/* MCP Training System — GitHub Pages（surface 层级 + 双 accent + 流程区块） */

:root {
  color-scheme: dark;
  --surface-0: #09090b;
  --surface-1: #14141a;
  --surface-2: #1f1f27;
  --surface-3: #2a2a35;
  --text-primary: #fafafa;
  --text-secondary: #a1a1aa;
  --text-tertiary: #71717a;
  --border: #3f3f46;
  --border-strong: #52525b;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --accent-muted: rgba(99, 102, 241, 0.18);
  --accent-2: #c084fc;
  --accent-2-muted: rgba(192, 132, 252, 0.14);
  --success: #22c55e;
  --success-muted: rgba(34, 197, 94, 0.14);
  --cyan: #22d3ee;
  --cyan-muted: rgba(34, 211, 238, 0.12);
  --grid-line: rgba(255, 255, 255, 0.045);
  --glow-hero: rgba(99, 102, 241, 0.14);
  --shadow-card: none;
  --shadow-shot-light: none;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --bg: var(--surface-0);
  --bg-elevated: var(--surface-1);
  --bg-muted: var(--surface-2);
  --text: var(--text-primary);
}

[data-theme="light"] {
  color-scheme: light;
  --surface-0: #fafafa;
  --surface-1: #ffffff;
  --surface-2: #f4f4f5;
  --surface-3: #e4e4e7;
  --text-primary: #18181b;
  --text-secondary: #52525b;
  --text-tertiary: #71717a;
  --border: #e4e4e7;
  --border-strong: #d4d4d8;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-muted: rgba(79, 70, 229, 0.1);
  --accent-2: #9333ea;
  --accent-2-muted: rgba(147, 51, 234, 0.1);
  --success: #16a34a;
  --success-muted: rgba(22, 163, 74, 0.1);
  --cyan: #0891b2;
  --cyan-muted: rgba(8, 145, 178, 0.1);
  --grid-line: rgba(24, 24, 27, 0.07);
  --glow-hero: rgba(79, 70, 229, 0.08);
  --shadow-card: 0 1px 2px rgba(24, 24, 27, 0.05);
  --shadow-shot-light: 0 1px 3px rgba(24, 24, 27, 0.08);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 76px;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--surface-0);
  transition: background-color 0.25s ease, color 0.2s ease;
}

.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: 0;
}

.container {
  position: relative;
  z-index: 1;
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
}

/* —— 顶栏 —— */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--surface-1);
  border-bottom: 1px solid var(--border);
  transition:
    background-color 0.2s ease,
    border-color 0.2s ease,
    box-shadow 0.2s ease;
}

.topbar.is-scrolled {
  background: var(--surface-1);
  border-bottom-color: var(--border-strong);
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.06);
}

[data-theme="dark"] .topbar.is-scrolled {
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.35);
}

.topbar-inner {
  display: flex;
  align-items: center;
  padding: 12px 0;
  gap: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand-mark {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-muted);
  border: 1px solid var(--border);
  color: var(--accent);
  font-weight: 800;
  font-size: 13px;
  letter-spacing: 0.02em;
}

.brand-mark .brand-svg {
  display: block;
}

.brand-title {
  font-weight: 800;
  font-size: 15px;
  line-height: 1.2;
  color: var(--text-primary);
}

.brand-subtitle {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 220px;
}

.topnav {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
}

.topnav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: color 0.15s ease, background 0.15s ease;
}

.topnav-link:hover {
  color: var(--text-primary);
  background: var(--surface-2);
}

.topnav-cta {
  color: var(--text-primary);
  background: var(--surface-2);
  border: 1px solid var(--border);
}

.topnav-cta:hover {
  background: var(--accent-muted);
  border-color: var(--accent);
  color: var(--accent);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  flex-shrink: 0;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  color: var(--text-primary);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.theme-toggle:hover {
  border-color: var(--accent);
  background: var(--accent-muted);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

/* —— 动效 —— */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition:
    opacity 0.65s cubic-bezier(0.22, 1, 0.36, 1),
    transform 0.65s cubic-bezier(0.22, 1, 0.36, 1);
  transition-delay: var(--reveal-delay, 0s);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* —— Hero —— */
.hero {
  position: relative;
  padding: 56px 0 48px;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  right: -15%;
  top: -25%;
  width: min(70vw, 520px);
  height: min(55vh, 420px);
  background: radial-gradient(ellipse at center, var(--glow-hero) 0%, transparent 68%);
  pointer-events: none;
  z-index: 0;
}

.hero .container {
  z-index: 1;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  gap: 40px;
  align-items: start;
}

.eyebrow {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: 12px;
}

.hero-title {
  margin: 0;
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.15;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.hero-desc {
  margin: 16px 0 24px;
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.75;
  max-width: 36em;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 700;
  font-size: 14px;
  border: 1px solid transparent;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

[data-theme="light"] .btn-primary {
  color: #fff;
}

.btn-ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text-primary);
}

.btn-ghost:hover {
  background: var(--surface-2);
  border-color: var(--text-secondary);
}

.badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 24px;
}

.badge {
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border: 1px solid var(--border);
  background: var(--surface-1);
  color: var(--text-secondary);
}

