/* ============================================================
   MaxMind 官网 — 纯黑极简 · 高质感
   无光晕 / 无渐变 / 无彩色强调，图片直接呈现（不加边框）
   ============================================================ */
:root {
  --bg: #000000;
  --txt: #f5f5f7;
  --txt-2: #a1a1a6;
  --txt-3: #6e6e73;
  --line: rgba(255, 255, 255, 0.10);
  --line-soft: rgba(255, 255, 255, 0.07);
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC",
          system-ui, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --maxw: 1120px;
}

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  background: var(--bg);
  color: var(--txt);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }
::selection { background: rgba(255, 255, 255, 0.9); color: #000; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 28px; }
.section { padding: 150px 0; scroll-margin-top: 84px; }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 1000;
  background: #fff; color: #000; padding: 10px 16px; font-size: 0.85rem;
}
.skip-link:focus { left: 0; }

/* ---------- 顶栏 ---------- */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  transition: background 0.3s ease, border-color 0.3s ease;
  background: transparent;
  border-bottom: 1px solid transparent;
}
.site-header.scrolled {
  background: rgba(0, 0, 0, 0.72);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  border-bottom-color: var(--line-soft);
}
.header-inner {
  display: flex; align-items: center; gap: 34px;
  height: 72px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--txt); }
.brand-name { font-size: 1.08rem; font-weight: 600; letter-spacing: -0.01em; }
.site-nav { display: flex; gap: 34px; margin-left: auto; }
.site-nav a {
  color: var(--txt-2); font-size: 0.92rem; padding: 6px 0;
  transition: color 0.2s ease;
}
.site-nav a:hover, .site-nav a.active { color: var(--txt); }
.header-actions { display: flex; align-items: center; gap: 12px; }

/* ---------- 按钮（白 / 描边，克制的胶囊） ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 24px; border-radius: 999px;
  font-size: 0.92rem; font-weight: 500; white-space: nowrap;
  border: 1px solid transparent; cursor: pointer;
  transition: opacity 0.2s ease, transform 0.2s ease, background 0.2s ease;
}
.btn-lg { padding: 15px 34px; font-size: 1rem; }
.btn-primary { background: #fff; color: #000; }
.btn-primary:hover { transform: translateY(-1px); }
.btn-ghost { border-color: var(--line); color: var(--txt-2); background: transparent; }
.btn-ghost:hover { color: var(--txt); border-color: rgba(255, 255, 255, 0.35); }
.arr { transition: transform 0.2s ease; display: inline-block; }
.btn:hover .arr { transform: translateX(3px); }

.nav-toggle { display: none; flex-direction: column; gap: 5px; padding: 10px; border: 0; background: none; cursor: pointer; }
.nav-toggle span { width: 20px; height: 1.5px; background: var(--txt); transition: 0.25s ease; }
.nav-toggle.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ---------- 通用 ---------- */
.eyebrow {
  font-size: 0.7rem; letter-spacing: 0.34em; text-transform: uppercase;
  color: var(--txt-3); margin-bottom: 26px;
}
.section-title {
  font-size: clamp(2rem, 4.6vw, 3.4rem);
  font-weight: 600; letter-spacing: -0.03em; line-height: 1.15;
  margin-bottom: 22px;
}
.section-lead {
  color: var(--txt-2); font-size: clamp(1rem, 1.6vw, 1.12rem);
  max-width: 640px; line-height: 1.9;
}

/* ---------- Hero ---------- */
.hero {
  min-height: 100svh;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  padding: 130px 0 60px;
}
.hero-inner { display: flex; flex-direction: column; align-items: center; }
.logo-img {
  width: min(560px, 82vw);
  height: auto;
  margin: 0 0 54px;
  /* 如果你的 Logo 是浅色图（白底/白字），把下面这行去掉即可 */
}
.hero-title {
  font-size: clamp(2.1rem, 5vw, 4.2rem);
  font-weight: 600; letter-spacing: -0.035em; line-height: 1.1;
  margin-bottom: 24px;
}
.hero-sub {
  color: var(--txt-2); max-width: 560px;
  font-size: clamp(1rem, 1.6vw, 1.14rem); line-height: 1.9;
  margin-bottom: 46px;
}
.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }

