@font-face {
  font-family: "JianDu WenKai";
  src: url("./assets/jiandu-wenkai.woff2") format("woff2");
  font-display: swap;
  font-style: normal;
  font-weight: 400;
}

:root {
  color-scheme: light dark;
  --paper: #f7f4ec;
  --paper-deep: #eee9dc;
  --ink: #201d18;
  --ink-soft: #665f55;
  --line: #d8d0bf;
  --bamboo: #d8bd82;
  --bamboo-deep: #ad8743;
  --seal: #a83d28;
  --seal-strong: #8f2f1e;
  --reading: #fffefa;
  --max: 1180px;
  --reading-max: 760px;
  --display: "JianDu WenKai", "Songti SC", "STSong", "Noto Serif CJK SC", serif;
  --serif: "Songti SC", "STSong", "Noto Serif CJK SC", "Source Han Serif SC", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #171512;
    --paper-deep: #211e19;
    --ink: #eee9df;
    --ink-soft: #bdb5a7;
    --line: #3d382f;
    --bamboo: #8d7447;
    --bamboo-deep: #c4a568;
    --seal: #d26046;
    --seal-strong: #e47a5e;
    --reading: #24211c;
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(to right, transparent 0, rgb(81 63 35 / 2%) 50%, transparent 100%),
    radial-gradient(circle at 18% 12%, rgb(173 135 67 / 8%), transparent 30%);
  content: "";
  pointer-events: none;
}

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

a {
  color: inherit;
  text-underline-offset: 0.22em;
  text-decoration-thickness: 1px;
}

a:hover {
  color: var(--seal-strong);
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--seal) 72%, transparent);
  outline-offset: 4px;
}

::selection {
  background: color-mix(in srgb, var(--bamboo) 58%, transparent);
  color: var(--ink);
}

.site-header {
  position: relative;
  z-index: 10;
  display: flex;
  width: min(calc(100% - 40px), var(--max));
  min-height: 76px;
  margin: 0 auto;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.wordmark {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  font-size: 14px;
  letter-spacing: 0.22em;
  text-decoration: none;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 13px;
}

.site-nav a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  text-decoration: none;
}

.hero {
  display: grid;
  width: min(calc(100% - 40px), var(--max));
  min-height: calc(100svh - 76px);
  margin: 0 auto;
  padding: 72px 0 84px;
  align-items: center;
  grid-template-columns: minmax(0, 1.04fr) minmax(340px, 0.96fr);
  gap: clamp(52px, 8vw, 112px);
}

.hero-copy {
  position: relative;
}

.app-identity {
  display: flex;
  margin-bottom: 34px;
  align-items: center;
  gap: 16px;
}

.app-icon {
  width: 72px;
  height: 72px;
  border-radius: 16px;
  box-shadow: 0 12px 32px rgb(51 38 17 / 14%);
}

.app-name {
  margin: 0 0 4px;
  font-size: 24px;
  font-weight: 500;
  letter-spacing: 0.16em;
  font-family: var(--display);
}

.app-kind {
  margin: 0;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 13px;
}

.hero h1 {
  max-width: 8em;
  margin: 0;
  font-size: clamp(54px, 6.2vw, 88px);
  font-weight: 400;
  font-family: var(--display);
  letter-spacing: -0.025em;
  line-height: 1.14;
  text-wrap: balance;
}

.hero h1 span {
  display: block;
}

.hero h1 span:last-child {
  color: var(--seal);
}

.hero-lead {
  max-width: 29em;
  margin: 34px 0 0;
  color: var(--ink-soft);
  font-size: 18px;
  line-height: 1.9;
}

.hero-actions {
  display: flex;
  margin-top: 34px;
  align-items: center;
  flex-wrap: wrap;
  gap: 18px;
  font-family: var(--sans);
}