.badge-accent {
  background: var(--accent-2-muted);
  border-color: var(--accent-2);
  color: var(--accent-2);
}

.badge-success {
  background: var(--success-muted);
  border-color: var(--success);
  color: var(--success);
}

.badge-info {
  background: var(--accent-muted);
  border-color: var(--accent);
  color: var(--accent);
}

.hero-card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: var(--shadow-card);
}

.hero-card-title {
  font-weight: 800;
  font-size: 13px;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
}

.hero-preview {
  position: relative;
  margin-top: 14px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  outline: 1px solid rgba(255, 255, 255, 0.04);
  overflow: hidden;
  background: var(--surface-2);
  box-shadow: var(--shadow-shot-light);
}

.hero-preview::before {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2), var(--cyan));
  opacity: 0.55;
}

[data-theme="light"] .hero-preview {
  outline-color: rgba(24, 24, 27, 0.06);
  box-shadow: var(--shadow-shot-light);
}

.hero-preview-img {
  width: 100%;
  display: block;
  height: auto;
  min-height: 200px;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  vertical-align: middle;
}

.hero-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.tab-pill {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 700;
  font-size: 12px;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface-2);
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.tab-pill:hover {
  color: var(--text-primary);
  border-color: var(--accent);
  background: var(--accent-muted);
}

.tab-pill-cta {
  border-color: var(--accent);
  background: var(--accent-muted);
  color: var(--accent);
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.9em;
  padding: 2px 6px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text-primary);
}

/* —— 区块 —— */
.section {
  padding: 72px 0;
}

.section-alt {
  background: var(--surface-2);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-flow {
  background: var(--surface-0);
}

.section-kicker {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin: 0 0 8px;
}

.section-head {
  margin-bottom: 40px;
  max-width: 680px;
}

.section-title {
  margin: 0;
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
  color: var(--text-primary);
}

.section-desc {
  margin: 12px 0 0;
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.7;
}

/* —— 产品流程 #flow —— */
.flow-steps {
  display: flex;
  flex-wrap: wrap;
  align-items: stretch;
  gap: 0;
  margin-bottom: 28px;
}

.flow-step {
  flex: 1 1 200px;
  min-width: 160px;
  display: flex;
  gap: 14px;
  padding: 18px 16px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
}

.flow-step-num {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 15px;
  color: var(--accent);
  background: var(--accent-muted);
  border: 1px solid var(--border);
}

.flow-step-body {
  min-width: 0;
}

.flow-step-title {
  margin: 0;
  font-size: 15px;
  font-weight: 800;
  color: var(--text-primary);
}

.flow-step-desc {
  margin: 8px 0 0;
  font-size: 13px;
  line-height: 1.65;
  color: var(--text-secondary);
}

.flow-step-ref {
  margin: 10px 0 0;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-tertiary);
}

.flow-step-ref a {
  color: var(--accent);
  text-decoration: none;
}

.flow-step-ref a:hover {
  text-decoration: underline;
}

.flow-connector {
  flex: 0 0 auto;
  width: 24px;
  align-self: center;
  height: 2px;
  background: linear-gradient(90deg, var(--border-strong), var(--accent-2));
  opacity: 0.65;
  border-radius: 1px;
}

@media (max-width: 960px) {
  .flow-connector {
    width: 100%;
    height: 16px;
    margin: 0;
    background: linear-gradient(180deg, var(--border-strong), var(--accent-2));
    opacity: 0.45;
  }
}

.flow-agent-path {
  padding: 16px 18px;
  margin: 0 0 36px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-secondary);
  background: var(--accent-2-muted);
  border: 1px solid var(--accent-2);
  border-radius: var(--radius-md);
}

.flow-agent-path a {
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
}

.flow-agent-path a:hover {
  text-decoration: underline;
}

.flow-subtitle {
  margin: 0 0 12px;
  font-size: 18px;
  font-weight: 800;
  color: var(--text-primary);
}

.flow-lead {
  margin: 0 0 24px;
  max-width: 720px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text-secondary);
}

.role-cards {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin-bottom: 40px;
}

.role-card {
  padding: 18px 16px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  transition: border-color 0.2s ease;
}

.role-card:hover {
  border-color: var(--accent);
}

.role-card-mark {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 14px;
  color: var(--accent-2);
  background: var(--accent-2-muted);
  border: 1px solid var(--border);
  margin-bottom: 12px;
}

.role-card-title {
  font-size: 14px;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.role-card-desc {
  margin: 0;
  font-size: 12px;
  line-height: 1.6;
  color: var(--text-secondary);
}

.entry-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 16px;
}

.entry-col {
  padding: 20px 18px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
}

.entry-col-title {
  font-size: 15px;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 10px;
}

.entry-col-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--text-secondary);
}

.flow-footnote {
  margin: 0;
  font-size: 14px;
  color: var(--text-tertiary);
  line-height: 1.65;
}

/* —— 形象化 SVG 示意图 —— */
.hero-pipeline {
  margin-top: 8px;
  margin-bottom: 4px;
  max-width: 100%;
  overflow: hidden;
}

