:root {
  --ink: #12202b;
  --muted: #4d5d6a;
  --paper: #eef3f1;
  --panel: rgba(255, 255, 255, 0.55);
  --line: rgba(18, 32, 43, 0.12);
  --accent: #0f7a6c;
  --accent-ink: #073f38;
  --glow: #9fd7c8;
  --phone-shadow: 0 28px 60px rgba(18, 32, 43, 0.22);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  color: var(--ink);
  font-family: "Instrument Sans", sans-serif;
  background:
    radial-gradient(900px 520px at 12% -10%, var(--glow), transparent 60%),
    radial-gradient(700px 480px at 100% 0%, #d7e4f2, transparent 55%),
    linear-gradient(165deg, #f7faf8 0%, var(--paper) 45%, #e4ebe8 100%);
  overflow-x: hidden;
}

.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  opacity: 0.18;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.55'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
  z-index: 0;
}

.hero,
.flow,
.strip,
.guide,
.note,
footer {
  position: relative;
  z-index: 1;
}

.hero {
  min-height: 100svh;
  display: grid;
  align-items: center;
  gap: 0.85rem 1.5rem;
  padding: clamp(1.5rem, 5vw, 3.5rem);
  max-width: 72rem;
  margin: 0 auto;
  grid-template-columns: 1fr;
}

.hero-copy {
  max-width: 34rem;
}

.brand {
  margin: 0;
  font-family: "Newsreader", serif;
  font-size: clamp(3.4rem, 12vw, 6.4rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 0.92;
  opacity: 0;
  transform: translateY(18px);
  animation: rise 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) 0.05s forwards;
}

.brand-sub {
  margin: 0.15rem 0 0;
  font-family: "Instrument Sans", sans-serif;
  font-size: clamp(1.55rem, 5.5vw, 2.35rem);
  font-weight: 650;
  letter-spacing: 0.02em;
  line-height: 1.1;
  color: var(--accent-ink);
  opacity: 0;
  transform: translateY(14px);
  animation: rise 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) 0.12s forwards;
}

.tagline {
  margin: 0 0 0.35rem;
  font-family: "Newsreader", serif;
  font-size: clamp(1.55rem, 4.4vw, 2.35rem);
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.02em;
  opacity: 0;
  transform: translateY(18px);
  animation: rise 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) 0.18s forwards;
}

.lead {
  margin: 0;
  max-width: 34rem;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.65;
  opacity: 0;
  transform: translateY(18px);
  animation: rise 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) 0.32s forwards;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.35rem;
  opacity: 0;
  transform: translateY(18px);
  animation: rise 0.9s cubic-bezier(0.2, 0.8, 0.2, 1) 0.46s forwards;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.85rem;
  padding: 0.7rem 1.15rem;
  border-radius: 0.55rem;
  text-decoration: none;
  font-weight: 600;
  transition: transform 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(1px);
}

.btn.primary {
  background: var(--accent);
  color: #f4fffc;
}

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

.btn.ghost {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--line);
}

.btn.ghost:hover {
  background: var(--panel);
}

.hero-visual {
  justify-self: center;
  width: min(100%, 22rem);
  opacity: 0;
  transform: translateY(28px) scale(0.98);
  animation: rise-soft 1.05s cubic-bezier(0.2, 0.8, 0.2, 1) 0.28s forwards;
}

.hero-visual picture {
  display: block;
}

.hero-shot {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 1.15rem;
  box-shadow: var(--phone-shadow);
  object-fit: cover;
  object-position: top center;
}

.flow {
  padding: 0 clamp(1.5rem, 5vw, 3.5rem) 2rem;
  max-width: 72rem;
  margin: 0 auto;
}

.flow-title {
  margin: 0 0 1.25rem;
  font-family: "Newsreader", serif;
  font-size: clamp(1.55rem, 4.5vw, 2rem);
  letter-spacing: -0.02em;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.2;
}

