:root {
  color-scheme: light dark;
  --page: #f6f8fa;
  --surface: #ffffff;
  --surface-soft: #eef3f8;
  --text: #1f2328;
  --muted: #59636e;
  --line: #d0d7de;
  --line-strong: #afb8c1;
  --accent: #0969da;
  --accent-hover: #075bbd;
  --accent-text: #ffffff;
  --shadow: 0 24px 70px rgba(31, 35, 40, 0.13);
  --radius: 12px;
  --max-width: 1180px;
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  background: var(--page);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button:focus-visible,
a:focus-visible,
[tabindex]:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 55%, transparent);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 20;
  padding: 8px 12px;
  border-radius: var(--radius);
  color: var(--accent-text);
  background: var(--accent);
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 75%, transparent);
  background: color-mix(in srgb, var(--page) 92%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.header-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  align-items: center;
  gap: 28px;
  width: min(calc(100% - 40px), var(--max-width));
  min-height: 66px;
  margin: 0 auto;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  width: fit-content;
  font-size: 0.94rem;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
}

.brand img {
  border-radius: 9px;
}

.site-nav {
  display: flex;
  gap: 24px;
  white-space: nowrap;
}

.site-nav a,
footer a {
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 600;
  text-decoration: none;
}

.site-nav a:hover,
footer a:hover,
.text-link:hover {
  color: var(--accent);
}

.language-switch {
  display: flex;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}

.language-switch button {
  min-width: 44px;
  min-height: 32px;
  padding: 4px 9px;
  border: 0;
  border-radius: 7px;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
}

.language-switch button[aria-pressed="true"] {
  color: var(--accent-text);
  background: var(--accent);
}

main,
footer {
  width: min(calc(100% - 40px), var(--max-width));
  margin: 0 auto;
}

.support-section {
  display: grid;
  grid-template-columns: minmax(240px, 0.68fr) minmax(520px, 1.32fr);
  gap: clamp(44px, 7vw, 92px);
  align-items: start;
  border-top: 1px solid var(--line);
}

.support-copy {
  position: sticky;
  top: 106px;
}

.support-kicker {
  margin-bottom: 10px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.support-copy h2 {
  max-width: 7ch;
}

.support-copy > p:not(.support-kicker) {
  max-width: 36ch;
  color: var(--muted);
}

.support-note {
  margin: 26px 0 0;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 0.84rem;
}

.support-payments {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.support-payment {
  min-width: 0;
  margin: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  box-shadow: 0 14px 38px rgba(31, 35, 40, 0.08);
}

.support-payment-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 38px;
  padding: 0 3px 10px;
}

.support-payment-head strong {
  font-size: 0.9rem;
}

.support-payment-head span {
  padding: 3px 8px;
  border-radius: 999px;
  color: var(--muted);
  background: var(--surface-soft);
  font-size: 0.7rem;
  font-weight: 700;
}

.support-payment img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 10px;
  background: #ffffff;
}

.support-payment figcaption {
  padding: 11px 3px 1px;
  color: var(--muted);
  font-size: 0.76rem;
  text-align: center;
}

.support-payment-wechat {
  border-top-color: #07c160;
}

.support-payment-alipay {
  border-top-color: #1677ff;
}

.hero {
  display: grid;
  grid-template-columns: minmax(300px, 0.82fr) minmax(560px, 1.32fr);
  align-items: center;
  gap: clamp(42px, 6vw, 84px);
  min-height: calc(100dvh - 66px);
  padding: 48px 0 56px;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 10ch;
  margin-bottom: 20px;
  font-size: clamp(2.8rem, 5vw, 4.8rem);
  line-height: 1.04;
  letter-spacing: -0.055em;
}

h2 {
  margin-bottom: 14px;
  font-size: clamp(2rem, 3.4vw, 3.25rem);
  line-height: 1.1;
  letter-spacing: -0.04em;
}

h3 {
  margin-bottom: 7px;
  font-size: 1.08rem;
  line-height: 1.35;
}

.hero-summary {
  max-width: 40ch;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: 1.04rem;
}

.hero-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 18px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 17px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 0.92rem;
  font-weight: 700;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
  transition: transform 140ms ease, background-color 140ms ease;
}

.button:active {
  transform: translateY(1px);
}

.button-primary {
  color: var(--accent-text);
  background: var(--accent);
}

.button-primary:hover {
  background: var(--accent-hover);
}

.text-link {
  color: var(--text);
  font-size: 0.92rem;
  font-weight: 650;
  text-underline-offset: 4px;
}

