/* ============================================================
   Google AI Overview GEO Optimization — English Version
   CSS: ai-overview-optimization.css
   Theme: Google brand colors (Blue, Purple, Yellow, Red, Green)
   Base: Pure white / light warm gray, dark gray text, CTA #991B2D
   Font: Inter (English)
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

/* ── CSS Variables ── */
:root {
  --aio-bg:          #FFFFFF;
  --aio-bg-alt:      #F8F8F8;
  --aio-bg-dark:     #0D0D0D;
  --aio-text:        #1A1A1A;
  --aio-text-sub:    #555555;
  --aio-text-light:  #888888;
  --aio-border:      #E5E5E5;
  --aio-cta:         #991B2D;
  --aio-cta-hover:   #7A1524;
  /* Google brand colors */
  --aio-blue:        #4285F4;
  --aio-purple:      #8B5CF6;
  --aio-yellow:      #FBBC04;
  --aio-red:         #EA4335;
  --aio-green:       #34A853;
  /* Soft tints */
  --aio-blue-tint:   #EBF2FF;
  --aio-purple-tint: #F3EEFF;
  --aio-yellow-tint: #FFFBEA;
  --aio-red-tint:    #FFF0EE;
  --aio-green-tint:  #EDFAF1;
  /* Gradient */
  --aio-grad:        linear-gradient(135deg, #4285F4 0%, #8B5CF6 100%);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--aio-bg);
  color: var(--aio-text);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

/* ── Buttons ── */
.aio-btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--aio-cta);
  color: #fff;
  padding: 14px 28px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
  transition: background 0.2s, transform 0.15s;
}
.aio-btn-primary:hover { background: var(--aio-cta-hover); transform: translateY(-1px); }
.aio-btn-primary:active { transform: scale(0.97); }

.aio-btn-secondary {
  display: inline-flex; align-items: center; gap: 8px;
  background: transparent;
  color: var(--aio-text);
  padding: 14px 28px;
  border-radius: 8px;
  border: 1.5px solid var(--aio-border);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: border-color 0.2s, background 0.2s;
}
.aio-btn-secondary:hover { border-color: var(--aio-text); background: var(--aio-bg-alt); }

.aio-btn-light {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(255,255,255,0.12);
  color: #fff;
  padding: 14px 28px;
  border-radius: 8px;
  border: 1.5px solid rgba(255,255,255,0.3);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: background 0.2s;
}
.aio-btn-light:hover { background: rgba(255,255,255,0.2); }

/* ── Hero ── */
.aio-hero {
  padding: 120px 48px 80px;
  background: var(--aio-bg);
  min-height: 100vh;
  display: flex;
  align-items: center;
}
.aio-hero-inner {
  max-width: 1280px;
  margin: 0 auto;
  width: 100%;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.aio-hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--aio-bg-alt);
  border: 1px solid var(--aio-border);
  border-radius: 100px;
  padding: 6px 16px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--aio-text-sub);
  margin-bottom: 24px;
}
.aio-hero-badge img { width: 18px; height: 18px; object-fit: contain; }

.aio-hero-title {
  font-size: clamp(2rem, 3.5vw, 3.2rem);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.03em;
  color: var(--aio-text);
  margin-bottom: 20px;
}
.aio-hero-title .highlight {
  background: var(--aio-grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.aio-hero-desc {
  font-size: 1rem;
  color: var(--aio-text-sub);
  line-height: 1.75;
  margin-bottom: 28px;
  max-width: 520px;
}

.aio-hero-features {
  list-style: none;
  margin-bottom: 36px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.aio-hero-features li {
  display: flex; align-items: center; gap: 10px;
  font-size: 0.92rem; color: var(--aio-text-sub);
}
.aio-hero-features li::before {
  content: '';
  width: 20px; height: 20px; flex-shrink: 0;
  background: var(--aio-cta);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M5 13l4 4L19 7'/%3E%3C/svg%3E");
  background-size: 12px;
  background-repeat: no-repeat;
  background-position: center;
}

