:root {
  --navy: #101b2d;
  --ink: #182235;
  --paper: #f4f1e9;
  --orange: #ff6b35;
  --line: rgba(16,27,45,.16);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font-family: "Noto Sans JP", sans-serif; }
a { color: inherit; }
.topbar { height: 76px; padding: 0 clamp(22px,5vw,76px); display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); }
.brand { display: flex; gap: 10px; align-items: center; font-family: "Noto Serif JP", serif; font-weight: 900; text-decoration: none; letter-spacing: .04em; }
.brand-icon { width: 38px; height: 38px; border-radius: 50%; object-fit: cover; background: #fff; }
.small-link, .text-link { font-weight: 700; text-underline-offset: 5px; }
.hero { min-height: 680px; padding: 90px clamp(24px,7vw,110px); display: grid; grid-template-columns: 1.1fr .9fr; gap: 70px; align-items: center; background: var(--navy); color: white; overflow: hidden; }
.eyebrow { margin: 0 0 18px; color: var(--orange); font-size: .77rem; font-weight: 900; letter-spacing: .22em; }
.hero h1 { margin: 0; font-family: "Noto Serif JP", serif; font-size: clamp(2.55rem,5vw,5.7rem); line-height: 1.25; letter-spacing: -.035em; }
.hero h1 em { color: #ffd66b; font-style: normal; }
.intro { max-width: 620px; margin: 32px 0; color: #d5d9e0; line-height: 2; font-size: 1.05rem; }
.primary-button { display: inline-flex; gap: 28px; align-items: center; padding: 16px 24px; color: var(--navy); background: white; border-radius: 999px; text-decoration: none; font-weight: 900; }
.hero-stack { position: relative; height: 470px; }
.book-shape { position: absolute; width: 250px; aspect-ratio: 2/3; padding: 34px 26px; display: flex; flex-direction: column; justify-content: space-between; box-shadow: 0 28px 60px rgba(0,0,0,.4); font-family: "Noto Serif JP", serif; font-weight: 900; line-height: 1.65; }
.book-shape small { font-family: "Noto Sans JP"; font-size: .65rem; letter-spacing: .18em; }
.book-a { left: 18%; top: 0; color: #162238; background: #f7cf52; transform: rotate(-8deg); }
.book-b { left: 38%; top: 52px; color: #0e2738; background: #68d4e5; transform: rotate(6deg); }
.book-c { left: 5%; top: 105px; color: white; background: #f05d43; transform: rotate(-16deg); }
.catalog { padding: 110px clamp(24px,7vw,110px); }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 30px; margin-bottom: 34px; }
.section-heading h2, .author h2 { margin: 0; font-family: "Noto Serif JP", serif; font-size: clamp(2rem,4vw,3.8rem); }
.section-heading > p { color: #586170; }
.filters { display: flex; gap: 8px; margin-bottom: 46px; border-bottom: 1px solid var(--line); }
.filter { padding: 12px 18px; border: 0; border-bottom: 3px solid transparent; background: transparent; color: #636b78; font: inherit; font-weight: 700; cursor: pointer; }
.filter.is-active { border-bottom-color: var(--orange); color: var(--ink); }
.book-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 58px 34px; }
.book-card { min-width: 0; }
.book-card[hidden] { display: none; }
.cover { position: relative; width: 100%; aspect-ratio: 2/3; padding: clamp(24px,3vw,42px); display: flex; flex-direction: column; box-shadow: 0 18px 38px rgba(23,31,46,.16); overflow: hidden; transition: transform .25s, box-shadow .25s; }
.book-card:hover .cover { transform: translateY(-7px); box-shadow: 0 25px 50px rgba(23,31,46,.23); }
.cover::after { content:""; position:absolute; inset: 0 auto 0 0; width: 6px; background: rgba(0,0,0,.16); }
.cover-real { padding: 0; background: #fff; text-decoration: none; }
.cover-real::after { width: 4px; background: rgba(16,27,45,.12); pointer-events: none; }
.cover-real img { width: 100%; height: 100%; display: block; object-fit: contain; }