.flow-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.75rem;
}

.flow-item {
  margin: 0;
  opacity: 0;
  transform: translateY(16px);
}

.flow-item.is-in {
  animation: rise 0.75s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.flow-item figure {
  margin: 0;
}

.flow-item img {
  display: block;
  width: 100%;
  max-width: 18rem;
  margin: 0 auto;
  height: auto;
  border-radius: 1rem;
  box-shadow: var(--phone-shadow);
}

.flow-item figcaption {
  margin-top: 0.85rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.98rem;
  line-height: 1.45;
}

.flow-item figcaption strong {
  display: block;
  margin-bottom: 0.2rem;
  color: var(--ink);
  font-size: 1.02rem;
}

.strip {
  display: grid;
  gap: 1rem;
  padding: 0 clamp(1.5rem, 5vw, 3.5rem) 1.25rem;
  max-width: 52rem;
  margin: 0 auto;
}

.strip p {
  margin: 0;
  padding: 0.95rem 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 1rem;
  opacity: 0;
  transform: translateX(-10px);
}

.strip p.is-in {
  animation: slide 0.7s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.strip strong {
  display: inline-block;
  min-width: 3.5rem;
  margin-right: 0.85rem;
  color: var(--ink);
}

.note {
  margin: 0 auto 3rem;
  padding: 0.25rem clamp(1.5rem, 5vw, 3.5rem) 0;
  max-width: 40rem;
}

.guide {
  position: relative;
  z-index: 1;
  margin: 0 auto 2.75rem;
  padding: 0 clamp(1.5rem, 5vw, 3.5rem);
  max-width: 40rem;
}

#install.guide {
  padding-top: 2.75rem;
  margin-top: 0.75rem;
}

.guide-title {
  margin: 0 0 0.85rem;
  font-family: "Newsreader", serif;
  font-size: clamp(1.55rem, 4.5vw, 2rem);
  letter-spacing: -0.02em;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.2;
}

.guide-lead {
  margin: 0 0 1.25rem;
  color: var(--muted);
  line-height: 1.65;
}

.guide-card {
  margin: 0 0 1.25rem;
  padding: 1.1rem 1.05rem 1.15rem;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--panel);
  backdrop-filter: blur(8px);
  opacity: 0;
  transform: translateY(14px);
}

.guide-card.is-in {
  animation: rise 0.75s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.guide-card h3 {
  margin: 0 0 0.55rem;
  font-size: clamp(1.2rem, 3.5vw, 1.4rem);
  font-family: "Newsreader", serif;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.guide-card h4 {
  margin: 1.1rem 0 0.45rem;
  font-size: 0.98rem;
  color: var(--ink);
}

.guide-note {
  margin: 0.65rem 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.55;
}

.guide-note a,
.guide-card a {
  color: var(--accent-ink);
  font-weight: 600;
}

.guide-steps {
  margin: 0.35rem 0 0;
  padding-left: 1.2rem;
  color: var(--ink);
  line-height: 1.55;
}

.guide-steps li {
  margin: 0.45rem 0;
}

.guide-list {
  margin: 0.35rem 0 0;
  padding-left: 1.2rem;
  color: var(--muted);
  line-height: 1.55;
}

.guide-list li {
  margin: 0.35rem 0;
}

.mono-link {
  word-break: break-all;
  font-size: 0.88rem;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.88em;
  padding: 0.08em 0.28em;
  border-radius: 0.3rem;
  background: rgba(18, 32, 43, 0.06);
}

.trouble {
  margin: 0;
}

.trouble > div {
  padding: 0.85rem 0;
  border-top: 1px solid var(--line);
}

.trouble > div:first-child {
  border-top: 0;
  padding-top: 0.15rem;
}

.trouble dt {
  margin: 0 0 0.3rem;
  font-weight: 700;
  color: var(--ink);
}

.trouble dd {
  margin: 0;
  color: var(--muted);
  line-height: 1.55;
  font-size: 0.95rem;
}