.primary-link {
  display: inline-flex;
  min-height: 48px;
  padding: 0 22px;
  align-items: center;
  justify-content: center;
  background: var(--ink);
  color: var(--paper);
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.primary-link:hover {
  background: var(--seal-strong);
  color: #fffaf1;
}

.launch-state {
  color: var(--ink-soft);
  font-size: 13px;
}

.device-stage {
  position: relative;
  min-height: 660px;
  margin: 0;
}

.device-stage::before {
  position: absolute;
  top: 5%;
  right: 4%;
  bottom: 6%;
  left: 12%;
  border: 1px solid var(--line);
  content: "";
  transform: rotate(2.5deg);
}

.phone {
  position: absolute;
  top: 0;
  right: 12%;
  width: min(330px, 72%);
  padding: 10px;
  overflow: hidden;
  background: #111;
  border-radius: 48px;
  box-shadow: 0 34px 70px rgb(37 27 14 / 24%);
  transform: rotate(-2.5deg);
  animation: settle 900ms cubic-bezier(0.16, 1, 0.3, 1) both;
}

.phone img {
  width: 100%;
  height: auto;
  aspect-ratio: 660 / 1434;
  border-radius: 39px;
}

.vertical-note {
  position: absolute;
  right: 0;
  bottom: 7%;
  margin: 0;
  color: var(--ink-soft);
  font-size: 14px;
  letter-spacing: 0.24em;
  line-height: 1.8;
  writing-mode: vertical-rl;
}

.seal {
  position: absolute;
  bottom: 4%;
  left: 2%;
  display: grid;
  width: 52px;
  height: 52px;
  place-items: center;
  border: 2px solid var(--seal);
  color: var(--seal);
  font-size: 17px;
  line-height: 1.05;
  transform: rotate(-5deg);
}

.manifesto {
  border-block: 1px solid var(--line);
}

.manifesto-inner {
  display: grid;
  width: min(calc(100% - 40px), var(--max));
  margin: 0 auto;
  padding: 100px 0;
  grid-template-columns: 0.72fr 1.28fr;
  gap: clamp(52px, 9vw, 132px);
}

.manifesto h2,
.feature-copy h2,
.ownership h2,
.price-copy h2 {
  margin: 0;
  font-size: clamp(36px, 4.2vw, 60px);
  font-weight: 400;
  font-family: var(--display);
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.manifesto-copy {
  display: grid;
  gap: 22px;
}

.manifesto-copy p,
.feature-copy p,
.ownership p,
.price-copy p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 17px;
  line-height: 1.95;
}

.principles {
  display: grid;
  margin-top: 22px;
  border-top: 1px solid var(--line);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.principle {
  min-height: 148px;
  padding: 24px 24px 24px 0;
  border-bottom: 1px solid var(--line);
}

.principle:nth-child(odd) {
  padding-right: 30px;
  border-right: 1px solid var(--line);
}

.principle:nth-child(even) {
  padding-left: 30px;
}

.principle strong {
  display: block;
  margin-bottom: 9px;
  font-size: 18px;
  font-weight: 500;
}

.principle span {
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.75;
}

.feature {
  display: grid;
  width: min(calc(100% - 40px), var(--max));
  margin: 0 auto;
  padding: 116px 0;
  align-items: center;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(52px, 9vw, 132px);
}

.feature-copy {
  max-width: 430px;
}

.feature-copy p {
  margin-top: 24px;
}

.book-list {
  margin: 32px 0 0;
  padding: 0;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 2;
  list-style: none;
}

.book-list strong {
  color: var(--ink);
  font-weight: 600;
}

.screen-pair {
  position: relative;
  min-height: 680px;
}

.screen {
  position: absolute;
  width: min(300px, 60%);
  margin: 0;
  padding: 8px;
  background: var(--reading);
  box-shadow: 0 26px 56px rgb(43 33 19 / 16%);
}

