/* ==========================================================
   上线性能与顺滑度增强引擎 (Smoothness & Performance Optimization)
   ========================================================== */
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  width: 100%;
}

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

/* 硬件加速与流畅悬停 */
a, button, .media-news-card, .btn-media-primary, .btn-media-secondary, .faq-card, .intro-panel {
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  transform: translateZ(0);
}

/* 移动端平滑滚动与防抖 */
.table-wrapper, .table-container, .code-box, pre {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

/* 媒体图片防溢出与自适应 */
img, svg, video, canvas {
  max-width: 100%;
  height: auto;
  display: block;
}

/* 消除点击高亮延迟 */
a, button, input, select, textarea {
  -webkit-tap-highlight-color: transparent;
}


:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #667085;
  --line: #e4e7ec;
  --blue: #1a73e8;
  --green: #0f9d58;
  --yellow: #fbbc04;
  --red: #ea4335;
  --soft-blue: #eef4ff;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.68;
}
a { color: var(--blue); text-decoration: none; font-weight: 700; }
a:hover { text-decoration: underline; }
.container { width: min(1120px, calc(100% - 40px)); margin: 0 auto; }
.notice { background: #fff8e1; color: #76520b; border-bottom: 1px solid #f1d18a; padding: 10px 0; font-size: 13px; }
.site-header { background: #fff; border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 20; }
.header-inner { min-height: 66px; display: flex; justify-content: space-between; align-items: center; gap: 20px; }
.brand { color: var(--text); font-size: 21px; font-weight: 950; letter-spacing: -0.03em; }
.brand::before { content: "G"; color: var(--blue); margin-right: 8px; font-weight: 950; }
.nav, .footer-links { display: flex; flex-wrap: wrap; gap: 10px; }
.nav a, .footer-links a { color: var(--muted); padding: 7px 10px; border-radius: 999px; font-size: 14px; }
.nav a:hover, .footer-links a:hover { background: var(--soft-blue); color: var(--blue); text-decoration: none; }
.hero { padding: 48px 0 28px; border-bottom: 1px solid var(--line); }
.eyebrow { display: inline-flex; padding: 5px 11px; border-radius: 999px; background: var(--soft-blue); color: var(--blue); font-size: 13px; font-weight: 900; margin-bottom: 16px; }
.hero h1 { max-width: 880px; font-size: clamp(34px, 5.3vw, 66px); line-height: 1.06; letter-spacing: -0.06em; margin-bottom: 18px; }
.hero p { max-width: 820px; color: var(--muted); font-size: 18px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-width: 178px; padding: 12px 18px; border-radius: 999px; border: 1px solid var(--line); font-weight: 900; background: #fff; }
.button.primary { background: var(--blue); color: #fff; border-color: var(--blue); }
.button.secondary { color: var(--blue); }
.serp-box { margin-top: 26px; display: grid; gap: 12px; max-width: 920px; }
.answer-card, .summary-card { background: var(--card); border: 1px solid var(--line); border-radius: 18px; padding: 18px; box-shadow: 0 12px 26px rgba(16,24,40,.06); }
.answer-card { border-left: 5px solid var(--blue); }
.answer-card strong { color: var(--text); display: block; margin-bottom: 6px; font-size: 18px; }
.answer-card p, .summary-card p { color: var(--muted); }
.summary-card .url { color: var(--green); font-size: 13px; margin-bottom: 4px; }
.summary-card h3 { color: var(--blue); margin-bottom: 6px; font-size: 20px; }
.quick-answer-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 12px; }
.quick-answer { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: 14px; color: var(--muted); }
.quick-answer strong { display: block; color: var(--text); margin-bottom: 4px; }
.section { padding: 42px 0; }
.section-head { display: flex; justify-content: space-between; align-items: end; gap: 24px; margin-bottom: 20px; }
.section h2 { font-size: clamp(28px, 4vw, 44px); line-height: 1.08; letter-spacing: -0.05em; }
.section-note { max-width: 450px; color: var(--muted); }
.grid-6 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.card, .intro-box, .article { background: var(--card); border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 12px 26px rgba(16,24,40,.05); }
.card { min-height: 196px; padding: 22px; }
.card .num { display: inline-flex; padding: 4px 9px; border-radius: 999px; background: var(--soft-blue); color: var(--blue); font-weight: 900; font-size: 12px; margin-bottom: 28px; }
.card h3 { font-size: 21px; margin-bottom: 8px; }
.card p, .intro-box p, .intro-box li, td { color: var(--muted); }
.card strong, td strong { color: var(--green); }
.intro-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.intro-box { padding: 26px; }
.intro-box h3 { font-size: 26px; margin-bottom: 12px; }
.intro-box ul { margin: 14px 0 0 20px; }
.table-wrap { overflow-x: auto; background: #fff; border: 1px solid var(--line); border-radius: 18px; }
table { width: 100%; min-width: 760px; border-collapse: collapse; }
th, td { padding: 16px 18px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
th { background: #f2f4f7; color: #344054; font-size: 13px; }
tr:last-child td { border-bottom: 0; }
.faq-list { display: grid; gap: 12px; }
details { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 18px; }
summary { cursor: pointer; list-style: none; font-weight: 900; }
summary::-webkit-details-marker { display: none; }
details p { margin-top: 10px; color: var(--muted); }
.article { max-width: 880px; margin: 40px auto; padding: 36px; }
.article h1 { font-size: clamp(34px, 5vw, 60px); line-height: 1.06; letter-spacing: -0.05em; margin-bottom: 20px; }
.article h2 { font-size: 28px; margin: 34px 0 12px; border-top: 1px solid var(--line); padding-top: 20px; }
.article p, .article li { color: var(--muted); margin-bottom: 12px; }
.article ul { margin-left: 20px; }
.site-footer { margin-top: 40px; padding: 34px 0; background: #fff; border-top: 1px solid var(--line); }
.site-footer p { margin-top: 14px; color: var(--muted); font-size: 14px; }
@media (max-width: 820px) {
  .header-inner { align-items: flex-start; flex-direction: column; padding: 16px 0; }
  .quick-answer-grid, .grid-6, .intro-grid { grid-template-columns: 1fr; }
  .section-head { display: block; }
  .section-note { margin-top: 10px; }
}