/* ========== Reset & Base ========== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", sans-serif;
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  background: var(--canvas);
  color: var(--ink);
}

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

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

:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 4px;
}

[id] {
  scroll-margin-top: 80px;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 16px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--surface);
  border-radius: var(--radius-sm);
  transform: translateY(-150%);
}

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

/* ========== Design Tokens ========== */
:root {
  --canvas: #F7F7F4;
  --surface: #FFFFFF;
  --ink: #171716;
  --muted: #6C6C68;
  --primary: #1677E8;
  --warm: #FC543D;
  --border: rgba(23, 23, 22, 0.08);
  --border-strong: rgba(23, 23, 22, 0.15);
  --radius: 15px;
  --radius-sm: 8px;
  --page-padding: clamp(22px, 5.5vw, 88px);
}

/* ========== Typography ========== */
.display-title {
  font-size: clamp(44px, 5.5vw, 86px);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.05;
  color: var(--ink);
}

.hero-title-row {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.hero-badge {
  font-size: 16px;
  font-weight: 600;
  color: #fff;
  background: var(--warm);
  padding: 7px 18px;
  border-radius: 100px;
  letter-spacing: 0.01em;
  line-height: 1.4;
  white-space: nowrap;
}

.section-title {
  font-size: clamp(26px, 3.2vw, 44px);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

/* ========== Layout ========== */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--page-padding);
}

/* ========== Navigation ========== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--canvas);
  border-bottom: 1px solid var(--border);
  height: 56px;
  display: flex;
  align-items: center;
}

.nav-inner {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--page-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-brand img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.nav-brand-name {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.nav-brand-kind {
  padding-left: 10px;
  border-left: 1px solid var(--border-strong);
  color: var(--muted);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0;
}

.nav-links {
  display: flex;
  flex-shrink: 0;
  align-items: center;
  gap: 20px;
}

.nav-link {
  font-size: 13px;
  color: var(--muted);
  transition: color 200ms ease;
}

.nav-link:hover {
  color: var(--ink);
}

.nav-download {
  font-size: 13px;
  font-weight: 500;
  color: #fff;
  background: var(--primary);
  padding: 7px 18px;
  border-radius: var(--radius-sm);
  transition: opacity 200ms ease;
}

.nav-download:hover {
  opacity: 0.88;
  color: #fff;
}

/* ========== Hero ========== */
.hero {
  padding: clamp(64px, 10vw, 120px) 0 clamp(48px, 7vw, 96px);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
  gap: clamp(40px, 5vw, 80px);
  align-items: start;
}

.hero-tagline {
  font-size: clamp(17px, 2vw, 22px);
  line-height: 1.5;
  color: var(--muted);
  margin-top: 20px;
  max-width: 420px;
}

.hero-tagline strong {
  display: block;
  margin-bottom: 12px;
  color: var(--ink);
  font-weight: 600;
}

.hero-features {
  list-style: none;
  margin-top: 32px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.hero-features li {
  font-size: 14px;
  color: var(--muted);
  padding-left: 16px;
  position: relative;
}

.hero-features li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 9px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--warm);
}

.hero-ctas {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
  margin-top: 40px;
}

.btn-primary {
  display: inline-flex;
  white-space: nowrap;
  align-items: center;
  font-size: 14px;
  font-weight: 500;
  color: #fff;
  background: var(--primary);
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  transition: opacity 200ms ease;
  border: none;
  cursor: pointer;
}

.btn-primary:hover {
  opacity: 0.88;
}

.btn-text {
  font-size: 14px;
  color: var(--muted);
  transition: color 200ms ease;
}

.btn-text:hover {
  color: var(--ink);
}

.github-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.hero-image {
  position: relative;
  aspect-ratio: 6 / 5;
  overflow: hidden;
  border-radius: var(--radius);
  box-shadow: 0 -6px 20px rgba(23, 23, 22, 0.08), 0 12px 40px rgba(23, 23, 22, 0.12), 0 4px 10px rgba(23, 23, 22, 0.06);
}

.hero-image img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  object-position: center;
}

/* ========== Story Sections ========== */
.story {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  grid-template-areas: "text image";
  gap: clamp(40px, 5vw, 80px);
  align-items: center;
  padding: clamp(60px, 9vw, 120px) 0;
  border-top: 1px solid var(--border);
}

.story:nth-child(even) {
  grid-template-areas: "image text";
}

.story-image {
  grid-area: image;
  min-width: 0;
}

.story-text {
  grid-area: text;
  min-width: 0;
}

.story-number {
  display: block;
  font-size: clamp(2.25rem, 3.2vw, 2.75rem);
  font-weight: 600;
  color: var(--warm);
  line-height: 1.2;
  letter-spacing: 0.02em;
  font-variant-numeric: tabular-nums;
  margin-bottom: 1rem;
}

