/* ============================================
   俄罗斯搜索引擎入口 — 全局样式
   设计规范：Oberon（高对比 / 等宽标题 / 扁平 / 点阵网格）
   ============================================ */

:root {
  --color-primary: #ed4f00;
  --color-primary-hover: #d64700;
  --color-primary-active: #c03e00;
  --color-bg: #ffffff;
  --color-bg-alt: #f2f0ee;
  --color-bg-dark: #202020;
  --color-text: #000000;
  --color-text-secondary: #202020;
  --color-text-muted: #9e9e9e;
  --color-text-inverse: #ffffff;
  --color-text-inverse-muted: #b8b8b8;
  --color-border-light: #cfcecc;
  --color-border-medium: #dbdbd3;
  --color-border-dark: #cccbc4;
  --font-mono: "Geist Mono", "SF Mono", "JetBrains Mono", Menlo, Consolas, "Courier New", monospace;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --duration-fast: 0.15s;
  --duration-base: 0.4s;
  --container: 1200px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* ---------- 排版 ---------- */
h1, h2, h3, h4 {
  font-family: var(--font-mono);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.05em;
}
h1 { font-size: 62px; }
h2 { font-size: 42px; }
h3 { font-size: 26px; }
h4 { font-size: 18px; }

p { line-height: 1.75; }

a { color: inherit; }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 64px;
}

/* ---------- 顶部导航 ---------- */
.nav-bar {
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
  position: sticky;
  top: 0;
  z-index: 10;
}
.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 20px 64px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
}
.nav-logo {
  font-family: var(--font-mono);
  font-size: 18px;
  letter-spacing: -0.05em;
  color: var(--color-text-inverse);
  text-decoration: none;
  white-space: nowrap;
}
.nav-logo .dot { color: var(--color-primary); }
.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}
.nav-link {
  color: var(--color-text-inverse);
  font-size: 15px;
  text-decoration: none;
  padding: 8px 12px;
  transition: color var(--duration-fast) ease-in-out;
}
.nav-link:hover { color: var(--color-primary); }
.nav-link.active { color: var(--color-primary); font-weight: 500; }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-inverse);
  font-size: 24px;
  cursor: pointer;
  padding: 8px;
  line-height: 1;
}

/* ---------- 按钮 ---------- */
.button-primary,
.button-secondary,
.button-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  padding: 16px 32px;
  border: none;
  border-radius: 240px;
  cursor: pointer;
  text-decoration: none;
  transition: background-color var(--duration-fast) ease-in-out,
              color var(--duration-fast) ease-in-out,
              border-color var(--duration-fast) ease-in-out,
              transform var(--duration-fast) ease-in-out;
}
.button-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}
.button-primary:hover { background-color: var(--color-primary-hover); transform: translateY(-1px); }
.button-primary:active { background-color: var(--color-primary-active); transform: translateY(0); }
.button-secondary {
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
}
.button-secondary:hover { background-color: #3d3b3b; transform: translateY(-1px); }
.button-secondary:active { background-color: #000000; transform: translateY(0); }
.button-ghost {
  background-color: transparent;
  color: var(--color-text);
  font-size: 15px;
  padding: 12px 24px;
  border: 1px solid var(--color-text);
}
.button-ghost:hover {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
}
.button-lg { font-size: 18px; padding: 20px 44px; }

/* ---------- Hero ---------- */
.hero {
  background-color: var(--color-bg-alt);
  background-image: radial-gradient(var(--color-border-light) 1px, transparent 1px);
  background-size: 24px 24px;
  padding: 96px 0 80px;
  text-align: center;
}
.hero .eyebrow {
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin-bottom: 24px;
  text-transform: uppercase;
}
.hero h1 { margin-bottom: 24px; }
.hero .hero-sub {
  max-width: 720px;
  margin: 0 auto 48px;
  font-size: 18px;
  color: var(--color-text-secondary);
}
.hero-cta {
  display: flex;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}
.hero-note {
  font-size: 13px;
  color: var(--color-text-muted);
}

/* ---------- 通用 Section ---------- */
.section { padding: 80px 0; }
.section-alt { background-color: var(--color-bg-alt); }
.section-dark {
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
}
.section-head { margin-bottom: 48px; max-width: 800px; }
.section-head .kicker {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-primary);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.section-head h2 { margin-bottom: 16px; }
.section-head p { color: var(--color-text-secondary); }
.section-dark .section-head p { color: var(--color-text-inverse-muted); }

