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

body {
  background: #fafaf9;
  color: #1a1a1a;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* ================================================================
   Hero
================================================================ */
.hero {
  position: relative;
  height: 100svh;
  min-height: 480px;
  width: 100%;
  display: flex;
  align-items: flex-end;
  justify-content: flex-start;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  opacity: 0;
  transform: scale(1.05);
  animation: heroReveal 2s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

@keyframes heroReveal {
  to { opacity: 1; transform: scale(1); }
}

.hero-title {
  position: relative;
  z-index: 10;
  padding: 0 1.5rem 3rem;
  max-width: 56rem;
  opacity: 0;
  transform: translateY(60px);
  animation: slideUp 1.2s cubic-bezier(0.22, 1, 0.36, 1) 0.6s forwards;
}

@media (min-width: 640px)  { .hero-title { padding: 0 2.5rem 4rem; } }
@media (min-width: 1024px) { .hero-title { padding: 0 5rem 4rem; } }

.hero-title h1 {
  font-size: clamp(2.8rem, 11vw, 8rem);
  font-weight: 300;
  line-height: 0.92;
  letter-spacing: -0.02em;
  color: white;
  mix-blend-mode: difference;
}

.h1-particle { display: block; }
.h1-flow     { display: block; text-align: center; }

@keyframes slideUp {
  to { opacity: 1; transform: translateY(0); }
}

.scroll-indicator {
  position: absolute;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 10;
  cursor: pointer;
  background: none;
  border: none;
  padding: 0.5rem;
  opacity: 0;
  mix-blend-mode: difference;
  animation: fadeIn 0.4s ease 2.5s forwards;
}

@media (min-width: 768px) { .scroll-indicator { right: 4rem; bottom: 2rem; } }

@keyframes fadeIn { to { opacity: 1; } }

.scroll-indicator svg {
  animation: bounce 2s ease-in-out infinite;
  display: block;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(8px); }
}

/* ================================================================
   共通
================================================================ */
.content { position: relative; background: #fafaf9; }

section {
  padding: 4rem 1.5rem;
}
@media (min-width: 640px)  { section { padding: 6rem 2.5rem; } }
@media (min-width: 1024px) { section { padding: 8rem 5rem; } }

.max-w { max-width: 80rem; margin: 0 auto; }

.label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: #9ca3af;
}
@media (min-width: 640px) { .label { font-size: 0.75rem; } }

.heading-xl {
  font-size: clamp(2rem, 8vw, 3rem);
  font-weight: 300;
  line-height: 1.05;
  margin-bottom: 1.5rem;
}
@media (min-width: 640px) { .heading-xl { line-height: 1.0; margin-bottom: 2rem; } }

/* ================================================================
   About
================================================================ */
.about-grid {
  display: grid;
  gap: 2rem;
}
@media (min-width: 768px) {
  .about-grid {
    grid-template-columns: 2fr 10fr;
    gap: 3rem;
  }
}

.about-label { padding-top: 0.25rem; }

.text-body {
  font-size: clamp(1rem, 2.5vw, 1.375rem);
  color: #4b5563;
  line-height: 1.75;
  max-width: 48rem;
}

/* ================================================================
   Dark sections
================================================================ */
.dark-section { background: #1a1a1a; color: white; }
.dark-section .heading-xl { color: white; }

.dark-text {
  font-size: clamp(1rem, 2.5vw, 1.375rem);
  color: #d1d5db;
  line-height: 1.75;
}

.dark-inner {
  max-width: 56rem;
  margin: 0;
}
@media (min-width: 768px) { .dark-inner { margin-left: auto; } }

/* ================================================================
   Operations
================================================================ */
.ops-header { margin-bottom: 3rem; }
@media (min-width: 640px) { .ops-header { margin-bottom: 5rem; } }

.ops-header .label {
  display: block;
  margin-bottom: 1rem;
}
@media (min-width: 640px) { .ops-header .label { margin-bottom: 1.5rem; } }

.ops-header h2 { max-width: 48rem; }

.op-card {
  border-top: 1px solid #e5e7eb;
  padding: 1.5rem 0;
  transition: background-color 0.5s;
}
@media (min-width: 640px) { .op-card { padding: 2rem 0; } }
.op-card:hover { background: rgba(249, 250, 251, 0.5); }

/* モバイル: 番号+タイトル横並び → 説明を下に */
.op-header-row {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 0.75rem;
}

/* デスクトップ: 3カラムグリッド */
@media (min-width: 768px) {
  .op-card-inner {
    display: grid;
    grid-template-columns: 1.5rem 1fr 2fr;
    gap: 2rem;
    align-items: start;
  }
  .op-header-row {
    display: contents;
  }
  .op-header-row .op-num,
  .op-header-row .op-title-wrap {
    display: block;
  }
}

