:root {
  --ink: #15202b;
  --ink-soft: #3a4a5a;
  --sky: #3a9ee0;
  --sky-deep: #1f7fc0;
  --mist: #d9e8f4;
  --paper: #eef4f9;
  --white: #fbfcfe;
  --line: rgba(21, 32, 43, 0.12);
  --shadow: 0 24px 60px rgba(31, 70, 110, 0.18);
  --font-display: "Sora", "Noto Sans SC", sans-serif;
  --font-body: "Noto Sans SC", "Sora", sans-serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.65;
  background:
    radial-gradient(1200px 700px at 12% -10%, #c8e4f8 0%, transparent 55%),
    radial-gradient(900px 600px at 100% 8%, #b7d8ef 0%, transparent 50%),
    linear-gradient(165deg, #f7fbfe 0%, var(--paper) 42%, #e3eef7 100%);
  min-height: 100vh;
  overflow-x: hidden;
}

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

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

.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 50;
  opacity: 0.045;
  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='0.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}

.top {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem clamp(1.25rem, 4vw, 3rem);
  backdrop-filter: blur(14px);
  background: rgba(247, 251, 254, 0.72);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s var(--ease), background 0.3s var(--ease);
}

.top.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(247, 251, 254, 0.9);
}

.top-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.04em;
}

.top-nav {
  display: flex;
  gap: 1.5rem;
  font-size: 0.92rem;
  color: var(--ink-soft);
}

.top-nav a {
  position: relative;
}

.top-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -0.2rem;
  width: 100%;
  height: 1px;
  background: var(--sky);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease);
}

.top-nav a:hover::after {
  transform: scaleX(1);
}

.hero {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
  min-height: calc(100svh - 4rem);
  padding: clamp(2rem, 6vh, 4rem) clamp(1.25rem, 4vw, 3rem) clamp(3rem, 8vh, 5rem);
}

.hero-copy {
  max-width: 34rem;
  animation: rise 0.9s var(--ease) both;
}

.brand {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(3.4rem, 8vw, 5.6rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.06em;
  color: var(--ink);
}

.hero h1 {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 3.2vw, 2.25rem);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.lead {
  margin: 0 0 1.75rem;
  color: var(--ink-soft);
  font-size: 1.05rem;
  max-width: 28rem;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  align-items: center;
}

.btn-primary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.85rem;
  padding: 0 1.35rem;
  border-radius: 0.55rem;
  font-weight: 500;
  font-size: 0.98rem;
  transition: transform 0.25s var(--ease), background 0.25s var(--ease), color 0.25s var(--ease), border-color 0.25s var(--ease);
}

.btn-primary {
  background: var(--ink);
  color: var(--white);
  border: 1px solid var(--ink);
}

.btn-primary:hover {
  background: var(--sky-deep);
  border-color: var(--sky-deep);
  transform: translateY(-2px);
}

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

.btn-ghost:hover {
  border-color: var(--sky);
  color: var(--ink);
}

.hero-stage {
  position: relative;
  animation: rise 1s var(--ease) 0.12s both;
}

.desk {
  position: relative;
  aspect-ratio: 5 / 4;
  border-radius: 1.25rem;
  overflow: hidden;
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.7), rgba(255, 255, 255, 0.15)),
    url("assets/app.png") center 42% / 38% no-repeat,
    linear-gradient(160deg, #8ec8ef 0%, #5aa7d8 45%, #3d7eae 100%);
  box-shadow: var(--shadow);
  isolation: isolate;
}

.desk-glow {
  position: absolute;
  inset: -20%;
  background: radial-gradient(circle at 30% 20%, rgba(255, 255, 255, 0.55), transparent 45%);
  pointer-events: none;
}

.snip-layer {
  position: absolute;
  inset: 0;
}

.snip-dim {
  position: absolute;
  background: rgba(12, 24, 36, 0.42);
}

.snip-dim-tl { top: 0; left: 0; width: 18%; height: 22%; }
.snip-dim-tr { top: 0; right: 0; width: 28%; height: 22%; }
.snip-dim-bl { bottom: 0; left: 0; width: 18%; height: 48%; }
.snip-dim-br { bottom: 0; right: 0; width: 28%; height: 48%; }

.snip-box {
  position: absolute;
  left: 18%;
  top: 22%;
  width: 54%;
  height: 30%;
  border: 1.5px solid rgba(255, 255, 255, 0.95);
  animation: snip-in 1.1s var(--ease) 0.35s both;
}

.corner {
  position: absolute;
  width: 14px;
  height: 14px;
  border: 2.5px solid #7ec8f5;
}

