:root {
  --bg: #f6f7f9;
  --bg-alt: #eef1f4;
  --ink: #1a2228;
  --ink-muted: #5a6570;
  --primary: #0d7377;
  --primary-soft: rgba(13, 115, 119, 0.12);
  --line: rgba(26, 34, 40, 0.08);
  --font-display: "Outfit", system-ui, sans-serif;
  --font-body: "Source Sans 3", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
  --max: 42rem;
  --pad: clamp(1.25rem, 4vw, 2.5rem);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background: var(--bg);
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.page-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(
      120% 80% at 12% -10%,
      rgba(13, 115, 119, 0.09),
      transparent 55%
    ),
    radial-gradient(
      90% 60% at 100% 0%,
      rgba(26, 34, 40, 0.04),
      transparent 50%
    ),
    linear-gradient(180deg, #f8fafb 0%, var(--bg) 40%, #f3f5f7 100%);
  pointer-events: none;
}

a {
  color: var(--primary);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: 68rem;
  margin: 0 auto;
  padding: 1.25rem var(--pad);
}

.logo {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.02em;
  color: var(--ink);
  text-decoration: none;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1.25rem;
}

.nav a {
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--ink-muted);
  text-decoration: none;
}

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

.hero {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: calc(100svh - 4.5rem);
  max-width: 68rem;
  margin: 0 auto;
  padding: clamp(2rem, 8vh, 4rem) var(--pad) clamp(3rem, 10vh, 5rem);
}

.hero-tag {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: clamp(0.9rem, 2.2vw, 1.05rem);
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--primary);
}

.hero-brand {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(3.25rem, 12vw, 6.5rem);
  font-weight: 700;
  line-height: 0.95;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.hero-identity {
  max-width: 28rem;
  margin: 1.35rem 0 0;
  font-size: clamp(1.05rem, 2.4vw, 1.25rem);
  font-weight: 500;
  line-height: 1.45;
  color: var(--ink-muted);
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  width: fit-content;
  margin-top: 2rem;
  padding: 0.7rem 1.15rem;
  border: 1px solid var(--primary);
  border-radius: 0.25rem;
  background: transparent;
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--primary);
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease;
}

.hero-cta::after {
  content: "↓";
  font-size: 0.85em;
}

.hero-cta:hover {
  background: var(--primary);
  color: #fff;
}

.hero-horizon {
  position: absolute;
  left: var(--pad);
  right: var(--pad);
  bottom: 1.5rem;
  height: 1px;
  background: linear-gradient(
    90deg,
    transparent,
    var(--primary) 20%,
    var(--primary) 80%,
    transparent
  );
  opacity: 0.35;
}

.hero-horizon::after {
  content: "";
  position: absolute;
  left: 12%;
  top: 50%;
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 50%;
  background: var(--primary);
  transform: translate(-50%, -50%);
  box-shadow: 0 0 0 6px var(--primary-soft);
  animation: pulse-dot 2.8s ease-in-out infinite;
}

.section {
  max-width: 68rem;
  margin: 0 auto;
  padding: clamp(3.5rem, 10vh, 5.5rem) var(--pad);
}

.section-alt {
  background: linear-gradient(
    180deg,
    transparent,
    rgba(238, 241, 244, 0.85) 12%,
    rgba(238, 241, 244, 0.85) 88%,
    transparent
  );
}

.section-label {
  margin: 0 0 0.65rem;
  font-family: var(--font-display);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--primary);
}

.section-title {
  max-width: var(--max);
  margin: 0 0 1.25rem;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.section-body {
  max-width: var(--max);
  margin: 0;
  color: var(--ink-muted);
}

.section-body strong {
  color: var(--ink);
  font-weight: 600;
}

.placeholder {
  border-left: 2px solid var(--line);
  padding-left: 1rem;
}

.site-footer {
  max-width: 68rem;
  margin: 0 auto;
  padding: 2rem var(--pad) 3rem;
  border-top: 1px solid var(--line);
}

.site-footer p {
  margin: 0;
  font-family: var(--font-display);
  font-size: 0.875rem;
  color: var(--ink-muted);
}

.reveal {
  opacity: 0;
  transform: translateY(0.85rem);
  transition:
    opacity 0.65s ease,
    transform 0.65s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

.hero .reveal:nth-child(1) {
  transition-delay: 0.05s;
}
.hero .reveal:nth-child(2) {
  transition-delay: 0.18s;
}
.hero .reveal:nth-child(3) {
  transition-delay: 0.3s;
}
.hero .reveal:nth-child(4) {
  transition-delay: 0.42s;
}

@keyframes pulse-dot {
  0%,
  100% {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
  50% {
    transform: translate(-50%, -50%) scale(1.15);
    opacity: 0.75;
  }
}

@media (max-width: 560px) {
  .site-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero {
    min-height: calc(100svh - 6rem);
  }

  .hero-brand {
    word-break: keep-all;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .hero-horizon::after {
    animation: none;
  }
}