/* Siftr — an editorial reading window. Real app screens sit directly on the
   paper ground without coloured backing boxes; a full-width chapter rule
   separates the hero from the iPad + iPhone reading showcase. */
@import url("assets/fonts/fonts.css");
:root {
  color-scheme: light;
  --paper: #f7f5ef;
  --ink: #1c2a23;
  --green: #14483b;
  --field: #e6ebe2;
  --field-hover: #dbe3d6;
  --rule: #d5ddd0;
  --rule-strong: #bcc8b6;
  --dark: #0e211a;
  --light: #f2f2e8;
  --muted: #465147;
  --accent: #a9d7bc;
  --radius-sm: 10px;
  --radius-md: 14px;
  --font-text: "Source Serif 4", Georgia, "Songti SC", "Hiragino Mincho ProN", serif;
  --font-ui: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", sans-serif;
  --ease-out: cubic-bezier(.2, .7, .2, 1);
  --gutter: clamp(20px, 3vw, 48px);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 24px; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 1.0625rem/1.65 var(--font-ui); -webkit-font-smoothing: antialiased; }
::selection { background: var(--green); color: var(--paper); }
a { color: inherit; text-underline-offset: .22em; text-decoration-thickness: .08em; }
a:hover { text-decoration-thickness: .14em; }
a:focus-visible, select:focus-visible { outline: 3px solid currentColor; outline-offset: 5px; }
main:focus { outline: none; }
p, figure, h1, h2, h3, ul, ol { margin: 0; }
img { display: block; max-width: 100%; height: auto; }
h1, h2 { font-family: var(--font-text); font-weight: 600; letter-spacing: -.03em; text-wrap: balance; }
h1 { font-size: clamp(2.125rem, 3.3vw, 3.125rem); line-height: 1.12; }
h1 span { display: block; }
h2 { font-size: clamp(1.85rem, 2.6vw, 2.6rem); line-height: 1.2; }
h3 { font-size: 1.2rem; line-height: 1.4; font-weight: 600; }
:lang(zh) h1, :lang(zh) h2,
:lang(ja) h1, :lang(ja) h2,
:lang(ko) h1, :lang(ko) h2 { letter-spacing: -.005em; }
:lang(zh) h1, :lang(ja) h1, :lang(ko) h1 { font-size: clamp(2.4rem, 4.2vw, 3.85rem); line-height: 1.18; }
:lang(zh) h2, :lang(ja) h2, :lang(ko) h2 { line-height: 1.25; }
p { overflow-wrap: break-word; }

.wrap, .panel-footer { width: min(100%, 1360px); margin-inline: auto; padding-inline: var(--gutter); }

/* 顶栏：品牌、章节导航、语言选择合流为同一刊头，底缘细线收口。 */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px 32px;
  padding-block: 18px;
  border-bottom: 1px solid var(--rule);
}
.brand {
  font: 400 2.25rem/1 "Young Serif", var(--font-text);
  text-decoration: none;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  flex: none;
}
.section-nav {
  display: flex;
  align-items: center;
  gap: 8px 28px;
  flex-wrap: wrap;
  margin-left: auto;
}
.section-nav a {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  font-size: .96875rem;
  color: var(--muted);
  text-decoration: none;
  transition: color .15s ease;
}
.section-nav a:hover {
  color: var(--ink);
  text-decoration: underline;
}
.language-picker { flex: none; }
.language-picker select {
  font: 400 .9375rem/1.4 var(--font-ui);
  color: var(--ink);
  background: var(--field);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  min-height: 44px;
  padding: 8px 28px 8px 12px;
  cursor: pointer;
}
.section-nav:not([data-language="zh-Hans"]):not(.is-active),
.language-panel:not([data-language="zh-Hans"]):not(.is-active) { display: none; }
.section-nav[hidden], .language-panel[hidden] { display: none; }

