/* ==========================================================================
   ReadRelay 官网样式表
   设计基调：克制的纸面留白 + 墨色排版，呼应应用图标的温润质感
   组织顺序：令牌 → 基础 → 排版 → 布局 → 顶栏 → 首屏 → 组件 → 内页 → 动效
   ========================================================================== */

/* 1. 设计令牌 ------------------------------------------------------------- */
:root {
  --paper: #f7f7f8;
  --surface: #ffffff;
  --surface-soft: #f1f2f4;
  --ink: #2e3540;
  --ink-soft: #4c545f;
  --muted: #6e7682;
  --line: #e4e6ea;
  --line-strong: #d3d7dd;
  --accent: #2e3540;
  --accent-ink: #ffffff;
  --link: #46658c;
  --ok: #3f7a5a;
  --shadow-sm: 0 1px 2px rgba(28, 32, 40, 0.04);
  --shadow-md: 0 10px 30px -18px rgba(28, 32, 40, 0.28);
  --shadow-lg: 0 30px 70px -40px rgba(28, 32, 40, 0.45);
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --container: 1080px;
  --gutter: clamp(1.25rem, 4vw, 2.5rem);
  --section-y: clamp(3.5rem, 8vw, 6.5rem);
  --header-h: 60px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #16181c;
    --surface: #1d2025;
    --surface-soft: #23272d;
    --ink: #eceef1;
    --ink-soft: #c3c8cf;
    --muted: #969ca6;
    --line: #2c3138;
    --line-strong: #3a4048;
    --accent: #eceef1;
    --accent-ink: #16181c;
    --link: #9db8da;
    --ok: #7fbf9c;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 10px 30px -18px rgba(0, 0, 0, 0.7);
    --shadow-lg: 0 30px 70px -40px rgba(0, 0, 0, 0.85);
  }
}

/* 2. 基础与重置 ----------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background-color: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro SC", "SF Pro Text",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 3px;
  border-radius: 4px;
}

/* 3. 排版 ----------------------------------------------------------------- */
h1,
h2,
h3 {
  margin: 0 0 0.6em;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.25;
  color: var(--ink);
}

h1 {
  font-size: clamp(2rem, 5.2vw, 3.1rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.5rem, 3.4vw, 2.1rem);
}

h3 {
  font-size: 1.125rem;
  line-height: 1.4;
}

p {
  margin: 0 0 1em;
  color: var(--ink-soft);
}

.lead {
  font-size: clamp(1.02rem, 2.2vw, 1.2rem);
  color: var(--muted);
}

.eyebrow {
  margin: 0 0 0.75rem;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

/* 4. 布局 ----------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-block: var(--section-y);
}

.section--tight {
  padding-block: clamp(2rem, 4vw, 3rem);
}

.section-head {
  max-width: 42rem;
  margin-bottom: clamp(1.75rem, 4vw, 2.75rem);
}

.section-head--center {
  margin-inline: auto;
  text-align: center;
}

[id] {
  scroll-margin-top: calc(var(--header-h) + 16px);
}

.grid {
  display: grid;
  gap: clamp(1rem, 2.5vw, 1.5rem);
}

.grid--2 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 20rem), 1fr));
}

.grid--3 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
}

.grid--4 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 13rem), 1fr));
}

/* 5. 顶栏 ----------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  background-color: color-mix(in srgb, var(--paper) 82%, transparent);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s ease, background-color 0.25s ease;
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
}

.nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  margin-right: auto;
  color: var(--ink);
  font-weight: 600;
  font-size: 1.02rem;
  letter-spacing: -0.01em;
}

.brand:hover {
  text-decoration: none;
}

.brand img {
  width: 28px;
  height: 28px;
  border-radius: 7px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.35rem;
  font-size: 0.94rem;
}

.nav-links a {
  color: var(--muted);
}

.nav-links a:hover,
.nav-links a[aria-current="true"] {
  color: var(--ink);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  color: var(--ink);
  cursor: pointer;
}

.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
  display: block;
  width: 16px;
  height: 1.5px;
  margin-inline: auto;
  background-color: currentColor;
  content: "";
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle span::before {
  transform: translateY(-5px);
}

