/* 深读官网共用样式：首页 index.html 与使用指南 guide.html */

:root {
  --ink: #1B1F2A;
  --ink-2: #4A5060;
  --ink-3: #7A7F8E;
  --paper: #FBFAF7;
  --paper-2: #F4F2EC;
  --line: #E6E2D8;
  --dark: #171717;
  --gold: #F2B84B;
  --accent: #171717;
  --accent-hover: #000000;
  --radius: 14px;
  --content: 1120px;
  --serif: "Noto Serif SC", "Songti SC", "STSong", serif;
  --sans: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", system-ui, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  line-height: 1.7;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

/* 链接与正文同为近黑，正文里的链接靠下划线认出来 */
.guide-section a:not(.btn), .faq a { text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--line); }
.guide-section a:not(.btn):hover, .faq a:hover { text-decoration-color: currentColor; }

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

h1, h2, h3 { margin: 0; font-weight: 600; }

.serif { font-family: var(--serif); }

.wrap {
  width: 100%;
  max-width: calc(var(--content) + 48px);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 导航 ---------- */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(251, 250, 247, 0.86);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}
.site-nav.scrolled { border-bottom-color: var(--line); }

.site-nav .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.02em;
}
.brand:hover { color: var(--ink); }
.brand img { width: 26px; height: 26px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  font-size: 14px;
}
.nav-links a { color: var(--ink-2); }
.nav-links a:hover,
.nav-links a[aria-current="page"] { color: var(--ink); }

/* 语言切换：中 / EN，当前语言加深 */
.lang-switch {
  display: inline-flex;
  padding: 2px;
  border-radius: 8px;
  border: 1px solid var(--line);
  font-size: 12px;
}
.lang-switch a {
  padding: 3px 8px;
  border-radius: 6px;
  color: var(--ink-3);
}
.lang-switch a[aria-current] { background: var(--paper-2); color: var(--ink); }

.nav-cta {
  padding: 7px 14px;
  border-radius: 8px;
  background: var(--dark);
  color: #fff !important;
  font-weight: 500;
}
.nav-cta:hover { background: #333333; }

/* ---------- 按钮 ---------- */

.download-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  height: 48px;
  padding: 0 22px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 500;
  border: 1px solid transparent;
  transition: background 0.15s, border-color 0.15s, transform 0.15s, box-shadow 0.15s;
}
.btn svg { flex: none; }
.btn:hover { transform: translateY(-1px); }

.btn-primary {
  background: var(--dark);
  color: #fff;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2), 0 6px 16px -6px rgba(0, 0, 0, 0.45);
}
.btn-primary:hover { background: #333333; color: #fff; }

.btn-secondary {
  background: #fff;
  color: var(--ink);
  border-color: var(--line);
}
.btn-secondary:hover { color: var(--ink); border-color: #CFCABD; }

.btn.is-disabled { color: var(--ink-3); background: var(--paper-2); border-color: var(--line); cursor: default; }
.btn.is-disabled:hover { transform: none; }

.btn-small { height: 38px; padding: 0 14px; font-size: 14px; border-radius: 8px; }

/* ---------- 截图窗口框 ---------- */

.window {
  margin: 0;
  border-radius: 12px;
  background: #fff;
  border: 1px solid var(--line);
  box-shadow:
    0 1px 2px rgba(27, 31, 42, 0.04),
    0 24px 48px -24px rgba(27, 31, 42, 0.22);
  overflow: hidden;
}

.window-bar {
  display: flex;
  gap: 7px;
  padding: 12px 14px;
  border-bottom: 1px solid #EFECE4;
  background: #FAF9F5;
}
.window-bar i {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: #E3DFD5;
}

.window-body { position: relative; aspect-ratio: 16 / 10; background: var(--paper-2); }
.window-body img { width: 100%; height: 100%; object-fit: cover; object-position: top left; }

/* 截图还没补时的占位文字 */
.window-body .placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  text-align: center;
  color: var(--ink-3);
  font-size: 13px;
}