/* 首屏：左文右图，iPhone 直接落在纸面底子上，无色块衬底。 */
.hero {
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  align-items: center;
  gap: clamp(32px, 5vw, 72px);
  padding-top: clamp(36px, 4.5vw, 56px);
  padding-bottom: 24px;
}
.hero-copy { padding-block: 16px; }
.lead { font-size: clamp(1.0625rem, 1.2vw, 1.225rem); line-height: 1.7; max-width: 34em; color: var(--ink); }
.hero-copy .lead { margin-top: 24px; max-width: 30em; }
.action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background: var(--green);
  color: var(--paper);
  border-radius: var(--radius-sm);
  min-height: 48px;
  padding: 13px 24px;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: transform .16s ease, background-color .16s ease;
}
.action .apple-mark { width: 1.125rem; height: 1.125rem; flex: none; }
.action:hover { transform: translateY(-2px); }
.action:active { transform: translateY(1px); }
.hero-copy .action { margin-top: 28px; }
.compatibility { color: var(--muted); font-size: .9375rem; margin-top: 14px; }
.hero-visual {
  justify-self: center;
  text-align: center;
}
.hero-shots { display: flex; justify-content: center; }
.reader-shot {
  width: clamp(268px, 22vw, 332px);
  filter: drop-shadow(0 20px 38px rgb(20 34 27 / .15));
}
figcaption { font-size: .9375rem; padding-top: 18px; color: var(--muted); text-align: center; }

.section { margin-top: 112px; }

/* 第二屏（阅读体验）：通过通栏分节眉线与首屏明确切分；右侧并排展示 iPad + iPhone 阅读页，同样直接落在纸面底子上。 */
.reading {
  position: relative;
  margin-top: 72px;
  padding-top: 88px;
  display: grid;
  grid-template-columns: .84fr 1.16fr;
  gap: clamp(32px, 4.5vw, 64px);
  align-items: center;
}
.reading::before {
  content: "";
  position: absolute;
  top: 0;
  left: var(--gutter);
  right: var(--gutter);
  height: 1px;
  background: var(--rule-strong);
}
.reading::after {
  content: "";
  position: absolute;
  top: -1px;
  left: var(--gutter);
  width: 64px;
  height: 3px;
  background: var(--green);
}
.reading-copy .lead { margin-top: 22px; }
.reading-points {
  list-style: none;
  margin-top: 28px;
  padding: 0;
  border-top: 1px solid var(--rule);
}
.reading-points li {
  padding-block: 14px;
  border-bottom: 1px solid var(--rule);
  font-size: .96875rem;
  line-height: 1.6;
}
.reading-points strong {
  display: block;
  color: var(--ink);
  font-weight: 600;
  margin-bottom: 2px;
}
.reading-points span { color: var(--muted); }
.reading-visual {
  width: 100%;
  text-align: center;
}
.reading-shots {
  display: flex;
  justify-content: center;
  align-items: flex-end;
  gap: 0;
  padding-bottom: 14px;
}
.pad-shot {
  width: 68%;
  max-width: 440px;
  flex: 0 0 auto;
  position: relative;
  z-index: 1;
  filter: drop-shadow(0 20px 38px rgb(20 34 27 / .15));
}
.phone-shot {
  width: 39%;
  max-width: 244px;
  flex: 0 0 auto;
  margin-left: clamp(-78px, -6.8vw, -50px);
  margin-bottom: -14px;
  position: relative;
  z-index: 2;
  filter: drop-shadow(-14px 20px 36px rgb(14 33 26 / .28));
}

/* 接入方式：全宽浅绿底带 + 三步管道。 */
.connect { background: var(--field); padding-block: 80px; }
.section-intro {
  display: grid;
  grid-template-columns: .92fr 1.08fr;
  gap: clamp(32px, 5vw, 72px);
  align-items: start;
}
.section-intro p { max-width: 38em; }
.text-link { display: inline-flex; gap: 10px; min-height: 44px; align-items: center; margin-top: 14px; font-weight: 600; color: var(--green); }
.pipeline {
  margin: 48px 0 0;
  padding: 28px 0 0;
  border-top: 1px solid var(--rule);
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 48px;
}
.pipeline li { position: relative; }
.pipeline li + li::before { content: "→"; position: absolute; left: -32px; top: 0; color: var(--green); font-size: 1.25rem; }
.pipeline p { margin-top: 12px; max-width: 28em; color: var(--muted); }

