/* ================================================================
   VARIABLES
================================================================ */
:root {
  --color-bg: #F8F7F4;
  --color-text: #1A1A1A;
  --color-accent: #2D6A4F;
  --color-accent-dark: #1F4F38;
  --color-surface: #FFFFFF;
  --color-muted: #9E9E9E;
  --color-border: #E8E6E1;

  --font-serif: 'Noto Serif JP', serif;
  --font-sans: 'Noto Sans JP', sans-serif;
  --font-en: 'Inter', sans-serif;

  --max-width: 1200px;
  --section-py: 120px;
  --container-px: 24px;
  --header-h: 70px;

  --transition: 0.3s ease;
}

/* ================================================================
   RESET & BASE
================================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

section {
  scroll-margin-top: var(--header-h);
}

/* ================================================================
   CONTAINER
================================================================ */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--container-px);
}

/* ================================================================
   HEADER
================================================================ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  z-index: 100;
  background-color: rgba(248, 247, 244, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.site-header.scrolled {
  border-color: var(--color-border);
  box-shadow: 0 1px 20px rgba(0, 0, 0, 0.04);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--container-px);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-family: var(--font-en);
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--color-text);
  transition: color var(--transition);
}

.site-logo:hover {
  color: var(--color-accent);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 40px;
}

.site-nav a {
  font-family: var(--font-en);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text);
  position: relative;
  transition: color var(--transition);
}

.site-nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background-color: var(--color-accent);
  transition: width var(--transition);
}

.site-nav a:hover {
  color: var(--color-accent);
}

.site-nav a:hover::after {
  width: 100%;
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  z-index: 200;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background-color: var(--color-text);
  transition: transform var(--transition), opacity var(--transition);
  transform-origin: center;
}

.nav-toggle.active span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ================================================================
   SECTION COMMON
================================================================ */
.section {
  padding: var(--section-py) 0;
}

.section-alt {
  background-color: var(--color-surface);
}

.section-header {
  margin-bottom: 64px;
}

.section-label {
  display: block;
  font-family: var(--font-en);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 12px;
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 400;
  line-height: 1.3;
}

/* ================================================================
   HERO
================================================================ */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: calc(var(--header-h) + 60px) 0 80px;
  position: relative;
}

.hero-content {
  max-width: 780px;
}

.hero-label {
  display: block;
  font-family: var(--font-en);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 36px;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(2.8rem, 8vw, 5.5rem);
  font-weight: 400;
  line-height: 1.35;
  letter-spacing: 0.04em;
  margin-bottom: 28px;
}

.hero-sub {
  font-family: var(--font-en);
  font-size: 0.9rem;
  color: var(--color-muted);
  letter-spacing: 0.06em;
  margin-bottom: 52px;
}

/* Button */
.btn {
  display: inline-block;
  padding: 14px 40px;
  font-family: var(--font-en);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  transition: background-color var(--transition), color var(--transition);
}

.btn-primary {
  background-color: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background-color: var(--color-accent-dark);
}

/* Scroll indicator */
.hero-scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.hero-scroll-text {
  font-family: var(--font-en);
  font-size: 0.65rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.hero-scroll-line {
  width: 1px;
  height: 56px;
  background-color: var(--color-border);
  position: relative;
  overflow: hidden;
}

.hero-scroll-line::after {
  content: '';
  position: absolute;
  top: -100%;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: var(--color-accent);
  animation: scrollDown 2.2s ease infinite;
}

@keyframes scrollDown {
  0%   { top: -100%; }
  100% { top: 100%; }
}

/* ================================================================
   ABOUT
================================================================ */
.about-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
}

.about-card {
  background-color: var(--color-surface);
  padding: 48px 40px;
  transition-delay: var(--delay, 0s);
}

.about-card-title {
  font-family: var(--font-en);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 20px;
}

