/* ===== reset ===== */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body,h1,h2,h3,h4,p,ul,ol,figure,blockquote,dl,dd{margin:0}
ul,ol{padding:0;list-style:none}
button,input,select,textarea{font:inherit;color:inherit}
img,svg,video{display:block;max-width:100%}
table{border-collapse:collapse;width:100%}

/* ===== tokens ===== */
:root{
  --blue-900:#08243A;
  --blue-700:#123E5E;
  --blue-500:#1E7A9C;
  --teal-500:#2FB6A8;
  --teal-200:#A8E4DC;
  --coral-500:#FF6B4A;
  --coral-200:#FFC7B8;
  --coral-deep:#E04E2E;
  --gold-400:#E8B45A;
  --paper:#F7FAFB;
  --mist:#E4EBF0;
  --ink:#101A22;
  --line:#E4EBF0;
  --line-strong:rgba(8,36,58,.16);
  --muted:rgba(18,62,94,.7);
  --accent:var(--blue-500);
  --wave:var(--blue-500);
  --accent-soft:rgba(30,122,156,.09);
  --shadow:0 2px 12px rgba(8,36,58,.06);
  --shadow-lift:0 2px 12px rgba(8,36,58,.12);
  --radius:14px;
  --pill:999px;
  --wrap:1200px;
  --font-head:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Noto Sans SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-body:var(--font-head);
  --step:clamp(48px,7vw,96px);
}
html[data-device="mobile"]{--accent:#2FB6A8;--wave:#2FB6A8;--accent-soft:rgba(47,182,168,.10)}
html[data-device="screen"]{--accent:#FF6B4A;--wave:#FF6B4A;--accent-soft:rgba(255,107,74,.10)}

/* ===== base ===== */
html{scroll-behavior:smooth}
body{
  background:var(--paper);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:16.5px;
  line-height:1.85;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{font-family:var(--font-head);color:var(--blue-900);line-height:1.15}
a{color:var(--blue-700);text-decoration:none;transition:color .2s ease-out,border-color .32s ease-out,background-color .32s ease-out}
a:hover{color:var(--ink)}
p{max-width:70ch}
::selection{background:var(--teal-200);color:var(--blue-900)}

/* ===== layout ===== */
.container{width:min(var(--wrap),92vw);margin-inline:auto}
.section{padding:var(--step) 0}
.section-head{max-width:62ch;margin-bottom:clamp(24px,3vw,40px)}
.eyebrow{
  display:block;font-size:12px;font-weight:600;letter-spacing:.18em;
  text-transform:uppercase;color:var(--accent);margin-bottom:10px;
  transition:color .32s ease-out;
}
.display-title{font-size:clamp(2.3rem,5.6vw,4.5rem);font-weight:300;letter-spacing:.02em;line-height:1.06}
.sheet-title{font-size:clamp(1.7rem,3.4vw,2.5rem);font-weight:600;letter-spacing:.02em}

/* ===== header ===== */
.site-header{
  position:sticky;top:0;z-index:80;
  background:var(--paper);
  border-bottom:1px solid var(--line);
}
.skip-link{
  position:absolute;left:50%;top:6px;transform:translate(-50%,-200%);
  z-index:99;background:var(--blue-900);color:var(--paper);
  padding:8px 16px;border-radius:var(--pill);font-size:13px;
  transition:transform .2s ease-out;
}
.skip-link:focus{transform:translate(-50%,0);color:var(--paper)}
.scroll-progress{
  position:absolute;left:0;right:0;bottom:-1px;height:2px;
  background:var(--accent);transform:scaleX(0);transform-origin:0 50%;
  transition:transform .1s linear,background-color .32s ease-out;
}
.wave-line{color:var(--wave);height:12px;overflow:hidden;transition:color .32s ease-out}
.wave-line svg{width:100%;height:12px;display:block;opacity:.55}

