:root {
  --ink: #0b1424;
  --ink-soft: #243044;
  --fog: #d7dee8;
  --paper: #f4f6f9;
  --gold: #b8893a;
  --gold-soft: #d4a85a;
  --line: rgba(11, 20, 36, 0.12);
  --serif: 'Noto Serif SC', 'Songti SC', 'SimSun', serif;
  --sans: 'DM Sans', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: var(--sans);
  background: var(--paper);
  line-height: 1.6;
}

.atmosphere {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 80% 55% at 12% -10%, rgba(184, 137, 58, 0.18), transparent 55%),
    radial-gradient(ellipse 70% 50% at 95% 8%, rgba(36, 72, 120, 0.16), transparent 50%),
    linear-gradient(165deg, #eef2f7 0%, #f7f8fa 45%, #ebeff5 100%);
  animation: atmosphere-shift 18s ease-in-out infinite alternate;
}

@keyframes atmosphere-shift {
  from {
    filter: hue-rotate(0deg) saturate(1);
  }
  to {
    filter: hue-rotate(8deg) saturate(1.05);
  }
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  max-width: 72rem;
  margin: 0 auto;
}

.brand {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: 0.06em;
  color: var(--ink);
  text-decoration: none;
}

.hero {
  max-width: 42rem;
  margin: 0 auto;
  padding: 18vh 1.5rem 8rem;
  text-align: left;
}

.brand-mark {
  margin: 0 0 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.28em;
  color: var(--gold);
  text-transform: uppercase;
  opacity: 0;
  animation: rise 0.8s ease forwards 0.1s;
}

.hero h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.75rem, 8vw, 4.5rem);
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.15;
  color: var(--ink);
  opacity: 0;
  animation: rise 0.9s ease forwards 0.25s;
}

.lead {
  margin: 1.25rem 0 0;
  max-width: 28rem;
  font-size: 1.0625rem;
  color: var(--ink-soft);
  opacity: 0;
  animation: rise 0.9s ease forwards 0.45s;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
  opacity: 0;
  animation: rise 0.9s ease forwards 0.6s;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0 1.25rem;
  border-radius: 0.25rem;
  font-size: 0.9375rem;
  font-weight: 500;
  text-decoration: none;
  transition:
    transform 0.2s ease,
    background 0.2s ease,
    color 0.2s ease,
    border-color 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn.primary {
  background: var(--ink);
  color: #f8fafc;
}

.btn.primary:hover {
  background: #162033;
}

.btn.ghost {
  border: 1px solid var(--line);
  color: var(--ink);
  background: rgba(255, 255, 255, 0.45);
}

.btn.ghost:hover {
  border-color: rgba(11, 20, 36, 0.28);
  background: rgba(255, 255, 255, 0.75);
}

.about {
  max-width: 42rem;
  margin: 0 auto;
  padding: 0 1.5rem 6rem;
  border-top: 1px solid var(--line);
  padding-top: 3.5rem;
}

.about h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.about p {
  margin: 1rem 0 0;
  color: var(--ink-soft);
}

.foot {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  justify-content: space-between;
  max-width: 72rem;
  margin: 0 auto;
  padding: 1.5rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.875rem;
}

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

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

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 640px) {
  .hero {
    padding-top: 12vh;
  }
}