.cover-label { align-self: flex-start; padding: 5px 9px; border: 1px solid currentColor; font-size: .68rem; font-weight: 700; letter-spacing: .08em; }
.cover h3 { margin: auto 0 12px; font-family: "Noto Serif JP", serif; font-size: clamp(1.35rem,2.1vw,2.2rem); line-height: 1.55; }
.cover p { margin: 0; font-size: .78rem; line-height: 1.7; }
.cover small { margin-top: 28px; font-size: .7rem; font-weight: 700; letter-spacing: .12em; }
.cover-summer { color:#17223a; background:#f7cd4b; }
.cover-red { color:white; background:#b22e35; }
.cover-cyan { color:#112a37; background:#69d4e3; }
.cover-black { color:white; background:#16191f; }
.cover-yellow { color:#32210a; background:#f0b83d; }
.cover-green { color:white; background:#285d4a; }
.cover-blue { color:white; background:#2b5797; }
.cover-purple { color:white; background:#704b91; }
.cover-white { color:#192234; background:#f9f8f4; border:1px solid var(--line); }
.cover-indigo { color:white; background:#373b72; }
.cover-salmon { color:#301c20; background:#e98d82; }
.cover-olive { color:white; background:#69723a; }
.cover-brown { color:white; background:#704737; }
.cover-pink { color:#351c2b; background:#dfa0be; }
.book-info { padding: 24px 2px 0; }
.genre { margin: 0 0 8px; color: var(--orange); font-size: .72rem; font-weight: 900; letter-spacing: .16em; }
.book-info h3 { margin: 0; font-family:"Noto Serif JP",serif; font-size: 1.28rem; line-height: 1.55; }
.book-info > p:not(.genre) { min-height: 5.7em; margin: 14px 0 20px; color: #5b6470; line-height: 1.9; }
.buy-button { display: flex; justify-content: space-between; padding: 15px 18px; border: 1px solid var(--ink); text-decoration: none; font-weight: 900; transition: .2s; }
.buy-button:hover, .buy-button:focus-visible { color:white; background:var(--ink); }
.empty { text-align:center; padding:60px; color:#626b78; }
.author { margin: 0 clamp(24px,7vw,110px) 110px; padding: clamp(38px,6vw,82px); display: grid; grid-template-columns: 170px 1fr; gap: clamp(32px,6vw,90px); align-items: center; color: white; background: var(--navy); }
.author-icon { width: 160px; aspect-ratio: 1; object-fit: cover; border: 4px solid white; border-radius: 50%; background: white; box-shadow: 0 18px 42px rgba(0,0,0,.28); }
.author p:not(.eyebrow) { max-width: 720px; color:#d5d9e0; line-height:2; }
.author .text-link { display:inline-block; margin-top:14px; color:white; }
footer { padding: 32px clamp(24px,7vw,110px); display:flex; justify-content:space-between; align-items:center; border-top:1px solid var(--line); }
footer p { display:flex; align-items:center; gap:10px; font-family:"Noto Serif JP",serif; font-weight:900; }
.footer-icon { width:34px; height:34px; border-radius:50%; object-fit:cover; background:#fff; }
footer small { color:#6b7280; }
@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; padding-top:70px; }
  .hero-stack { height:370px; transform:scale(.82); transform-origin:center top; }
  .book-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .author { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .topbar { height:66px; }
  .hero { min-height:auto; padding:65px 24px 20px; gap:45px; }
  .hero h1 { font-size:2.45rem; }
  .hero-stack { height:345px; margin:0 -30px; transform:scale(.72); }
  .section-heading { align-items:flex-start; flex-direction:column; }
  .catalog { padding-top:76px; padding-bottom:76px; }
  .book-grid { grid-template-columns:1fr; gap:54px; }
  .cover { max-width:390px; margin:auto; }
  .book-info > p:not(.genre) { min-height:0; }
  .author { margin-bottom:76px; padding:36px 26px; }
  .author-icon { width:110px; }
  footer { align-items:flex-start; flex-direction:column; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior:auto; }
  .cover { transition:none; }
}