.screen:first-child {
  top: 0;
  left: 0;
  transform: rotate(-2deg);
}

.screen:last-child {
  right: 0;
  bottom: 0;
  transform: rotate(2.2deg);
}

.screen-pair.single .screen {
  top: 0;
  right: auto;
  bottom: auto;
  left: 50%;
  transform: translateX(-50%) rotate(1.5deg);
}

.screen img {
  width: 100%;
  height: auto;
  aspect-ratio: 660 / 1434;
}

.ink-section {
  background: var(--ink);
  color: var(--paper);
}

.reading-proof {
  display: grid;
  width: min(calc(100% - 40px), var(--max));
  margin: 0 auto;
  padding: 112px 0;
  align-items: center;
  grid-template-columns: 0.92fr 1.08fr;
  gap: clamp(58px, 10vw, 144px);
}

.reading-proof blockquote {
  margin: 0;
  font-size: clamp(32px, 4vw, 56px);
  line-height: 1.65;
}

.reading-proof blockquote cite {
  display: block;
  margin-top: 18px;
  color: color-mix(in srgb, var(--paper) 68%, transparent);
  font-family: var(--sans);
  font-size: 13px;
  font-style: normal;
}

.tablet-screen {
  max-width: 560px;
  margin: 0 auto;
  padding: 10px;
  background: #111;
  border-radius: 30px;
  box-shadow: 0 28px 68px rgb(0 0 0 / 34%);
}

.tablet-screen img {
  width: 100%;
  height: auto;
  aspect-ratio: 1032 / 1376;
  border-radius: 21px;
}

.ownership {
  display: grid;
  width: min(calc(100% - 40px), var(--max));
  margin: 0 auto;
  padding: 108px 0;
  grid-template-columns: 1fr 1fr;
  gap: clamp(56px, 10vw, 150px);
}

.ownership-copy p {
  margin-top: 24px;
}

.data-flow {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.data-flow li {
  display: grid;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  grid-template-columns: 110px 1fr;
  gap: 24px;
}

.data-flow strong {
  font-weight: 500;
}

.data-flow span {
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.75;
}

.price-band {
  border-block: 1px solid var(--line);
}

.price-inner {
  display: grid;
  width: min(calc(100% - 40px), var(--max));
  margin: 0 auto;
  padding: 88px 0;
  align-items: end;
  grid-template-columns: 1fr auto;
  gap: 48px;
}

.price-copy p {
  max-width: 36em;
  margin-top: 20px;
}

.price {
  color: var(--seal);
  font-size: clamp(56px, 8vw, 104px);
  line-height: 0.9;
  white-space: nowrap;
}

.price small {
  display: block;
  margin-top: 16px;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 12px;
  text-align: right;
}

.faq {
  width: min(calc(100% - 40px), 880px);
  margin: 0 auto;
  padding: 108px 0;
}

.faq h2 {
  margin: 0 0 36px;
  font-size: 34px;
  font-weight: 400;
}

.faq details {
  border-top: 1px solid var(--line);
}

.faq details:last-of-type {
  border-bottom: 1px solid var(--line);
}

.faq summary {
  padding: 22px 4px;
  cursor: pointer;
  font-size: 17px;
}

.faq details p {
  max-width: 62em;
  margin: -4px 0 24px;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.8;
}

.legal-links {
  display: flex;
  margin-top: 34px;
  flex-wrap: wrap;
  gap: 24px;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 13px;
}

.legal-links a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
}

.site-footer {
  padding: 32px 20px;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 12px;
  line-height: 1.9;
  text-align: center;
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
}

.legal-page {
  min-height: 100svh;
}

.legal-main {
  width: min(calc(100% - 40px), var(--reading-max));
  margin: 0 auto;
  padding: 78px 0 110px;
}

.legal-main h1 {
  margin: 0 0 12px;
  font-size: clamp(38px, 6vw, 58px);
  font-weight: 400;
  font-family: var(--display);
}