.paper-preview {
  overflow: hidden;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.preview-toolbar {
  display: flex;
  align-items: center;
  gap: 9px;
  min-height: 42px;
  padding: 0 15px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  background: var(--surface-soft);
  font-size: 0.76rem;
  font-weight: 700;
}

.preview-count {
  margin-left: auto;
  font-variant-numeric: tabular-nums;
}

.paper-row {
  padding: 15px 17px;
  border-bottom: 1px solid var(--line);
}

.paper-row:last-child {
  border-bottom: 0;
}

.paper-row h2 {
  max-width: none;
  margin: 0 0 3px;
  color: var(--accent);
  font-size: 0.96rem;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.paper-row p {
  margin-bottom: 9px;
  color: var(--muted);
  font-size: 0.76rem;
}

.paper-row-journal {
  background: color-mix(in srgb, var(--accent) 4%, var(--surface));
}

.badge-row,
.row-example {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
}

.rank-badge,
.venue-chip,
.hover-sample > span {
  display: inline-flex;
  align-items: center;
  min-height: 22px;
  padding: 2px 8px;
  border: 1px solid currentColor;
  border-radius: 7px;
  font-size: 0.7rem;
  font-weight: 750;
  line-height: 1.2;
  white-space: nowrap;
}

.badge-ccf {
  color: #a13228;
  background: #fff4f2;
}

.badge-ccf-b {
  color: #8a4a13;
  background: #fff8e8;
}

.badge-none {
  color: #667085;
  background: #f3f4f6;
}

.badge-cas {
  color: #75508f;
  background: #faf4ff;
}

.badge-xinrui {
  color: #007f61;
  background: #edfff8;
}

.badge-warning {
  color: #b42318;
  background: #fff2f0;
}

.badge-jcr {
  color: #2864a5;
  background: #f1f7ff;
}

.badge-wos {
  color: #5365a6;
  background: #f3f4ff;
}

.badge-cssci {
  color: #8a3f72;
  background: #fff3fa;
}

.badge-pku {
  color: #276749;
  background: #f0fff4;
}

.badge-ei {
  color: #8a4a13;
  background: #fff8e8;
}

.filter-example {
  display: grid;
  grid-template-columns: auto auto;
  justify-self: end;
  gap: 7px 14px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 9px;
  color: var(--muted);
  background: var(--surface-soft);
  font-size: 0.74rem;
  font-weight: 700;
}

.warning-filter-demo {
  grid-column: 1 / -1;
  color: #b42318;
}

.venue-chip {
  color: var(--muted);
  background: var(--surface-soft);
}

.support-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.support-strip span {
  padding: 17px 12px;
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 700;
  text-align: center;
}

.support-strip span + span {
  border-left: 1px solid var(--line);
}.support-strip span:nth-child(5) {
  border-left: 0;
}

.support-strip span:nth-child(n + 5) {
  border-top: 1px solid var(--line);
}

.section {
  padding: 104px 0;
}

.section-heading {
  max-width: 650px;
  margin-bottom: 50px;
}

.section-heading p,
.coverage-list p,
.privacy-copy p,
.final-cta p {
  color: var(--muted);
}

.section-heading p {
  margin-bottom: 0;
  font-size: 1.04rem;
}

.coverage-list {
  border-top: 1px solid var(--line-strong);
}

.coverage-list article {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(250px, 0.72fr);
  align-items: center;
  gap: 24px;
  padding: 27px 0;
  border-bottom: 1px solid var(--line);
}

.coverage-list p {
  max-width: 58ch;
  margin-bottom: 0;
  font-size: 0.92rem;
}

.row-example {
  justify-content: flex-end;
}

.hover-sample {
  position: relative;
  justify-self: end;
  cursor: default;
}

.hover-sample > span {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 7%, var(--surface));
}

.sample-tooltip {
  position: absolute;
  right: 0;
  bottom: calc(100% + 10px);
  z-index: 3;
  display: grid;
  gap: 3px;
  width: 235px;
  padding: 12px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  color: var(--text);
  background: var(--surface);
  box-shadow: 0 14px 36px rgba(31, 35, 40, 0.18);
  font-size: 0.78rem;
  opacity: 0;
  pointer-events: none;
  transform: translateY(5px);
  transition: opacity 120ms ease, transform 120ms ease;
}

.sample-tooltip span {
  color: var(--muted);
}

.hover-sample:hover .sample-tooltip,
.hover-sample:focus .sample-tooltip,
.hover-sample:focus-within .sample-tooltip {
  opacity: 1;
  transform: translateY(0);
}