.header-bar{
  position:relative;
  width:min(1240px,94vw);margin:10px auto 0;
  display:flex;align-items:center;gap:16px;
  padding:10px 14px 10px 20px;
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--pill);
  box-shadow:var(--shadow);
  transition:padding .2s ease-out,box-shadow .2s ease-out,border-color .32s ease-out;
}
.site-header[data-scrolled] .header-bar{padding:6px 10px 6px 16px;box-shadow:var(--shadow-lift)}
.brand{display:flex;flex-direction:column;flex:0 0 auto;line-height:1.15;color:var(--ink)}
.brand-mark{font-weight:600;font-size:1.05rem;letter-spacing:.08em;color:var(--blue-900)}
.brand-tagline{font-size:11px;letter-spacing:.1em;color:var(--muted);margin-top:2px}
.site-nav{margin-left:8px}
.nav-list{display:flex;align-items:center;gap:2px}
.nav-link{
  display:block;padding:8px 12px;border-radius:var(--pill);
  font-size:14px;color:var(--blue-700);border:1px solid transparent;
  transition:border-color .32s ease-out,background-color .2s ease-out,color .2s ease-out;
}
.nav-link:hover{border-color:var(--accent);background:var(--accent-soft);color:var(--ink)}
.nav-link[aria-current="page"]{background:var(--accent);border-color:var(--accent);color:#fff}
.header-tools{margin-left:auto;display:flex;align-items:center;gap:10px}
.device-switch{
  display:flex;gap:2px;padding:3px;background:var(--mist);
  border:1px solid var(--line);border-radius:var(--pill);
}
.device-btn{
  border:0;background:transparent;cursor:pointer;
  padding:5px 11px;border-radius:var(--pill);
  font-size:12px;letter-spacing:.04em;color:var(--blue-700);
  transition:background-color .2s ease-out,color .2s ease-out,box-shadow .2s ease-out;
}
.device-btn:hover{color:var(--ink)}
.device-btn[aria-pressed="true"]{background:var(--paper);color:var(--ink);box-shadow:var(--shadow)}
.header-cta{
  display:inline-flex;align-items:center;padding:9px 18px;border-radius:var(--pill);
  background:var(--coral-500);border:1px solid var(--coral-500);color:#fff;
  font-size:13px;font-weight:600;letter-spacing:.02em;white-space:nowrap;
  transition:background-color .2s ease-out,border-color .2s ease-out;
}
.header-cta:hover{background:var(--coral-deep);border-color:var(--coral-deep);color:#fff}
.nav-toggle{
  display:none;flex-direction:column;align-items:center;justify-content:center;gap:4px;
  width:40px;height:40px;border:1px solid var(--line);border-radius:var(--pill);
  background:var(--paper);cursor:pointer;
  transition:border-color .32s ease-out;
}
.nav-toggle:hover{border-color:var(--accent)}
.nav-toggle-bar{width:16px;height:1.5px;background:var(--blue-700);transition:transform .2s ease-out,opacity .2s ease-out}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}
.header-ticker{
  display:flex;align-items:center;gap:10px;
  width:min(1240px,94vw);margin:8px auto 0;
  max-height:40px;overflow:hidden;
  font-size:12px;color:var(--muted);letter-spacing:.02em;
  transition:max-height .25s ease-out,opacity .25s ease-out,margin-top .25s ease-out;
}
.header-ticker::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--accent);flex:0 0 auto}
.site-header[data-scrolled] .header-ticker{max-height:0;opacity:0;margin-top:0}

/* ===== footer ===== */
.site-footer{background:var(--blue-900);color:rgba(247,250,251,.78);margin-top:var(--step)}
.site-footer .wave-line{margin-top:-1px}
.footer-inner{
  width:min(var(--wrap),92vw);margin-inline:auto;
  padding:clamp(36px,5vw,64px) 0 clamp(24px,3vw,36px);
  display:grid;gap:clamp(28px,4vw,56px);
  grid-template-columns:1.2fr 1.6fr 1.4fr;
}
.footer-mark{font-family:var(--font-head);font-size:1.5rem;font-weight:600;letter-spacing:.08em;color:var(--paper)}
.footer-tagline{font-size:12px;letter-spacing:.14em;color:var(--teal-200);margin-top:4px}
.footer-lead{font-size:13.5px;line-height:1.8;color:rgba(247,250,251,.66);margin:14px 0 18px;max-width:34ch}
.footer-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.footer-col-title{font-size:12px;letter-spacing:.16em;text-transform:uppercase;color:var(--teal-200);margin-bottom:12px}
.footer-list li+li{margin-top:8px}
.footer-link{
  font-size:14px;color:rgba(247,250,251,.82);
  border-bottom:1px solid transparent;padding-bottom:1px;
  transition:color .2s ease-out,border-color .2s ease-out;
}
.footer-link:hover{color:var(--paper);border-color:var(--wave)}
.footer-contact-title{font-size:12px;letter-spacing:.16em;text-transform:uppercase;color:var(--teal-200);margin-bottom:12px}
.footer-contact-line{font-size:13.5px;line-height:1.8;color:rgba(247,250,251,.82)}
.footer-contact-note{font-size:12.5px;line-height:1.75;color:rgba(247,250,251,.6);margin-top:10px;max-width:38ch}
.footer-bottom{
  width:min(var(--wrap),92vw);margin-inline:auto;
  border-top:1px solid rgba(247,250,251,.14);
  padding:18px 0 26px;
  display:flex;flex-wrap:wrap;gap:8px 24px;align-items:center;justify-content:space-between;
  font-size:12.5px;color:rgba(247,250,251,.6);
}
.footer-legal,.footer-copy{margin:0}