/* ---------- M1.5 能力 ---------- */
.feature-grid {
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 64px; margin: 88px 0 120px;
}
.feature { border-top: 1px solid var(--line); padding-top: 26px; }
.feature-num {
  font-family: var(--mono); font-size: 0.78rem; color: var(--txt-3);
  letter-spacing: 0.08em; margin-bottom: 22px;
}
.feature h3 { font-size: 1.3rem; font-weight: 600; letter-spacing: -0.01em; margin-bottom: 12px; }
.feature p { color: var(--txt-2); font-size: 0.95rem; line-height: 1.8; }

.m15 { text-align: center; border-top: 1px solid var(--line); padding-top: 90px; }
.m15-big {
  display: block;
  font-size: clamp(5rem, 16vw, 13rem);
  font-weight: 700; letter-spacing: -0.05em; line-height: 0.95;
  color: var(--txt);
}
.m15-note {
  display: block; margin-top: 26px; color: var(--txt-3); font-size: 0.82rem;
  letter-spacing: 0.14em; text-transform: uppercase;
}

/* ---------- 研发之路 ---------- */
.split { border-top: 1px solid var(--line-soft); }
.road-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 90px; align-items: center; }
.road-steps { list-style: none; margin-top: 46px; }
.road-steps li {
  display: flex; align-items: baseline; gap: 18px;
  padding: 18px 0; color: var(--txt-2); font-size: 0.98rem;
  border-bottom: 1px solid var(--line-soft);
}
.road-steps li:last-child { border-bottom: 0; }
.road-steps span {
  font-family: var(--mono); font-size: 0.82rem; color: var(--txt-3);
  letter-spacing: 0.06em;
}
.road-figure { margin: 0; }
.road-figure img { width: 100%; height: auto; }
.road-figure figcaption {
  text-align: left; margin-top: 16px;
  color: var(--txt-3); font-size: 0.72rem; letter-spacing: 0.24em; text-transform: uppercase;
}

/* ---------- 开放平台 ---------- */
.platform { border-top: 1px solid var(--line-soft); }
.platform-inner { text-align: center; }
.platform-inner .section-lead { margin: 0 auto; }
.platform-feats {
  display: grid; grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
  margin: 84px 0 60px;
}
.platform-feats > div { padding: 34px 26px; }
.platform-feats > div + div { border-left: 1px solid var(--line-soft); }
.platform-feats strong {
  display: block; font-weight: 600; font-size: 1.05rem; margin-bottom: 10px;
}
.platform-feats span { color: var(--txt-2); font-size: 0.86rem; }
.platform-cta {
  display: flex; flex-direction: column; align-items: center; gap: 22px;
}
.api-base {
  font-family: var(--mono); font-size: 0.9rem; color: var(--txt-3);
  cursor: pointer; transition: color 0.2s ease;
}
.api-base:hover { color: var(--txt); }
.platform-hint { margin-top: 26px; color: var(--txt-3); font-size: 0.8rem; }

/* ---------- 页脚 ---------- */
.site-footer { border-top: 1px solid var(--line-soft); padding: 70px 0 56px; }
.footer-grid {
  display: grid; grid-template-columns: 1fr auto 1fr; gap: 34px; align-items: start;
}
.footer-brand p { color: var(--txt-3); font-size: 0.88rem; margin-top: 16px; max-width: 300px; }
.footer-nav { display: flex; gap: 28px; justify-content: center; flex-wrap: wrap; padding-top: 4px; }
.footer-nav a { color: var(--txt-2); font-size: 0.9rem; transition: color 0.2s ease; }
.footer-nav a:hover { color: var(--txt); }
.footer-copy { text-align: right; color: var(--txt-3); font-size: 0.82rem; align-self: center; }