.hero-pipeline-svg {
  width: 100%;
  max-width: 560px;
  height: auto;
  display: block;
}

.hero-pipeline-caption {
  margin: 10px 0 0;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  letter-spacing: 0.02em;
}

.section-figure {
  margin: 0 0 36px;
  padding: 16px 18px 14px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}

.section-figure-svg {
  width: 100%;
  height: auto;
  display: block;
}

.section-figure-cap {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.55;
  color: var(--text-secondary);
  text-align: center;
}

.flow-schematic {
  margin: 0 0 32px;
  padding: 14px 16px 12px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  overflow-x: auto;
}

.flow-schematic-svg {
  width: min(100%, 720px);
  min-width: 520px;
  height: auto;
  display: block;
  margin: 0 auto;
}

.flow-schematic-cap {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.55;
  color: var(--text-secondary);
  text-align: center;
}

.mcp-hub-wrap {
  margin: -8px 0 20px;
  display: flex;
  justify-content: center;
  padding: 8px 0;
}

.mcp-hub-svg {
  width: 100%;
  max-width: 400px;
  height: auto;
  display: block;
  opacity: 0.95;
}

.entry-col-visual {
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  background: var(--surface-2);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.entry-col-visual svg {
  display: block;
}

.stack-layers {
  margin: 0 0 28px;
  padding: 16px 18px 14px;
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}

.stack-layers-svg {
  width: 100%;
  max-width: 560px;
  height: auto;
  display: block;
  margin: 0 auto;
}

.stack-layers-cap {
  margin: 12px 0 0;
  font-size: 12px;
  font-weight: 600;
  text-align: center;
  color: var(--text-tertiary);
}

.shot::before {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2), var(--cyan));
  opacity: 0.55;
}

@media (max-width: 920px) {
  .role-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .entry-compare {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .role-cards {
    grid-template-columns: 1fr;
  }
}

/* —— 栅格与能力卡 —— */
.grid {
  display: grid;
  gap: 16px;
}

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

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 22px;
  min-height: 150px;
  box-shadow: var(--shadow-card);
  transition: border-color 0.2s ease;
}

.card:hover {
  border-color: var(--accent);
}

.card-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-muted);
  border: 1px solid var(--border);
  font-weight: 800;
  font-size: 14px;
  color: var(--accent);
  margin-bottom: 14px;
}

.card-icon-svg svg {
  display: block;
}

.card-title {
  margin: 0;
  font-size: 16px;
  font-weight: 800;
  line-height: 1.3;
  color: var(--text-primary);
}

.card-desc {
  margin: 10px 0 0;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.65;
}

/* —— 截图导航与卡片 —— */
.shot-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: -12px 0 28px;
}

.shot-nav-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 14px;
  font-size: 12px;
  font-weight: 800;
  color: var(--text-secondary);
  text-decoration: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-1);
  transition:
    color 0.15s ease,
    border-color 0.15s ease,
    background 0.15s ease;
}

.shot-nav-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-muted);
}

.shot-anchor {
  scroll-margin-top: 88px;
}

.shot {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  outline: 1px solid rgba(255, 255, 255, 0.04);
}

[data-theme="light"] .shot {
  outline-color: rgba(24, 24, 27, 0.06);
  box-shadow: var(--shadow-shot-light);
}

.shot-label {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.shot-label-main {
  font-weight: 800;
  font-size: 13px;
  color: var(--text-primary);
}

.shot-label-flow {
  font-size: 12px;
  font-weight: 600;
  color: var(--accent-2);
}

.shot-img {
  width: 100%;
  display: block;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: var(--surface-2);
}

.tip {
  margin-top: 28px;
  padding: 18px 20px;
  border-radius: var(--radius-md);
  background: var(--cyan-muted);
  border: 1px solid var(--cyan);
}

.tip-title {
  font-weight: 800;
  font-size: 14px;
  color: var(--text-primary);
}

.tip-body {
  margin-top: 8px;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.7;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.chip {
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  background: var(--surface-1);
  border: 1px solid var(--border);
  color: var(--text-primary);
  font-size: 13px;
  font-weight: 700;
  box-shadow: var(--shadow-card);
}

.footer {
  padding: 48px 0 56px;
  border-top: 1px solid var(--border);
  background: var(--surface-1);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
}

.footer-title {
  font-weight: 800;
  font-size: 16px;
  color: var(--text-primary);
}

.footer-desc {
  margin-top: 8px;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.6;
  max-width: 320px;
}

.footer-right {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.footer-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 700;
  font-size: 13px;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface-2);
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.footer-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-muted);
}

@media (max-width: 920px) {
  .hero-inner {
    grid-template-columns: 1fr;
  }
  .grid-3 {
    grid-template-columns: 1fr;
  }
  .grid-2 {
    grid-template-columns: 1fr;
  }
  .topnav {
    display: none;
  }
  .theme-toggle {
    margin-left: auto;
  }
  .hero {
    padding-top: 36px;
  }
  .section {
    padding: 48px 0;
  }
  .flow-schematic-svg {
    min-width: 0;
    width: 100%;
  }
}