/* ===== buttons ===== */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 20px;border-radius:var(--pill);
  border:1px solid var(--line-strong);background:transparent;
  font-size:14px;font-weight:600;letter-spacing:.02em;color:var(--blue-700);
  cursor:pointer;transition:background-color .2s ease-out,border-color .32s ease-out,color .2s ease-out;
}
.btn:hover{background:var(--accent-soft);border-color:var(--accent);color:var(--ink)}
.btn-primary{background:var(--coral-500);border-color:var(--coral-500);color:#fff}
.btn-primary:hover{background:var(--coral-deep);border-color:var(--coral-deep);color:#fff}
.btn-line{background:transparent}
.site-footer .btn-line{border-color:rgba(247,250,251,.32);color:var(--paper)}
.site-footer .btn-line:hover{background:rgba(247,250,251,.08);border-color:var(--wave);color:var(--paper)}

/* ===== breadcrumbs ===== */
.breadcrumbs{display:flex;flex-wrap:wrap;gap:6px;font-size:13px;color:var(--muted);padding:18px 0 0}
.breadcrumbs a{color:var(--blue-700);border-bottom:1px solid transparent}
.breadcrumbs a:hover{border-color:var(--accent)}
.breadcrumbs li+li::before{content:"/";margin-right:6px;color:var(--line-strong)}

/* ===== editorial chapters ===== */
.chapter{
  display:grid;gap:clamp(20px,3vw,40px);
  grid-template-columns:minmax(0,8fr) minmax(0,3fr);
  padding:clamp(32px,4vw,56px) 0;
  border-top:1px solid var(--line);
}
.chapter-head{display:flex;align-items:baseline;gap:18px;flex-wrap:wrap}
.chapter-num{
  font-family:var(--font-head);
  font-size:clamp(64px,9vw,120px);font-weight:300;line-height:.85;
  letter-spacing:.02em;color:var(--mist);
  transition:color .32s ease-out;
}
.chapter:hover .chapter-num{color:var(--accent-soft)}
.chapter-title{font-size:clamp(1.35rem,2.3vw,1.75rem);font-weight:600;letter-spacing:.02em}
.note-col{font-size:13px;line-height:1.7;color:var(--muted);align-self:start}
.chapter-note{margin-bottom:12px}
.anchor-index{position:sticky;top:96px}
.anchor-index li{margin-bottom:2px}
.anchor-index a{
  display:block;padding:6px 0 6px 12px;
  border-left:1px solid var(--line);
  font-size:13px;color:var(--muted);
  transition:color .2s ease-out,border-color .32s ease-out;
}
.anchor-index a:hover{color:var(--ink)}
.anchor-index a.is-active{color:var(--ink);border-left-color:var(--accent)}

/* ===== pills ===== */
.pill-tabs{display:flex;flex-wrap:wrap;gap:8px}
.pill{
  border:1px solid var(--line);background:var(--paper);cursor:pointer;
  padding:8px 16px;border-radius:var(--pill);font-size:14px;color:var(--blue-700);
  transition:border-color .32s ease-out,background-color .2s ease-out,color .2s ease-out;
}
.pill:hover{border-color:var(--accent);color:var(--ink)}
.pill.is-active,.pill[aria-pressed="true"]{border-color:var(--accent);background:var(--accent-soft);color:var(--ink);font-weight:600}

