/* ============ 基础变量 ============ */
:root {
  --bg: #08090a;
  --bg-soft: #0e1012;
  --border: #1e2226;
  --text: #f2f4f5;
  --muted: #8b939a;
  --accent: #e6e9eb;
  --maxw: 760px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, -apple-system, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  letter-spacing: 0.01em;
}

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

.muted { color: var(--muted); }

/* ============ 导航 ============ */
.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.1rem 1.5rem;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
}

.brand {
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  gap: 1.4rem;
  font-size: 0.875rem;
  color: var(--muted);
}

.nav-links a { transition: color 0.2s ease; }
.nav-links a:hover { color: var(--text); }

/* ============ 布局 ============ */
main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 4.5rem 0;
  border-top: 1px solid var(--border);
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.section.in-view {
  opacity: 1;
  transform: none;
}

.section-title {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 2rem;
}

/* ============ Hero ============ */
.hero {
  padding: 6rem 0 4.5rem;
}

.eyebrow {
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.6rem;
}

.hero-title {
  font-size: clamp(2.6rem, 9vw, 4.2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 1.2rem;
}

.hero-sub {
  font-size: 1.06rem;
  max-width: 34em;
  margin-bottom: 1.4rem;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 2.2rem;
}

.dot { opacity: 0.5; }

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-block;
  padding: 0.62rem 1.25rem;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 500;
  border: 1px solid var(--border);
  transition: all 0.2s ease;
}

.btn-solid {
  background: var(--accent);
  color: #0a0b0c;
  border-color: var(--accent);
}

.btn-solid:hover { opacity: 0.85; }

.btn-ghost { color: var(--muted); }

.btn-ghost:hover {
  color: var(--text);
  border-color: #34393e;
}

/* ============ 正文 ============ */
.prose { max-width: 38em; }
.prose p + p { margin-top: 1rem; }

/* ============ 时间线 ============ */
.timeline {
  list-style: none;
  position: relative;
  padding-left: 1.4rem;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 1px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  padding-bottom: 2.6rem;
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.timeline-item.in-view {
  opacity: 1;
  transform: none;
}

.timeline-item:last-child { padding-bottom: 0; }

.timeline-item::before {
  content: "";
  position: absolute;
  left: calc(-1.4rem + 0.5px);
  top: 0.6rem;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--bg);
  border: 1px solid #4a5259;
}

.timeline-period {
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-bottom: 0.4rem;
  font-variant-numeric: tabular-nums;
}

.timeline-body h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  letter-spacing: -0.01em;
}

.bullets {
  margin-top: 0.7rem;
  padding-left: 1.1rem;
  color: var(--muted);
  font-size: 0.94rem;
}

.bullets li + li { margin-top: 0.3rem; }

/* ============ 联系 ============ */
.contact-list {
  list-style: none;
  margin-top: 1.6rem;
  display: grid;
  gap: 0.85rem;
}

.contact-list li {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border);
}

.contact-list .label {
  flex: 0 0 4.5rem;
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 0.06em;
}

.contact-list a {
  border-bottom: 1px solid #2a2f34;
  transition: border-color 0.2s ease;
}

.contact-list a:hover { border-color: var(--text); }

/* ============ 页脚 ============ */
.footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 3.5rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
}

/* ============ 移动端 ============ */
@media (max-width: 560px) {
  .hero { padding: 4rem 0 3rem; }
  .section { padding: 3.2rem 0; }
  .nav-links { gap: 1rem; font-size: 0.82rem; }
}

/* 尊重系统「减少动态效果」设置 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .section, .timeline-item {
    opacity: 1 !important;
    transform: none !important;
    transition: none !important;
  }
}