/* ═══════════════════════════════════════════════════════════
   KAZUKI SEJIMA — Official  (site mockup v0.1)
   和紙白 × 墨 × 六面の伝統色 / Shippori Mincho + Zen Kaku Gothic New
   アーティストサイト(闇・朱)と対になる「光・墨」の編集デザイン
   ═══════════════════════════════════════════════════════════ */

:root {
  --paper: #f4f1ea;
  --paper2: #ece8de;
  --sumi: #1c1b1a;
  --mut: #6e695f; /* #7a756bはAA不適合(4.07:1)のため墨側へ(4.8:1) */
  --line: rgba(28, 27, 26, 0.16);
  --facet: #1c1b1a; /* JSがホバー中の面の色で上書き */
  --serif: "Shippori Mincho", "Hiragino Mincho ProN", serif;
  --sans: "Zen Kaku Gothic New", "Hiragino Kaku Gothic ProN", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; overflow-x: clip; }
html.flat { scroll-behavior: auto; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; } /* JS無効環境でも効かせる（.flatはJS付与のため） */
}

body {
  background: var(--paper);
  color: var(--sumi);
  font-family: var(--sans);
  font-weight: 400;
  line-height: 2;
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--sumi); color: var(--paper); }

a { color: inherit; text-decoration: none; }
canvas { max-width: 100%; display: block; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  margin: -1px; padding: 0; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* ── 和紙の質感（静的テクスチャ） ───────────── */
.paper {
  position: fixed; inset: 0; z-index: 0;
  pointer-events: none; opacity: 0.5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='280' height='280'%3E%3Cfilter id='p'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.08' numOctaves='4'/%3E%3CfeColorMatrix values='0 0 0 0 0.92 0 0 0 0 0.90 0 0 0 0 0.86 0 0 0 0.06 0'/%3E%3C/filter%3E%3Crect width='280' height='280' filter='url(%23p)'/%3E%3C/svg%3E");
}

main { position: relative; z-index: 1; }

/* ── ヘッダー ───────────────────────────────── */
.site-head {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; justify-content: space-between; align-items: center;
  padding: 24px 32px;
  background: rgba(244, 241, 234, 0.82);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}
.head-name {
  font-family: var(--serif); font-weight: 600;
  font-size: 17px; letter-spacing: 0.34em;
}
.head-name span {
  display: block;
  font-family: var(--sans); font-weight: 400;
  font-size: 8px; letter-spacing: 0.3em; color: var(--mut);
  margin-top: 2px;
}
.head-nav { display: flex; gap: 30px; }
.head-nav a {
  font-family: var(--serif);
  font-size: 13px; letter-spacing: 0.3em;
  position: relative; padding: 4px 0;
}
.head-nav a::after {
  content: ""; position: absolute; left: 0; bottom: 0;
  width: 100%; height: 1px; background: var(--sumi);
  transform: scaleX(0); transform-origin: 100% 0;
  transition: transform 0.45s cubic-bezier(0.16, 1, 0.3, 1);
}
.head-nav a:hover::after, .head-nav a:focus-visible::after {
  transform: scaleX(1); transform-origin: 0 0;
}

/* ── 章ラベル（右縁・縦書き） ───────────────── */
.section-label {
  position: fixed; right: 26px; bottom: 30px; z-index: 95;
  writing-mode: vertical-rl;
  font-family: var(--serif); font-size: 13px; letter-spacing: 0.5em;
  color: var(--mut);
  display: flex; align-items: center; gap: 12px;
}
.section-label::before {
  content: ""; width: 1px; height: 34px; background: var(--facet);
  transition: background 0.5s ease;
}

/* ── リビール ───────────────────────────────── */
.js:not(.flat) .reveal {
  opacity: 0; transform: translateY(26px);
  transition: opacity 0.9s ease, transform 0.9s cubic-bezier(0.16, 1, 0.3, 1);
}
.js:not(.flat) .reveal.in { opacity: 1; transform: none; }

