/* Netflix 教程页 — 高效布局：Grid + 少量过渡 */
:root {
  --navy: #0a1628;
  --navy-mid: #132337;
  --accent: #e50914;
  --cta-orange: #f5a623;
  --cta-orange-hover: #e09415;
  --bg: #ffffff;
  --bg-muted: #f4f6f8;
  --border: #dde2e8;
  --text: #1a1a1a;
  --text-muted: #5c6570;
  --max-width: 1200px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 64px;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

img {
  max-width: 100%;
  height: auto;
  vertical-align: middle;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Header */
.site-header {
  background: var(--navy);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 12px 20px;
  min-height: 48px;
  display: flex;
  justify-content: center;
  align-items: center;
  box-sizing: border-box;
}

.logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 0;
  max-width: 100%;
}

.logo img {
  display: block;
  width: min(120px, calc(100vw - 40px));
  height: auto;
  aspect-ratio: 120 / 32;
  object-fit: contain;
}

/* Page grid: main ~75%, sidebar ~25% */
.page-wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 20px 48px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 36px;
  align-items: start;
}

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

.article-header h1 {
  margin: 0 0 20px;
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 28px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.author-avatar {
  border-radius: 50%;
  flex-shrink: 0;
}

.author-name {
  display: block;
  font-weight: 700;
  color: var(--navy);
}

.article-meta time {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.article-tag {
  font-size: 0.8125rem;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--bg-muted);
  color: var(--text-muted);
  font-weight: 600;
}

.section-block h3 {
  margin: 28px 0 12px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--navy);
}

.section-block > h2 + p + h3 {
  margin-top: 20px;
}

.related-articles .related-list {
  margin: 0;
  padding-left: 1.25rem;
}

.related-articles .related-list li {
  margin-bottom: 12px;
  line-height: 1.5;
}

.related-articles .related-list a {
  color: var(--navy);
  font-weight: 600;
  text-decoration: none;
}

.related-articles .related-list a:hover {
  color: var(--cta-orange-hover);
  text-decoration: underline;
}

.intro p {
  margin: 0 0 16px;
  color: var(--text);
}

.official-netflix-note {
  margin: 24px 0;
  padding: 16px 18px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #f8fafc;
  font-size: 0.9375rem;
  color: var(--text-muted);
}

.official-netflix-note p {
  margin: 0;
}

/* Product card */
.product-card {
  margin: 36px 0;
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg-muted);
}

.product-card-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
}

.product-logo {
  flex-shrink: 0;
}

.product-summary {
  flex: 1 1 200px;
  min-width: 0;
}

.product-summary p {
  margin: 8px 0 0;
  font-size: 0.9375rem;
  color: var(--text-muted);
}

.stars {
  color: var(--cta-orange);
  font-weight: 700;
}

.stars span {
  color: var(--text);
  margin-left: 6px;
  font-size: 0.9375rem;
}

.stars.small {
  font-size: 0.8125rem;
  display: block;
  margin-top: 4px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.9375rem;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: var(--cta-orange);
  color: #1a1a1a;
}

.btn-primary:hover {
  background: var(--cta-orange-hover);
  color: #111;
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1rem;
}

.btn-sm {
  padding: 8px 14px;
  font-size: 0.8125rem;
  background: var(--navy);
  color: #fff;
}

.btn-sm:hover {
  background: var(--navy-mid);
}

/* Sections */
.section-block {
  margin: 40px 0;
}

.section-block h2 {
  margin: 0 0 16px;
  font-size: 1.35rem;
  color: var(--navy);
}

.chart-section .chart-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 28px;
  padding: 24px;
  background: var(--bg-muted);
  border-radius: 10px;
  border: 1px solid var(--border);
}

.donut-wrap {
  margin: 0;
  flex-shrink: 0;
}

.chart-bullets {
  margin: 0;
  padding-left: 1.25rem;
  flex: 1 1 220px;
  color: var(--text-muted);
}

.chart-bullets li {
  margin-bottom: 10px;
}

.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: 8px;
  border: 1px solid var(--border);
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
}

.compare-table thead th {
  background: var(--navy);
  color: #fff;
  padding: 14px 16px;
  text-align: left;
  font-weight: 700;
}

.compare-table tbody th,
.compare-table tbody td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}

.compare-table tbody tr:nth-child(even) {
  background: #fafbfc;
}

.compare-table tbody th {
  font-weight: 600;
  text-align: left;
  color: var(--text);
}

.table-note {
  margin: 12px 0 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* CTA banners */
.cta-banner {
  margin: 36px 0;
  padding: 28px 24px;
  background: linear-gradient(135deg, #e8eef5 0%, #f0f4f8 100%);
  border: 1px solid var(--border);
  border-radius: 10px;
  text-align: center;
}

.cta-banner p {
  margin: 0 0 16px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--navy);
}

.cta-banner-alt {
  background: linear-gradient(135deg, #fdf6e8 0%, #f8f0e0 100%);
}

/* Steps */
.step-figure {
  margin: 20px 0 0;
  text-align: center;
}

.step-figure img {
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(10, 22, 40, 0.08);
}

.step-figure figcaption {
  margin-top: 12px;
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* FAQ */
.faq-list {
  margin: 0;
}

.faq-list dt {
  margin-top: 20px;
  font-weight: 700;
  color: var(--navy);
}

.faq-list dt:first-child {
  margin-top: 0;
}

.faq-list dd {
  margin: 8px 0 0;
  color: var(--text-muted);
}

/* Sidebar */
.sidebar {
  min-width: 0;
}

.sidebar-sticky {
  position: sticky;
  top: 64px;
}

.sidebar-heading {
  margin: 0 0 14px;
  font-size: 1.05rem;
  color: var(--navy);
}

.toc-nav {
  padding: 16px 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg-muted);
}

.toc-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.toc-list li {
  margin: 0;
  padding: 0;
  border-bottom: 1px solid var(--border);
}

.toc-list li:last-child {
  border-bottom: none;
}

.toc-list a {
  display: block;
  padding: 10px 4px 10px 0;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--navy);
  text-decoration: none;
  line-height: 1.4;
  transition: color 0.15s ease, padding-left 0.15s ease;
}

.toc-list a:hover {
  color: var(--cta-orange-hover);
  padding-left: 6px;
}

/* Footer */
.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 20px 40px;
  text-align: center;
  font-size: 0.875rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

/* Responsive */
@media (max-width: 900px) {
  .page-wrap {
    grid-template-columns: 1fr;
  }

  .sidebar-sticky {
    position: static;
  }
}

@media (max-width: 520px) {
  .product-card-inner {
    flex-direction: column;
    align-items: stretch;
    text-align: center;
  }

  .product-card-inner .btn-primary {
    width: 100%;
  }
}