:root {
  --bg: #f8f7f4;
  --surface: #f0efe9;
  --text: #111110;
  --muted: #888480;
  --border: rgba(17, 17, 16, 0.1);
  --border-strong: rgba(17, 17, 16, 0.18);
  --content: 1080px;
  --header-h: 60px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  background: var(--bg);
  color: var(--text);
  font-family: "Noto Sans JP", sans-serif;
  font-weight: 300;
  -webkit-font-smoothing: antialiased;
  line-height: 1.7;
}

a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
p, ul { margin: 0; padding: 0; }
ul { list-style: none; }

/* ─── Layout ──────────────────────────── */

.page {
  max-width: var(--content);
  margin: 0 auto;
  padding: 0 48px;
}

/* ─── Header ──────────────────────────── */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  padding: 0 48px;
  transition: background 0.4s ease, border-color 0.4s ease;
  border-bottom: 1px solid transparent;
}

/* backdrop を疑似要素に分離して fixed 子要素の包含ブロック問題を回避 */
.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(248, 247, 244, 0);
  backdrop-filter: blur(0px);
  -webkit-backdrop-filter: blur(0px);
  transition: background 0.4s ease, backdrop-filter 0.4s ease;
  z-index: -1;
}

.site-header.scrolled {
  border-bottom-color: var(--border);
}

.site-header.scrolled::before {
  background: rgba(248, 247, 244, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-logo {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  flex-shrink: 0;
}

.brand-name {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--text);
}

.nav-panel {
  display: flex;
  align-items: center;
  gap: 32px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.site-nav a {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.82rem;
  color: var(--muted);
  letter-spacing: 0.02em;
  transition: color 0.2s;
  position: relative;
}

.site-nav a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--text);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.site-nav a:hover { color: var(--text); }
.site-nav a:hover::after { transform: scaleX(1); }

.header-contact {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.82rem;
  color: var(--muted);
  white-space: nowrap;
  transition: color 0.2s;
}

.header-contact:hover { color: var(--text); }

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid var(--border-strong);
  background: transparent;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  border-radius: 4px;
}

.nav-toggle span {
  width: 16px;
  height: 1px;
  background: var(--text);
  transition: transform 0.25s ease;
}

body.is-nav-open .nav-toggle span:first-child {
  transform: translateY(3px) rotate(45deg);
}
body.is-nav-open .nav-toggle span:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

/* ─── Hero ────────────────────────────── */

.hero {
  display: flex;
  align-items: center;
  min-height: 100svh;
  padding: calc(var(--header-h) + 40px) 0 80px;
  border-bottom: 1px solid var(--border);
}

.hero-inner {
  width: 100%;
}

.hero-label {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 32px;
}

h1 {
  font-family: "Instrument Serif", serif;
  font-weight: 400;
  font-size: clamp(3.6rem, 8vw, 7.5rem);
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin: 0 0 36px;
}

/* Mask slide-in per line */
.h1-line {
  display: block;
  overflow: hidden;
}

.h1-line-inner {
  display: block;
  animation: maskUp 1s cubic-bezier(0.16, 1, 0.3, 1) var(--d, 0s) both;
}

@keyframes maskUp {
  from { transform: translateY(108%); }
  to   { transform: translateY(0); }
}

.hero-sub {
  font-size: 1rem;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 44px;
  max-width: 32rem;
}

.hero-cta {
  display: flex;
  align-items: center;
  gap: 24px;
}

.cta-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 44px;
  padding: 0 24px;
  background: var(--text);
  color: var(--bg);
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  border-radius: 4px;
  transition: opacity 0.2s;
}

.cta-primary::after {
  content: "→";
  font-size: 0.9em;
  transition: transform 0.2s;
}

.cta-primary:hover { opacity: 0.75; }
.cta-primary:hover::after { transform: translateX(3px); }
.cta-primary { transition: opacity 0.2s, transform 0.5s cubic-bezier(0.16, 1, 0.3, 1); }

.cta-email {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.82rem;
  color: var(--muted);
  letter-spacing: 0.01em;
}

/* Fade-in for non-masked hero elements */
.anim-fade {
  animation: fadeUp 0.8s cubic-bezier(0.16, 1, 0.3, 1) var(--d, 0s) both;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ─── Section base ────────────────────── */

.section {
  padding: 96px 0;
  border-bottom: 1px solid var(--border);
}

.section-label {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.67rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 40px;
}

/* ─── About ───────────────────────────── */

.about-body p {
  font-size: 1.15rem;
  line-height: 2;
  color: var(--muted);
  max-width: 38rem;
}

/* ─── Services ────────────────────────── */

.services-list {
  border-top: 1px solid var(--border);
}

.service-item {
  display: flex;
  align-items: baseline;
  gap: 28px;
  padding: 24px 0;
  border-bottom: 1px solid var(--border);
  transition: transform 0.35s cubic-bezier(0.16, 1, 0.3, 1),
              color 0.25s;
}

