:root {
  --brand: #3158e8;
  --brand-dark: #2344bd;
  --brand-soft: #eef2ff;
  --text: #172033;
  --muted: #667085;
  --line: #e6eaf1;
  --surface: #ffffff;
  --surface-alt: #f7f8fb;
  --warning-bg: #fff8e7;
  --warning-line: #f2d28b;
  --success-bg: #edf9f2;
  --success: #207a4a;
  --shadow: 0 18px 45px rgba(23, 32, 51, 0.08);
  --radius: 18px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--text);
  background: var(--surface-alt);
  font: 16px/1.72 -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

img {
  display: block;
  width: auto;
  max-width: 100%;
  height: auto;
  margin: 20px auto;
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: 0 10px 28px rgba(23, 32, 51, 0.08);
}

button, input { font: inherit; }

.site-header {
  position: sticky;
  z-index: 50;
  top: 0;
  border-bottom: 1px solid rgba(230, 234, 241, 0.9);
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(16px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(1160px, calc(100% - 40px));
  min-height: 68px;
  margin: 0 auto;
}

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 750;
  letter-spacing: 0.01em;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  color: var(--brand);
}

.brand-mark svg { width: 100%; height: 100%; }
.brand-name { font-size: 1rem; }
.brand-divider { width: 1px; height: 18px; background: var(--line); }
.brand-subtitle { color: var(--muted); font-size: 0.9rem; font-weight: 600; }

.header-menu { display: flex; align-items: center; gap: 8px; }

.header-menu a {
  padding: 9px 13px;
  border-radius: 10px;
  color: #4d576b;
  font-size: 0.92rem;
  font-weight: 650;
}

.header-menu a:hover,
.header-menu a.active { color: var(--brand); background: var(--brand-soft); }

.header-menu-button {
  display: none;
  width: 42px;
  height: 42px;
  padding: 10px;
  border: 0;
  border-radius: 10px;
  background: var(--surface-alt);
}

.header-menu-button span {
  display: block;
  height: 2px;
  margin: 4px 0;
  border-radius: 2px;
  background: var(--text);
}

.page-shell {
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  gap: 32px;
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
  padding: 34px 0 72px;
}

.tutorial-nav {
  position: sticky;
  top: 96px;
  align-self: start;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.tutorial-nav .nav-label {
  display: block;
  margin-bottom: 10px;
  color: #98a2b3;
  font-size: 0.78rem;
  font-weight: 750;
  letter-spacing: 0.08em;
}

.tutorial-nav a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-radius: 10px;
  color: #4d576b;
  font-size: 0.92rem;
  font-weight: 650;
}

.tutorial-nav a:hover { color: var(--brand); background: var(--brand-soft); }
.tutorial-nav a + a { margin-top: 3px; }
.tutorial-nav .secondary-link { margin-top: 12px; border-top: 1px solid var(--line); border-radius: 0; padding-top: 16px; color: var(--brand); }

.tutorial-main { min-width: 0; }

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
  color: var(--muted);
  font-size: 0.88rem;
}

.breadcrumb a:hover { color: var(--brand); }

.page-heading {
  padding: 30px 32px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.heading-tag {
  display: inline-flex;
  padding: 5px 10px;
  border-radius: 999px;
  color: var(--brand);
  background: var(--brand-soft);
  font-size: 0.8rem;
  font-weight: 750;
}

.page-heading h1 {
  margin: 14px 0 8px;
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.page-heading p { max-width: 720px; margin: 0; color: var(--muted); }

.quick-links {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-top: 20px;
}

.quick-links a,
.quick-links button {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: #3f4a5e;
  background: #fbfcfe;
  font-size: 0.9rem;
  font-weight: 700;
  text-align: left;
}

.quick-links button { width: 100%; cursor: pointer; }

.quick-links button > span:last-child { display: grid; gap: 1px; }

.quick-links button small {
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 600;
  line-height: 1.35;
}

.quick-links button:hover {
  border-color: #b7c5ff;
  background: #f6f8ff;
}

.quick-links button.is-active {
  border-color: var(--brand);
  color: var(--brand);
  background: var(--brand-soft);
  box-shadow: inset 0 0 0 1px var(--brand);
}

.quick-links button.is-active small { color: #5366ad; }

.tutorial-page-status {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 14px;
  color: var(--muted);
  font-size: 0.84rem;
}

.tutorial-page-status strong {
  color: var(--brand);
  font-size: 0.86rem;
  white-space: nowrap;
}

.platform-dot {
  display: grid;
  flex: 0 0 28px;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: 8px;
  color: #fff;
  background: var(--brand);
  font-size: 0.72rem;
}

.notice {
  display: flex;
  gap: 13px;
  margin: 22px 0;
  padding: 16px 18px;
  border: 1px solid var(--warning-line);
  border-radius: 14px;
  background: var(--warning-bg);
  color: #755615;
}

.notice strong { display: block; color: #5c410a; }
.notice p { margin: 2px 0 0; }
.notice-icon { font-size: 1.1rem; font-weight: 800; }
.notice.info { border-color: #cfd9ff; color: #3d4e89; background: var(--brand-soft); }
.notice.info strong { color: #273870; }

.tutorial-section {
  scroll-margin-top: 92px;
  margin-top: 22px;
  padding: 28px 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.tutorial-panel[hidden] { display: none; }