/* ---------- 入场（克制） ---------- */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .feature-grid { grid-template-columns: 1fr; gap: 40px; margin: 60px 0 90px; }
  .road-grid { grid-template-columns: 1fr; gap: 60px; }
  .platform-feats { grid-template-columns: repeat(2, 1fr); }
  .platform-feats > div:nth-child(3) { border-left: 0; }
  .platform-feats > div { padding: 26px 20px; }
  .footer-grid { grid-template-columns: 1fr; text-align: center; }
  .footer-nav { padding-top: 0; }
  .footer-copy { text-align: center; }
  .footer-brand p { margin-left: auto; margin-right: auto; }
}
@media (max-width: 720px) {
  .section { padding: 96px 0; }
  .site-nav {
    position: fixed; top: 72px; right: 0; bottom: 0;
    width: min(76vw, 300px);
    flex-direction: column; gap: 4px; padding: 30px 26px;
    background: #000;
    border-left: 1px solid var(--line-soft);
    transform: translateX(105%);
    transition: transform 0.3s ease;
  }
  .site-nav.open { transform: none; }
  .site-nav a { font-size: 1.05rem; padding: 14px 0; border-bottom: 1px solid var(--line-soft); color: var(--txt); }
  .nav-toggle { display: inline-flex; }
  .hero { min-height: 88svh; }
  .logo-img { margin-bottom: 40px; }
  .m15 { padding-top: 70px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ============================================================
   长篇版新增组件 — 依旧纯黑 / 细分割线 / 克制的排版
   ============================================================ */
.split-intro { border-top: 1px solid var(--line-soft); }
.big-lead { font-size: clamp(1.06rem, 1.8vw, 1.3rem); line-height: 2.05; max-width: 780px; }
.accent { border-bottom: 1px solid rgba(255, 255, 255, 0.4); padding-bottom: 3px; }

/* 走马灯 */
.marquee {
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  overflow: hidden; white-space: nowrap;
  padding: 22px 0;
}
.marquee-track {
  display: inline-flex; align-items: center; gap: 44px;
  animation: mx-marquee 46s linear infinite;
  will-change: transform;
}
.marquee-track span {
  font-size: 0.98rem; letter-spacing: 0.22em; text-transform: uppercase;
  color: var(--txt-2); font-weight: 300;
}
.marquee-track i { color: var(--txt-3); font-style: normal; font-size: 0.7rem; }
@keyframes mx-marquee { from { transform: translateX(0); } to { transform: translateX(-50%); } }

/* 双栏正文 */
.text-cols {
  column-count: 2; column-gap: 72px;
  margin-top: 48px;
}
.text-cols p {
  color: var(--txt-2); font-size: 1.02rem; line-height: 2.1;
  margin-bottom: 30px; break-inside: avoid;
  text-align: justify;
}

/* 引语 */
.quote { padding: 130px 0; border-top: 1px solid var(--line-soft); text-align: center; }
.quote-text {
  font-size: clamp(1.7rem, 3.8vw, 2.9rem);
  font-weight: 500; letter-spacing: -0.02em; line-height: 1.6;
}
.quote-src { margin-top: 34px; color: var(--txt-3); font-size: 0.86rem; letter-spacing: 0.18em; text-transform: uppercase; }

/* 特性四列 */
.feature-grid.cols-4 { grid-template-columns: repeat(4, 1fr); margin: 88px 0 120px; }

/* 设计理念 */
.principles { display: grid; grid-template-columns: 1fr 1fr; gap: 22px 72px; margin-top: 84px; }
.principle { border-top: 1px solid var(--line); padding: 30px 0 10px; }
.principle-num { color: var(--txt-3); font-size: 0.76rem; letter-spacing: 0.2em; text-transform: uppercase; margin-bottom: 22px; }
.principle h3 { font-size: 1.3rem; font-weight: 600; margin-bottom: 14px; letter-spacing: -0.01em; }
.principle p { color: var(--txt-2); font-size: 0.98rem; line-height: 1.95; }

/* 场景 */
.scene-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0 84px; margin-top: 84px; }
.scene { border-top: 1px solid var(--line); padding: 34px 0 46px; }
.scene-no { color: var(--txt-3); font-size: 0.76rem; letter-spacing: 0.2em; text-transform: uppercase; }
.scene h3 { font-size: 1.25rem; font-weight: 600; margin: 16px 0 14px; letter-spacing: -0.01em; }
.scene p { color: var(--txt-2); font-size: 0.97rem; line-height: 2; }

/* 质量四行 */
.rows-four { display: grid; grid-template-columns: repeat(4, 1fr); gap: 72px; margin-top: 84px; }
.row-item { border-top: 1px solid var(--line); padding-top: 26px; }
.row-item h3 { font-size: 1.12rem; font-weight: 600; margin-bottom: 16px; }
.row-item p { color: var(--txt-2); font-size: 0.94rem; line-height: 1.95; }

/* 时间线 */
.road-timeline { min-width: 0; }
.timeline { list-style: none; margin-top: 14px; }
.timeline li { padding: 26px 0; border-top: 1px solid var(--line-soft); }
.timeline .tl-no {
  font-family: var(--mono); font-size: 0.8rem; color: var(--txt-3);
  letter-spacing: 0.1em; display: block; margin-bottom: 10px;
}
.timeline h3 { font-size: 1.3rem; font-weight: 600; margin-bottom: 10px; letter-spacing: -0.01em; }
.timeline p { color: var(--txt-2); font-size: 0.97rem; line-height: 2; }

