:root {
  color-scheme: light;
  --canvas: #f3f6fa;
  --paper: #ffffff;
  --ink: #25354a;
  --muted: #607086;
  --blue: #345fa8;
  --rule: #d9e1ec;
  --sans: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  --serif: "Songti SC", "STSong", "SimSun", serif;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 32px;
}

body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.8;
  -webkit-text-size-adjust: 100%;
}

::selection { color: var(--paper); background: var(--blue); }

a { color: inherit; text-decoration: none; }

a:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 6px;
  border-radius: 2px;
}

p, h1, h2, dl, dd { margin: 0; }

.site-shell { width: min(1080px, calc(100% - 112px)); margin: 0 auto; }

.skip-link {
  position: absolute;
  top: -100px;
  left: 20px;
  z-index: 10;
  padding: 8px 18px;
  color: var(--paper);
  background: var(--blue);
}

.skip-link:focus { top: 12px; }

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 106px;
  border-bottom: 1px solid var(--rule);
}

.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 18px; font-weight: 600; letter-spacing: .04em; }
.brand-mark { width: 29px; height: 29px; flex: 0 0 auto; color: var(--blue); }
.site-nav { display: flex; gap: 32px; font-size: 13px; color: var(--muted); }
.site-nav a:hover { color: var(--blue); }

.intro {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 286px;
  align-items: center;
  gap: 64px;
  padding: 84px 0 88px;
}

.eyebrow { display: flex; align-items: center; gap: 10px; font-size: 12px; color: var(--blue); letter-spacing: .1em; }
.small-line { width: 24px; height: 2px; background: var(--blue); }

h1 {
  margin-top: 24px;
  font-family: var(--serif);
  font-size: clamp(36px, 4.7vw, 58px);
  font-weight: 600;
  line-height: 1.45;
  letter-spacing: .025em;
}

.ink-underline { position: relative; white-space: nowrap; }
.ink-underline::after {
  position: absolute;
  content: "";
  left: 1px;
  right: 2px;
  bottom: -6px;
  height: 8px;
  border-top: 2px solid var(--blue);
  border-radius: 50%;
  transform: rotate(-2deg);
  opacity: .7;
}

.intro-description { margin-top: 30px; font-size: 14px; color: var(--muted); line-height: 2; }
.text-link { display: inline-flex; align-items: center; gap: 20px; margin-top: 28px; padding-bottom: 3px; border-bottom: 1px solid #a5b7d4; color: var(--blue); font-size: 13px; }
.text-link:hover { border-bottom-color: var(--blue); }
.text-link span { font-size: 19px; line-height: 1; }

.note {
  position: relative;
  align-self: center;
  padding: 27px 24px 25px 29px;
  background: var(--paper);
  border: 1px solid #e2e8f0;
  box-shadow: 5px 6px 0 -1px #e6ecf4, 5px 6px 0 0 #d8e1ec;
  transform: rotate(2deg);
}

.note::before { position: absolute; content: ""; top: 0; bottom: 0; left: 13px; border-left: 1px solid #e3eaf4; }
.note-topline { display: flex; justify-content: space-between; align-items: center; color: var(--muted); font-size: 10px; letter-spacing: .08em; }
.note-fold { width: 14px; height: 18px; border: 1px solid #b6c7df; border-top: 3px solid #7894be; }
.note-title { margin-top: 24px; font-family: var(--serif); font-size: 23px; font-weight: 600; letter-spacing: .04em; }
.note-prompts { padding: 0; margin: 18px 0 0; list-style: none; font-size: 13px; color: var(--muted); }
.note-prompts li { padding: 10px 0; border-bottom: 1px solid #e6edf5; }
.note-prompts li::before { content: ""; display: inline-block; width: 8px; height: 8px; margin-right: 11px; border: 1px solid #9eb1cd; }
.note-caption { margin-top: 24px; color: var(--blue); font-family: var(--serif); font-size: 13px; }

.content-section { border-top: 1px solid var(--rule); }
.topics { display: grid; grid-template-columns: 270px minmax(0, 1fr); gap: 66px; padding: 54px 0 59px; }
.section-kicker { color: var(--blue); font-size: 12px; letter-spacing: .08em; }
h2 { margin-top: 12px; font-family: var(--serif); font-size: 24px; font-weight: 600; line-height: 1.6; }
.section-intro { margin-top: 15px; max-width: 255px; color: var(--muted); font-size: 13px; line-height: 1.95; }
.topic-row { display: grid; grid-template-columns: 140px minmax(0, 1fr); gap: 25px; padding: 23px 0; border-bottom: 1px solid var(--rule); }
.topic-row:first-child { padding-top: 0; }
.topic-row:last-child { border: 0; padding-bottom: 0; }
.topic-row dt { font-size: 16px; font-weight: 500; }
.topic-keyword { display: block; margin-top: 5px; font-size: 11px; font-weight: 400; color: var(--muted); }
.topic-row dd { font-size: 13px; color: var(--muted); line-height: 1.95; }

