:root {
  font-family:
    Inter, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: #181a1d;
  background: #fff;
  line-height: 1.6;
  font-synthesis: none;
  --muted: #61666e;
  --line: #e3e5e8;
  --accent: #256653;
  color-scheme: light;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
}
h1,
h2,
p,
figure,
dl,
dd {
  margin: 0;
}
a {
  color: inherit;
  text-underline-offset: 4px;
}
button {
  font: inherit;
  cursor: pointer;
}
a,
button,
summary {
  touch-action: manipulation;
}
a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 3px solid #668aff;
  outline-offset: 5px;
}
[hidden] {
  display: none !important;
}
::selection {
  background: #dce5ff;
}
h1,
h2,
p,
dd,
figcaption {
  overflow-wrap: anywhere;
}
.container {
  width: min(1280px, calc(100% - 96px));
  margin-inline: auto;
}
.skip {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 10;
  padding: 12px 20px;
  background: #111;
  color: white;
  transform: translateY(-160%);
}
.skip:focus {
  transform: none;
}
.header {
  height: 80px;
  display: flex;
  align-items: center;
  gap: 34px;
  border-bottom: 1px solid var(--line);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 650;
  text-decoration: none;
  white-space: nowrap;
}
.brand img {
  border-radius: 7px;
}
.brand-en {
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 10px;
  letter-spacing: 0.05em;
  font-weight: 400;
  color: var(--muted);
  margin-left: 5px;
}
.header nav {
  display: flex;
  gap: 29px;
  margin-left: auto;
}
.header nav a,
.language {
  font-size: 13px;
  text-decoration: none;
  color: #52575e;
}
.header nav a:hover,
.language:hover {
  color: var(--accent);
}
.language {
  padding-left: 26px;
  border-left: 1px solid var(--line);
  white-space: nowrap;
}
.hero {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 60px;
  align-items: end;
  padding: 52px 0 48px;
}
.product-type {
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 10px;
  letter-spacing: 0.07em;
  color: var(--muted);
  margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(44px, 5.5vw, 76px);
  font-weight: 600;
  line-height: 1.08;
  letter-spacing: -0.065em;
  white-space: pre-line;
}
.hero-copy {
  padding-bottom: 4px;
}
.lead {
  font-size: 17px;
  line-height: 1.9;
  white-space: pre-line;
  letter-spacing: -0.02em;
}
.actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 23px;
}
.button {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  min-height: 44px;
  padding: 10px 18px;
  font-size: 13px;
  font-weight: 550;
  border: 1px solid #cbd0d6;
  border-radius: 5px;
  text-decoration: none;
  transition:
    background 0.15s,
    color 0.15s;
}
.button:hover {
  background: #f0f2f5;
}
.primary,
.preview-link {
  color: white;
  background: #191b1f;
  border-color: #191b1f;
}
.primary:hover,
.preview-link:hover {
  background: #343944;
  color: white;
}
.hero:has(#reader-link:not([hidden])) .preview-link {
  color: var(--muted);
  background: none;
  border-color: transparent;
}
.small {
  font-size: 11px;
  line-height: 1.8;
  color: var(--muted);
}
#reader-pending {
  margin-top: 9px;
}
.hero-note {
  font-size: 11px;
  color: var(--muted);
  margin-top: 17px;
}
.preview-section {
  scroll-margin-top: 20px;
}
.preview-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 54px;
  border-top: 1px solid #cfd4db;
}
.preview-label {
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.theme-picker {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
}
.theme-picker button {
  display: flex;
  align-items: center;
  gap: 6px;
  border: 1px solid transparent;
  border-radius: 4px;
  min-height: 31px;
  padding: 5px 10px;