/* 核心能力：四项保证 + 对称「暗—亮—暗」三机展示 + 四列刊物工具表。 */
.feature-columns {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 36px 72px;
  margin-top: 44px;
}
.feature-columns article p { margin-top: 10px; max-width: 34em; color: var(--muted); }
.proofs {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 284px));
  gap: clamp(20px, 3.2vw, 44px);
  justify-content: center;
  margin-top: 56px;
  padding-block: 48px 12px;
  border-top: 1px solid var(--rule);
}
.proofs figure { min-width: 0; }
.proofs img {
  width: 100%;
  margin-inline: auto;
  filter: drop-shadow(0 18px 34px rgb(20 34 27 / .15));
}
.more-tools { margin-top: 64px; }
.tools-title { font-family: var(--font-text); font-size: 1.35rem; }
.tools-content {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px 36px;
}
.tool-list {
  list-style: none;
  padding: 0;
  border-top: 1px solid var(--rule);
}
.tool-list li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding-block: 10px;
  border-bottom: 1px solid var(--rule);
  font-size: .9375rem;
  line-height: 1.45;
}
.tool-list strong { font-weight: 600; color: var(--ink); }
.tool-list span { color: var(--muted); text-align: right; }

/* 常见问题：全宽浅绿底带，双列问答。 */
.faq { background: var(--field); padding-block: 80px; }
.faq-content {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 36px 72px;
  margin-top: 44px;
}
.qa h3 { font-family: var(--font-text); font-weight: 600; margin-bottom: 8px; }
.qa p { max-width: 34em; color: var(--muted); }

/* 更多作品与友情链接：独立浅底卡片，外边缘严格对齐全页基准线。 */
.friends-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px 28px;
  margin-top: 40px;
}
.friend-card {
  display: flex;
  align-items: flex-start;
  gap: 18px;
  padding: 22px 24px;
  background: var(--field);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: inherit;
  transition: transform .16s ease, background-color .16s ease;
}
.friend-card:hover {
  background: var(--field-hover);
  transform: translateY(-2px);
}
.friend-card img { width: 48px; height: 48px; border-radius: 11px; flex: none; }
.friend-body { min-width: 0; }
.friend-card strong { display: block; font-family: var(--font-text); font-weight: 600; font-size: 1.2rem; line-height: 1.3; }
.friend-tagline { display: block; margin-top: 6px; font-size: .9375rem; line-height: 1.6; color: var(--muted); }
.friend-meta { display: block; margin-top: 8px; font-size: .875rem; color: var(--muted); }
.friend-avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 11px;
  background: var(--green);
  color: var(--paper);
  font-weight: 600;
  flex: none;
}

/* 收尾与页脚 */
.closing { background: var(--dark); color: var(--light); padding-block: 96px; text-align: center; }
.closing .wrap { width: min(100%, 880px); }
.closing p { margin: 20px auto 0; max-width: 34em; color: var(--accent); }
.cta-row { display: flex; flex-wrap: wrap; gap: 20px 32px; align-items: center; justify-content: center; margin-top: 32px; }
.closing .action { color: var(--dark); background: var(--accent); }
.panel-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px 40px;
  padding-block: 36px;
  font-size: .96875rem;
}
.panel-footer .links { display: flex; gap: 10px 24px; flex-wrap: wrap; }
.panel-footer a { min-height: 44px; display: inline-flex; align-items: center; }
.panel-footer .legal { flex-basis: 100%; display: block; margin-top: 2px; font-size: .875rem; color: var(--muted); }
.who { color: var(--muted); }

/* 入场动效：首屏与各节主标题始终可见，仅内部条目随滚动轻浮一次。 */
.js .reveal { opacity: 0; translate: 0 18px; }
.js .reveal.in { opacity: 1; translate: 0 0; transition: opacity .5s var(--ease-out), translate .5s var(--ease-out); transition-delay: var(--d, 0ms); }

/* 平板视口（701px–1000px） */
@media (min-width: 701px) and (max-width: 1000px) {
  h1 { font-size: clamp(1.75rem, 2.9vw, 2.3rem); }
  :lang(zh) h1, :lang(ja) h1, :lang(ko) h1 { font-size: clamp(2rem, 3.6vw, 2.75rem); }
  .site-header { flex-wrap: wrap; gap: 8px 20px; padding-block: 14px 10px; }
  .brand { order: 1; }
  .language-picker { order: 2; margin-left: auto; }
  .section-nav { order: 3; flex-basis: 100%; margin-left: 0; padding-top: 6px; border-top: 1px solid var(--rule); gap: 2px 24px; }
  .hero { gap: 28px; }
  .reader-shot { width: 252px; }
  .reading { gap: 28px; grid-template-columns: .9fr 1.1fr; padding-top: 68px; margin-top: 56px; }
  .pad-shot { width: 68%; max-width: 340px; }
  .phone-shot { width: 39%; max-width: 192px; margin-left: -52px; margin-bottom: -10px; }
  .section-intro { gap: 32px; }
  .pipeline { gap: 32px; }
  .pipeline li + li::before { left: -24px; }
  .tools-content { grid-template-columns: repeat(2, 1fr); gap: 28px 36px; }
  .faq-content { grid-template-columns: 1fr; gap: 32px; margin-top: 36px; }
}

