:root {
  color-scheme: light;
  --bg: #f8f7fc;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #7c3aed;
  --border: #e5e7eb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

header {
  background: linear-gradient(135deg, #7c3aed 0%, #5b21b6 100%);
  color: #fff;
  padding: 2.5rem 1.25rem 2rem;
}

header .lang-panel h1 {
  margin: 0 0 0.35rem;
  font-size: 1.75rem;
}

header .lang-panel p {
  margin: 0;
  opacity: 0.92;
}

header .lang-panel nav {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

nav a {
  color: #ede9fe;
  text-decoration: none;
  font-size: 0.95rem;
}

nav a:hover {
  text-decoration: underline;
}

.header-top {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 1rem;
  width: 100%;
}

.lang-switcher {
  display: inline-flex !important;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.35rem;
  padding: 0.35rem 0.45rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.18);
  border: 1px solid rgba(255, 255, 255, 0.85);
}

.lang-switcher-label {
  color: #5b21b6;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0 0.35rem 0 0.5rem;
  white-space: nowrap;
}

.lang-switcher a {
  color: #5b21b6;
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 700;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  line-height: 1.2;
}

.lang-switcher a:hover {
  background: rgba(124, 58, 237, 0.12);
}

.lang-switcher a.is-active,
.lang-switcher a[aria-current="true"] {
  background: #7c3aed;
  color: #fff;
}

html[data-content-lang="zh"] .lang-panel[data-lang="en"],
html[data-content-lang="en"] .lang-panel[data-lang="zh"] {
  display: none;
}

html[data-content-lang="en"] .lang-panel[data-lang="en"],
html[data-content-lang="zh"] .lang-panel[data-lang="zh"] {
  display: block;
}

/* Before language boot runs, default to Chinese content. */
html:not([data-content-lang]) .lang-panel[data-lang="en"] {
  display: none;
}

main {
  max-width: 760px;
  margin: -1.25rem auto 3rem;
  padding: 0 1rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.5rem 1.25rem;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
}

section + section {
  margin-top: 2rem;
}

h2 {
  margin: 0 0 0.75rem;
  font-size: 1.15rem;
  color: #111827;
}

h3 {
  margin: 1rem 0 0.5rem;
  font-size: 1rem;
}

p,
li {
  color: var(--text);
}

.meta {
  color: var(--muted);
  font-size: 0.92rem;
  margin-bottom: 1.25rem;
}

ul {
  padding-left: 1.25rem;
}

a {
  color: var(--accent);
}

footer {
  max-width: 760px;
  margin: 0 auto 2rem;
  padding: 0 1rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.lang-label {
  display: inline-block;
  margin-bottom: 0.5rem;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  background: #ede9fe;
  color: #5b21b6;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.contact-box {
  background: #f5f3ff;
  border: 1px solid #ddd6fe;
  border-radius: 12px;
  padding: 1rem 1.1rem;
}

@media (min-width: 640px) {
  header {
    padding-left: max(1.25rem, calc((100% - 760px) / 2 + 1rem));
    padding-right: max(1.25rem, calc((100% - 760px) / 2 + 1rem));
  }

  .card {
    padding: 2rem 1.75rem;
  }
}