.corner.tl { left: -2px; top: -2px; border-right: 0; border-bottom: 0; border-radius: 4px 0 0 0; }
.corner.tr { right: -2px; top: -2px; border-left: 0; border-bottom: 0; border-radius: 0 4px 0 0; }
.corner.bl { left: -2px; bottom: -2px; border-right: 0; border-top: 0; border-radius: 0 0 0 4px; }
.corner.br { right: -2px; bottom: -2px; border-left: 0; border-top: 0; border-radius: 0 0 4px 0; }

.snip-measure {
  position: absolute;
  left: 0;
  top: calc(100% + 8px);
  padding: 0.15rem 0.45rem;
  border-radius: 0.3rem;
  background: rgba(21, 32, 43, 0.82);
  color: #fff;
  font-family: var(--font-display);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
}

.pin-window {
  position: absolute;
  right: 9%;
  bottom: 11%;
  width: min(42%, 190px);
  padding: 0.85rem 0.85rem 1rem;
  border-radius: 0.7rem;
  background: rgba(251, 252, 254, 0.96);
  border: 1px solid rgba(255, 255, 255, 0.8);
  box-shadow: 0 16px 40px rgba(20, 50, 80, 0.22);
  text-align: center;
  animation: float-pin 4.5s ease-in-out infinite;
}

.pin-window img {
  margin: 0 auto 0.55rem;
  width: 64px;
  height: 64px;
}

.pin-window p {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.08em;
}

.section-head {
  max-width: 36rem;
  margin-bottom: 2.5rem;
}

.section-head h2 {
  margin: 0 0 0.7rem;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.4vw, 2.4rem);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.section-head p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 1.02rem;
}

.flow,
.craft,
.download {
  padding: clamp(3.5rem, 9vh, 6rem) clamp(1.25rem, 4vw, 3rem);
}

.keys {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.keys li {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: 1.25rem;
  align-items: start;
  padding: 1.4rem 0;
  border-bottom: 1px solid var(--line);
}

.keys kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 3.4rem;
  min-height: 2.4rem;
  padding: 0 0.7rem;
  border-radius: 0.45rem;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.7);
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
}

.keys strong {
  display: block;
  margin-bottom: 0.25rem;
  font-size: 1.08rem;
}

.keys span {
  color: var(--ink-soft);
}

.craft-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.5rem, 4vw, 2.75rem);
  border-top: 1px solid var(--line);
  padding-top: 2rem;
}

.craft-list article h3 {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 600;
}

.craft-list article p {
  margin: 0;
  color: var(--ink-soft);
}

.download-panel {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 1.5rem;
  align-items: center;
  padding: clamp(1.5rem, 4vw, 2.25rem);
  border-radius: 1rem;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.85), rgba(255, 255, 255, 0.45)),
    linear-gradient(120deg, var(--mist), #c5dff0);
  border: 1px solid rgba(255, 255, 255, 0.7);
  box-shadow: var(--shadow);
}

.download-mark {
  border-radius: 0.85rem;
  background: #fff;
}

.download-copy h2 {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
}

.download-copy p {
  margin: 0;
  color: var(--ink-soft);
}

.download-actions {
  text-align: right;
  max-width: 18rem;
}

.download-actions .hint {
  margin: 0.75rem 0 0;
  font-size: 0.82rem;
  color: var(--ink-soft);
  text-align: left;
}

.download-actions code {
  font-family: var(--font-display);
  font-size: 0.8rem;
}

.foot {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 2rem clamp(1.25rem, 4vw, 3rem) 2.5rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.foot-brand {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.06em;
  margin-right: 0.4rem;
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(22px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes snip-in {
  from {
    opacity: 0;
    transform: scale(0.92);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

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

@media (max-width: 960px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-top: 1.5rem;
  }

  .hero-stage {
    order: -1;
  }

  .desk {
    max-width: 520px;
    margin: 0 auto;
  }

  .craft-list {
    grid-template-columns: 1fr;
  }

  .download-panel {
    grid-template-columns: auto 1fr;
  }

  .download-actions {
    grid-column: 1 / -1;
    text-align: left;
    max-width: none;
  }
}

@media (max-width: 640px) {
  .top-nav {
    gap: 1rem;
    font-size: 0.85rem;
  }

  .keys li {
    grid-template-columns: 4.2rem 1fr;
    gap: 0.9rem;
  }

  .foot {
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero-copy,
  .hero-stage,
  .snip-box,
  .pin-window,
  .reveal {
    animation: none !important;
    transition: none !important;
    opacity: 1 !important;
    transform: none !important;
  }
}