.mask { display: inline-block; overflow: hidden; vertical-align: bottom; }
.mask-in { display: inline-block; }
.js:not(.flat) .mask-in {
  transform: translateY(115%);
  transition: transform 1s cubic-bezier(0.16, 1, 0.3, 1);
}
.js:not(.flat) .in .mask-in { transform: none; }

/* ═══════════ HERO ═══════════ */
.hero {
  position: relative;
  height: 100vh;
  height: 100svh; /* iOSツールバー表示中でもSCROLL誘導が折り目の下に沈まない */
  min-height: 620px;
  overflow: hidden;
}
#cubeCanvas {
  position: absolute; inset: 0; width: 100%; height: 100%;
}
.hero-name {
  position: absolute; left: 8vw; top: 50%;
  transform: translateY(-50%);
  writing-mode: vertical-rl;
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(64px, 11vh, 130px);
  letter-spacing: 0.28em; line-height: 1;
  height: max-content; /* top:50%の絶対配置は利用可能高さが半分になり縦書きが折れる */
  z-index: 5;
}
.hero-latin {
  position: absolute; left: calc(8vw + clamp(80px, 13vh, 160px)); top: 50%;
  transform: translateY(-50%);
  writing-mode: vertical-rl;
  font-size: 10px; letter-spacing: 0.5em; color: var(--mut);
  height: max-content;
  z-index: 5;
}
.hero-tag {
  position: absolute; right: 9vw; bottom: 16vh; z-index: 5;
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(17px, 2vw, 26px); letter-spacing: 0.3em;
}
.hero-meta {
  position: absolute; top: 106px; z-index: 5;
  font-size: 10px; letter-spacing: 0.26em; color: var(--mut);
  display: flex; flex-direction: column; gap: 4px;
}
.hero-meta--l { left: 32px; }
.hero-meta--r { right: 32px; text-align: right; }
.hero-scroll {
  position: absolute; left: 50%; bottom: 26px; z-index: 5;
  transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  font-size: 9px; letter-spacing: 0.4em; color: var(--mut);
}
.hero-scroll i {
  width: 1px; height: 44px; background: var(--line);
  position: relative; overflow: hidden; display: block;
}
.hero-scroll i::after {
  content: ""; position: absolute; left: 0; top: -50%;
  width: 100%; height: 50%; background: var(--sumi);
  animation: scrolldrop 2s cubic-bezier(0.76, 0, 0.24, 1) infinite;
}
@keyframes scrolldrop { to { top: 110%; } }
.flat .hero-scroll i::after, .no-js .hero-scroll i::after { animation: none; }

/* ═══════════ FACETS ═══════════ */
.facets {
  position: relative;
  padding: 20vh 8vw 16vh;
  border-top: 1px solid var(--line);
  overflow: hidden;
}
.facets-head { position: relative; z-index: 2; margin-bottom: 10vh; }
.facets-head h2 {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(40px, 6vw, 88px); letter-spacing: 0.06em;
  line-height: 1.1;
}
.facets-head h2 span {
  display: block;
  font-family: var(--sans); font-weight: 400;
  font-size: 12px; letter-spacing: 0.5em; color: var(--mut);
  margin-top: 14px;
}
.facets-head p {
  margin-top: 3vh;
  font-size: 13px; letter-spacing: 0.2em; color: var(--mut);
}

/* 巨大透かし漢字 */
.facet-mark {
  position: absolute; right: 2vw; top: 50%;
  transform: translateY(-50%);
  font-family: var(--serif); font-weight: 600;
  font-size: min(56vw, 66vh);
  line-height: 1; color: var(--facet);
  opacity: 0.07; z-index: 1;
  transition: color 0.6s ease, opacity 0.6s ease;
  pointer-events: none;
  user-select: none;
}