/* ===== cards ===== */
.card-grid{display:grid;gap:20px;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));align-items:start}
.card{
  background:var(--paper);border:1px solid var(--line);border-radius:var(--radius);
  padding:22px;box-shadow:var(--shadow);
  transition:transform .2s ease-out,border-color .32s ease-out,box-shadow .2s ease-out;
}
.card:hover{transform:translateY(-2px);border-color:var(--accent);box-shadow:var(--shadow-lift)}
.card--price{border-top:2px solid var(--coral-500)}
.card-title{font-size:1.05rem;font-weight:600;color:var(--blue-900);margin-bottom:10px}
.card-price{display:flex;align-items:baseline;gap:6px;margin:6px 0 10px}
.price-num{
  font-size:clamp(1.8rem,2.6vw,2.2rem);font-weight:600;line-height:1;
  color:var(--coral-500);font-variant-numeric:tabular-nums;
}
.price-unit{font-size:13px;color:var(--muted)}

/* ===== collapsible panels ===== */
.panel{
  border:1px solid var(--line);border-radius:var(--radius);
  background:var(--paper);box-shadow:var(--shadow);margin-bottom:12px;
  transition:border-color .32s ease-out;
}
.panel:hover{border-color:var(--accent)}
.panel-summary{
  display:flex;align-items:center;justify-content:space-between;gap:14px;
  padding:14px 18px;cursor:pointer;font-weight:600;color:var(--blue-700);
}
.panel-summary::-webkit-details-marker{display:none}
.panel-summary::after{content:"+";color:var(--accent);font-size:18px;line-height:1}
.panel[open] .panel-summary::after{content:"–"}
.panel-body{padding:0 18px 18px;font-size:15px;color:var(--blue-700)}

/* ===== tags ===== */
.tag{
  display:inline-block;padding:3px 10px;border-radius:var(--pill);
  background:var(--teal-200);color:var(--blue-900);
  font-size:12px;letter-spacing:.04em;
}
.tag--gold{background:rgba(232,180,90,.26);color:#6f5210}

/* ===== media ===== */
.media{
  position:relative;overflow:hidden;
  border:1px solid var(--line);border-radius:var(--radius);
  background:linear-gradient(180deg,rgba(30,122,156,.12),rgba(47,182,168,.05) 60%,rgba(247,250,251,1));
  aspect-ratio:16/9;
}
.media::after{
  content:"";position:absolute;left:0;right:0;top:42%;height:1px;
  background:var(--wave);opacity:.35;transition:background-color .32s ease-out;
}
.media--wide{aspect-ratio:21/9}
.media--tall{aspect-ratio:4/5}
.media img{width:100%;height:100%;object-fit:cover}
.media-caption{margin-top:8px;font-size:13px;line-height:1.7;color:var(--muted)}

/* ===== accessibility ===== */
:focus-visible{outline:2px solid var(--coral-500);outline-offset:2px;border-radius:4px}
.site-footer :focus-visible{outline-color:var(--teal-200)}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important}
  [data-reveal]{opacity:1!important;transform:none!important}
}

/* ===== responsive ===== */
@media (max-width:1080px){
  .nav-toggle{display:inline-flex}
  .site-nav{
    position:absolute;left:0;right:0;top:calc(100% + 10px);
    display:none;margin-left:0;padding:12px;
    background:var(--paper);border:1px solid var(--line);
    border-radius:20px;box-shadow:var(--shadow-lift);
  }
  .site-nav[data-open]{display:block}
  .nav-list{flex-direction:column;align-items:stretch;gap:4px}
  .nav-link{padding:12px 14px;border-radius:12px;font-size:15px}
  .nav-link[aria-current="page"]{color:#fff}
  .header-ticker{display:none}
  .footer-inner{grid-template-columns:1fr 1fr;gap:32px}
  .footer-contact{grid-column:1 / -1}
  .chapter{grid-template-columns:1fr}
  .anchor-index{position:static}
}
@media (max-width:860px){
  .header-cta{display:none}
}
@media (max-width:640px){
  body{font-size:16px}
  .header-bar{width:94vw;gap:10px;padding:8px 10px 8px 14px;border-radius:22px}
  .brand-tagline{display:none}
  .device-btn{padding:4px 9px;font-size:11px}
  .footer-inner{grid-template-columns:1fr}
  .footer-cols{grid-template-columns:1fr 1fr}
  .footer-bottom{flex-direction:column;align-items:flex-start}
  .chapter-num{font-size:clamp(56px,18vw,88px)}
}