/* 手机视口（≤700px） */
@media (max-width: 700px) {
  body { font-size: 1rem; }
  .site-header { flex-wrap: wrap; gap: 8px 16px; padding-block: 14px 8px; }
  .brand { font-size: 1.9rem; order: 1; }
  .language-picker { order: 2; margin-left: auto; }
  .section-nav { order: 3; flex-basis: 100%; margin-left: 0; padding-top: 6px; border-top: 1px solid var(--rule); gap: 0 18px; }
  .section-nav a { min-height: 40px; font-size: .9375rem; }
  h1 { font-size: clamp(1.75rem, 6.8vw, 2.3rem); line-height: 1.15; }
  :lang(zh) h1, :lang(ja) h1, :lang(ko) h1 { font-size: clamp(2rem, 7.8vw, 2.65rem); line-height: 1.18; }
  h2 { font-size: 1.7rem; }
  .lead { font-size: 1.0625rem; }
  .hero { display: flex; flex-direction: column; gap: 32px; padding-top: 24px; padding-bottom: 0; align-items: stretch; }
  .hero-copy { padding: 0; }
  .hero-copy .lead { margin-top: 18px; }
  .hero-copy .action { margin-top: 22px; }
  .compatibility { margin-top: 12px; }
  .hero-visual { padding: 8px 0 0; }
  .reader-shot { width: 264px; }
  .section { margin-top: 76px; }
  .reading { display: flex; flex-direction: column; align-items: stretch; gap: 32px; margin-top: 56px; padding-top: 56px; }
  .reading-copy .lead { margin-top: 18px; }
  .pad-shot { width: 68%; max-width: 268px; }
  .phone-shot { width: 40%; max-width: 156px; margin-left: -44px; margin-bottom: -10px; }
  .connect { padding-block: 52px; }
  .section-intro { display: block; }
  .section-intro p { margin-top: 18px; }
  .pipeline { grid-template-columns: 1fr; gap: 28px; margin-top: 32px; padding-top: 24px; }
  .pipeline li + li::before { content: none; }
  .pipeline p { margin-top: 8px; }
  .feature-columns { grid-template-columns: 1fr; gap: 28px; margin-top: 32px; }
  .proofs {
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    padding-block: 32px 8px;
    margin-top: 36px;
  }
  .proofs figcaption { font-size: .78125rem; padding-top: 10px; line-height: 1.35; }
  .more-tools { margin-top: 44px; }
  .tools-content { grid-template-columns: 1fr; gap: 24px; }
  .faq { padding-block: 56px; }
  .faq-content { grid-template-columns: 1fr; gap: 28px; margin-top: 32px; }
  .friends-grid { grid-template-columns: 1fr; gap: 14px; margin-top: 28px; }
  .friend-card { padding: 18px 18px; }
  .closing { padding-block: 64px; }
  .closing p { margin-top: 18px; }
  .cta-row { flex-direction: column; align-items: center; gap: 12px; margin-top: 24px; }
  .panel-footer { display: block; padding-block: 28px; }
  .panel-footer .links { margin-block: 14px; gap: 6px 18px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; translate: none; transition: none; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}
@media (prefers-contrast: more) {
  :root { --muted: #1c2a23; --field: #dce5d8; --rule: #b4c0ae; --rule-strong: #8e9e88; }
}
@media (forced-colors: active) {
  .action { border: 2px solid ButtonText; /* taste-skill-ignore: forced-colors 辅助模式必需的可见边界，非视觉装饰 */ }
  .friend-card img, .pad-shot, .phone-shot, .reader-shot { outline: 1px solid CanvasText; /* taste-skill-ignore: forced-colors 下图片需要可辨边界 */ }
}