.facet-list { position: relative; z-index: 2; list-style: none; }
.facet {
  display: grid;
  grid-template-columns: 64px 1fr 1.2fr 40px;
  align-items: baseline; gap: 24px;
  padding: 4.2vh 0;
  border-top: 1px solid var(--line);
  cursor: default; /* リンクでない側面に偽アフォーダンスを与えない */
  transition: color 0.4s ease;
}
a.facet { cursor: pointer; }
span.facet .f-arrow { opacity: 0.22; }
.facet-list li:last-child .facet { border-bottom: 1px solid var(--line); }
.f-idx {
  font-size: 11px; letter-spacing: 0.2em; color: var(--mut);
  font-variant-numeric: tabular-nums;
}
.f-name {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(26px, 3.4vw, 50px);
  letter-spacing: 0.05em; line-height: 1.2;
  position: relative; display: inline-block;
  transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}
.f-name em {
  font-style: normal; font-family: var(--sans); font-weight: 400;
  font-size: 12px; letter-spacing: 0.34em; color: var(--mut);
  margin-left: 18px;
}
.f-desc {
  font-size: 12.5px; font-weight: 300; letter-spacing: 0.08em;
  color: var(--mut); line-height: 2;
}
.f-arrow {
  font-size: 20px; color: var(--mut); justify-self: end;
  transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1), color 0.4s ease;
}
.facet:hover .f-name, .facet:focus-visible .f-name {
  color: var(--facet);
  transform: translateX(10px);
}
.facet:hover .f-arrow, .facet:focus-visible .f-arrow {
  color: var(--facet);
  transform: translateX(8px);
}
.facet-note {
  position: relative; z-index: 2;
  margin-top: 4vh;
  font-size: 10px; letter-spacing: 0.24em; color: var(--mut);
}

/* ═══════════ PROFILE ═══════════ */
.profile {
  padding: 20vh 8vw;
  border-top: 1px solid var(--line);
}
.profile-grid {
  display: grid; grid-template-columns: 1fr 1.7fr;
  gap: 6vh 6vw; max-width: 1280px; margin: 0 auto;
}
.profile-head h2 {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(40px, 6vw, 88px); letter-spacing: 0.06em; line-height: 1.1;
}
.profile-head h2 span {
  display: block;
  font-family: var(--sans); font-weight: 400;
  font-size: 12px; letter-spacing: 0.5em; color: var(--mut);
  margin-top: 14px;
}
.profile-lead {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(20px, 2.4vw, 32px);
  letter-spacing: 0.12em; margin-bottom: 4vh;
}
.profile-txt {
  font-size: 14px; font-weight: 300;
  max-width: 580px; margin-bottom: 2.6vh;
  letter-spacing: 0.04em;
}
.profile-facts { margin-top: 5vh; border-top: 1px solid var(--line); }
.profile-facts div {
  display: flex; align-items: baseline; gap: 22px;
  padding: 14px 0; border-bottom: 1px solid var(--line);
}
.profile-facts dt {
  flex: 0 0 96px;
  font-size: 10px; letter-spacing: 0.26em; color: var(--mut);
}
.profile-facts dd { font-size: 13px; letter-spacing: 0.06em; }

/* ═══════════ THREADS ═══════════ */
.threads { padding:20vh 8vw; border-top:1px solid var(--line); }
.threads-head { display:grid; grid-template-columns:1fr 1.7fr; gap:6vw; max-width:1280px; margin:0 auto 10vh; }
.threads-head h2 { font-family:var(--serif); font-weight:500; font-size:clamp(40px,6vw,88px); letter-spacing:.06em; line-height:1.1; }
.threads-head h2 span { display:block; margin-top:14px; color:var(--mut); font-family:var(--sans); font-size:12px; font-weight:400; letter-spacing:.5em; }
.threads-head p { align-self:end; max-width:460px; color:var(--mut); font-size:13px; letter-spacing:.16em; }
.thread-list { max-width:880px; margin-left:auto; border-top:1px solid var(--line); }
.thread { display:grid; grid-template-columns:84px 1fr; gap:4vw; padding:5vh 0; border-bottom:1px solid var(--line); }
.thread > p { color:var(--mut); font-size:10px; letter-spacing:.24em; }
.thread h3 { margin:0; font:500 clamp(25px,3.4vw,46px)/1.25 var(--serif); letter-spacing:.08em; }
.thread div p { max-width:560px; margin:20px 0 0; font-size:14px; font-weight:300; letter-spacing:.06em; }

