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

main { opacity: 0; }

body {
  font-family: 'Inter', -apple-system, sans-serif;
  font-weight: 300;
  background: #fff;
  color: rgba(0, 0, 0, 0.55);
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

/* Language toggle */
.lang-toggle {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
  z-index: 200;
  display: flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 11px;
  font-weight: 200;
  letter-spacing: 0.05em;
  color: rgba(0, 0, 0, 0.55);
}
.lang-toggle span { opacity: 0.4; }
.lang-toggle button {
  background: none;
  border: none;
  cursor: pointer;
  font: inherit;
  color: inherit;
  padding: 0;
  letter-spacing: inherit;
  transition: opacity 0.15s;
}
.lang-toggle button.active {
  text-decoration: underline;
  text-underline-offset: 3px;
}
.lang-toggle button:not(.active):hover { opacity: 0.35; }

/* Language visibility */
[data-lang="en"] .ja { display: none; }
[data-lang="ja"] .en { display: none; }

/* Site header */
.site-header {
  position: fixed;
  top: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 89;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
}
.site-title {
  font-size: 13px;
  font-weight: 200;
  letter-spacing: 0.05em;
  color: rgba(0, 0, 0, 0.55);
  text-decoration: none;
  white-space: nowrap;
  transition: opacity 0.15s;
}
.site-title:hover { opacity: 0.3; }
.page-name {
  font-size: 10px;
  font-weight: 200;
  letter-spacing: 0.06em;
  color: rgba(0, 0, 0, 0.3);
  white-space: nowrap;
}

/* Hamburger */
.menu-btn {
  position: fixed;
  top: 1.5rem;
  left: 1.5rem;
  z-index: 100;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}
.menu-btn span {
  display: block;
  width: 20px;
  height: 1.5px;
  background: rgba(0, 0, 0, 0.55);
  transition: transform 0.25s, opacity 0.25s;
}
.menu-btn:hover span { opacity: 0.35; }
.menu-btn.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.menu-btn.open span:nth-child(2) { opacity: 0; }
.menu-btn.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* Side panel */
.side-panel {
  position: fixed;
  top: 0;
  left: 0;
  height: 100%;
  width: 240px;
  background: #fff;
  z-index: 90;
  transform: translateX(-100%);
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  padding: 5rem 2rem 2rem;
  border-right: 1px solid rgba(0, 0, 0, 0.06);
}
.side-panel.open { transform: translateX(0); }

.side-panel nav {
  display: flex;
  flex-direction: column;
}
.side-panel nav a {
  font-size: 13px;
  font-weight: 300;
  color: rgba(0, 0, 0, 0.5);
  text-decoration: none;
  padding: 0.5rem 0;
  letter-spacing: 0.03em;
  transition: opacity 0.15s;
}
.side-panel nav a:hover { opacity: 0.3; }
.side-panel nav a.active { opacity: 0.9; }

/* Overlay */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: none;
}
.overlay.open { display: block; }

/* Main */
main {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

.tagline {
  font-size: 13px;
  font-weight: 300;
  letter-spacing: 0.02em;
  color: rgba(0, 0, 0, 0.55);
  line-height: 1.8;
  text-align: center;
}

.page-label {
  font-size: 11px;
  font-weight: 200;
  letter-spacing: 0.1em;
  color: rgba(0, 0, 0, 0.28);
  text-transform: uppercase;
}

/* Contact */
.contact-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}
.contact-label {
  font-size: 11px;
  font-weight: 200;
  letter-spacing: 0.06em;
  color: rgba(0, 0, 0, 0.3);
}
.contact-email {
  font-size: 13px;
  font-weight: 300;
  letter-spacing: 0.03em;
  color: rgba(0, 0, 0, 0.55);
  text-decoration: none;
  transition: opacity 0.15s;
}
.contact-email:hover { opacity: 0.35; }

/* About — EN */
.about-text {
  max-width: 380px;
  text-align: center;
}
.about-text p {
  font-size: 12px;
  font-weight: 300;
  color: rgba(0, 0, 0, 0.6);
  line-height: 1.9;
  letter-spacing: 0.01em;
}

/* About — JA */
.about-qa {
  max-width: 420px;
  width: 100%;
}
.qa-item {
  padding: 1rem 0;
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}
.qa-item:first-child { border-top: 1px solid rgba(0, 0, 0, 0.06); }
.qa-item .q {
  font-size: 12px;
  font-weight: 300;
  color: rgba(0, 0, 0, 0.4);
  margin-bottom: 0.4rem;
  letter-spacing: 0.01em;
}
.qa-item .a {
  font-size: 12px;
  font-weight: 300;
  color: rgba(0, 0, 0, 0.75);
  letter-spacing: 0.01em;
  line-height: 1.7;
}

/* Playground */
.project-list {
  width: 100%;
  max-width: 420px;
}
.project-list a {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.75rem 0;
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
  text-decoration: none;
  color: rgba(0, 0, 0, 0.55);
  font-size: 13px;
  font-weight: 300;
  letter-spacing: 0.01em;
  transition: opacity 0.15s;
}
.project-list a:first-child { border-top: 1px solid rgba(0, 0, 0, 0.06); }
.project-list a:hover { opacity: 0.35; }
.project-list a .url {
  font-size: 11px;
  font-weight: 200;
  color: rgba(0, 0, 0, 0.3);
}