/* ---------- 网格卡片 ---------- */
.grid { display: grid; gap: 24px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-medium);
  padding: 32px;
  transition: transform var(--duration-base) ease-out, border-color var(--duration-fast) ease-in-out;
}
.card:hover { transform: translateY(-4px); border-color: var(--color-primary); }
.card h3, .card h4 { margin-bottom: 12px; }
.card p { font-size: 15px; color: var(--color-text-secondary); }
.card .card-num {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-primary);
  margin-bottom: 16px;
  display: block;
}

.card-dark {
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
  border: none;
  padding: 48px 32px;
}
.card-dark p { color: var(--color-text-inverse-muted); }
.card-dark h3, .card-dark h4 { color: var(--color-text-inverse); }

/* ---------- 入口大卡片 ---------- */
.entry-card {
  border: 1px solid var(--color-border-medium);
  background: var(--color-bg);
  padding: 48px 40px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: transform var(--duration-base) ease-out, border-color var(--duration-fast) ease-in-out;
}
.entry-card:hover { transform: translateY(-4px); border-color: var(--color-primary); }
.entry-card .entry-tag {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-primary);
  letter-spacing: 0.08em;
}
.entry-card h3 { font-size: 26px; }
.entry-card .entry-url {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-text-muted);
  word-break: break-all;
}
.entry-card p { font-size: 15px; color: var(--color-text-secondary); flex: 1; }
.entry-card .button-primary,
.entry-card .button-secondary { align-self: flex-start; }

/* ---------- 对比表格 ---------- */
.table-wrap { overflow-x: auto; border: 1px solid var(--color-border-medium); }
table.compare {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  background: var(--color-bg);
}
table.compare th,
table.compare td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--color-border-medium);
  vertical-align: top;
}
table.compare th {
  font-family: var(--font-mono);
  font-weight: 400;
  font-size: 14px;
  letter-spacing: -0.02em;
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
  white-space: nowrap;
}
table.compare tr:last-child td { border-bottom: none; }
table.compare td:first-child { font-weight: 500; white-space: nowrap; }

/* ---------- 步骤 ---------- */
.steps { counter-reset: step; display: grid; gap: 24px; grid-template-columns: repeat(4, 1fr); }
.step {
  border-top: 2px solid var(--color-bg-dark);
  padding-top: 20px;
}
.step::before {
  counter-increment: step;
  content: "0" counter(step);
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--color-primary);
  display: block;
  margin-bottom: 12px;
}
.step h4 { margin-bottom: 8px; font-size: 17px; }
.step p { font-size: 14px; color: var(--color-text-secondary); }

/* ---------- FAQ ---------- */
.faq-list { max-width: 860px; }
.faq-item {
  border-bottom: 1px solid var(--color-border-medium);
}
.faq-item summary {
  font-family: var(--font-mono);
  font-size: 17px;
  letter-spacing: -0.03em;
  padding: 24px 40px 24px 0;
  cursor: pointer;
  list-style: none;
  position: relative;
  transition: color var(--duration-fast) ease-in-out;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 22px;
  color: var(--color-primary);
  transition: transform var(--duration-fast) ease-in-out;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item summary:hover { color: var(--color-primary); }
.faq-item .faq-answer {
  padding: 0 0 24px;
  font-size: 15px;
  color: var(--color-text-secondary);
  line-height: 1.8;
}
.faq-item .faq-answer p + p { margin-top: 12px; }

/* ---------- 文章/内页正文 ---------- */
.article {
  max-width: 860px;
}
.article h2 { font-size: 32px; margin: 56px 0 20px; }
.article h3 { font-size: 22px; margin: 40px 0 16px; }
.article p { margin-bottom: 16px; color: var(--color-text-secondary); }
.article ul, .article ol { margin: 0 0 16px 24px; color: var(--color-text-secondary); }
.article li { margin-bottom: 8px; line-height: 1.7; }
.article a { color: var(--color-text); text-decoration: underline; transition: color var(--duration-fast) ease-in-out; }
.article a:hover { color: var(--color-primary); }
.article .button-primary,
.article .button-secondary { color: var(--color-text-inverse) !important; text-decoration: none; }
.article .button-primary:hover,
.article .button-secondary:hover { color: var(--color-text-inverse) !important; }
.article .lead { font-size: 18px; color: var(--color-text-secondary); }
.article strong { color: var(--color-text); }