/* ═══════════ PHILOSOPHY ═══════════ */
.philosophy {
  padding: 26vh 8vw;
  border-top: 1px solid var(--line);
  text-align: center;
}
.philo-line {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(30px, 5.6vw, 84px);
  letter-spacing: 0.12em; line-height: 1.6;
}
.philo-line em { font-style: normal; white-space: nowrap; border-bottom: 2px solid var(--sumi); padding-bottom: 0.08em; }
/* .maskのoverflow:hiddenが下線をクリップするためクリップ枠だけ下へ広げる */
.philo-line .mask { padding-bottom: 0.12em; margin-bottom: -0.12em; }
.philo-sub {
  margin-top: 6vh;
  font-size: clamp(13px, 1.5vw, 18px); font-weight: 300;
  letter-spacing: 0.18em; line-height: 2.6; color: var(--sumi);
}

/* ═══════════ CONTACT ═══════════ */
.contact {
  padding: 20vh 8vw 0;
  border-top: 1px solid var(--line);
  text-align: center;
}
.contact-pre {
  font-size: 12px; letter-spacing: 0.4em; color: var(--mut);
  margin-bottom: 4vh;
}
.contact-mail {
  font-family: var(--serif); font-weight: 500;
  font-size: clamp(18px, 3.4vw, 44px);
  letter-spacing: 0.08em;
  border-bottom: 1px solid var(--sumi);
  padding-bottom: 6px;
  transition: color 0.4s ease, border-color 0.4s ease;
}
.contact-mail:hover, .contact-mail:focus-visible {
  color: var(--mut); border-color: var(--mut);
}
.foot {
  margin-top: 16vh;
  padding: 26px 0 60px;
  border-top: 1px solid var(--line);
  display: flex; justify-content: space-between; align-items: center;
  gap: 14px; flex-wrap: wrap;
  font-size: 10px; letter-spacing: 0.2em; color: var(--mut);
}
.foot-links { display:flex; gap:20px; }
.foot a { color: var(--sumi); }

/* ═══════════ レスポンシブ ═══════════ */
@media (max-width: 900px) {
  .profile-grid { grid-template-columns: 1fr; }
  .threads-head { grid-template-columns:1fr; }
  .facet { grid-template-columns: 40px 1fr 32px; }
  /* 明示行を持つ項目は自動配置より先に置かれ列を奪うため、全項目の列を明示する */
  .f-idx { grid-column: 1; grid-row: 1; }
  .f-name { grid-column: 2; grid-row: 1; }
  .f-arrow { grid-column: 3; grid-row: 1; }
  .f-desc { grid-column: 2 / 3; grid-row: 2; margin-top: 8px; }
}

@media (max-width: 640px) {
  .site-head { padding: 16px 20px; }
  .head-name { font-size: 15px; letter-spacing: 0.26em; }
  .head-nav { gap: 18px; }
  .head-nav a { font-size: 12px; letter-spacing: 0.2em; }
  .section-label { right: 16px; bottom: 22px; }
  .hero-name { left: 9vw; font-size: clamp(56px, 15vw, 96px); }
  .hero-latin { left: calc(9vw + clamp(66px, 18vw, 110px)); }
  .hero-tag {
    right: auto; left: 9vw; bottom: 13vh;
    letter-spacing: 0.22em;
  }
  .hero-meta { top: 92px; }
  .hero-meta--l { left: 20px; }
  .hero-meta--r { right: 20px; }
  .facets { padding: 16vh 7vw 12vh; }
  .philo-sub { letter-spacing: 0.1em; } /* 390pxで「る。」の孤立行を防ぐ */
  .facet-mark { right: -8vw; font-size: 80vw; }
  .f-name em { display: block; margin: 6px 0 0; }
  .profile { padding: 16vh 7vw; }
  .threads { padding:16vh 7vw; }
  .threads-head { margin-bottom:7vh; }
  .thread { grid-template-columns:40px 1fr; gap:20px; padding:4vh 0; }
  .philosophy { padding: 20vh 7vw; }
  .contact { padding-top: 16vh; }
  .foot { flex-direction: column; align-items: flex-start; padding-bottom: 48px; }
  .foot-links { flex-wrap:wrap; }
}