  font-size: 11px;
  color: #646a73;
  background: transparent;
}
.theme-picker button::before {
  content: "";
  display: block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #fff;
  border: 1px solid #abb2bd;
}
.theme-picker button[data-theme="dark"]::before {
  background: #343548;
  border-color: #343548;
}
.theme-picker button[data-theme="paper"]::before {
  background: #e4cf9f;
  border-color: #cdb783;
}
.theme-picker button[data-theme="academic"]::before {
  background: #a0a3a9;
  border-color: #a0a3a9;
}
.theme-picker button[data-theme="blue"]::before {
  background: #89b1d5;
  border-color: #89b1d5;
}
.theme-picker button[data-theme="black"]::before {
  background: #1a1c20;
  border-color: #1a1c20;
}
.theme-picker button[aria-pressed="true"] {
  color: #181a1d;
  border-color: #c5cbd3;
  background: #f4f5f7;
}
.theme-picker button:hover {
  background: #f4f5f7;
}
.product-preview {
  padding: 10px 10px 0;
  background: #edeff2;
  border: 1px solid #d4d9e0;
  border-radius: 10px;
  box-shadow: 0 20px 50px -34px #17294666;
  overflow: hidden;
}
#reader-preview {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid #dce0e5;
  border-radius: 4px;
  box-shadow: 0 3px 16px #1b29430a;
}
.product-preview figcaption {
  font-size: 10px;
  color: #61666e;
  padding: 10px 3px;
  text-align: right;
}
.preview-unavailable {
  min-height: 240px;
  display: grid;
  place-items: center;
  padding: 24px;
}
.section {
  padding-block: 85px;
  scroll-margin-top: 25px;
}
.feature-section,
.help-section {
  display: grid;
  grid-template-columns: 1fr 1.55fr;
  gap: 100px;
}
.section-label {
  font-size: 11px;
  color: var(--muted);
  margin-bottom: 18px;
  letter-spacing: 0.03em;
}
.section-intro h2 {
  font-size: 38px;
  font-weight: 550;
  line-height: 1.25;
  letter-spacing: -0.05em;
  white-space: pre-line;
}
.section-intro > p:last-child {
  font-size: 13px;
  color: var(--muted);
  margin-top: 22px;
  line-height: 1.9;
  white-space: pre-line;
}
.capabilities > div {
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: 8px 28px;
}
.capabilities > div:first-child {
  padding-top: 0;
}
.capabilities dt {
  font-size: 14px;
  font-weight: 550;
}
.capabilities dd {
  font-size: 13px;
  color: #515760;
  line-height: 1.85;
}
.format-note {
  grid-column: 2;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  color: #686f78;
  font-size: 10px;
  letter-spacing: -0.02em;
  overflow-wrap: anywhere;
}
.help-section {
  border-top: 1px solid var(--line);
}
.questions details {
  border-bottom: 1px solid var(--line);
}
.questions details:first-child {
  border-top: 1px solid var(--line);
}
.questions summary {
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  cursor: pointer;
  padding: 21px 0;
  font-size: 14px;
}
.questions summary::-webkit-details-marker {
  display: none;
}
.questions summary::after {
  content: "+";
  font-size: 21px;
  font-weight: 300;
  color: #6b727c;
  flex-shrink: 0;
}
.questions details[open] summary::after {
  content: "−";
}
.questions details p {
  font-size: 13px;
  color: var(--muted);
  padding: 0 25px 22px 0;
  line-height: 1.9;
}
.contact-band {
  background: #17191d;
  color: #f4f5f7;
}
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
}
.contact-grid > section {
  padding: 58px 60px 54px 0;
  scroll-margin-top: 20px;
}
.contact-grid > section + section {
  padding-left: 60px;
  padding-right: 0;
  border-left: 1px solid #34373d;
}
.contact-grid .section-label {
  color: #abb2bd;
  margin-bottom: 19px;
}
.contact-grid h2 {
  font-size: 34px;
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.035em;
  white-space: pre-line;
