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

html { scroll-behavior: smooth; }
body.menu-open { overflow: hidden; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #333;
  line-height: 1.8;
  background: linear-gradient(145deg, #e9eaf4 0%, #e1e8f0 52%, #e0eee5 100%);
  background-attachment: fixed;
}

nav {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 40px;
  background: linear-gradient(110deg, #e5e9f4 0%, #e1eee6 100%);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}

nav.scrolled { border-bottom-color: #eee; background: rgba(255, 255, 255, 0.96); }
.logo { font-size: 18px; font-weight: 700; color: #111; text-decoration: none; }
.nav-links { display: flex; gap: 24px; }
.nav-links a { font-size: 14px; color: #666; text-decoration: none; transition: color 0.2s; }
.nav-links a:hover { color: #111; }
.language-toggle { min-width: 36px; padding: 7px 4px; border: 0; border-bottom: 1px solid transparent; background: transparent; color: #666; font-size: 12px; font-weight: 600; line-height: 1; cursor: pointer; transition: color 0.2s, border-color 0.2s; }
.language-toggle:hover { color: #111; border-bottom-color: #8d958d; }
.hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; background: none; border: none; padding: 4px; }
.hamburger span { display: block; width: 22px; height: 2px; background: #333; transition: 0.3s; }
.mobile-menu {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  height: 100dvh;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 36px;
  z-index: 99;
}
.mobile-menu.open { display: flex; }
.mobile-menu a { font-size: 22px; color: #333; text-decoration: none; }

.hero {
  position: relative;
  min-height: 100vh;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
}
.hero h1 { font-size: 48px; font-weight: 700; color: #111; margin-bottom: 16px; }
.hero .subtitle { font-size: 18px; color: #888; max-width: 520px; margin-bottom: 40px; }
.not-found-page { min-height: 100vh; min-height: 100svh; display: flex; flex-direction: column; }
.not-found { flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 32px 24px; text-align: center; }
.not-found-footer { padding-top: 24px; padding-bottom: 24px; }
.not-found-scene { position: relative; display: grid; place-items: center; width: min(480px, 100%); height: 166px; margin-bottom: 14px; }
.not-found-route { position: absolute; left: 8%; right: 8%; top: 52%; border-top: 2px dashed #91a49a; transform: rotate(-8deg); }
.not-found-point { position: absolute; z-index: 1; width: 12px; height: 12px; border: 3px solid #f8faf8; border-radius: 50%; }
.not-found-point-start { left: 8%; top: 67%; background: #de8066; }
.not-found-point-end { right: 8%; top: 35%; background: #d3a943; }
.not-found-code { position: relative; display: flex; align-items: center; gap: 20px; color: #283632; font-size: 112px; font-weight: 650; line-height: 1; }
.not-found-zero { position: relative; display: block; width: 70px; height: 96px; border: 9px solid #688477; border-radius: 48%; transform: rotate(16deg); }
.not-found-zero::after { position: absolute; top: 10px; right: 7px; width: 9px; height: 9px; border-radius: 50%; background: #d3a943; content: ""; }
.not-found-scene-label { position: absolute; right: 5%; bottom: 4px; color: #839088; font-size: 11px; }
.not-found-kicker { color: #75877e; font-size: 12px; }
.not-found h1 { margin-top: 6px; color: #222; font-size: 28px; font-weight: 600; }
.not-found-message { margin-top: 8px; color: #777; font-size: 15px; }
.not-found-home { margin-top: 24px; padding-bottom: 2px; border-bottom: 1px solid #929a94; color: #444; font-size: 14px; text-decoration: none; transition: color 0.2s, border-color 0.2s; }
.not-found-home:hover { border-bottom-color: #333; color: #111; }
.scroll-indicator { position: absolute; bottom: 26px; left: 0; right: 0; width: fit-content; margin: 0 auto; display: flex; flex-direction: column; align-items: center; gap: 8px; color: #999; font-size: 11px; text-decoration: none; transition: color 0.2s; }
.scroll-indicator:hover { color: #444; }
.scroll-mouse { display: flex; justify-content: center; width: 22px; height: 34px; padding-top: 6px; border: 1px solid #aaa; border-radius: 12px; }
.scroll-mouse span { width: 2px; height: 6px; border-radius: 2px; background: #777; animation: scroll-wheel 1.5s ease-in-out infinite; }
@keyframes scroll-wheel {
  0% { opacity: 0; transform: translateY(0); }
  25% { opacity: 1; }
  75% { opacity: 1; }
  100% { opacity: 0; transform: translateY(8px); }
}

section { padding: 80px 24px; }
.section-inner { max-width: 720px; margin: 0 auto; }
.section-title { font-size: 14px; font-weight: 600; color: #aaa; text-transform: uppercase; margin-bottom: 24px; }
.about-text { font-size: 16px; color: #555; }
.about-text + .about-text { margin-top: 14px; }

.focus-list { border-top: 1px solid #eee; }
.focus-row { display: grid; grid-template-columns: 150px 1fr; align-items: baseline; gap: 24px; padding: 20px 0; border-bottom: 1px solid #eee; }
.focus-row h3 { color: #333; font-size: 16px; font-weight: 600; }
.focus-row p { color: #666; font-size: 15px; }

.tags { display: flex; flex-wrap: wrap; gap: 10px; }
.section-intro { margin: -12px 0 22px; color: #777; font-size: 15px; }
.tags span { padding: 8px 18px; border-radius: 20px; background: linear-gradient(120deg, #f0f2f8 0%, #edf3ef 100%); color: #555; font-size: 14px; }

.approach-list { border-top: 1px solid #eee; }
.approach-item { display: grid; grid-template-columns: 42px 1fr; gap: 16px; padding: 18px 0; border-bottom: 1px solid #eee; }
.approach-item > span { padding-top: 2px; color: #aaa; font-size: 12px; font-variant-numeric: tabular-nums; }
.approach-item h3 { color: #444; font-size: 15px; font-weight: 600; }
.approach-item p { margin-top: 3px; color: #777; font-size: 14px; }

.contact-note { margin: -8px 0 24px; color: #777; font-size: 15px; }
.contact-links { display: flex; flex-direction: column; gap: 14px; }
.contact-links a { font-size: 15px; color: #555; text-decoration: none; display: flex; align-items: center; gap: 10px; transition: color 0.2s; }
.contact-links a:hover { color: #111; }
.contact-links .icon { width: 20px; text-align: center; font-size: 16px; }

footer { text-align: center; padding: 40px 24px; font-size: 13px; color: #bbb; border-top: 1px solid #eee; }
footer a { color: #999; text-decoration: none; }
footer a:hover { color: #555; }
footer .beian { margin-top: 8px; display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }
.fade-in { opacity: 0; transform: translateY(20px); transition: opacity 0.6s ease, transform 0.6s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }
:focus-visible { outline: 2px solid #555; outline-offset: 4px; }

@media (max-width: 768px) {
  nav { padding: 16px 20px; }
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .hero h1 { font-size: 32px; }
  .hero .subtitle { font-size: 16px; }
  section { padding: 60px 20px; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 28px; }
  .not-found-scene { height: 142px; }
  .not-found-code { gap: 14px; font-size: 88px; }
  .not-found-zero { width: 56px; height: 76px; border-width: 7px; }
  .not-found h1 { font-size: 24px; }
  .focus-row { grid-template-columns: 1fr; gap: 4px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
  .fade-in { opacity: 1; transform: none; }
}