/* 平台页内“三步接入” */
.center { margin-left: auto; margin-right: auto; }
.howto { margin: 70px auto 0; max-width: 680px; text-align: left; }
.howto h3 {
  font-size: 0.8rem; letter-spacing: 0.24em; text-transform: uppercase;
  color: var(--txt-3); margin-bottom: 8px; text-align: center;
}
.howto-list { list-style: none; margin-top: 18px; }
.howto-list li { display: flex; gap: 26px; align-items: flex-start; padding: 26px 0; border-top: 1px solid var(--line-soft); }
.howto-list li > span {
  font-family: var(--mono); color: var(--txt-3); font-size: 0.86rem;
  flex-shrink: 0; padding-top: 4px;
}
.howto-list strong { display: block; font-weight: 600; font-size: 1.08rem; margin-bottom: 6px; }
.howto-list p { color: var(--txt-2); font-size: 0.95rem; line-height: 1.9; }
.howto-list code { font-family: var(--mono); color: var(--txt); font-size: 0.9em; }

/* FAQ */
.faq-wrap { max-width: 860px; }
.faq { border-bottom: 1px solid var(--line-soft); }
.faq:first-of-type { border-top: 1px solid var(--line-soft); }
.faq summary {
  list-style: none; cursor: pointer;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  padding: 26px 4px;
  font-size: 1.06rem; font-weight: 500; letter-spacing: -0.01em;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; flex-shrink: 0;
  color: var(--txt-3); font-size: 1.3rem; font-weight: 300;
  transition: transform 0.25s ease;
}
.faq[open] summary::after { transform: rotate(45deg); }
.faq p {
  color: var(--txt-2); font-size: 0.97rem; line-height: 2;
  padding: 0 4px 30px; max-width: 720px;
}
.faq code { font-family: var(--mono); color: var(--txt); font-size: 0.9em; }

/* 结尾 CTA */
.cta-band { padding: 150px 0; border-top: 1px solid var(--line-soft); }
.cta-inner { text-align: center; }
.cta-title { font-size: clamp(2rem, 4.6vw, 3.4rem); font-weight: 600; letter-spacing: -0.03em; line-height: 1.2; margin-bottom: 22px; }
.cta-sub { color: var(--txt-2); max-width: 540px; margin: 0 auto 44px; font-size: 1.05rem; }

/* 页脚多栏 */
.footer-top {
  display: grid; grid-template-columns: 2fr repeat(3, 1fr);
  gap: 40px; padding-bottom: 60px;
}
.footer-brand p { color: var(--txt-3); font-size: 0.88rem; margin-top: 16px; max-width: 300px; line-height: 1.8; }
.footer-col { display: flex; flex-direction: column; gap: 12px; }
.footer-col h4 {
  font-size: 0.78rem; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--txt-3); margin-bottom: 8px; font-weight: 500;
}
.footer-col a { color: var(--txt-2); font-size: 0.92rem; transition: color 0.2s ease; }
.footer-col a:hover { color: var(--txt); }
.footer-bottom {
  border-top: 1px solid var(--line-soft);
  padding-top: 30px;
  display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap;
  color: var(--txt-3); font-size: 0.82rem;
}
.footer-tagline { letter-spacing: 0.14em; text-transform: uppercase; }

/* ---------- 长篇版响应式 ---------- */
@media (max-width: 1080px) {
  .feature-grid.cols-4 { grid-template-columns: repeat(2, 1fr); gap: 40px 48px; }
  .rows-four { grid-template-columns: repeat(2, 1fr); gap: 44px; }
}
@media (max-width: 960px) {
  .text-cols { column-count: 1; }
  .principles { grid-template-columns: 1fr; gap: 10px; }
  .scene-grid { grid-template-columns: 1fr; gap: 0; }
  .road-grid { grid-template-columns: 1fr; gap: 60px; }
  .footer-top { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}
@media (max-width: 720px) {
  .feature-grid.cols-4 { grid-template-columns: 1fr; }
  .rows-four { grid-template-columns: 1fr; }
  .marquee-track { gap: 28px; }
  .cta-band { padding: 100px 0; }
}