  margin-bottom: 18px;
}
.contact-copy {
  font-size: 13px;
  color: #b6bdc8;
  max-width: 410px;
  line-height: 1.9;
}
.contact-grid .small {
  color: #a4acb8;
  max-width: 430px;
  margin-top: 22px;
  font-size: 11px;
}
.contact-grid .button {
  border-color: #535b68;
  font-size: 12px;
  min-height: 40px;
  padding: 9px 14px;
}
.contact-grid .primary {
  background: #f3f5f8;
  color: #181b20;
  border-color: #f3f5f8;
}
.contact-grid .button:hover {
  background: #30353d;
  color: white;
}
.contact-grid .primary:hover {
  background: white;
  color: #181b20;
}
.support-methods {
  display: flex;
  align-items: flex-start;
  gap: 24px;
  flex-wrap: wrap;
  margin-top: 24px;
}
.support-methods article {
  min-width: 0;
  max-width: 100%;
}
.support-methods a,
.support-methods summary {
  font-size: 13px;
  color: #e2e8f1;
}
.support-methods summary,
#international-link {
  min-height: 32px;
  line-height: 32px;
}
#international-link {
  display: block;
}
.support-methods summary {
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 4px;
}
.support-methods summary::marker {
  font-size: inherit;
}
.channel-status {
  font-size: 12px;
  color: #b6bdc8;
}
.qr-details figure {
  margin-top: 18px;
  max-width: 280px;
}
.qr-details img {
  display: block;
  width: 280px;
  max-width: 100%;
  height: auto;
  border-radius: 3px;
  background: white;
}
.qr-details figcaption {
  font-size: 11px;
  line-height: 1.8;
  color: #b6bdc8;
  margin-top: 9px;
}
.qr-details .small {
  max-width: 280px;
}
.support-methods:has(details[open]) {
  flex-direction: column;
}
#email-row {
  font-size: 12px;
  margin-top: 16px;
}
footer {
  min-height: 96px;
  display: flex;
  align-items: center;
  gap: 25px;
  font-size: 11px;
  color: var(--muted);
}
footer .brand {
  font-size: 17px;
  color: #191b1f;
}
footer > span:nth-child(2) {
  margin-right: auto;
}
footer > a {
  text-decoration: none;
}
footer > a:hover {
  text-decoration: underline;
}
@media (min-width: 1600px) {
  .hero {
    padding-block: 64px;
  }
}
@media (max-width: 1000px) {
  .container {
    width: calc(100% - 64px);
  }
  .header {
    gap: 23px;
  }
  .header nav {
    gap: 22px;
  }
  .hero {
    gap: 35px;
  }
  .lead {
    font-size: 15px;
  }
  .feature-section,
  .help-section {
    gap: 55px;
    grid-template-columns: 1fr 1.4fr;
  }
  .section-intro h2 {
    font-size: 31px;
  }
  .capabilities > div {
    grid-template-columns: 82px 1fr;
    gap: 10px 16px;
  }
  .contact-grid > section {
    padding-right: 35px;
  }
  .contact-grid > section + section {
    padding-left: 35px;
  }
  .contact-grid h2 {
    font-size: 29px;
  }
}
@media (max-width: 680px) {
  .container {
    width: calc(100% - 36px);
  }
  .header {
    height: auto;
    padding: 20px 0 15px;
    gap: 18px;
    flex-wrap: wrap;
  }
  .header .brand {
    font-size: 18px;
  }
  .header .brand-en {
    font-size: 9px;
  }
  .header nav {
    order: 3;
    width: 100%;
    justify-content: space-between;
    gap: 12px;
  }
  .header nav a {
    font-size: 12px;
  }
  .language {
    font-size: 12px;
    margin-left: auto;
    padding-left: 0;
    border: 0;
  }
  .hero {
    grid-template-columns: 1fr;
    gap: 25px;
    padding: 36px 0 30px;
  }
  .hero h1 {
    font-size: clamp(39px, 10.8vw, 66px);
  }
  .product-type {
    font-size: 9px;
    margin-bottom: 15px;
  }
  .lead {
    font-size: 14px;
    line-height: 1.8;
  }
  .hero-copy {
    padding: 0;
  }
  .actions {
    margin-top: 18px;
  }
  .hero-note {
    margin-top: 12px;
    font-size: 10px;
  }
  .small {
    font-size: 10px;
  }
  .button {
    min-height: 42px;