.legal-updated {
  margin: 0 0 54px;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 13px;
}

.legal-main h2 {
  margin: 54px 0 14px;
  font-size: 24px;
  font-weight: 500;
  font-family: var(--display);
}

.legal-main h3 {
  margin: 34px 0 10px;
  font-size: 18px;
  font-weight: 500;
}

.legal-main p,
.legal-main li {
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.9;
}

.legal-main ul {
  padding-left: 1.25em;
}

.legal-contact {
  margin-top: 56px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

@keyframes settle {
  from {
    opacity: 0;
    transform: translateY(22px) rotate(-2.5deg);
  }
  to {
    opacity: 1;
    transform: translateY(0) rotate(-2.5deg);
  }
}

@media (max-width: 820px) {
  .site-header {
    min-height: 66px;
  }

  .site-nav {
    gap: 16px;
  }

  .site-nav .optional {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: 54px 0 76px;
    grid-template-columns: 1fr;
    gap: 58px;
  }

  .hero h1 {
    font-size: clamp(50px, 15vw, 72px);
  }

  .device-stage {
    min-height: 660px;
  }

  .phone {
    right: 14%;
    width: min(300px, 72vw);
  }

  .manifesto-inner,
  .feature,
  .reading-proof,
  .ownership,
  .price-inner {
    padding-block: 78px;
    grid-template-columns: 1fr;
    gap: 44px;
  }

  .feature-copy {
    max-width: none;
  }

  .screen-pair {
    min-height: 560px;
  }

  .screen {
    width: min(270px, 58%);
  }

  .reading-proof blockquote {
    order: 2;
  }

  .tablet-screen {
    width: min(560px, 88vw);
  }

  .price {
    font-size: 72px;
  }

  .price small {
    text-align: left;
  }
}

@media (max-width: 520px) {
  .site-header,
  .hero,
  .manifesto-inner,
  .feature,
  .reading-proof,
  .ownership,
  .price-inner,
  .faq,
  .legal-main {
    width: min(calc(100% - 32px), var(--max));
  }

  .wordmark {
    letter-spacing: 0.12em;
  }

  .site-nav {
    gap: 13px;
    font-size: 12px;
  }

  .app-icon {
    width: 60px;
    height: 60px;
    border-radius: 14px;
  }

  .hero-lead {
    font-size: 16px;
  }

  .device-stage {
    display: grid;
    min-height: 0;
    padding: 12px 0 26px;
    place-items: center;
  }

  .device-stage::before {
    top: 5%;
    right: 6%;
    bottom: 6%;
    left: 6%;
  }

  .phone {
    position: relative;
    top: auto;
    right: auto;
    width: min(278px, 72vw);
  }

  .vertical-note {
    right: 2px;
  }

  .principles {
    grid-template-columns: 1fr;
  }

  .principle,
  .principle:nth-child(odd),
  .principle:nth-child(even) {
    min-height: auto;
    padding: 22px 0;
    border-right: 0;
  }

  .screen-pair {
    display: grid;
    min-height: 0;
    padding: 0 4px 18px;
    align-items: start;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }

  .screen,
  .screen:first-child {
    position: relative;
    top: auto;
    right: auto;
    bottom: auto;
    left: auto;
    width: 100%;
    transform: rotate(-1.2deg);
  }

  .screen:last-child {
    position: relative;
    top: 22px;
    right: auto;
    bottom: auto;
    left: auto;
    width: 100%;
    transform: rotate(1.2deg);
  }

  .screen-pair.single {
    grid-template-columns: 1fr;
  }

  .screen-pair.single .screen {
    top: auto;
    left: auto;
    width: min(238px, 68vw);
    justify-self: center;
    transform: rotate(1deg);
  }

  .data-flow li {
    grid-template-columns: 88px 1fr;
    gap: 16px;
  }

  .legal-links {
    gap: 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .phone {
    animation: none;
  }
}