.aio-hero-actions {
  display: flex; gap: 16px; flex-wrap: wrap;
}

/* Hero Chat Column */
.aio-hero-chat-col {
  background: var(--aio-bg-alt);
  border-radius: 20px;
  padding: 8px;
  box-shadow: 0 8px 48px rgba(66,133,244,0.1), 0 2px 12px rgba(0,0,0,0.06);
}
.aio-chat-window {
  background: #fff;
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--aio-border);
}
.aio-chat-header {
  background: #0D0D0D;
  padding: 16px 20px;
  display: flex; align-items: center; gap: 12px;
}
.aio-chat-header-logo {
  width: 36px; height: 36px; object-fit: contain;
  background: #fff; border-radius: 8px; padding: 4px;
}
.aio-chat-header-title {
  font-size: 0.95rem; font-weight: 700; color: #fff;
}
.aio-chat-header-sub {
  font-size: 0.75rem; color: rgba(255,255,255,0.5);
}

.aio-chat-search {
  padding: 12px 16px;
  background: #F8F9FA;
  border-bottom: 1px solid var(--aio-border);
  display: flex; align-items: center; gap: 10px;
}
.aio-chat-search-input {
  flex: 1;
  font-size: 0.88rem;
  color: var(--aio-text);
  background: #fff;
  border: 1px solid var(--aio-border);
  border-radius: 24px;
  padding: 8px 16px;
}
.aio-chat-search-icon {
  width: 32px; height: 32px;
  background: var(--aio-blue);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.aio-chat-search-icon svg { width: 16px; height: 16px; }

.aio-chat-body { padding: 16px; }

.aio-chat-overview-box {
  background: linear-gradient(135deg, #EBF2FF 0%, #F3EEFF 100%);
  border: 1px solid rgba(66,133,244,0.2);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 12px;
}
.aio-chat-overview-label {
  display: flex; align-items: center; gap: 6px;
  font-size: 0.78rem; font-weight: 700;
  color: var(--aio-blue);
  margin-bottom: 10px;
  letter-spacing: 0.04em;
}
.sparkle {
  width: 14px; height: 14px;
  background: var(--aio-grad);
  border-radius: 3px;
  clip-path: polygon(50% 0%, 61% 35%, 98% 35%, 68% 57%, 79% 91%, 50% 70%, 21% 91%, 32% 57%, 2% 35%, 39% 35%);
}
.aio-chat-overview-text {
  font-size: 0.85rem; color: var(--aio-text); line-height: 1.65;
}
.aio-chat-sources {
  display: flex; gap: 6px; flex-wrap: wrap; margin-top: 10px;
}
.aio-chat-source-chip {
  display: flex; align-items: center; gap: 4px;
  background: #fff;
  border: 1px solid var(--aio-border);
  border-radius: 100px;
  padding: 3px 10px;
  font-size: 0.75rem; color: var(--aio-text-sub);
}
.aio-chat-source-chip .num {
  width: 16px; height: 16px;
  background: var(--aio-blue);
  color: #fff;
  border-radius: 50%;
  font-size: 0.65rem; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}

.aio-chat-organic { display: flex; flex-direction: column; gap: 8px; }
.aio-chat-organic-item {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 12px;
  background: var(--aio-bg-alt);
  border-radius: 8px;
  border: 1px solid var(--aio-border);
}
.aio-chat-organic-dot {
  width: 8px; height: 8px; border-radius: 50%; flex-shrink: 0;
}
.aio-chat-organic-text {
  font-size: 0.8rem; color: var(--aio-text-sub);
}
.aio-chat-organic-text span { color: var(--aio-blue); font-weight: 600; }

/* ── Stats Band ── */
.aio-stats-band {
  background: var(--aio-bg-dark);
  padding: 48px;
}
.aio-stats-grid {
  max-width: 1280px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(4, 1fr);
  gap: 0;
}
.aio-stat-item {
  text-align: center;
  padding: 24px 32px;
  border-right: 1px solid rgba(255,255,255,0.08);
}
.aio-stat-item:last-child { border-right: none; }
.aio-stat-num {
  font-size: 2.4rem; font-weight: 900; line-height: 1;
  margin-bottom: 10px; letter-spacing: -0.03em;
}
.aio-stat-num.blue  { color: var(--aio-blue); }
.aio-stat-num.purple{ color: var(--aio-purple); }
.aio-stat-num.yellow{ color: var(--aio-yellow); }
.aio-stat-num.green { color: var(--aio-green); }
.aio-stat-num.red   { color: var(--aio-red); }
.aio-stat-label {
  font-size: 0.82rem; color: rgba(255,255,255,0.55); line-height: 1.5;
}