.tutorial-panel.is-active { animation: tutorial-panel-in 0.22s ease both; }

@keyframes tutorial-panel-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.section-title-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
}

.section-title-row h2 { margin: 0; font-size: 1.45rem; line-height: 1.3; }
.section-title-row p { margin: 5px 0 0; color: var(--muted); }

.download-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 9px 15px;
  border-radius: 11px;
  color: #fff;
  background: var(--brand);
  font-size: 0.9rem;
  font-weight: 750;
  white-space: nowrap;
}

.download-button:hover { background: var(--brand-dark); }
.download-button.secondary { color: var(--brand); background: var(--brand-soft); }

.step-list { margin: 24px 0 0; padding: 0; list-style: none; counter-reset: step; }

.step-list > li {
  position: relative;
  min-height: 42px;
  padding-left: 52px;
  counter-increment: step;
}

.step-list > li + li { margin-top: 26px; }

.step-list > li::before {
  position: absolute;
  top: -2px;
  left: 0;
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 10px;
  color: var(--brand);
  background: var(--brand-soft);
  content: counter(step);
  font-size: 0.9rem;
  font-weight: 800;
}

.step-list h3 { margin: 0 0 6px; font-size: 1.05rem; }
.step-list p { margin: 6px 0; color: #4f5b70; }
.step-list a:not(.download-button) { color: var(--brand); text-decoration: underline; text-underline-offset: 3px; }

.button-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 14px 0; }

.chip-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.chip { padding: 6px 10px; border-radius: 999px; color: #485268; background: #f0f2f6; font-size: 0.82rem; font-weight: 650; }

details.client-guide {
  margin-top: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  overflow: hidden;
  background: #fbfcfe;
}

details.client-guide > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  color: #344054;
  font-weight: 750;
}

details.client-guide > summary::-webkit-details-marker { display: none; }
details.client-guide > summary::after { content: "+"; color: var(--brand); font-size: 1.25rem; }
details.client-guide[open] > summary::after { content: "−"; }
.client-guide-content { padding: 4px 18px 20px; border-top: 1px solid var(--line); }
.client-guide-content h3 { margin-top: 20px; }
.client-guide-content p { color: #4f5b70; }

.inline-warning {
  padding: 12px 14px;
  border-left: 4px solid #e5a31a;
  border-radius: 4px 10px 10px 4px;
  background: var(--warning-bg);
  color: #654b15;
}

.next-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 22px;
  padding: 22px 24px;
  border-radius: var(--radius);
  color: #fff;
  background: linear-gradient(135deg, #274ad0, #5676ee);
}

.next-card strong { display: block; font-size: 1.08rem; }
.next-card span { color: rgba(255, 255, 255, 0.8); font-size: 0.9rem; }
.next-card b { font-size: 1.35rem; }

.site-footer { border-top: 1px solid var(--line); background: var(--surface); }

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  width: min(1160px, calc(100% - 40px));
  min-height: 90px;
  margin: 0 auto;
  color: var(--muted);
  font-size: 0.86rem;
}

.footer-links { display: flex; flex-wrap: wrap; gap: 16px; }
.footer-links a:hover { color: var(--brand); }

.back-to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  width: 44px;
  height: 44px;
  border: 0;
  border-radius: 13px;
  color: #fff;
  background: var(--brand);
  box-shadow: 0 10px 26px rgba(49, 88, 232, 0.3);
  cursor: pointer;
  opacity: 0;
  transform: translateY(10px);
  transition: 0.2s ease;
  pointer-events: none;
}

.back-to-top.visible { opacity: 1; transform: translateY(0); pointer-events: auto; }

@media (max-width: 900px) {
  .page-shell { grid-template-columns: 1fr; }
  .tutorial-nav { position: static; display: flex; gap: 8px; overflow-x: auto; padding: 12px; }
  .tutorial-nav .nav-label { display: none; }
  .tutorial-nav a { flex: 0 0 auto; background: var(--surface-alt); }
  .tutorial-nav .secondary-link { margin: 0; border: 0; border-radius: 10px; padding-top: 10px; }
}

@media (max-width: 760px) {
  .header-inner, .page-shell, .footer-inner { width: min(100% - 28px, 1160px); }
  .brand-divider, .brand-subtitle { display: none; }
  .header-menu-button { display: block; }
  .header-menu {
    position: absolute;
    top: 60px;
    right: 14px;
    left: 14px;
    display: none;
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background: var(--surface);
    box-shadow: var(--shadow);
  }
  .header-menu.open { display: grid; }
  .page-shell { gap: 18px; padding-top: 20px; }
  .page-heading, .tutorial-section { padding: 22px 18px; }
  .quick-links { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .section-title-row { display: block; }
  .section-title-row .download-button { margin-top: 14px; }
  .step-list > li { padding-left: 46px; }
  .next-card { align-items: flex-start; }
  .footer-inner { align-items: flex-start; flex-direction: column; padding: 24px 0; }
}

@media (max-width: 430px) {
  .quick-links { grid-template-columns: 1fr; }
  .tutorial-page-status { align-items: flex-start; flex-direction: column; gap: 4px; }
  .page-heading h1 { font-size: 1.75rem; }
  .button-row .download-button { width: 100%; }
}