:root {
  color-scheme: light;
  --blue: #229ed9;
  --blue-dark: #168acd;
  --text: #3f3f3f;
  --muted: #7a7a7a;
  --border: #d9d9d9;
  --soft-border: #ebebeb;
  --page: #ffffff;
  --max: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background: var(--page);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.45;
}

a {
  color: #0088cc;
  text-decoration: none;
}

a:hover,
a:focus-visible {
  color: var(--blue-dark);
  text-decoration: underline;
}

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

.topbar {
  border-top: 1px solid #d6d6d6;
  border-bottom: 1px solid #e5e5e5;
  background: #fff;
}

.topbar-inner {
  display: flex;
  width: min(var(--max), calc(100% - 32px));
  min-height: 63px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin: 0 auto;
}

.main-nav,
.side-nav,
.footer nav,
.text-links {
  display: flex;
  align-items: center;
  gap: 30px;
}

.main-nav a,
.side-nav a {
  position: relative;
  display: inline-flex;
  min-height: 63px;
  align-items: center;
  color: #0088cc;
  font-size: 17px;
}

.main-nav a.is-active::after {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 0;
  height: 3px;
  content: "";
  background: var(--blue);
}

.side-nav {
  gap: 18px;
}

.side-nav a {
  font-size: 16px;
}

.language-switch {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  min-height: 63px;
}

.language-switch button {
  padding: 0 2px;
  border: 0;
  background: transparent;
  color: #0088cc;
  font: inherit;
  cursor: pointer;
}

.language-switch button + button::before {
  margin-right: 6px;
  color: #b5b5b5;
  content: "/";
}

.language-switch button.is-active {
  color: #444;
  font-weight: 700;
}

.language-switch button:hover,
.language-switch button:focus-visible {
  color: var(--blue-dark);
  text-decoration: underline;
}

main {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 310px;
  gap: 58px;
  align-items: start;
  padding: 50px 0 28px;
}

.hero-main {
  text-align: center;
}

.logo-mark {
  display: grid;
  width: 150px;
  height: 150px;
  place-items: center;
  margin: 0 auto 14px;
  border-radius: 50%;
  background: var(--blue);
}

.logo-mark span {
  display: grid;
  width: 88px;
  height: 88px;
  place-items: center;
  border: 4px solid #fff;
  border-radius: 24px;
  color: #fff;
  font-size: 34px;
  font-weight: 700;
  letter-spacing: 0;
}

h1 {
  margin: 0;
  color: #444;
  font-size: 42px;
  line-height: 1.12;
  font-weight: 700;
  letter-spacing: 0;
}

.tagline {
  margin: 8px 0 0;
  color: #888;
  font-size: 23px;
}

.intro {
  max-width: 650px;
  margin: 22px auto 0;
  color: #555;
  font-size: 17px;
}

.hero-points {
  display: flex;
  max-width: 720px;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 14px;
  padding: 0;
  margin: 20px auto 0;
  list-style: none;
}

.hero-points li {
  padding: 6px 12px;
  border: 1px solid #d5edf8;
  border-radius: 18px;
  background: #f6fbfe;
  color: #0088cc;
  font-size: 14px;
  line-height: 1.25;
}

.project-note {
  max-width: 650px;
  margin: 12px auto 0;
  color: #888;
  font-size: 13px;
}

.link-panel {
  margin-top: 10px;
  padding-left: 24px;
  border-left: 4px solid var(--blue);
}

.link-panel h2 {
  margin: 0 0 16px;
  color: #0088cc;
  font-size: 21px;
  line-height: 1.2;
}

.link-item {
  display: block;
  margin-bottom: 18px;
}

.link-item strong {
  display: block;
  color: #111;
  font-size: 16px;
  line-height: 1.35;
}

.link-item span {
  display: block;
  margin-top: 3px;
  color: #0088cc;
  line-height: 1.45;
}

.link-item.is-pending span {
  color: #777;
}

.app-links {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 24px;
  max-width: 960px;
  margin: 28px auto 34px;
}

.app-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: #0088cc;
  font-size: 18px;
  text-align: center;
}

.app-icon {
  display: inline-grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 2px solid var(--blue);
  border-radius: 50%;
  color: var(--blue);
  font-size: 12px;
  font-weight: 700;
}

.preview {
  max-width: 640px;
  margin: 54px auto 62px;
  overflow: hidden;
}

.preview img {
  width: 100%;
  height: auto;
  object-fit: contain;
}

.demo-section {
  max-width: 930px;
  margin: 26px auto 62px;
  padding: 42px 0 0;
  border-top: 1px solid var(--soft-border);
  text-align: center;
}

.demo-section h2 {
  margin: 0 0 10px;
  color: #444;
  font-size: 28px;
  line-height: 1.2;
}

.demo-section p {
  max-width: 760px;
  margin: 0 auto 22px;
  color: #666;
}

.demo-video {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 1px solid #d5edf8;
  border-radius: 8px;
  background: #f7fbff;
}

.feature-section,
.text-section {
  max-width: 930px;
  margin: 0 auto;
  padding: 42px 0;
  border-top: 1px solid var(--soft-border);
}

.feature-section h2,
.text-section h2 {
  margin: 0 0 22px;
  color: #444;
  font-size: 28px;
  line-height: 1.2;
  text-align: center;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 28px 48px;
}

.feature-grid article {
  min-width: 0;
}

.feature-grid h3 {
  margin: 0 0 7px;
  color: #0088cc;
  font-size: 20px;
}

.feature-grid p,
.text-section p {
  margin: 0;
  color: #666;
}

.text-section {
  text-align: center;
}

.text-section p {
  max-width: 760px;
  margin: 0 auto;
}

.text-links {
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 18px;
}

.footer {
  display: flex;
  width: min(var(--max), calc(100% - 32px));
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin: 28px auto 0;
  padding: 25px 0 34px;
  border-top: 1px solid var(--border);
  color: #888;
}

.footer p {
  margin: 0;
}

.footer nav {
  gap: 22px;
}

@media (max-width: 900px) {
  .topbar-inner {
    min-height: auto;
    align-items: flex-start;
    padding: 10px 0;
  }

  .main-nav,
  .side-nav,
  .language-switch {
    flex-wrap: wrap;
    gap: 18px;
  }

  .main-nav a,
  .side-nav a,
  .language-switch {
    min-height: 34px;
  }

  .language-switch {
    gap: 4px;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 34px;
    padding-top: 40px;
  }

  .link-panel {
    width: min(520px, 100%);
    margin: 0 auto;
  }

  .app-links {
    grid-template-columns: 1fr;
    max-width: 420px;
    gap: 16px;
  }
}

@media (max-width: 620px) {
  .topbar-inner {
    display: block;
  }

  .side-nav {
    margin-top: 4px;
  }

  .logo-mark {
    width: 122px;
    height: 122px;
  }

  .logo-mark span {
    width: 72px;
    height: 72px;
    border-radius: 20px;
    font-size: 28px;
  }

  h1 {
    font-size: 36px;
  }

  .tagline {
    font-size: 20px;
  }

  .intro {
    font-size: 16px;
  }

  .preview {
    margin-top: 34px;
    margin-bottom: 42px;
  }

  .demo-section {
    margin-bottom: 42px;
    padding-top: 34px;
  }

  .feature-grid {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .feature-section h2,
  .text-section h2 {
    font-size: 25px;
  }

  .footer {
    display: grid;
  }
}