@font-face {
  font-family: "Assistant";
  src: url("assets/fonts/Assistant-Regular-Latin.woff2") format("woff2");
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  unicode-range: U+0020-007E;
}

@font-face {
  font-family: "Assistant";
  src: url("assets/fonts/Assistant-SemiBold-Latin.woff2") format("woff2");
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  unicode-range: U+0020-007E;
}

@font-face {
  font-family: "Assistant";
  src: url("assets/fonts/Assistant-Bold-Latin.woff2") format("woff2");
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  unicode-range: U+0020-007E;
}

:root {
  color-scheme: light;
  --ink: #1b1b1f;
  --muted: #66666f;
  --paper: #ffffff;
  --app-bg: #f7f7f8;
  --line: #e4e4e7;
  --line-strong: #cfd0d4;
  --primary: #292a2e;
  --primary-hover: #17181b;
  --focus-ring: #6f7075;
  --page: min(1180px, calc(100vw - 64px));
  --header-height: 68px;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-window: 0 12px 32px rgba(28, 27, 40, 0.09);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --type-caption: 0.8125rem;
  --type-label: 0.875rem;
  --type-body: 1rem;
  --type-lead: 1.25rem;
  --type-hero: clamp(2.375rem, 4.3vw, 3.5rem);
  --type-section: clamp(2rem, 3.2vw, 2.75rem);
  --type-closing: clamp(1.875rem, 2.8vw, 2.5rem);
  --font-cjk: "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC",
    "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-interface: "Assistant", "PingFang SC", "Microsoft YaHei",
    "Noto Sans CJK SC", "Noto Sans SC", -apple-system, BlinkMacSystemFont,
    "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 24px);
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--font-cjk);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.page-en {
  font-family: var(--font-interface);
}

body,
button,
a {
  font: inherit;
}

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

button {
  color: inherit;
}

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

p,
h1,
h2 {
  margin: 0;
}

p {
  text-wrap: pretty;
}

h1,
h2 {
  text-wrap: balance;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 100;
  padding: 10px 14px;
  color: white;
  background: var(--ink);
  border-radius: var(--radius);
  transform: translateY(-160%);
  transition: transform 160ms var(--ease);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.header-inner {
  width: var(--page);
  height: 100%;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
}

.brand,
.button,
.site-nav,
.header-language,
.footer-links {
  font-family: var(--font-interface);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  letter-spacing: -0.015em;
}

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

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.site-nav a,
.footer-links a {
  color: var(--muted);
  font-size: var(--type-label);
  font-weight: 600;
  transition: color 150ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.header-language:hover,
.header-language:focus-visible,
.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--ink);
}

.header-actions {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-mobile-actions {
  display: none;
}

.header-language {
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  font-size: var(--type-label);
  font-weight: 600;
  transition: color 150ms ease;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: var(--radius);
}

.nav-toggle span {
  width: 19px;
  height: 1.5px;
  margin: 5px auto;
  display: block;
  background: currentColor;
  transition: transform 160ms var(--ease);
}

.nav-toggle[aria-expanded="true"] span:first-child {
  transform: translateY(3.25px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:last-child {
  transform: translateY(-3.25px) rotate(-45deg);
}

.button {
  min-height: 44px;
  padding: 0 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: 0.92rem;
  font-weight: 700;
  transition:
    color 150ms ease,
    background-color 150ms ease,
    border-color 150ms ease,
    transform 150ms var(--ease);
}

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

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

.button-small {
  min-height: 38px;
  padding-inline: 14px;
  font-size: 0.84rem;
}

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

.button-primary:hover,
.button-primary:focus-visible {
  color: white;
  background: var(--primary-hover);
}

.button-secondary {
  color: var(--ink);
  background: white;
  border-color: var(--line-strong);
}

.button-secondary:hover {
  background: var(--app-bg);
  border-color: #aaabb0;
}

.site-nav .nav-download {
  display: none;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 3px;
}

.hero {
  padding: clamp(64px, 7vw, 88px) 0 clamp(76px, 7vw, 96px);
}

.hero-inner {
  width: min(720px, calc(100vw - 40px));
  margin: 0 auto;
  text-align: center;
}

.hero-icon {
  width: 104px;
  height: 104px;
  margin: 0 auto 26px;
}

.hero h1 {
  font-size: var(--type-hero);
  line-height: 1.1;
  letter-spacing: -0.01em;
}

.page-en .hero h1 {
  letter-spacing: -0.025em;
}

.hero h1 span {
  white-space: nowrap;
}

.hero-description {
  max-width: 42rem;
  margin: 22px auto 0;
  color: var(--muted);
  font-size: var(--type-body);
  line-height: 1.7;
}

.hero-actions {
  margin-top: 28px;
  display: flex;
  justify-content: center;
  gap: 10px;
}

