:root {
  color-scheme: light;
  --paper: #f8f9f6;
  --ink: #254957;
  --body: #50666e;
  --blue: #367590;
  --line: #dce5e5;
  --serif: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  font-synthesis: none;
  color: var(--ink);
  background: var(--paper);
}

* { box-sizing: border-box; }
body { margin: 0; }
img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-underline-offset: .3em; }
a:hover { color: var(--blue); }
a:focus-visible { outline: 2px solid var(--blue); outline-offset: 6px; border-radius: 2px; }
p, h1, h2, figure { margin: 0; }
.content-width { width: min(100% - 64px, 960px); margin-inline: auto; }
.skip-link { position: absolute; top: 12px; left: 12px; padding: 12px 20px; background: white; transform: translateY(-160%); z-index: 2; }
.skip-link:focus { transform: translateY(0); }

.hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr); align-items: center; gap: 56px; min-height: min(760px, 100svh); padding: 48px max(40px, calc((100% - 1160px) / 2)); background: linear-gradient(180deg, var(--paper) 42%, #eef4f3 76%, #e4eff2 100%); }
.hero-copy { min-width: 0; }
.app-brand { display: flex; align-items: center; gap: 20px; text-align: left; }
.app-icon { width: 72px; flex-shrink: 0; border-radius: 22%; box-shadow: 0 5px 18px #2549570d; }
.app-name { font-family: var(--serif); font-size: 2rem; font-weight: 600; letter-spacing: .16em; }
.app-name span { display: block; font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", sans-serif; font-size: .75rem; font-weight: 400; letter-spacing: .15em; margin-top: 5px; color: var(--body); }
h1 { font-family: var(--serif); font-weight: 500; font-size: clamp(2rem, 3.1vw, 2.75rem); line-height: 1.65; letter-spacing: .08em; margin-top: 32px; }
h1 span { display: block; }
.introduction { margin-top: 18px; color: var(--body); font-size: 1rem; line-height: 2; letter-spacing: .03em; }
.download { margin-top: 28px; }
.release-label { display: inline-flex; justify-content: center; align-items: center; min-height: 50px; padding: 12px 26px; background: var(--ink); color: #fff; border-radius: 10px; font-size: .9375rem; font-weight: 500; letter-spacing: .04em; }
.compatibility { margin-top: 12px; color: var(--body); font-size: .75rem; letter-spacing: .03em; line-height: 1.8; }
.app-preview { min-width: 0; text-align: center; }
.screens { display: flex; justify-content: center; align-items: flex-end; gap: 24px; width: min(100%, 560px); margin-inline: auto; }
.screen { border: 7px solid #35464b; box-shadow: 0 20px 40px -15px #25495740, 0 2px 5px #25495725; background: #faf8f2; object-fit: contain; }
.screen-reading { display: block; width: 61%; flex-shrink: 0; }
.screen-reading img { width: 100%; border-radius: 19px; }
.screen-bookshelf { width: 32%; border-radius: 27px; }
figcaption { color: var(--body); font-family: var(--serif); font-size: .875rem; letter-spacing: .1em; margin-top: 30px; }

.features { display: grid; grid-template-columns: repeat(3, 1fr); padding-block: 80px; }
.feature { padding-inline: 30px; }
.feature + .feature { border-left: 1px solid var(--line); }
.feature-icon { color: var(--blue); margin-bottom: 20px; }
.feature h2 { font-family: var(--serif); font-weight: 500; font-size: 1.375rem; line-height: 1.8; letter-spacing: .04em; }
.feature p { margin-top: 16px; color: var(--body); font-size: 1rem; line-height: 2; }

.acknowledgment { border-top: 1px solid var(--line); padding-block: 65px 68px; text-align: center; }
.section-label { font-size: .8125rem; color: var(--blue); letter-spacing: .12em; margin-bottom: 22px; }
.acknowledgment h2 { font-family: var(--serif); font-weight: 500; font-size: clamp(1.5rem, 3vw, 1.875rem); line-height: 1.9; letter-spacing: .06em; }
.acknowledgment h2 + p { margin-top: 24px; font-size: 1rem; line-height: 2.1; color: var(--body); }
.text-link { display: inline-block; margin-top: 22px; padding: 7px 0; font-size: .875rem; text-decoration-thickness: 1px; }
.closing { text-align: center; padding: 44px 24px 48px; background: #eef3f2; }
.closing-icon { margin-inline: auto; border-radius: 22%; }
.closing > p:first-of-type { font-family: var(--serif); letter-spacing: .08em; font-size: 1.25rem; margin-block: 16px 24px; }
.footer { padding-block: 30px; display: flex; align-items: center; gap: 18px 30px; flex-wrap: wrap; font-size: .8125rem; color: var(--body); }
.footer a { display: inline-block; padding-block: 10px; text-decoration: none; }
.footer a:hover { text-decoration: underline; }
.footer nav { display: flex; flex-wrap: wrap; gap: 10px 24px; margin-left: auto; }
.footer small { width: 100%; font-size: .75rem; color: var(--body); }

@media (max-width: 900px) {
  .content-width { width: min(100% - 48px, 480px); }
  .hero { display: block; min-height: 0; padding: 40px 0 0; text-align: center; }
  .hero-copy { padding-inline: 24px; }
  .app-brand { justify-content: center; gap: 16px; }
  .app-name { font-size: 1.75rem; }
  h1 { font-size: clamp(1.625rem, 8vw, 2rem); margin-top: 28px; line-height: 1.7; }
  h1 span { display: block; }
  .introduction { max-width: 310px; margin: 18px auto 0; font-size: 1rem; }
  .introduction br { display: none; }
  .download { margin-top: 24px; }
  .app-preview { margin-top: 36px; padding: 0 26px 28px; }
  .screens { gap: 16px; }
  .screen { border-width: 4px; }
  .screen-reading { width: 53%; }
  .screen-reading img { border-radius: 21px; }
  .screen-bookshelf { width: 41%; border-radius: 19px; }
  figcaption { margin-top: 24px; font-size: .8125rem; }
  .features { grid-template-columns: 1fr; padding-block: 22px; }
  .feature { position: relative; padding: 28px 0 28px 54px; }
  .feature + .feature { border-left: 0; border-top: 1px solid var(--line); }
  .feature-icon { position: absolute; left: 4px; top: 36px; }
  .feature h2 { font-size: 1.25rem; line-height: 1.75; }
  .feature p { margin-top: 10px; font-size: 1rem; }
  .feature p br { display: none; }
  .acknowledgment { padding-block: 44px; }
  .acknowledgment h2 { font-size: 1.375rem; }
  .acknowledgment h2 + p { text-align: left; font-size: 1rem; }
  .desktop-break { display: none; }
  .closing { padding-block: 36px; }
  .footer { display: block; text-align: center; padding-block: 22px; }
  .footer nav { justify-content: center; gap: 4px 18px; margin: 4px 0 14px; }
  .footer small { display: block; }
}

@media (prefers-reduced-motion: no-preference) {
  .hero-copy { animation: appear .7s ease-out both; }
  @keyframes appear { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
}