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; min-height: auto; }
  .hero-board { max-width: 620px; }
  .section-heading.split, .tool-cta, .interactive-card, .amazon-route { grid-template-columns: 1fr; gap: 2.5rem; }
  .guide-grid { grid-template-columns: 1fr 1fr; }
  .guide-card:nth-child(2n + 1) { border-left: 0; }
  .guide-card:nth-child(3n + 1):not(:first-child) { border-left: 1px solid var(--line); }
  .principle-grid { grid-template-columns: 1fr; }
  .principle-grid article { min-height: auto; padding-left: 0; }
  .principle-grid article + article { padding-left: 0; border-left: 0; }
  .article-layout { grid-template-columns: minmax(0, 1fr); }
  .article-body { max-width: none; }
  .article-side { position: static; }
  .side-card { max-width: 500px; }
}

@media (max-width: 680px) {
  .preview-bar { align-items: flex-start; flex-direction: column; gap: 0; }
  .site-frame { border: 0; }
  .shell { width: min(100% - 36px, 1120px); }
  .site-header { align-items: flex-start; flex-direction: column; gap: .75rem; padding: .9rem 18px; }
  .site-header nav { width: 100%; justify-content: space-between; gap: .4rem; }
  .site-header nav a { font-size: .7rem; }
  .hero { margin-top: 1.6rem; padding: 2.8rem 0 3rem; gap: 2.4rem; }
  .hero h1 { font-size: clamp(2rem, 9.8vw, 2.45rem); }
  .hero-lead { font-size: .86rem; }
  .hero-board { padding: 1rem; }
  .board-stage { grid-template-columns: 28px 1fr auto; gap: .65rem; }
  .section { padding-block: 4.2rem; }
  .section-heading h2 { font-size: 1.7rem; }
  .guide-grid { grid-template-columns: 1fr; }
  .guide-card { min-height: auto; padding-inline: 0; }
  .guide-card + .guide-card, .guide-card:nth-child(3n + 1):not(:first-child) { border-left: 0; }
  .guide-card h3 { margin-top: 2rem; }
  .amazon-route { padding: 2.6rem 0; }
  .amazon-route-intro h2 br { display: none; }
  .amazon-route-steps a { grid-template-columns: 26px 1fr; }
  .amazon-route-steps b { grid-column: 2; }
  .tool-cta { width: 100%; margin-block: 2rem; padding: 2.4rem 1.2rem; }
  .page-hero, .article-header { margin-top: 1.6rem; padding: 2.6rem 0 2.4rem; }
  .article-header h1 { font-size: clamp(1.55rem, 6.2vw, 1.75rem); line-height: 1.5; letter-spacing: -.018em; }
  .article-layout { gap: 2rem; margin-top: 1.5rem; }
  .article-body section { margin-top: 2.5rem; padding-top: 1.5rem; }
  .page-hero h1 br { display: none; }
  .metric-row { grid-template-columns: 1fr; }
  .metric-row div + div { border-left: 0; border-top: 1px solid var(--line); }
  .check-steps li, .decision-table > div { grid-template-columns: 1fr; gap: .35rem; }
  .result-columns { grid-template-columns: 1fr; }
  .result-columns div + div { padding-left: 0; border-left: 0; }
  .article-meta { gap: .2rem .8rem; }
  .article-meta span + span::before { margin-right: .8rem; }
  .site-footer { grid-template-columns: 1fr; }
  .site-footer > small { grid-column: auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}

/* Comparison tables use external CSS so production style-src self applies. */
.seller-comparison{max-width:100%;overflow-x:auto;margin:20px 0}.seller-comparison table{width:100%;min-width:640px;border-collapse:collapse;font-size:14px;line-height:1.7}.seller-comparison caption{text-align:left;font-weight:700;margin-bottom:12px}.seller-comparison th,.seller-comparison td{padding:12px;border:1px solid #d9d9d9;text-align:left;vertical-align:top;white-space:normal;overflow-wrap:anywhere}.seller-comparison th:first-child{width:46%}.seller-comparison small{display:block;font-weight:400;margin-top:6px}.seller-comparison:focus{outline:2px solid #245b83;outline-offset:3px}