:root {
  /* 近似 OpenClaw docs 的浅色配色 */
  --bg: #f9fafb;
  --bg-alt: #f3f4f6;
  --bg-card: #ffffff;
  --text: #111827;
  --text-muted: #6b7280;
  /* OpenClaw logo 近似橙色 */
  --accent: #f97316;
  --accent-soft: rgba(249, 115, 22, 0.08);
  --border-subtle: rgba(209, 213, 219, 1);
  --radius-lg: 14px;
  --radius-md: 10px;
  --shadow-soft: 0 18px 45px rgba(15, 23, 42, 0.08);
  --shadow-light: 0 10px 30px rgba(15, 23, 42, 0.06);
}

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

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.oa2a-container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

.oa2a-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(18px);
  background: rgba(249, 250, 251, 0.92);
  border-bottom: 1px solid rgba(229, 231, 235, 1);
}

.oa2a-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.oa2a-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.oa2a-logo-img {
  display: block;
  /* 根据视口宽度自适应，限制最小/最大值 */
  height: clamp(28px, 3vw, 40px);
}

.oa2a-nav {
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: 14px;
}

.oa2a-nav a {
  color: var(--text-muted);
}

.oa2a-nav a:hover {
  color: var(--accent);
  text-decoration: none;
}

.oa2a-section {
  padding: 72px 0;
}

.oa2a-section-alt {
  background: var(--bg-alt);
}

.oa2a-hero {
  padding-top: 72px;
  padding-bottom: 64px;
}

.oa2a-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2.7fr);
  gap: 56px;
  align-items: center;
}

.oa2a-hero-text h1 {
  font-size: 34px;
  line-height: 1.16;
  margin: 0 0 16px;
}

.oa2a-hero-subtitle {
  margin: 0 0 18px;
  font-size: 15px;
  color: var(--text-muted);
}

.oa2a-hero-bullets {
  margin: 0 0 22px;
  padding-left: 18px;
  font-size: 14px;
  color: var(--text-muted);
}

.oa2a-hero-bullets li + li {
  margin-top: 4px;
}

.oa2a-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.oa2a-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 9px 18px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid transparent;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s ease-out;
}

.oa2a-btn-primary {
  background: linear-gradient(135deg, #fb923c, #f97316);
  color: #7c2d12;
  box-shadow: 0 14px 30px rgba(248, 113, 22, 0.35);
}

.oa2a-btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 40px rgba(248, 113, 22, 0.45);
  text-decoration: none;
}

.oa2a-btn-secondary {
  border-color: rgba(209, 213, 219, 1);
  color: var(--text-muted);
  background: #ffffff;
}

.oa2a-btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.oa2a-hero-diagram {
  display: flex;
  justify-content: center;
}

.oa2a-diagram-card {
  width: 100%;
  max-width: 380px;
  border-radius: var(--radius-lg);
  padding: 18px 18px 16px;
  background: radial-gradient(circle at top, #f9fafb, #e5e7eb);
  border: 1px solid rgba(209, 213, 219, 1);
  box-shadow: var(--shadow-soft);
  display: grid;
  grid-template-columns: 1.1fr 1.3fr 1.2fr;
  gap: 10px;
  font-size: 11px;
}

.oa2a-diagram-col {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: stretch;
}

.oa2a-diagram-center {
  align-items: center;
}

.oa2a-diagram-stack {
  margin-top: 6px;
  padding: 8px 10px;
  border-radius: 10px;
  background: #f9fafb;
  border: 1px solid rgba(209, 213, 219, 1);
  display: flex;
  flex-direction: column;
  gap: 3px;
  text-align: center;
  color: var(--text-muted);
}

.oa2a-pill {
  padding: 6px 8px;
  border-radius: 999px;
  border: 1px solid rgba(209, 213, 219, 1);
  background: #ffffff;
  text-align: center;
  color: var(--text-muted);
}

.oa2a-pill-consumer {
  background: linear-gradient(135deg, rgba(248, 113, 22, 0.12), rgba(254, 215, 170, 0.9));
  border-color: rgba(248, 113, 22, 0.6);
}

.oa2a-pill-core {
  background: radial-gradient(circle at 30% 10%, rgba(248, 113, 22, 0.18), #fff7ed);
  border-color: rgba(248, 113, 22, 0.75);
}

.oa2a-pill-runtime {
  border-style: dashed;
  border-color: rgba(248, 250, 252, 0.35);
}

.oa2a-section h2 {
  font-size: 24px;
  margin: 0 0 8px;
}

.oa2a-section-lead {
  margin: 0 0 24px;
  font-size: 14px;
  color: var(--text-muted);
}

.oa2a-how-grid {
  align-items: center;
}

.oa2a-how-text {
  padding-right: 12px;
}

.oa2a-how-diagram {
  display: flex;
  flex-direction: column;
  gap: 10px;
  position: relative;
}

.oa2a-how-card {
  position: relative;
  border-radius: 12px;
  padding: 10px 12px;
  background: #f3f4f6;
  border: 1px solid rgba(209, 213, 219, 1);
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.06);
  font-size: 12px;
}

.oa2a-how-card-top {
  transform: translateY(0);
}

.oa2a-how-card-middle {
  transform: translateY(4px);
}

.oa2a-how-card-bottom {
  transform: translateY(8px);
}

.oa2a-how-label {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 4px;
  color: #111827;
}

.oa2a-how-card ul {
  margin: 0;
  padding-left: 16px;
  color: #4b5563;
}

.oa2a-grid {
  display: grid;
  gap: 20px;
}

.oa2a-grid-2 {
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1.5fr);
}

.oa2a-grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.oa2a-card {
  border-radius: var(--radius-lg);
  padding: 18px 18px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-light);
  font-size: 14px;
}

.oa2a-card h3 {
  margin: 0 0 8px;
  font-size: 16px;
}

.oa2a-card p {
  margin: 0 0 10px;
  color: var(--text-muted);
}

.oa2a-card ul {
  margin: 0;
  padding-left: 16px;
  color: var(--text-muted);
}

.oa2a-ascii {
  margin: 0;
  padding: 14px 16px;
  border-radius: var(--radius-md);
  background: #e5e7eb;
  border: 1px solid rgba(209, 213, 219, 1);
  font-size: 11px;
  color: #374151;
  overflow-x: auto;
}

.oa2a-link {
  font-size: 13px;
  color: var(--accent);
}

.oa2a-link:hover {
  text-decoration: underline;
}

.oa2a-links-row {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 13px;
}

.oa2a-footer {
  border-top: 1px solid rgba(229, 231, 235, 1);
  padding: 18px 0 24px;
  background: #f9fafb;
}

.oa2a-footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-muted);
}

.oa2a-footer-links {
  display: flex;
  gap: 14px;
}

pre code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
  font-size: 11px;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
    "Courier New", monospace;
  font-size: 12px;
  background: #e5e7eb;
  padding: 1px 4px;
  border-radius: 4px;
}

@media (max-width: 900px) {
  .oa2a-hero-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .oa2a-grid-3 {
    grid-template-columns: minmax(0, 1fr);
  }

  .oa2a-grid-2 {
    grid-template-columns: minmax(0, 1fr);
  }

  .oa2a-header-inner {
    gap: 10px;
  }

  .oa2a-nav {
    gap: 10px;
    font-size: 12px;
    flex-wrap: wrap;
    justify-content: flex-end;
  }
}