.about-card p {
  font-size: 0.9rem;
  line-height: 2;
  color: #444;
}

.skill-list li {
  font-size: 0.9rem;
  line-height: 2.2;
  color: #444;
  padding-left: 14px;
  position: relative;
}

.skill-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: var(--color-accent);
}

/* ================================================================
   WORKS
================================================================ */
.works-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.work-card {
  background-color: var(--color-surface);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
  transition-delay: var(--delay, 0s);
}

.work-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.08);
}

.work-card-image {
  aspect-ratio: 16 / 10;
  background-color: var(--card-color, var(--color-accent));
  position: relative;
  overflow: hidden;
}

.work-card-image::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.06) 0%, transparent 60%);
}

.work-card-body {
  padding: 32px;
}

.work-tag {
  display: inline-block;
  font-family: var(--font-en);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  border: 1px solid var(--color-accent);
  padding: 3px 10px;
  margin-bottom: 16px;
}

.work-title {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  line-height: 1.5;
  margin-bottom: 12px;
}

.work-desc {
  font-size: 0.875rem;
  color: #666;
  line-height: 1.9;
  margin-bottom: 24px;
}

.work-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-en);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--color-accent);
  transition: gap var(--transition);
}

.work-link:hover {
  gap: 14px;
}

/* ================================================================
   PROCESS
================================================================ */
.process-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 48px;
}

.process-step {
  transition-delay: var(--delay, 0s);
}

.process-num {
  display: block;
  font-family: var(--font-en);
  font-size: 2.8rem;
  font-weight: 300;
  color: var(--color-border);
  line-height: 1;
  margin-bottom: 24px;
  letter-spacing: -0.02em;
}

.process-title {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 14px;
}

.process-desc {
  font-size: 0.875rem;
  color: #666;
  line-height: 1.9;
}

/* ================================================================
   CONTACT
================================================================ */
.contact-content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.contact-lead {
  font-size: 1rem;
  color: #555;
  margin-top: 8px;
  margin-bottom: 48px;
  line-height: 1.9;
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
}

.contact-link {
  display: inline-block;
  font-family: var(--font-en);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 4px;
  transition: color var(--transition), border-color var(--transition);
}

.contact-link:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* ================================================================
   FOOTER
================================================================ */
.site-footer {
  padding: 40px 0;
  background-color: var(--color-text);
  color: rgba(255, 255, 255, 0.5);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-logo {
  font-family: var(--font-en);
  font-size: 0.9rem;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.85);
  letter-spacing: 0.05em;
}

.footer-copy {
  font-family: var(--font-en);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
}

/* ================================================================
   SCROLL ANIMATIONS
================================================================ */
.fade-in {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
  transition-delay: var(--delay, 0s);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ================================================================
   RESPONSIVE
================================================================ */
@media (max-width: 1024px) {
  :root {
    --section-py: 90px;
  }

  .process-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
  }
}

@media (max-width: 768px) {
  :root {
    --section-py: 72px;
  }

  /* Mobile nav */
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background-color: var(--color-surface);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 44px;
    transition: right var(--transition);
    box-shadow: -24px 0 48px rgba(0, 0, 0, 0.08);
    z-index: 150;
  }

  .site-nav.open {
    right: 0;
  }

  .site-nav a {
    font-size: 0.9rem;
    letter-spacing: 0.16em;
  }

  /* About */
  .about-grid {
    grid-template-columns: 1fr;
  }

  /* Works */
  .works-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  /* Process */
  .process-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  /* Footer */
  .footer-inner {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

  /* Hero scroll */
  .hero-scroll {
    display: none;
  }
}

@media (max-width: 480px) {
  .about-card {
    padding: 36px 24px;
  }

  .work-card-body {
    padding: 24px;
  }
}

.work-card-image--photo {
  background-size: cover;
  background-position: center;
  background-color: #000;
}

.work-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}

.work-ai-note {
  display: block;
  margin-top: 8px;
  font-size: 0.75rem;
  color: var(--color-muted);
  line-height: 1.6;
}