.op-num {
  font-size: 0.8rem;
  color: #9ca3af;
  font-weight: 300;
  flex-shrink: 0;
  min-width: 1.5rem;
  padding-top: 0.3rem;
}

.op-title {
  font-size: clamp(1.4rem, 4vw, 2.25rem);
  font-weight: 300;
}

.op-key {
  display: block;
  font-size: 0.8rem;
  color: #6b7280;
  font-family: monospace;
  letter-spacing: 0.05em;
  margin-top: 0.3rem;
}

.op-desc {
  color: #4b5563;
  font-size: clamp(0.95rem, 1.5vw, 1.125rem);
  line-height: 1.75;
}

.op-video {
  display: block;
  width: 100%;
  max-width: 100%;
  margin-top: 1.25rem;
  border-radius: 6px;
  background: #000;
}

.ops-note {
  margin-top: 2rem;
  font-size: 0.8rem;
  color: #9ca3af;
}

.ops-other {
  margin-top: 1.25rem;
  display: flex;
  align-items: baseline;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.ops-other-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: #9ca3af;
  flex-shrink: 0;
}

.ops-other-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}

.ops-other-item {
  font-size: 0.85rem;
  color: #6b7280;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.ops-other-key {
  font-family: monospace;
  font-size: 0.75rem;
  background: #f3f4f6;
  border: 1px solid #e5e7eb;
  border-radius: 4px;
  padding: 0.1rem 0.45rem;
  color: #374151;
}

/* stagger */
.op-card:nth-child(1) { transition-delay: 0s; }
.op-card:nth-child(2) { transition-delay: 0.08s; }
.op-card:nth-child(3) { transition-delay: 0.16s; }
.op-card:nth-child(4) { transition-delay: 0.24s; }
.op-card:nth-child(5) { transition-delay: 0.32s; }

/* ================================================================
   Parameters
================================================================ */
.params-section { background: #f5f5f4; }

.params-grid {
  display: grid;
  gap: 3rem;
}
@media (min-width: 768px) {
  .params-grid { grid-template-columns: 1fr 1fr; gap: 5rem; }
}

.params-heading {
  font-size: clamp(2rem, 6vw, 3.75rem);
  font-weight: 300;
  line-height: 1.1;
  margin-bottom: 1.25rem;
}
@media (min-width: 640px) { .params-heading { margin-bottom: 2rem; } }

.params-desc {
  color: #4b5563;
  font-size: clamp(1rem, 1.5vw, 1.125rem);
}

.params-label {
  display: block;
  margin-bottom: 1rem;
}
@media (min-width: 640px) { .params-label { margin-bottom: 1.5rem; } }

.param-items {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}
@media (min-width: 640px) { .param-items { gap: 3rem; } }

.param-item {
  border-left: 2px solid #1a1a1a;
  padding-left: 1.5rem;
}
@media (min-width: 640px) { .param-item { padding-left: 2rem; } }

.param-item h3 {
  font-size: clamp(1.1rem, 2.5vw, 1.875rem);
  font-weight: 300;
  margin-bottom: 0.4rem;
}

.param-item p {
  color: #4b5563;
  font-size: clamp(0.9rem, 1.5vw, 1rem);
  line-height: 1.6;
}

/* パラメータ説明画像 */
.param-img {
  display: block;
  width: 100%;
  max-width: 100%;
  margin-top: 1rem;
  border-radius: 6px;
  border: 1px solid #e5e7eb;
  background: #f9f9f8;
  object-fit: contain;
  cursor: zoom-in;
  transition: opacity 0.2s;
}
.param-img:hover { opacity: 0.85; }

/* ---- Lightbox ---- */
#lightbox {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}
#lightbox.active { display: flex; }

.lightbox-bg {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.85);
  animation: lbFadeIn 0.2s ease;
}
@keyframes lbFadeIn { from { opacity: 0; } to { opacity: 1; } }

#lightbox-img {
  position: relative;
  max-width: min(90vw, 1000px);
  max-height: 90svh;
  width: auto;
  height: auto;
  object-fit: contain;
  border-radius: 6px;
  animation: lbZoomIn 0.25s cubic-bezier(0.22, 1, 0.36, 1);
  cursor: default;
}
@keyframes lbZoomIn {
  from { opacity: 0; transform: scale(0.92); }
  to   { opacity: 1; transform: scale(1); }
}

#lightbox-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  z-index: 1001;
  background: rgba(255,255,255,0.15);
  border: none;
  color: white;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  font-size: 1.25rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}
#lightbox-close:hover { background: rgba(255,255,255,0.3); }

.params-note {
  color: #6b7280;
  font-style: italic;
  padding-top: 0.5rem;
  font-size: 0.875rem;
}
.params-note-link {
  display: inline-block;
  text-decoration: none;
  border-bottom: 1px solid #d1d5db;
  transition: color 0.2s, border-color 0.2s;
}
.params-note-link:hover { color: #1a1a1a; border-color: #1a1a1a; }