.story-title {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  line-height: 1.3;
  margin-bottom: 1rem;
}

.story-title span {
  display: block;
}

.story-desc {
  font-size: 16px;
  line-height: 1.75;
  color: var(--muted);
}

.story-image img {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: 0 -6px 20px rgba(23, 23, 22, 0.08), 0 12px 40px rgba(23, 23, 22, 0.12), 0 4px 10px rgba(23, 23, 22, 0.06);
}

/* ========== Format Strip ========== */
.formats {
  padding: clamp(48px, 7vw, 96px) 0;
  border-top: 1px solid var(--border);
}

.formats-label {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 24px;
}

.formats-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.format-tag {
  max-width: 100%;
  overflow-wrap: anywhere;
  font-size: 13px;
  font-weight: 500;
  padding: 8px 16px;
  border: 1px solid var(--border-strong);
  border-radius: 100px;
  color: var(--ink);
  background: var(--surface);
  transition: border-color 200ms ease, background 200ms ease;
}

.format-tag:hover {
  border-color: var(--primary);
  background: rgba(22, 119, 232, 0.04);
}

.format-tag .ext {
  color: var(--muted);
  font-weight: 400;
  margin-left: 4px;
}

.formats-note {
  margin: 18px 0 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

/* ========== System Info ========== */
.system {
  padding: clamp(48px, 7vw, 96px) 0;
  border-top: 1px solid var(--border);
}

.system-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(24px, 3vw, 48px);
}

.system-item {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.system-item .label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

.system-item .value {
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
}

/* ========== Footer ========== */
.footer {
  padding: clamp(32px, 4vw, 48px) 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-left img {
  width: 20px;
  height: 20px;
  border-radius: 5px;
}

.footer-left span {
  font-size: 13px;
  color: var(--muted);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-links a {
  font-size: 13px;
  color: var(--muted);
  transition: color 200ms ease;
}

.footer-links a:hover {
  color: var(--ink);
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero-image {
    order: -1;
  }

  .hero-tagline {
    max-width: none;
  }

  .story,
  .story:nth-child(even) {
    grid-template-columns: 1fr;
    grid-template-areas: "image" "text";
  }

  .story-title {
    display: flex;
    flex-wrap: wrap;
    column-gap: 0.5em;
    row-gap: 0.1em;
  }

  .system-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .footer-inner {
    flex-direction: column;
    gap: 16px;
    align-items: flex-start;
  }

  .nav-links {
    gap: 14px;
  }
}

@media (max-width: 480px) {
  .nav-brand {
    flex: 0 0 auto;
    white-space: nowrap;
  }

  .nav-brand-name {
    font-size: 14px;
  }

  .nav-brand-kind {
    display: none;
  }

  .hero-features {
    gap: 8px;
  }
}

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

  a, .format-tag {
    transition: none;
  }
}

/* Language navigation shares the same layout in both locales. */
.language-switch { display: flex; align-items: center; gap: 4px; font-size: 13px; white-space: nowrap; }
.language-switch a { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; min-width: 32px; color: var(--muted); }
.language-switch a[aria-current="page"] { color: var(--ink); font-weight: 600; }
.language-switch a:hover { color: var(--primary); }
.language-switch span { color: var(--muted); }
@media (max-width: 768px) {
  .nav-brand-kind { display: none; }
}
@media (max-width: 480px) {
  .nav-links { gap: 8px; }
  .nav-download { padding: 7px 10px; }
  .nav-brand { gap: 6px; }
}
@media (max-width: 359px) {
  .nav-links > .nav-link { display: none; }
}

/* Let the English title use the column gap without reducing desktop type. */
@media (min-width: 769px) {
  html[lang="en"] .hero-title-row { flex-wrap: nowrap; width: max-content; }
  html[lang="en"] .hero-title-row > * { flex-shrink: 0; }
}
@media (max-width: 768px) {
  html[lang="en"] .hero-text { container-type: inline-size; }
  html[lang="en"] .hero-title-row { flex-wrap: nowrap; gap: 8px; }
  html[lang="en"] .hero-title-row .display-title { font-size: clamp(36px, 14cqi, 76px); flex-shrink: 0; }
  html[lang="en"] .hero-badge { font-size: clamp(9px, 3cqi, 16px); padding: 7px 10px; flex-shrink: 0; }
}

/* Anchor artwork independently of translated copy height. On narrow desktops,
   leave room for the English title to extend into the column gap. */
@media (min-width: 769px) and (max-width: 1000px) {
  .hero-image { margin-top: calc(clamp(44px, 5.5vw, 86px) * 1.05 + 20px); }
}