.product-stage {
  width: var(--page);
  margin: clamp(52px, 6vw, 68px) auto 0;
}

.product-shot {
  position: relative;
  aspect-ratio: 2942 / 1848;
  overflow: hidden;
  margin: 0;
  background: var(--app-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-window);
}

.product-shot::after {
  content: "";
  position: absolute;
  inset: 0;
  border: 1px solid var(--line-strong);
  border-radius: inherit;
  pointer-events: none;
}

.product-shot picture,
.product-shot img {
  width: 100%;
  height: 100%;
}

.product-shot img {
  object-fit: cover;
}

.why-consider {
  padding: clamp(88px, 8vw, 112px) 0 clamp(96px, 9vw, 124px);
  background: var(--app-bg);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.why-inner {
  width: min(960px, calc(100vw - 64px));
  margin: 0 auto;
}

.why-header h2 {
  max-width: 48rem;
  font-size: var(--type-section);
  line-height: 1.14;
  letter-spacing: -0.01em;
}

.page-en .why-header h2,
.page-en .closing h2 {
  letter-spacing: -0.02em;
}

.why-thesis {
  max-width: 42rem;
  margin-top: 24px;
  color: #3f3f46;
  font-size: var(--type-lead);
  line-height: 1.62;
}

.why-essay {
  max-width: 43.5rem;
  margin-top: clamp(52px, 5vw, 68px);
  display: flex;
  flex-direction: column;
  gap: clamp(28px, 3vw, 36px);
}

.why-essay p {
  color: var(--muted);
  font-size: var(--type-body);
  line-height: 1.75;
}

.why-essay strong {
  color: var(--ink);
  font-weight: 600;
}

.closing {
  width: min(760px, calc(100vw - 40px));
  margin: 0 auto;
  padding: 96px 0 108px;
  text-align: center;
}

.closing img {
  margin: 0 auto 24px;
}

.closing h2 {
  font-size: var(--type-closing);
  line-height: 1.16;
  letter-spacing: -0.01em;
}

.site-footer {
  width: var(--page);
  min-height: 128px;
  margin: 0 auto;
  padding: 30px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--line);
}

.site-footer > div:first-child {
  display: flex;
  align-items: center;
  gap: 18px;
}

.site-footer p {
  color: var(--muted);
  font-size: var(--type-label);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
}

@media (max-width: 820px) {
  :root {
    --page: min(100% - 40px, 960px);
  }

  .header-inner {
    grid-template-columns: 1fr auto;
  }

  .header-actions {
    display: none;
  }

  .header-mobile-actions {
    display: flex;
    align-items: center;
    gap: 2px;
  }

  .nav-toggle {
    display: block;
  }

  .site-nav {
    position: absolute;
    top: var(--header-height);
    right: 0;
    left: 0;
    padding: 16px 20px 20px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: white;
    border-bottom: 1px solid var(--line);
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-nav > a:not(.nav-download) {
    min-height: 44px;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--line);
  }

  .site-nav > .nav-secondary-last {
    border-bottom: 0;
  }

  .site-nav .nav-download {
    width: 100%;
    margin-top: 14px;
    display: flex;
    color: white;
    border: 0;
  }

  .site-nav .nav-download:hover,
  .site-nav .nav-download:focus-visible {
    color: white;
  }
}

@media (max-width: 600px) {
  :root {
    --page: calc(100vw - 32px);
  }

  .hero {
    padding: 52px 0 64px;
  }

  .hero-inner {
    width: calc(100vw - 32px);
  }

  .hero-icon {
    width: 84px;
    height: 84px;
    margin-bottom: 22px;
  }

  .hero-description {
    margin-top: 18px;
    line-height: 1.68;
    text-align: left;
  }

  .hero-actions {
    margin-top: 24px;
    flex-direction: column;
  }

  .hero-actions .button {
    width: 100%;
  }

  .product-stage {
    margin-top: 44px;
  }

  .product-shot {
    aspect-ratio: 720 / 832;
    border-radius: var(--radius);
  }

  .why-consider {
    padding: 64px 0 72px;
  }

  .why-inner {
    width: calc(100vw - 32px);
  }

  .why-header h2 {
    line-height: 1.16;
  }

  .why-thesis {
    margin-top: 20px;
    font-size: 1.0625rem;
    line-height: 1.65;
  }

  .why-essay {
    margin-top: 42px;
    gap: 28px;
  }

  .why-essay p {
    line-height: 1.72;
  }

  .closing {
    padding: 80px 0 88px;
  }

  .closing img {
    width: 64px;
    height: 64px;
    margin-bottom: 20px;
  }

  .site-footer,
  .site-footer > div:first-child {
    align-items: flex-start;
    flex-direction: column;
  }

  .site-footer {
    padding-block: 28px 38px;
    gap: 28px;
  }

  .site-footer > div:first-child {
    gap: 10px;
  }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}