/* ---------- 首屏 ---------- */

.hero {
  padding: 72px 0 0;
  text-align: center;
}

.hero h1 {
  font-family: var(--serif);
  font-size: 48px;
  line-height: 1.3;
  letter-spacing: 0.01em;
}

.hero-tagline {
  margin: 16px 0 0;
  color: var(--ink-3);
  font-family: var(--serif);
  font-size: 20px;
  font-style: italic;
  letter-spacing: 0.01em;
}

.hero-lead {
  max-width: 680px;
  margin: 24px auto 0;
  color: var(--ink-2);
  font-size: 18px;
}

.hero .download-row { justify-content: center; margin-top: 40px; }

.hero-note {
  margin: 16px 0 0;
  color: var(--ink-3);
  font-size: 13px;
}
.hero-note a { color: var(--ink-2); border-bottom: 1px solid var(--line); }
.hero-note a:hover { color: var(--ink); }

.hero-shot {
  max-width: 1040px;
  margin: 72px auto 0;
}

/* 首屏宣传片：和截图窗口同一套圆角、发丝边、投影，不再套一层假窗口栏 */
.hero-video {
  max-width: 1040px;
  margin: 72px auto 0;
  aspect-ratio: 16 / 9;
  border-radius: 12px;
  background: var(--paper-2);
  border: 1px solid var(--line);
  box-shadow:
    0 1px 2px rgba(27, 31, 42, 0.04),
    0 24px 48px -24px rgba(27, 31, 42, 0.22);
  overflow: hidden;
}
.hero-video video { display: block; width: 100%; height: 100%; object-fit: cover; }

/* ---------- 段落标题 ---------- */

section { scroll-margin-top: 72px; }

.section { padding: 128px 0 0; }

.section-head { max-width: 640px; }
.section-head.center { margin: 0 auto; text-align: center; }

.kicker {
  margin: 0 0 12px;
  color: #B07A12;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
}

.section-head h2 {
  font-family: var(--serif);
  font-size: 38px;
  line-height: 1.35;
}

.section-head p {
  margin: 16px 0 0;
  color: var(--ink-2);
  font-size: 17px;
}

/* ---------- 功能：左侧吸顶目录 + 右侧分节（滚动联动高亮） ---------- */

.features-layout {
  display: grid;
  grid-template-columns: 180px minmax(0, 1fr);
  gap: 72px;
  margin-top: 80px;
}

.feature-nav {
  position: sticky;
  top: 112px;
  align-self: start;
}
.feature-nav ol {
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line);
}
.feature-nav a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-left: -1px;
  padding: 10px 0 10px 18px;
  border-left: 2px solid transparent;
  color: var(--ink-3);
  font-size: 15px;
  transition: color 0.2s, border-color 0.2s;
}
.feature-nav a:hover { color: var(--ink); }
.feature-nav a.active { color: var(--ink); border-left-color: var(--gold); font-weight: 500; }
.feature-nav .n { font-family: var(--serif); font-size: 14px; }

.features { display: grid; gap: 120px; }

.feature { scroll-margin-top: 112px; }
.feature-copy { max-width: 640px; }
.feature .window { margin-top: 36px; }

/* 桌面上目录已经标了序号，段内小标只在窄屏（目录隐藏时）显示 */
.feature-index {
  display: none;
  margin-bottom: 16px;
  color: var(--ink-3);
  font-family: var(--serif);
  font-size: 15px;
}

.feature h3 {
  font-family: var(--serif);
  font-size: 28px;
  line-height: 1.4;
}

.feature-copy > p {
  margin: 16px 0 0;
  color: var(--ink-2);
  font-size: 16px;
}

.points {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
  font-size: 15px;
}
.points li { display: flex; gap: 10px; color: var(--ink); }
.points strong { font-weight: 600; }
.points li::before {
  content: "";
  flex: none;
  width: 5px;
  height: 5px;
  margin-top: 11px;
  border-radius: 50%;
  background: var(--gold);
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 24px;
  font-size: 15px;
  font-weight: 500;
}
.text-link::after { content: "→"; transition: transform 0.15s; }
.text-link:hover::after { transform: translateX(3px); }