.about { display: grid; grid-template-columns: 270px minmax(0, 1fr); gap: 66px; padding: 44px 0 50px; }
.about h2 { font-size: 21px; }
.about-copy { color: var(--muted); font-size: 13px; line-height: 1.95; }
.about-copy p + p { margin-top: 12px; }
.about-copy .about-note { margin-top: 19px; padding-left: 14px; border-left: 2px solid #b8c9e0; font-size: 12px; }

.site-footer { display: flex; justify-content: space-between; gap: 28px; padding: 25px 0 32px; border-top: 1px solid var(--rule); }
.footer-name { display: flex; flex-direction: column; gap: 2px; font-size: 12px; }
.footer-domain { color: var(--muted); font-size: 10px; letter-spacing: .035em; }
.footer-meta { display: flex; align-items: flex-end; gap: 21px; color: var(--muted); font-size: 11px; }
.footer-meta a:hover { color: var(--blue); text-decoration: underline; text-underline-offset: 3px; }

@media (min-width: 1440px) {
  .intro { padding-top: 98px; padding-bottom: 100px; }
}

@media (max-width: 1000px) {
  .site-shell { width: calc(100% - 72px); }
  .intro { grid-template-columns: minmax(0, 1fr) 245px; gap: 35px; padding: 66px 0 72px; }
  h1 { font-size: 43px; }
  .desktop-break { display: none; }
  .note { padding: 23px 19px 23px 26px; }
  .note-title { font-size: 21px; }
  .topics, .about { grid-template-columns: 225px minmax(0, 1fr); gap: 36px; }
  .topic-row { grid-template-columns: 114px minmax(0, 1fr); gap: 16px; }
  .footer-meta { flex-direction: column; justify-content: center; align-items: flex-end; gap: 2px; }
}

@media (max-width: 740px) {
  html { scroll-padding-top: 24px; }
  .site-shell { width: calc(100% - 44px); }
  .site-header { min-height: 84px; gap: 15px; }
  .brand { font-size: 16px; gap: 8px; letter-spacing: 0; }
  .brand-mark { width: 26px; height: 26px; }
  .site-nav { gap: 17px; font-size: 12px; }
  .intro { grid-template-columns: 1fr; gap: 41px; padding: 49px 0 51px; }
  h1 { margin-top: 21px; font-size: clamp(35px, 7.4vw, 47px); }
  .intro-description { max-width: 440px; margin-top: 26px; font-size: 13px; }
  .text-link { margin-top: 23px; }
  .note { width: min(310px, calc(100% - 10px)); justify-self: center; margin: 0 4px 4px 0; padding: 23px 25px 23px 30px; transform: rotate(1deg); }
  .note-title { margin-top: 15px; font-size: 23px; }
  .note-prompts { margin-top: 10px; }
  .note-prompts li { padding: 8px 0; }
  .note-caption { margin-top: 18px; }
  .topics, .about { grid-template-columns: 1fr; gap: 29px; padding: 35px 0 38px; }
  h2 { margin-top: 9px; font-size: 24px; }
  .section-intro { max-width: 450px; margin-top: 10px; }
  .topic-row { grid-template-columns: 114px minmax(0, 1fr); gap: 22px; padding: 20px 0; }
  .about { gap: 20px; }
  .about h2 { font-size: 22px; }
  .site-footer { padding: 22px 0 26px; gap: 20px; }
  .footer-meta { font-size: 10px; }
}

@media (max-width: 390px) {
  .site-shell { width: calc(100% - 36px); }
  .site-header { flex-wrap: wrap; gap: 11px; padding: 18px 0 17px; }
  .site-nav { width: 100%; padding-left: 34px; gap: 24px; }
  .intro { padding-top: 37px; }
  h1 { font-size: 34px; }
  .intro-description { font-size: 13px; }
  .topic-row { grid-template-columns: 1fr; gap: 8px; }
  .topic-row dt { display: flex; align-items: baseline; gap: 15px; }
  .topic-keyword { margin-top: 0; }
  .site-footer { flex-direction: column; gap: 16px; }
  .footer-meta { align-items: flex-start; font-size: 11px; }
}

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