/* ── Section Base ── */
.aio-section { padding: 96px 48px; background: var(--aio-bg); }
.aio-section-alt { background: var(--aio-bg-alt); }
.aio-container { max-width: 1280px; margin: 0 auto; }

.aio-label {
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.12em;
  color: var(--aio-cta); text-transform: uppercase;
  margin-bottom: 12px;
}
.aio-heading {
  font-size: clamp(1.6rem, 2.8vw, 2.6rem);
  font-weight: 800; line-height: 1.22;
  letter-spacing: -0.025em;
  color: var(--aio-text);
  margin-bottom: 16px;
}
.aio-heading .grad {
  background: var(--aio-grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.aio-subheading {
  font-size: 1rem; color: var(--aio-text-sub);
  line-height: 1.75; max-width: 720px;
  margin-bottom: 56px;
}

/* ── Definition Layout ── */
.aio-def-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: stretch;
}
.aio-def-table-wrap {
  display: flex; flex-direction: column;
  height: 100%;
}
.aio-def-table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--aio-border);
  border-radius: 12px;
  overflow: hidden;
  flex: 1;
}
.aio-def-table thead tr {
  background: var(--aio-bg-dark);
}
.aio-def-table thead th {
  padding: 16px 20px;
  font-size: 0.78rem; font-weight: 700;
  color: rgba(255,255,255,0.8);
  text-align: left; letter-spacing: 0.06em;
  text-transform: uppercase;
}
.aio-def-table thead th:last-child { color: var(--aio-yellow); }
.aio-def-table tbody tr {
  border-bottom: 1px solid var(--aio-border);
  transition: background 0.15s;
}
.aio-def-table tbody tr:last-child { border-bottom: none; }
.aio-def-table tbody tr:hover { background: var(--aio-blue-tint); }
.aio-def-table tbody td {
  padding: 18px 20px;
  font-size: 0.88rem; color: var(--aio-text-sub);
  vertical-align: top;
}
.aio-def-table tbody td:first-child {
  font-weight: 600; color: var(--aio-text);
  white-space: nowrap;
}
.aio-def-table tbody td:last-child { color: var(--aio-text); }
.aio-def-table tbody td strong { color: var(--aio-text); font-weight: 700; }

.aio-def-boxes {
  display: flex; flex-direction: column; gap: 16px;
}
.aio-def-box {
  background: var(--aio-bg);
  border: 1px solid var(--aio-border);
  border-radius: 12px;
  padding: 24px;
  flex: 1;
  transition: box-shadow 0.2s, border-color 0.2s;
}
.aio-def-box:hover {
  box-shadow: 0 4px 20px rgba(66,133,244,0.08);
  border-color: rgba(66,133,244,0.3);
}
.aio-def-box-title {
  font-size: 0.92rem; font-weight: 700; color: var(--aio-text);
  margin-bottom: 10px;
}
.aio-def-box-text {
  font-size: 0.85rem; color: var(--aio-text-sub); line-height: 1.7;
}

/* ── Services Layout ── */
.aio-services-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}
.aio-service-list { display: flex; flex-direction: column; gap: 0; }
.aio-service-item {
  display: flex; gap: 16px;
  padding: 24px 0;
  border-bottom: 1px solid var(--aio-border);
}
.aio-service-item:last-child { border-bottom: none; }
.aio-service-icon {
  width: 44px; height: 44px; flex-shrink: 0;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem;
}
.aio-service-icon.blue   { background: var(--aio-blue-tint); }
.aio-service-icon.purple { background: var(--aio-purple-tint); }
.aio-service-icon.yellow { background: var(--aio-yellow-tint); }
.aio-service-icon.red    { background: var(--aio-red-tint); }
.aio-service-icon.green  { background: var(--aio-green-tint); }