/* ---------- 本地优先 ---------- */

.local {
  margin-top: 128px;
  padding: 96px 0;
  background: var(--dark);
  color: #EDEDED;
}
.local .section-head h2 { color: #fff; }
.local .section-head p { color: #A3A3A3; }
.local .kicker { color: var(--gold); }

.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 56px;
}

.card {
  padding: 28px;
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.1);
}
.card h3 { color: #fff; font-size: 17px; font-weight: 500; }
.card p { margin: 10px 0 0; color: #A3A3A3; font-size: 14px; }
.card .icon { margin-bottom: 18px; color: var(--gold); }

.providers {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-top: 40px;
  color: #A3A3A3;
  font-size: 13px;
}
.providers span {
  padding: 5px 12px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.14);
}

/* ---------- 收尾下载 ---------- */

.final {
  padding: 128px 0;
  text-align: center;
}
.final img { width: 64px; height: 64px; margin: 0 auto 28px; }
.final h2 { font-family: var(--serif); font-size: 38px; line-height: 1.35; }
.final p { margin: 12px 0 0; color: var(--ink-2); font-size: 17px; }
.final .download-row { justify-content: center; margin-top: 36px; }

/* ---------- 页脚 ---------- */

.site-footer { border-top: 1px solid var(--line); }
.site-footer .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-top: 28px;
  padding-bottom: 28px;
  color: var(--ink-3);
  font-size: 13px;
}
.site-footer .brand { font-size: 13px; color: var(--ink-2); }
.site-footer .brand img { width: 20px; height: 20px; }
.footer-links { display: flex; gap: 24px; }
.footer-links a { color: var(--ink-3); }
.footer-links a:hover { color: var(--ink); }

/* ---------- 使用指南 ---------- */

.guide {
  display: grid;
  grid-template-columns: 200px minmax(0, 1fr);
  gap: 72px;
  padding-top: 64px;
  padding-bottom: 128px;
}

.toc {
  position: sticky;
  top: 96px;
  align-self: start;
  font-size: 14px;
}
.toc p { margin: 0 0 12px; color: var(--ink-3); font-size: 12px; letter-spacing: 0.08em; }
.toc ol { margin: 0; padding: 0; list-style: none; display: grid; gap: 2px; }
.toc a {
  display: block;
  padding: 6px 12px;
  margin-left: -12px;
  border-radius: 6px;
  color: var(--ink-2);
}
.toc a:hover { color: var(--ink); background: var(--paper-2); }
.toc a.active { color: var(--ink); background: var(--paper-2); font-weight: 500; }

.guide-body { max-width: 720px; }

.guide-head h1 { font-family: var(--serif); font-size: 44px; line-height: 1.3; }
.guide-head p { margin: 16px 0 0; color: var(--ink-2); font-size: 17px; }

.guide-section { padding-top: 72px; }
.guide-section h2 {
  display: flex;
  align-items: baseline;
  gap: 14px;
  font-family: var(--serif);
  font-size: 28px;
  line-height: 1.4;
}
.guide-section h2 .num { color: var(--ink-3); font-size: 18px; }
.guide-section > p { margin: 14px 0 0; color: var(--ink-2); font-size: 16px; }
.guide-section h3 { margin-top: 36px; font-size: 17px; font-weight: 600; }

.steps {
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
  display: grid;
  gap: 14px;
}
.steps li {
  counter-increment: step;
  position: relative;
  padding-left: 40px;
  font-size: 15px;
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 1px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--paper-2);
  border: 1px solid var(--line);
  color: var(--ink-2);
  font-size: 12px;
  line-height: 22px;
  text-align: center;
}

.ui {
  padding: 1px 6px;
  border-radius: 4px;
  background: var(--paper-2);
  border: 1px solid var(--line);
  font-size: 0.92em;
  white-space: nowrap;
}

code {
  padding: 1px 6px;
  border-radius: 4px;
  background: var(--paper-2);
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.88em;
}