.nav-toggle span::after {
  transform: translateY(3.5px);
}

/* 6. 按钮 ----------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.72rem 1.35rem;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: 0.97rem;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  transition: transform 0.15s ease, opacity 0.15s ease, background-color 0.15s ease;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn--primary {
  background-color: var(--accent);
  color: var(--accent-ink);
}

.btn--ghost {
  border-color: var(--line-strong);
  background-color: var(--surface);
  color: var(--ink);
}

.btn--sm {
  padding: 0.5rem 1rem;
  font-size: 0.88rem;
}

.btn[aria-disabled="true"] {
  opacity: 0.6;
  cursor: default;
  transform: none;
}

/* 7. 首屏 ----------------------------------------------------------------- */
.hero {
  padding-block: clamp(2.5rem, 7vw, 5rem) clamp(2.5rem, 6vw, 4rem);
}

.hero__inner {
  display: grid;
  gap: clamp(2rem, 5vw, 3.5rem);
  align-items: center;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1.15rem;
  padding: 0.35rem 0.75rem 0.35rem 0.4rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background-color: var(--surface);
  font-size: 0.82rem;
  color: var(--muted);
}

.hero__badge img {
  width: 22px;
  height: 22px;
  border-radius: 6px;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.hero__meta {
  margin-top: 1.1rem;
  font-size: 0.86rem;
  color: var(--muted);
}

/* 8. 流转图（纯 CSS/SVG 绘制，非应用截图） -------------------------------- */
.flow {
  padding: clamp(1.25rem, 3vw, 1.75rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background-color: var(--surface);
  box-shadow: var(--shadow-lg);
}

.flow__title {
  margin: 0 0 1.1rem;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.flow__source {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--surface-soft);
}

.flow__source strong {
  display: block;
  font-size: 0.95rem;
}

.flow__source span {
  font-size: 0.8rem;
  color: var(--muted);
}

.flow__arrow {
  display: grid;
  place-items: center;
  padding: 0.6rem 0;
  color: var(--line-strong);
}

.flow__node {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.7rem 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--surface);
  font-size: 0.92rem;
}

.flow__node + .flow__node {
  margin-top: 0.55rem;
}

/* 可点击的流转节点：保持墨色文本，hover 时以边框提示可跳转 */
a.flow__node {
  color: var(--ink);
}

a.flow__node:hover {
  border-color: var(--line-strong);
  text-decoration: none;
}

a.flow__node:hover .flow__dot {
  background-color: var(--ink);
}

.flow__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--line-strong);
  flex: none;
}

.flow__node--md .flow__dot {
  background-color: #6f8bb0;
}

.flow__node--ob .flow__dot {
  background-color: #8f7bb5;
}

.flow__node--no .flow__dot {
  background-color: #7fa9a4;
}

.flow__node--fl .flow__dot {
  background-color: #6fa27f;
}

.flow__node small {
  margin-left: auto;
  font-size: 0.76rem;
  color: var(--muted);
}

/* 9. 卡片 ----------------------------------------------------------------- */
.card {
  padding: clamp(1.25rem, 3vw, 1.6rem);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background-color: var(--surface);
  box-shadow: var(--shadow-sm);
}

.card h3 {
  margin-bottom: 0.4rem;
}

.card p:last-child {
  margin-bottom: 0;
}

.card__icon {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  margin-bottom: 0.9rem;
  border-radius: 11px;
  background-color: var(--surface-soft);
  font-size: 1.05rem;
  line-height: 1;
}

.card__label {
  display: inline-block;
  margin: 0 0 0.5rem;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.card ul {
  margin: 0.6rem 0 0;
  padding-left: 1.15rem;
  font-size: 0.9rem;
  color: var(--muted);
}

.card li + li {
  margin-top: 0.3rem;
}

/* 9b. 行内代码、代码块与表格（落地页用于展示真实导出格式） ------------------ */
code {
  padding: 0.15em 0.4em;
  border-radius: 6px;
  background-color: var(--surface-soft);
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.88em;
  color: var(--ink);
}

pre {
  margin: 0 0 1.4em;
  padding: 1rem 1.15rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  overflow-x: auto;
}

pre code {
  padding: 0;
  background: none;
  font-size: 0.86rem;
  line-height: 1.75;
  white-space: pre;
}

table {
  width: 100%;
  margin: 0 0 1.5em;
  border-collapse: collapse;
  font-size: 0.94rem;
  color: var(--ink-soft);
}

th,
td {
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  background-color: var(--surface-soft);
  font-weight: 600;
  color: var(--ink);
}