/* ---------- 面包屑 ---------- */
.breadcrumb {
  font-size: 13px;
  color: var(--color-text-muted);
  padding: 20px 0;
}
.breadcrumb ol { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; }
.breadcrumb li + li::before { content: "/"; margin-right: 8px; color: var(--color-border-dark); }
.breadcrumb a { color: var(--color-text-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--color-primary); }

/* ---------- 页面标题区（内页） ---------- */
.page-hero {
  background-color: var(--color-bg-alt);
  background-image: radial-gradient(var(--color-border-light) 1px, transparent 1px);
  background-size: 24px 24px;
  padding: 64px 0;
}
.page-hero h1 { font-size: 42px; margin-bottom: 16px; }
.page-hero p { max-width: 720px; color: var(--color-text-secondary); font-size: 17px; }

/* ---------- 提示块 ---------- */
.notice {
  border-left: 3px solid var(--color-primary);
  background-color: var(--color-bg-alt);
  padding: 20px 24px;
  font-size: 15px;
  color: var(--color-text-secondary);
  margin: 24px 0;
}

/* ---------- 关键词标签云 ---------- */
.tag-cloud { display: flex; flex-wrap: wrap; gap: 12px; }
.tag-cloud a {
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 8px 16px;
  border: 1px solid var(--color-border-medium);
  text-decoration: none;
  color: var(--color-text-secondary);
  transition: all var(--duration-fast) ease-in-out;
}
.tag-cloud a:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ---------- CTA 横幅 ---------- */
.cta-banner {
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
  padding: 64px;
  text-align: center;
}
.cta-banner h2 { margin-bottom: 16px; font-size: 34px; }
.cta-banner p { color: var(--color-text-inverse-muted); margin-bottom: 32px; max-width: 640px; margin-left: auto; margin-right: auto; }
.cta-banner .hero-cta { margin-bottom: 0; }

/* ---------- 页脚 ---------- */
.footer {
  background-color: var(--color-bg-dark);
  color: var(--color-text-inverse);
  padding: 64px 0 32px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}
.footer h4 {
  font-size: 15px;
  margin-bottom: 16px;
  color: var(--color-text-inverse);
}
.footer p { font-size: 14px; color: var(--color-text-inverse-muted); line-height: 1.7; }
.footer ul { list-style: none; }
.footer li { margin-bottom: 10px; }
.footer a {
  font-size: 14px;
  color: var(--color-text-inverse-muted);
  text-decoration: none;
  transition: color var(--duration-fast) ease-in-out;
}
.footer a:hover { color: var(--color-primary); }
.footer-bottom {
  border-top: 1px solid #3d3b3b;
  padding-top: 24px;
  font-size: 13px;
  color: var(--color-text-inverse-muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 数据统计条 ---------- */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
.stat .stat-num {
  font-family: var(--font-mono);
  font-size: 42px;
  letter-spacing: -0.05em;
  color: var(--color-primary);
  display: block;
  margin-bottom: 8px;
}
.stat .stat-label { font-size: 14px; color: var(--color-text-inverse-muted); }

/* ---------- 响应式 ---------- */
@media (max-width: 1199px) {
  h1 { font-size: 48px; }
  h2 { font-size: 34px; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .stats { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 809px) {
  .container { padding: 0 24px; }
  .nav-inner { padding: 16px 24px; }
  h1 { font-size: 34px; }
  h2 { font-size: 28px; }
  h3 { font-size: 20px; }
  .hero { padding: 56px 0 48px; }
  .hero .hero-sub { font-size: 16px; }
  .section { padding: 48px 0; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .cta-banner { padding: 48px 24px; }
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    background-color: var(--color-bg-dark);
    padding: 8px 24px 24px;
    gap: 0;
    border-top: 1px solid #3d3b3b;
  }
  .nav-links.open { display: flex; }
  .nav-link { padding: 14px 0; border-bottom: 1px solid #2e2d2d; }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .hero-cta .button-primary, .hero-cta .button-secondary { width: 100%; }
  .page-hero h1 { font-size: 30px; }
}