.aio-service-content { flex: 1; }
.aio-service-title {
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  font-size: 0.95rem; font-weight: 700; color: var(--aio-text);
  margin-bottom: 6px;
}
.aio-service-tag {
  font-size: 0.68rem; font-weight: 700; letter-spacing: 0.06em;
  padding: 2px 8px; border-radius: 4px;
  text-transform: uppercase;
}
.aio-service-tag.blue   { background: var(--aio-blue-tint);   color: var(--aio-blue); }
.aio-service-tag.purple { background: var(--aio-purple-tint); color: var(--aio-purple); }
.aio-service-tag.yellow { background: var(--aio-yellow-tint); color: #B45309; }
.aio-service-tag.red    { background: var(--aio-red-tint);    color: var(--aio-red); }
.aio-service-tag.green  { background: var(--aio-green-tint);  color: var(--aio-green); }

.aio-service-desc {
  font-size: 0.85rem; color: var(--aio-text-sub); line-height: 1.7;
}

.aio-sticky-img-wrap {
  position: sticky; top: 88px;
}
.aio-sticky-img-wrap img {
  width: 100%; border-radius: 16px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.1);
  object-fit: cover;
}

/* ── Process Section ── */
.aio-process-steps-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
  margin-bottom: 48px;
}
.aio-process-step {
  background: #fff;
  border: 1px solid var(--aio-border);
  border-radius: 14px;
  padding: 24px 18px;
  text-align: center;
  transition: box-shadow 0.2s, transform 0.2s;
}
.aio-process-step:hover {
  box-shadow: 0 6px 24px rgba(66,133,244,0.1);
  transform: translateY(-3px);
}
.aio-process-num {
  width: 40px; height: 40px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem; font-weight: 800; color: #fff;
  margin: 0 auto 14px;
}
.aio-process-num.n1 { background: var(--aio-blue); }
.aio-process-num.n2 { background: var(--aio-purple); }
.aio-process-num.n3 { background: #A78BFA; }
.aio-process-num.n4 { background: var(--aio-yellow); color: #1A1A1A; }
.aio-process-num.n5 { background: var(--aio-green); }

.aio-process-step-title {
  font-size: 0.88rem; font-weight: 700; color: var(--aio-text);
  margin-bottom: 8px; line-height: 1.4;
}
.aio-process-step-desc {
  font-size: 0.78rem; color: var(--aio-text-sub); line-height: 1.6;
}

.aio-process-img-block {
  border-radius: 16px; overflow: hidden;
  box-shadow: 0 8px 40px rgba(0,0,0,0.08);
}
.aio-process-img-block img {
  width: 100%; display: block;
  object-fit: cover;
}

/* ── Why Us Layout ── */
.aio-whyus-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: stretch;
}
.aio-whyus-img-col {
  border-radius: 16px; overflow: hidden;
  box-shadow: 0 8px 40px rgba(0,0,0,0.1);
  display: flex; align-items: stretch;
}
.aio-whyus-img-col img {
  width: 100%; height: 100%;
  object-fit: contain;
  background: var(--aio-bg-alt);
  padding: 12px;
}
.aio-whyus-content { display: flex; flex-direction: column; justify-content: center; }
.aio-whyus-list { display: flex; flex-direction: column; gap: 28px; }
.aio-whyus-item { display: flex; gap: 16px; }
.aio-whyus-icon {
  width: 44px; height: 44px; flex-shrink: 0;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem;
}
.aio-whyus-icon.blue   { background: var(--aio-blue-tint); }
.aio-whyus-icon.purple { background: var(--aio-purple-tint); }
.aio-whyus-icon.yellow { background: var(--aio-yellow-tint); }
.aio-whyus-icon.red    { background: var(--aio-red-tint); }

.aio-whyus-item-title {
  font-size: 0.95rem; font-weight: 700; color: var(--aio-text);
  margin-bottom: 6px;
}
.aio-whyus-item-desc {
  font-size: 0.85rem; color: var(--aio-text-sub); line-height: 1.7;
}

/* ── FAQ Layout ── */
.aio-faq-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}
.aio-faq-list { display: flex; flex-direction: column; gap: 0; }
.aio-faq-item {
  border-bottom: 1px solid var(--aio-border);
}
.aio-faq-item:first-child { border-top: 1px solid var(--aio-border); }
.aio-faq-question {
  width: 100%; background: none; border: none; cursor: pointer;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 20px 0;
  text-align: left;
}
.aio-faq-question-text {
  font-size: 0.92rem; font-weight: 600; color: var(--aio-text); line-height: 1.5;
}
.aio-faq-chevron {
  width: 18px; height: 18px; flex-shrink: 0;
  color: var(--aio-text-sub);
  transition: transform 0.25s cubic-bezier(0.23,1,0.32,1);
}
.aio-faq-item.open .aio-faq-chevron { transform: rotate(180deg); }
.aio-faq-answer {
  max-height: 0; overflow: hidden;
  transition: max-height 0.35s cubic-bezier(0.23,1,0.32,1);
}
.aio-faq-item.open .aio-faq-answer { max-height: 300px; }
.aio-faq-answer-inner {
  font-size: 0.88rem; color: var(--aio-text-sub);
  line-height: 1.75; padding-bottom: 20px;
}