.note h2 {
  margin: 0 0 0.55rem;
  font-family: "Newsreader", serif;
  font-size: clamp(1.35rem, 4vw, 1.75rem);
  letter-spacing: -0.02em;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.2;
}

.note p {
  margin: 0;
  color: var(--muted);
  line-height: 1.7;
}

footer {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  padding: 1.25rem clamp(1.5rem, 5vw, 3.5rem) 2rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.92rem;
}

footer a {
  color: var(--ink);
  text-decoration: none;
  font-weight: 600;
}

footer a:hover {
  text-decoration: underline;
}

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

@keyframes rise-soft {
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes slide {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@media (min-width: 860px) {
  .hero {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    grid-template-areas:
      "brand visual"
      "brand-sub visual"
      "tagline visual"
      "lead visual"
      "actions visual";
    column-gap: 2.5rem;
    row-gap: 0.55rem;
    align-items: center;
    padding-block: clamp(1.5rem, 5vw, 3.25rem) clamp(1.25rem, 3vw, 2rem);
  }

  .brand {
    grid-area: brand;
    align-self: end;
    margin-bottom: 0;
  }

  .brand-sub {
    grid-area: brand-sub;
    align-self: start;
    margin-top: 0;
  }

  .tagline {
    grid-area: tagline;
    align-self: start;
    margin: 0;
  }

  .lead {
    grid-area: lead;
    align-self: start;
  }

  .actions {
    grid-area: actions;
    align-self: start;
    margin-top: 0.5rem;
  }

  .hero-visual {
    grid-area: visual;
    width: min(100%, 26rem);
    justify-self: end;
    align-self: center;
  }

  .hero-shot {
    max-height: calc(100svh - 4rem);
    width: auto;
    max-width: 100%;
    margin-left: auto;
  }

  .flow-list {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    align-items: start;
  }

  .flow-item img {
    max-width: none;
  }

  .strip {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem;
    max-width: 72rem;
  }

  .strip p {
    border-top: 0;
    border-left: 1px solid var(--line);
    padding: 0 0 0 1rem;
  }

  .strip p:first-child {
    border-left: 0;
    padding-left: 0;
  }
}

@media (max-width: 859px) {
  .hero {
    min-height: auto;
    padding-top: max(1.25rem, env(safe-area-inset-top));
    padding-bottom: 0.65rem;
    gap: 1.25rem;
  }

  .brand {
    font-size: clamp(2.6rem, 14vw, 3.6rem);
    margin-bottom: 0;
  }

  .brand-sub {
    margin: 0.25rem 0 0.65rem;
    font-size: clamp(1.45rem, 7vw, 2rem);
  }

  .tagline {
    font-size: clamp(1.25rem, 5.5vw, 1.65rem);
  }

  .lead {
    font-size: 0.98rem;
    line-height: 1.55;
  }

  .actions {
    margin-top: 0.15rem;
  }

  .btn {
    flex: 1 1 auto;
    min-width: calc(50% - 0.4rem);
  }

  .hero-visual {
    width: min(100%, 15.5rem);
    justify-self: center;
    margin: 0.15rem 0 0.35rem;
  }

  /* 3ステップは横スワイプで短く見せる */
  .flow {
    padding-inline: 0;
  }

  .flow-title {
    padding-inline: clamp(1.5rem, 5vw, 3.5rem);
  }

  .flow-list {
    display: flex;
    gap: 1rem;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
    padding: 0.15rem clamp(1.5rem, 5vw, 3.5rem) 0.75rem;
    scrollbar-width: none;
  }

  .flow-list::-webkit-scrollbar {
    display: none;
  }

  .flow-item {
    flex: 0 0 min(72vw, 15.5rem);
    scroll-snap-align: start;
  }

  .flow-item img {
    max-width: none;
    width: 100%;
  }

  .flow-item figcaption {
    font-size: 0.92rem;
  }

  .strip {
    gap: 0;
  }

  .strip p {
    padding: 0.8rem 0;
    font-size: 0.95rem;
  }
}