/* ============================================================
   全局设计系统 — 山东五岳寻迹
   ============================================================ */

:root {
  --ink-900: #0a0a0a;
  --ink-800: #1a1a1a;
  --ink-700: #2a2a2a;
  --ink-600: #404040;
  --ink-500: #737373;
  --ink-400: #a3a3a3;
  --ink-300: #d4d4d4;
  --ink-200: #e5e5e5;
  --ink-100: #f5f5f5;
  --ink-50:  #fafafa;

  --accent:       #3b82f6;
  --accent-light: #60a5fa;
  --accent-glow:  rgba(59, 130, 246, 0.25);

  --radius-sm: 4px;
  --radius-md: 12px;
  --radius-full: 9999px;

  --font-sans:  "Noto Sans SC", system-ui, sans-serif;
  --font-serif: "Playfair Display", Georgia, serif;

  --section-py: 120px;
  --container:  1200px;

  --ease-out:    cubic-bezier(0.22, 1, 0.36, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* ---------- 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  font-size: 16px;
  color: var(--ink-800);
  background: #fff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img, video { display: block; max-width: 100%; }
ul { list-style: none; }

/* ---------- 容器 ---------- */
.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 24px;
}

/* ============================================================
   导航栏
   ============================================================ */
.nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: 64px;
  background: transparent;
  transition: background 0.4s var(--ease-out), box-shadow 0.4s var(--ease-out);
}
.nav.scrolled {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 rgba(0,0,0,0.06), 0 4px 24px -8px rgba(0,0,0,0.08);
}
.nav.scrolled .nav-logo,
.nav.scrolled .nav-logo-dot {
  color: var(--ink-900);
  text-shadow: none;
}
.nav.scrolled .nav-link {
  color: var(--ink-600);
  text-shadow: none;
}
.nav.scrolled .nav-link:hover,
.nav.scrolled .nav-link.active {
  color: var(--accent);
}
.nav.scrolled .nav-link.active::after {
  background: var(--accent);
}
.nav.scrolled .nav-cta {
  background: var(--ink-900);
  text-shadow: none;
}
.nav.scrolled .nav-cta:hover {
  background: var(--accent);
}

.nav-inner {
  max-width: var(--container);
  margin-inline: auto;
  height: 100%;
  padding-inline: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.125rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink-900);
}
.nav-logo-dot {
  color: var(--accent);
  font-weight: 700;
}

.nav-links {
  display: flex;
  gap: 40px;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--ink-600);
  letter-spacing: 0.02em;
}

.nav-link {
  position: relative;
  padding-block: 4px;
  transition: color 0.3s var(--ease-out);
}
.nav-link::after {
  content: '';
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 1.5px;
  background: var(--accent);
  border-radius: 1px;
  transition: width 0.35s var(--ease-out);
}
.nav-link:hover { color: var(--ink-900); }
.nav-link.active {
  color: var(--accent);
  font-weight: 600;
}
.nav-link.active::after,
.nav-link:hover::after {
  width: 100%;
}
.nav-link.active::after {
  height: 2px;
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  background: var(--ink-900);
  color: #fff !important;
  padding: 8px 22px;
  border-radius: var(--radius-full);
  font-size: 0.8125rem;
  font-weight: 500;
  transition: background 0.3s var(--ease-out), transform 0.2s var(--ease-out);
}
.nav-cta:hover {
  background: var(--accent);
  transform: scale(1.03);
}

.nav-burger { display: none; }

@media (max-width: 768px) {
  .nav-links, .nav-cta { display: none; }
  .nav-burger { display: flex; }
}

/* ============================================================
   页脚
   ============================================================ */
.footer {
  background: var(--ink-50);
  border-top: 1px solid var(--ink-200);
  padding-block: 32px;
}
.footer-inner {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 24px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  font-size: 0.75rem;
  color: var(--ink-400);
  letter-spacing: 0.02em;
}
.footer-brand-dot { color: var(--accent); }

/* ============================================================
   按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  border-radius: var(--radius-full);
  font-size: 0.8125rem;
  font-weight: 500;
  transition: all 0.3s var(--ease-out);
  white-space: nowrap;
}
.btn-primary {
  background: var(--ink-900);
  color: #fff;
}
.btn-primary:hover {
  background: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 28px -8px var(--accent-glow);
}
.btn-accent {
  background: var(--accent);
  color: #fff;
}
.btn-accent:hover {
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px -6px var(--accent-glow);
}
.btn-block {
  width: 100%;
  max-width: 240px;
}

/* ============================================================
   区块标签 / 标题
   ============================================================ */
.section-label {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 24px;
}
.section-label::before {
  content: '';
  width: 28px; height: 1.5px;
  background: var(--accent);
  border-radius: 1px;
  opacity: 0.6;
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: var(--ink-900);
  margin-bottom: 24px;
}
.section-subtitle {
  font-size: 1rem;
  color: var(--ink-500);
  line-height: 1.8;
  max-width: 560px;
}

/* ============================================================
   滚动动效
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.stagger > *:nth-child(1) { transition-delay: 0s; }
.stagger > *:nth-child(2) { transition-delay: 0.08s; }
.stagger > *:nth-child(3) { transition-delay: 0.16s; }
.stagger > *:nth-child(4) { transition-delay: 0.24s; }
.stagger > *:nth-child(5) { transition-delay: 0.32s; }

.card-hover {
  transition: transform 0.4s var(--ease-spring), box-shadow 0.4s var(--ease-out);
}
.card-hover:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 48px -16px rgba(0,0,0,0.1);
}

/* ============================================================
   细分隔线
   ============================================================ */
.divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--ink-300), transparent);
}

/* ============================================================
   页面过渡
   ============================================================ */
.page-fade {
  animation: pageFadeIn 0.6s var(--ease-out) both;
}
@keyframes pageFadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ============================================================
   滚动条
   ============================================================ */
.mt-8 { margin-top: 2rem; }

.bg-ink-50  { background: var(--ink-50); }
.bg-ink-900 { background: var(--ink-900); }

/* ============================================================
   滚动条
   ============================================================ */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--ink-300); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--ink-400); }