/* ================================================================
   Recommendations
================================================================ */
.rec-header { margin-bottom: 3rem; }
@media (min-width: 640px) { .rec-header { margin-bottom: 5rem; } }

.rec-header .label {
  display: block;
  margin-bottom: 1rem;
}
@media (min-width: 640px) { .rec-header .label { margin-bottom: 1.5rem; } }

.rec-grid {
  display: grid;
  gap: 1.25rem;
}
@media (min-width: 640px) { .rec-grid { gap: 1.5rem; } }
@media (min-width: 768px) { .rec-grid { grid-template-columns: 1fr 1fr; gap: 2rem; } }

.rec-grid > div {
  display: flex;
  flex-direction: column;
}

.rec-card {
  border: 1px solid #e5e7eb;
  padding: 1.75rem;
  transition: border-color 0.3s;
  height: 100%;
  display: flex;
  flex-direction: column;
}
@media (min-width: 640px) { .rec-card { padding: 2.5rem; } }
.rec-card:hover { border-color: #9ca3af; }

.rec-num {
  font-size: clamp(2.5rem, 6vw, 3.75rem);
  font-weight: 300;
  color: #d1d5db;
  margin-bottom: 1.25rem;
  transition: color 0.3s;
  line-height: 1;
}
@media (min-width: 640px) { .rec-num { margin-bottom: 2rem; } }
.rec-card:hover .rec-num { color: #9ca3af; }

.rec-video {
  width: 100%;
  margin-top: auto;
  padding-top: 1.5rem;
  border-radius: 4px;
}

.rec-title {
  font-size: clamp(1.1rem, 2.5vw, 1.75rem);
  font-weight: 300;
  margin-bottom: 0.5rem;
  line-height: 1.3;
}

.rec-subtitle {
  font-size: 0.8rem;
  color: #6b7280;
  margin-bottom: 1rem;
  font-family: monospace;
  letter-spacing: 0.05em;
}
@media (min-width: 640px) { .rec-subtitle { margin-bottom: 1.5rem; font-size: 0.875rem; } }

.rec-desc {
  color: #4b5563;
  line-height: 1.7;
  font-size: clamp(0.9rem, 1.5vw, 1rem);
}

/* stagger */
.rec-grid > div:nth-child(1) { transition-delay: 0s; }
.rec-grid > div:nth-child(2) { transition-delay: 0.08s; }
.rec-grid > div:nth-child(3) { transition-delay: 0.16s; }
.rec-grid > div:nth-child(4) { transition-delay: 0.24s; }

/* ================================================================
   Final (dark)
================================================================ */
.final-wrap {
  max-width: 64rem;
  margin: 0 auto;
}

.final-heading {
  font-size: clamp(1.75rem, 6vw, 3.75rem);
  font-weight: 300;
  line-height: 1.1;
  margin-bottom: 2rem;
  color: white;
}
@media (min-width: 640px) { .final-heading { margin-bottom: 3rem; } }

.final-text {
  font-size: clamp(1rem, 2vw, 1.375rem);
  color: #9ca3af;
  line-height: 1.75;
}

/* ================================================================
   Footer
================================================================ */
footer {
  padding: 2rem 1.5rem;
  border-top: 1px solid #e5e7eb;
  background: #fafaf9;
}
@media (min-width: 640px)  { footer { padding: 2.5rem 2.5rem; } }
@media (min-width: 1024px) { footer { padding: 3rem 5rem; } }

.footer-inner {
  max-width: 80rem;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.footer-inner p { font-size: 0.8rem; color: #9ca3af; }

/* ================================================================
   Language switcher
================================================================ */
.lang-switcher {
  position: fixed;
  top: 1.25rem;
  right: 1.25rem;
  z-index: 100;
  display: flex;
  gap: 0.15rem;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: 999px;
  padding: 0.35rem 0.5rem;
  box-shadow: 0 1px 8px rgba(0,0,0,0.08);
  border: 1px solid rgba(0,0,0,0.06);
}

.lang-btn {
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  border: none;
  background: none;
  font-size: 0.7rem;
  font-weight: 400;
  color: #9ca3af;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  line-height: 1.5;
  font-family: inherit;
}

.lang-btn:hover { color: #1a1a1a; }
.lang-btn.active { background: #1a1a1a; color: #fff; }

/* ================================================================
   Back to top button
================================================================ */
#back-to-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 100;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  border: 1px solid #e5e7eb;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: #6b7280;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 0.3s, transform 0.3s, color 0.2s, border-color 0.2s;
}

#back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

#back-to-top:hover {
  color: #1a1a1a;
  border-color: #9ca3af;
}

/* ================================================================
   Scroll animation
================================================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

.reveal-fade {
  opacity: 0;
  transition: opacity 0.9s ease;
}
.reveal-fade.visible { opacity: 1; }