.aio-faq-right {
  position: sticky; top: 88px;
  display: flex; flex-direction: column; gap: 20px;
}
.aio-faq-img {
  width: 100%; border-radius: 16px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.08);
  object-fit: contain;
  background: var(--aio-bg-alt);
  padding: 16px;
}
.aio-faq-cta-inline {
  background: var(--aio-bg-alt);
  border: 1px solid var(--aio-border);
  border-radius: 14px;
  padding: 24px;
}
.aio-faq-cta-inline h4 {
  font-size: 0.95rem; font-weight: 700; color: var(--aio-text);
  margin-bottom: 8px;
}
.aio-faq-cta-inline p {
  font-size: 0.83rem; color: var(--aio-text-sub); line-height: 1.65;
  margin-bottom: 16px;
}

/* ── Bottom CTA ── */
.aio-bottom-cta {
  background: var(--aio-bg-dark);
  padding: 96px 48px;
  position: relative; overflow: hidden;
}
.aio-bottom-cta::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 60% 80% at 50% 50%, rgba(66,133,244,0.12) 0%, transparent 70%);
  pointer-events: none;
}
.aio-bottom-cta-inner {
  max-width: 720px; margin: 0 auto;
  text-align: center; position: relative; z-index: 1;
}
.aio-bottom-cta-inner h2 {
  font-size: clamp(1.8rem, 3vw, 2.8rem);
  font-weight: 900; line-height: 1.22;
  letter-spacing: -0.03em;
  color: #fff; margin-bottom: 20px;
}
.aio-bottom-cta-inner h2 span {
  background: var(--aio-grad);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.aio-bottom-cta-inner p {
  font-size: 1rem; color: rgba(255,255,255,0.6);
  line-height: 1.75; margin-bottom: 36px;
}
.aio-bottom-cta-actions {
  display: flex; gap: 16px; justify-content: center; flex-wrap: wrap;
}

/* ── Responsive ── */
@media (max-width: 1024px) {
  .aio-hero-inner,
  .aio-def-layout,
  .aio-services-layout,
  .aio-whyus-layout,
  .aio-faq-layout { grid-template-columns: 1fr; }
  .aio-hero { padding: 100px 24px 60px; min-height: auto; }
  .aio-process-steps-grid { grid-template-columns: repeat(3, 1fr); }
  .aio-sticky-img-wrap { position: static; }
  .aio-faq-right { position: static; }
  .aio-whyus-img-col { max-height: 400px; }
}
@media (max-width: 768px) {
  .aio-section { padding: 64px 24px; }
  .aio-stats-grid { grid-template-columns: repeat(2, 1fr); }
  .aio-process-steps-grid { grid-template-columns: repeat(2, 1fr); }
  .aio-bottom-cta { padding: 64px 24px; }
}
@media (max-width: 480px) {
  .aio-stats-grid { grid-template-columns: 1fr 1fr; }
  .aio-process-steps-grid { grid-template-columns: 1fr 1fr; }
  .aio-hero-actions { flex-direction: column; }
  .aio-bottom-cta-actions { flex-direction: column; align-items: center; }
}


/* ------------------------------------------------------------
   以下自 ai-overview-optimization.html 的内联 <style> 外移
   ------------------------------------------------------------ */
/* 布局顶部固定导航条 (#navbar) 浮于内容之上，给首屏额外留出顶部间距，避免遮挡 hero 内容 */
.aio-hero { padding-top: 140px; }
@media (max-width: 768px) { .aio-hero { padding-top: 112px; } }

/* 布局的一级导航链接带 .text-white，但导航条底色是白色 */
#navbar .text-white { color: #000000; }
#navbar a.bg-primary { color: #ffffff !important; }