.service-item:hover {
  transform: translateX(8px);
}

.service-num {
  font-family: "Space Grotesk", monospace;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--border-strong);
  flex-shrink: 0;
  transition: color 0.25s;
}

.service-item:hover .service-num {
  color: var(--muted);
}

.service-title {
  font-size: 1.1rem;
  font-weight: 400;
  letter-spacing: 0;
}

/* ─── Contact ─────────────────────────── */

.contact-heading {
  font-family: "Instrument Serif", serif;
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 400;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 40px;
}

.contact-block {
  display: grid;
  gap: 12px;
}

.contact-mail {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 1.15rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border-strong);
  transition: border-color 0.2s;
}

.contact-mail::after {
  content: "→";
  font-size: 0.88em;
  color: var(--muted);
  transition: transform 0.2s;
}

.contact-mail:hover { border-color: var(--text); }
.contact-mail:hover::after { transform: translateX(4px); }

.contact-note {
  font-size: 0.85rem;
  color: var(--muted);
  line-height: 1.7;
}

/* ─── Scroll reveal ───────────────────── */

.reveal {
  opacity: 0;
  transform: translateY(20px);
  filter: blur(4px);
  transition:
    opacity  0.75s cubic-bezier(0.16, 1, 0.3, 1) var(--reveal-delay, 0s),
    transform 0.75s cubic-bezier(0.16, 1, 0.3, 1) var(--reveal-delay, 0s),
    filter   0.75s cubic-bezier(0.16, 1, 0.3, 1) var(--reveal-delay, 0s);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
  filter: blur(0);
}

/* ─── Reduced motion ──────────────────── */

@media (prefers-reduced-motion: reduce) {
  .h1-line-inner, .anim-fade, .ch {
    animation: none;
  }
  .reveal {
    opacity: 1;
    transform: none;
    filter: none;
    transition: none;
  }
  .scroll-progress { display: none; }
}

/* ─── Responsive: 900px ───────────────── */

@media (max-width: 900px) {
  .page { padding: 0 32px; }
  .site-header { padding: 0 32px; }
}

/* ─── Responsive: 760px ───────────────── */

@media (max-width: 760px) {
  .page { padding: 0 20px; }
  .site-header { padding: 0 20px; }

  body.is-nav-open { overflow: hidden; }

  .nav-toggle { display: inline-flex; }

  .nav-panel {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    gap: 0;
    padding: 28px 20px;
    background: var(--bg);
    border-top: 1px solid var(--border-strong);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease;
    z-index: 40;
  }

  body.is-nav-open .nav-panel {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .site-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    width: 100%;
  }

  .site-nav a {
    display: block;
    padding: 14px 0;
    border-bottom: 1px solid var(--border);
    width: 100%;
    font-size: 1rem;
    color: var(--text);
  }

  .site-nav a::after { display: none; }

  .header-contact {
    margin-top: 20px;
    font-size: 0.88rem;
  }

  .hero {
    padding-top: calc(var(--header-h) + 24px);
    padding-bottom: 64px;
    min-height: 100svh;
  }

  .hero-cta { flex-direction: column; align-items: flex-start; gap: 12px; }

  .cta-email { display: none; }

  .service-item { gap: 16px; }
}

/* ─── Responsive: 480px ───────────────── */

@media (max-width: 480px) {
  h1 { font-size: clamp(2.8rem, 13vw, 4rem); }

  .section { padding: 72px 0; }

  .about-body p { font-size: 1rem; }
}

/* ─── H1 char stagger ─────────────────── */

.h1-line-inner.is-split { animation: none; }

.ch {
  display: inline-block;
  animation: charUp 1s cubic-bezier(0.16, 1, 0.3, 1) var(--char-delay, 0s) both;
}

@keyframes charUp {
  from { transform: translateY(110%); }
  to   { transform: translateY(0); }
}

/* ─── Scroll progress bar ─────────────── */

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: var(--text);
  transform-origin: left;
  transform: scaleX(0);
  z-index: 200;
  pointer-events: none;
  opacity: 0.22;
}

/* ─── Active nav section ──────────────── */

.site-nav a.is-active { color: var(--text); }
.site-nav a.is-active::after { transform: scaleX(1); }

/* ─── Skip link ───────────────────────── */

.skip-link {
  position: absolute;
  top: -200%;
  left: 16px;
  padding: 8px 16px;
  background: var(--text);
  color: var(--bg);
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.82rem;
  border-radius: 0 0 4px 4px;
  z-index: 9999;
  transition: top 0.2s;
}

.skip-link:focus { top: 0; }

/* ─── Footer ──────────────────────────── */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
}

.footer-copy {
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.04em;
  margin: 0;
}