    padding: 10px 16px;
    font-size: 12px;
  }
  .preview-top {
    display: block;
    padding: 12px 0 10px;
  }
  .preview-label {
    font-size: 10px;
  }
  .theme-picker {
    margin-top: 8px;
    gap: 2px;
  }
  .theme-picker button {
    font-size: 10px;
    padding: 5px 7px;
    gap: 4px;
  }
  .theme-picker button::before {
    width: 6px;
    height: 6px;
  }
  .product-preview {
    padding: 5px 5px 0;
    border-radius: 6px;
  }
  .product-preview figcaption {
    font-size: 9px;
    padding: 7px 2px;
  }
  .section {
    padding-block: 47px;
  }
  .feature-section,
  .help-section {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .section-label {
    margin-bottom: 12px;
    font-size: 10px;
  }
  .section-intro h2 {
    font-size: 30px;
  }
  .section-intro > p:last-child {
    margin-top: 14px;
    font-size: 12px;
  }
  .capabilities > div {
    grid-template-columns: 78px minmax(0, 1fr);
    gap: 8px 15px;
    padding: 18px 0;
  }
  .capabilities dt {
    font-size: 12px;
  }
  .capabilities dd {
    font-size: 12px;
    line-height: 1.85;
  }
  .format-note {
    font-size: 9px;
  }
  .questions summary {
    font-size: 13px;
    padding: 18px 0;
  }
  .questions details p {
    font-size: 12px;
    padding-right: 0;
  }
  .contact-grid {
    grid-template-columns: 1fr;
  }
  .contact-grid > section {
    padding: 38px 0;
  }
  .contact-grid > section + section {
    padding: 38px 0;
    border-left: 0;
    border-top: 1px solid #34373d;
  }
  .contact-grid h2 {
    font-size: 29px;
  }
  .contact-copy {
    font-size: 12px;
  }
  .contact-grid .small {
    font-size: 10px;
    margin-top: 17px;
  }
  .support-methods {
    gap: 20px;
    margin-top: 22px;
  }
  footer {
    flex-wrap: wrap;
    gap: 14px;
    min-height: 100px;
    padding-block: 23px;
    font-size: 10px;
  }
  footer .brand-en {
    display: none;
  }
  footer > span:nth-child(2) {
    flex: 1;
  }
  footer > a {
    white-space: nowrap;
  }
}
@media (max-width: 350px) {
  .header .brand-en {
    display: none;
  }
  .header nav {
    flex-wrap: wrap;
  }
  .capabilities > div {
    grid-template-columns: 1fr;
  }
  .format-note {
    grid-column: 1;
  }
  .contact-grid .actions {
    align-items: stretch;
    flex-direction: column;
  }
  .hero h1 {
    font-size: 35px;
  }
  .section-intro h2 {
    font-size: 27px;
  }
  .preview-label {
    display: block;
  }
  .theme-picker {
    row-gap: 5px;
  }
}
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none !important;
    scroll-behavior: auto !important;
  }
}

/* Product-led refinements: a real entry point, readable examples, and image inspection. */
.header {
  gap: 25px;
}
.header nav {
  gap: 23px;
}
.nav-reader {
  font-size: 12px;
  font-weight: 550;
  text-decoration: none;
  padding: 8px 13px;
  background: var(--accent);
  color: #fff;
  border-radius: 5px;
  white-space: nowrap;
}
.nav-reader:hover {
  background: #1b503e;
}
.hero .primary {
  background: var(--accent);
  border-color: var(--accent);
  padding-inline: 24px;
}
.hero .primary:hover {
  background: #1b503e;
  border-color: #1b503e;
}
.hero .lead {
  color: #444b53;
}
.hero h1 {
  letter-spacing: -0.055em;
}
#preview-full {
  display: block;
  cursor: zoom-in;
  text-decoration: none;
  border-radius: 4px;
}
#preview-full:focus-visible {
  outline-offset: -3px;
}
.product-preview figcaption {
  padding-block: 12px;
}
.feature-section {
  padding-bottom: 50px;
}
.rendering-example {
  padding-bottom: 78px;
}
.example-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 28px;
  margin-bottom: 23px;
}
.example-heading h2 {
  font-size: 25px;
  font-weight: 550;