.note {
  margin: 24px 0 0;
  padding: 16px 18px;
  border-radius: 10px;
  background: #FFF8E8;
  border: 1px solid #F3E2B8;
  color: #5E4A1C;
  font-size: 14px;
}
.note strong { color: #3F3010; }

.guide-section .window { margin-top: 28px; }
.guide-section .download-row { margin-top: 24px; }

.example-prompts {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 8px;
}
.example-prompts li {
  padding: 10px 14px;
  border-radius: 10px;
  background: #fff;
  border: 1px solid var(--line);
  font-size: 15px;
}

.faq { margin-top: 20px; display: grid; gap: 10px; }
.faq details {
  padding: 14px 18px;
  border-radius: 10px;
  background: #fff;
  border: 1px solid var(--line);
}
.faq summary { cursor: pointer; font-size: 15px; font-weight: 500; }
.faq details p { margin: 10px 0 0; color: var(--ink-2); font-size: 14px; }

/* ---------- 英文页字体：参照 Anthropic 官网，正文与标题用衬线体，界面元素用无衬线体 ---------- */

html[lang="en"] {
  --serif: "Newsreader", "Iowan Old Style", Georgia, serif;
  --sans: "DM Sans", system-ui, -apple-system, sans-serif;
}
html[lang="en"] body { font-family: var(--serif); font-size: 18px; }
html[lang="en"] :is(.site-nav, .btn, .hero-note, .kicker, .feature-nav, .feature-index, .providers, .toc, .ui, .note, .site-footer, .faq summary, .example-prompts) {
  font-family: var(--sans);
}
html[lang="en"] :is(.hero h1, .section-head h2, .feature h3, .final h2, .guide-head h1, .guide-section h2) {
  font-weight: 500;
  letter-spacing: -0.01em;
}
html[lang="en"] .hero h1 { font-size: 56px; }
html[lang="en"] .hero-tagline { font-size: 22px; }
html[lang="en"] .hero-lead,
html[lang="en"] .section-head p { font-size: 19px; }
html[lang="en"] .hero-lead { max-width: 820px; }
html[lang="en"] .feature-copy > p,
html[lang="en"] .guide-section > p { font-size: 18px; }
html[lang="en"] .points,
html[lang="en"] .steps li { font-size: 17px; }
html[lang="en"] .card h3 { font-family: var(--serif); font-size: 20px; }

/* ---------- 进场：只做一次轻微淡入 ---------- */

.js .reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.js .reveal.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .btn:hover { transform: none; }
}

/* ---------- 窄屏 ---------- */

@media (max-width: 960px) {
  .features-layout { grid-template-columns: 1fr; gap: 0; margin-top: 56px; }
  .feature-nav { display: none; }
  .feature-index { display: inline-block; }
  .cards { grid-template-columns: 1fr; }
  .guide { grid-template-columns: 1fr; gap: 0; }
  .toc { display: none; }
}

@media (max-width: 640px) {
  .nav-links > a:not(.nav-cta) { display: none; }
  .hero { padding-top: 40px; }
  .hero h1 { font-size: 28px; }
  html[lang="en"] .hero h1 { font-size: 38px; }
  .hero-tagline { font-size: 17px; }
  .br-wide { display: none; }
  .hero-lead { font-size: 16px; }
  .hero-shot { margin-top: 48px; }
  .hero-video { margin-top: 48px; }
  .section { padding-top: 96px; }
  .section-head h2,
  .final h2 { font-size: 28px; }
  .feature h3 { font-size: 24px; }
  .features { gap: 80px; }
  .local { margin-top: 96px; padding: 72px 0; }
  .final { padding: 96px 0; }
  .download-row .btn { width: 100%; justify-content: center; }
  .guide-head h1 { font-size: 34px; }
  .site-footer .wrap { flex-direction: column; align-items: flex-start; }
}