/* 10. 步骤 ---------------------------------------------------------------- */
.steps {
  counter-reset: step;
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr));
}

.step {
  position: relative;
  padding-top: 2.6rem;
}

.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  top: 0;
  left: 0;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background-color: var(--surface);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--ink);
}

.step h3 {
  margin-bottom: 0.35rem;
}

.step p {
  margin: 0;
  font-size: 0.92rem;
}

/* 11. FAQ ----------------------------------------------------------------- */
.faq {
  border-top: 1px solid var(--line);
}

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

.faq summary {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.1rem 0;
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::after {
  content: "+";
  margin-left: auto;
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--muted);
  transition: transform 0.2s ease;
}

.faq details[open] summary::after {
  transform: rotate(45deg);
}

.faq .faq__body {
  padding-bottom: 1.2rem;
  font-size: 0.96rem;
  color: var(--muted);
}

.faq .faq__body p:last-child {
  margin-bottom: 0;
}

.faq .faq__body ul {
  padding-left: 1.2rem;
  margin: 0 0 1em;
}

/* 12. 收尾 CTA 与页脚 ----------------------------------------------------- */
.cta {
  padding: clamp(2rem, 5vw, 3.25rem);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background-color: var(--surface);
  text-align: center;
  box-shadow: var(--shadow-md);
}

.cta h2 {
  margin-bottom: 0.5rem;
}

.cta p {
  max-width: 34rem;
  margin-inline: auto;
}

.cta .hero__actions {
  justify-content: center;
}

.site-footer {
  margin-top: var(--section-y);
  padding-block: 2.5rem;
  border-top: 1px solid var(--line);
  font-size: 0.88rem;
  color: var(--muted);
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem 2rem;
  align-items: flex-start;
  justify-content: space-between;
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
}

.site-footer a {
  color: var(--muted);
}

.site-footer p {
  margin: 0;
  font-size: 0.88rem;
}

/* 13. 内页（隐私 / 条款 / 支持） ----------------------------------------- */
.doc {
  max-width: 46rem;
  margin-inline: auto;
  padding-block: clamp(2.5rem, 6vw, 4rem);
}

.doc h2 {
  margin-top: 2.6rem;
}

.doc h3 {
  margin-top: 1.8rem;
}

.doc ul {
  padding-left: 1.25rem;
  color: var(--ink-soft);
}

.doc li + li {
  margin-top: 0.35rem;
}

.doc__meta {
  margin-top: 0.5rem;
  font-size: 0.88rem;
  color: var(--muted);
}

.doc__updated {
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--line);
}

.note {
  padding: 0.9rem 1.1rem;
  border: 1px solid var(--line);
  border-left: 3px solid var(--line-strong);
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  font-size: 0.92rem;
}

.breadcrumb {
  margin-bottom: 1.25rem;
  font-size: 0.86rem;
  color: var(--muted);
}

/* 14. 入场动效与无障碍降级 ---------------------------------------------- */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.skip-link {
  position: absolute;
  left: -9999px;
}

.skip-link:focus {
  left: var(--gutter);
  top: 10px;
  z-index: 100;
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  background-color: var(--surface);
  box-shadow: var(--shadow-md);
}

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

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .btn:hover {
    transform: none;
  }
}

/* 15. 响应式断点 --------------------------------------------------------- */
@media (max-width: 900px) {
  .hero__inner {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .nav-toggle {
    display: grid;
    place-items: center;
  }

  .nav-links {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.5rem var(--gutter) 1rem;
    border-bottom: 1px solid var(--line);
    background-color: var(--surface);
    box-shadow: var(--shadow-md);
  }

  .nav-links[data-open="true"] {
    display: flex;
  }

  .nav-links a {
    padding: 0.7rem 0;
    border-bottom: 1px solid var(--line);
    font-size: 1rem;
    color: var(--ink);
  }

  .nav-links a:last-child {
    border-bottom: 0;
  }

  .nav-cta {
    display: none;
  }
}

@media print {
  .site-header,
  .site-footer,
  .nav-toggle,
  .hero__actions {
    display: none;
  }
}