  letter-spacing: -0.03em;
}
.example-heading p {
  font-size: 12px;
  color: var(--muted);
}
.example-grid {
  display: grid;
  grid-template-columns: 1fr 1.12fr;
  border: 1px solid #dce1e5;
  border-radius: 8px;
  overflow: hidden;
}
.source-example {
  min-width: 0;
  background: #f7f8fa;
  padding: 22px 25px;
}
.example-label {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  font-size: 11px;
  color: #626d78;
  letter-spacing: 0.04em;
}
.example-label > span:last-child {
  font-family: ui-monospace, monospace;
  font-size: 10px;
}
.source-example pre {
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 11px;
  line-height: 1.9;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  margin: 24px 0 0;
  color: #454e5c;
}
.result-example {
  min-width: 0;
  padding: 22px 25px 16px;
  border-left: 1px solid #dce1e5;
  background: #fff;
  display: flex;
  flex-direction: column;
}
.result-images {
  display: flex;
  flex: 1;
  flex-direction: column;
  justify-content: center;
  gap: 30px;
  padding-block: 30px;
}
.result-images img {
  display: block;
  width: 100%;
  height: auto;
}
.result-images .formula-detail {
  width: 371px;
  max-width: 100%;
  align-self: flex-start;
}
.result-example figcaption {
  font-size: 10px;
  color: var(--muted);
}
#screenshot-dialog {
  width: min(1200px, calc(100% - 32px));
  max-width: none;
  max-height: calc(100dvh - 40px);
  padding: 0;
  border: 1px solid #cbd1d8;
  border-radius: 8px;
  background: #fff;
  color: #181a1d;
  box-shadow: 0 20px 80px #0005;
}
#screenshot-dialog[open] {
  display: flex;
  flex-direction: column;
}
#screenshot-dialog::backdrop {
  background: #151b28aa;
}
.screenshot-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 20px;
  flex-shrink: 0;
}
.screenshot-heading h2 {
  font-size: 15px;
  font-weight: 550;
}
.screenshot-heading button {
  background: #f2f4f6;
  border: 1px solid #d7dde4;
  border-radius: 4px;
  padding: 6px 14px;
  font-size: 12px;
  flex-shrink: 0;
}
.screenshot-help {
  margin: 0;
  padding: 0 20px 12px;
  font-size: 11px;
  color: var(--muted);
  flex-shrink: 0;
}
.preview-scroll {
  overflow: auto;
  overscroll-behavior: contain;
  min-height: 0;
  border-top: 1px solid #dce1e6;
  background: #f6f7fa;
}
.preview-scroll img {
  display: block;
  width: 100%;
  min-width: 960px;
  height: auto;
}
.preview-scroll .preview-unavailable {
  min-width: 0;
  min-height: 180px;
}
@media (max-width: 1050px) {
  .header {
    gap: 18px;
  }
  .header nav {
    gap: 17px;
  }
  .language {
    padding-left: 18px;
  }
  .nav-reader {
    padding-inline: 10px;
  }
  .example-heading {
    display: block;
  }
  .example-heading p {
    margin-top: 9px;
  }
  .source-example,
  .result-example {
    padding: 20px;
  }
  .result-images {
    gap: 24px;
  }
}
@media (max-width: 760px) {
  .nav-reader {
    display: none;
  }
  .example-grid {
    grid-template-columns: 1fr;
  }
  .result-example {
    border-left: 0;
    border-top: 1px solid #dce1e5;
  }
  .source-example pre {
    font-size: 11px;
    line-height: 1.8;
  }
  .result-images {
    padding-block: 24px;
  }
  .example-heading h2 {
    font-size: 23px;
  }
  .rendering-example {
    padding-bottom: 45px;
  }
  .feature-section {
    padding-bottom: 32px;
  }
  .screenshot-heading {
    padding: 12px;
  }
  .screenshot-heading h2 {
    font-size: 13px;
  }
  .screenshot-help {
    padding-inline: 12px;
    font-size: 10px;
  }
  .header .language {
    padding-left: 0;
  }
  .product-preview figcaption {
    padding: 8px 2px;
  }
  .hero .primary {
    padding-inline: 20px;
  }
}

footer {
  flex-wrap: wrap;
}