.privacy-section {
  display: grid;
  grid-template-columns: 96px minmax(0, 720px);
  align-items: start;
  justify-content: center;
  gap: 34px;
  margin-bottom: 104px;
  padding: 58px;
  border: 1px solid color-mix(in srgb, var(--accent) 28%, var(--line));
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--accent) 6%, var(--surface));
}

.privacy-mark {
  display: grid;
  place-items: center;
  width: 72px;
  height: 72px;
  border-radius: var(--radius);
  color: var(--accent-text);
  background: var(--accent);
  font-size: 2rem;
  font-weight: 800;
}

.privacy-copy h2 {
  font-size: clamp(1.9rem, 3vw, 2.8rem);
}

.privacy-copy p {
  max-width: 68ch;
}

.final-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
  padding: 0 0 90px;
}

.final-cta h2 {
  margin-bottom: 7px;
  font-size: clamp(2rem, 3.5vw, 3.2rem);
}

.final-cta p {
  margin-bottom: 0;
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 24px 0 34px;
  border-top: 1px solid var(--line);
}

footer p {
  margin: 0;
  color: var(--muted);
  font-size: 0.8rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #0d1117;
    --surface: #161b22;
    --surface-soft: #21262d;
    --text: #f0f6fc;
    --muted: #9da7b3;
    --line: #30363d;
    --line-strong: #484f58;
    --accent: #58a6ff;
    --accent-hover: #79b8ff;
    --accent-text: #0d1117;
    --shadow: 0 24px 70px rgba(0, 0, 0, 0.38);
  }

  .badge-ccf { color: #ff938a; background: #321b1b; }
  .badge-ccf-b { color: #e3b341; background: #2e2414; }
  .badge-none { color: #b1bac4; background: #252a31; }
  .badge-cas { color: #d2a8ff; background: #281d32; }
  .badge-jcr { color: #79c0ff; background: #17263a; }
  .badge-wos { color: #a5b4fc; background: #20223d; }
  .badge-cssci { color: #f0a6d2; background: #321d2b; }
  .badge-pku { color: #7ee2a8; background: #173126; }
  .badge-ei { color: #e3b341; background: #2e2414; }
  .sample-tooltip { box-shadow: 0 14px 36px rgba(0, 0, 0, 0.48); }
  .support-payment { box-shadow: 0 14px 38px rgba(0, 0, 0, 0.24); }
}

@media (max-width: 960px) {
  .site-nav { display: none; }
  .header-inner { grid-template-columns: minmax(0, 1fr) auto; }
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: 68px 0 74px;
  }
  .hero-copy { max-width: 650px; }
  h1 { max-width: 12ch; }
  .coverage-list article {
    grid-template-columns: minmax(0, 1fr) minmax(220px, 0.72fr);
  }
  .support-section {
    grid-template-columns: 1fr;
  }
  .support-copy {
    position: static;
  }
  .support-copy h2 {
    max-width: none;
  }
  .row-example,
  .hover-sample,
  .filter-example {
    grid-column: 2;
    justify-self: start;
    justify-content: flex-start;
  }
}

@media (max-width: 640px) {
  .header-inner,
  main,
  footer {
    width: min(calc(100% - 28px), var(--max-width));
  }
  .header-inner { gap: 12px; }
  .brand span { display: none; }
  .hero { gap: 38px; padding: 52px 0 60px; }
  h1 { font-size: clamp(2.55rem, 13vw, 3.5rem); }
  .paper-row { padding: 14px; }
  .paper-row h2 { font-size: 0.91rem; }
  .support-strip {
    grid-template-columns: repeat(2, 1fr);
  }
  .support-strip span:nth-child(odd) { border-left: 0; }
  .support-strip span:nth-child(n + 3) { border-top: 1px solid var(--line); }
  .section { padding: 78px 0; }
  .section-heading { margin-bottom: 36px; }
  .coverage-list article {
    grid-template-columns: 1fr;
    gap: 12px;
    padding: 25px 0;
  }
  .row-example,
  .hover-sample,
  .filter-example { grid-column: 1; justify-self: start; }
  .sample-tooltip { right: auto; left: 0; }
  .privacy-section {
    grid-template-columns: 1fr;
    gap: 24px;
    margin-bottom: 78px;
    padding: 34px 24px;
  }
  .privacy-mark { width: 56px; height: 56px; font-size: 1.55rem; }
  .support-payments {
    grid-template-columns: 1fr;
  }
  .support-payment {
    padding: 12px;
  }
  .final-cta {
    align-items: flex-start;
    flex-direction: column;
    padding-bottom: 70px;
  }
  footer {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}