:root {
  --bg: #ffffff;
  --primary: #4A77B1;
  --muted: #5C6975;
  --max-width: 980px;
}

/* Reset */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  width: 100%;
  min-height: 100%;
}

body {
  font-family: "Noto Sans SC", "Inter", -apple-system, BlinkMacSystemFont,
    system-ui, -system-ui, sans-serif;  background-color: var(--bg);
  color: #333333;
}

html[lang="zh-CN"] body {
  font-family: "Noto Serif SC", "Noto Serif", "Times New Roman", serif;
  font-weight: 300;
}


/* =========================
   Shared Top Navigation
   ========================= */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 24px 24px;
  background-color: rgba(255, 255, 255, 0.98);
  border-bottom: 1px solid rgba(34, 34, 34, 0.06);
}

.site-header-right {
  display: flex;
  align-items: center;
  gap: 0;
}

.site-brand a {
  text-decoration: none;
  color: #333333;
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  margin-left: 12px;
}

.site-nav {
  display: flex;
  gap: 32px;
  font-size: 14px;
  margin-right: 20px;
  letter-spacing: 0.20em;
  text-transform: uppercase;
}

.site-nav a {
  text-decoration: none;
  color: var(--muted);
  padding: 4px 0;
  transition: color 0.2s ease;
}

.site-nav a:hover {
  color: var(--primary);
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-left: 12px;
  font-size: 16px;
  letter-spacing: 0.01em;
  text-transform: none;
  color: #222222;
  font-family: "Noto Serif", "Noto Serif SC", "Times New Roman", serif;
  font-weight: 400;
}

.lang-switch-handle {
  text-align: right;
  font-size: 0.95em;
}

.lang-switch-handle a {
  background: none;
  border: none;
  padding: 0 0 4px;
  font: inherit;
  color: inherit !important;
  cursor: pointer;
  border-bottom: 3px solid transparent;
  text-decoration: none !important;
}

.lang-switch-handle a:visited,
.lang-switch-handle a:hover,
.lang-switch-handle a:active {
  color: inherit !important;
}

.lang-switch-handle a.active {
  color: #111111 !important;
  border-bottom-color: #f2d400 !important;
}

.lang-switch-handle a:focus-visible {
  outline: 2px solid #f2d400;
  outline-offset: 2px;
}

.lang-sep {
  color: currentColor;
  opacity: 0.6;
}
.nav-toggle {
  display: none;
  border: 1px solid var(--primary);
  background: transparent;
  padding: 4px 8px;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  cursor: pointer;
  color: var(--primary);
}


/* =========================
   Layout
   ========================= */

main {
  padding-top: 60px; /* room for fixed header */
}

/* Hero band */

.about-hero {
  background: linear-gradient(270deg, #4a77b1, #6d9fd8);
  color: #ffffff;
  padding: 80px 0 80px;
}

.about-hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.about-hero h1 {
  font-family: "Noto Sans SC", "Inter", sans-serif;
  font-size: 40px;          /* bigger title */
  font-weight: 300;         /* light, elegant */
  letter-spacing: 0.03em;   /* subtle spacing like reference */
  margin-bottom: 14px;
}

.about-hero p {
  font-family: "Noto Sans SC", "Inter", sans-serif;
  font-size: 17px;
  font-weight: 300;
  line-height: 1.9;
}

html[lang="zh-CN"] .about-hero h1,
html[lang="zh-CN"] .about-hero p {
  font-family: "Noto Serif SC", "Noto Serif", "Times New Roman", serif;
  font-weight: 300;
}

/* Main article */

.about-body {
  padding: 52px 0 60px;
  background-color: #ffffff;
}

.about-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.about-article h2 {
  font-size: 24px;
  font-weight: 500;
  margin: 0 0 14px;
  color: #222222;
}

.about-article p {
  font-size: 15px;
  color: var(--muted);
  line-height: 1.9;
  margin-bottom: 16px;
}

.about-article a {
  color: var(--primary);
  text-decoration: none;
}

.about-article a:hover {
  text-decoration: underline;
}

/* Image block */

.about-figure {
  margin: 30px 0 26px;
  text-align: center;
}

.about-image {
  max-width: 640px;
  width: 100%;
  border-radius: 6px;
  display: block;
  margin: 0 auto 8px;
}

.about-figure figcaption {
  font-size: 12px;
  color: #999999;
}

/* Footer */

#footer {
  border-top: 1px solid #eeeeee;
  padding: 22px 0;
  text-align: center;
  font-size: 13px;
  color: #999999;
}

/* Back to top */

#to-top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  width: 48px;
  height: 48px;
  border-radius: 10px;
  background: linear-gradient(180deg, #ffffff, #f3f7fa);
  box-shadow: 0 6px 18px rgba(40, 60, 80, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  opacity: 0;
  transform: translateY(16px);
  transition: all 0.25s ease;
}

#to-top.show {
  opacity: 1;
  transform: none;
}

#to-top::after {
  content: '↑';
  font-weight: 700;
  color: var(--primary);
}

/* Contact section (same as archive) */

.archive-contact {
  padding: 52px 0 40px;
  background-color: #f5fafc;
}

.archive-contact-inner {
  max-width: 520px;
  margin: 0 auto;
  text-align: center;
  padding: 0 24px;
}

.contact-divider {
  width: 72px;
  height: 2px;
  background-color: #d0d8e0;
  margin: 0 auto 18px;
}

.archive-contact p {
  font-size: 13px;
  color: #7a828c;
  margin-bottom: 16px;
}

/* pill-style email, not clickable */
.contact-pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 26px;
  border-radius: 999px;
  border: 1px solid #b6c5d4;
  font-size: 12px;
  color: #4a77b1;
  background-color: #ffffff;
}


/* =========================
   Responsive
   ========================= */

@media (max-width: 720px) {
  .site-header {
    padding: 10px 14px;
  }

  .lang-switch {
    display: none;
  }

  .nav-toggle {
    display: inline-block;
  }

  .site-nav {
    position: fixed;
    top: 52px;
    right: 0;
    flex-direction: column;
    gap: 10px;
    padding: 10px 18px 14px;
    background-color: rgba(244, 248, 251, 0.98);
    border-left: 1px solid rgba(34, 34, 34, 0.06);
    border-bottom: 1px solid rgba(34, 34, 34, 0.06);
    display: none;
  }

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

  .about-hero {
    padding: 40px 0 32px;
  }

  .about-hero-inner,
  .about-inner {
    padding: 0 16px;
  }
}