:root {
  --blue: #1f7ae0;
  --blue-deep: #0d4f9e;
  --blue-soft: #e8f3ff;
  --ink: #132033;
  --muted: #5a6b7d;
  --line: #d7e3f0;
  --bg: #f4f8fc;
  --card: #ffffff;
  --accent: #00b4c8;
  --warn: #e85d4c;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(19, 64, 120, 0.08);
  --max: 1120px;
  --font: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: "ZCOOL XiaoWei", "Noto Serif SC", serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 10% -10%, rgba(31, 122, 224, 0.14), transparent 60%),
    radial-gradient(900px 400px at 100% 0%, rgba(0, 180, 200, 0.12), transparent 55%),
    linear-gradient(180deg, #eef5fb 0%, var(--bg) 240px, #f7fafc 100%);
  line-height: 1.75;
  font-size: 16px;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

#ads img {
  max-width: 65px;
  width: 65px;
  height: 65px;
  object-fit: cover;
  object-position: center;
}

a {
  color: var(--blue-deep);
  text-decoration: none;
}

a:hover {
  color: var(--blue);
  text-decoration: underline;
}

.container {
  width: min(100% - 32px, var(--max));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.88);
  border-bottom: 1px solid rgba(215, 227, 240, 0.9);
}

.nav-wrap {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.05rem;
}

.brand:hover {
  text-decoration: none;
  color: var(--blue-deep);
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  object-fit: cover;
}

.nav {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.nav a {
  padding: 8px 12px;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.95rem;
  text-decoration: none;
}

.nav a:hover,
.nav a.active {
  color: var(--blue-deep);
  background: var(--blue-soft);
}

.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 10px;
  color: var(--ink);
  cursor: pointer;
}

.menu-toggle .bar {
  display: block;
  width: 20px;
  height: 2px;
  margin: 0 auto;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
  position: relative;
}

.menu-toggle .bar + .bar {
  margin-top: 5px;
}

.menu-toggle[aria-expanded="true"] .bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .bar:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] .bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.hero {
  padding: 48px 0 28px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 36px;
  align-items: center;
}

.eyebrow {
  display: inline-block;
  color: var(--blue);
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 10px;
}

.hero h1 {
  margin: 0 0 14px;
  font-family: var(--display);
  font-size: clamp(2rem, 4vw, 2.8rem);
  line-height: 1.25;
  color: var(--ink);
}

.hero-lead {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 1.05rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 20px;
  border-radius: 12px;
  font-weight: 700;
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-primary {
  color: #fff;
  background: linear-gradient(135deg, var(--blue) 0%, var(--accent) 100%);
  box-shadow: 0 8px 20px rgba(31, 122, 224, 0.28);
}

.btn-primary:hover {
  color: #fff;
}

.btn-ghost {
  color: var(--blue-deep);
  background: #fff;
  border: 1px solid var(--line);
}

.hero-visual {
  position: relative;
}

.hero-visual img {
  width: 100%;
  border-radius: 18px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, 0.8);
}

.section {
  padding: 42px 0;
}

.section-head {
  margin-bottom: 22px;
}

.section-head h2 {
  margin: 0 0 8px;
  font-family: var(--display);
  font-size: clamp(1.45rem, 2.5vw, 1.9rem);
  line-height: 1.3;
}

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

.prose {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  box-shadow: var(--shadow);
}

.prose h2,
.prose h3 {
  font-family: var(--display);
  scroll-margin-top: 88px;
}

.prose h2 {
  margin: 1.6em 0 0.6em;
  font-size: 1.45rem;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--blue-soft);
}

.prose h2:first-child {
  margin-top: 0;
}

.prose h3 {
  margin: 1.25em 0 0.45em;
  font-size: 1.15rem;
  color: var(--blue-deep);
}

.prose p {
  margin: 0 0 1em;
  color: #243447;
}

.prose ul,
.prose ol {
  margin: 0 0 1em;
  padding-left: 1.25em;
  color: #243447;
}

.prose li {
  margin-bottom: 0.45em;
}

.toc {
  background: linear-gradient(180deg, #f8fbff, #fff);
  border: 1px dashed var(--line);
  border-radius: 12px;
  padding: 16px 18px;
  margin: 0 0 24px;
}

.toc strong {
  display: block;
  margin-bottom: 8px;
}

.toc a {
  display: inline-block;
  margin: 4px 10px 4px 0;
}

.media-block {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 22px;
  align-items: start;
  margin: 22px 0 28px;
}

.media-block.reverse {
  grid-template-columns: 1.1fr 0.9fr;
}

.media-block.reverse .shot {
  order: 2;
}

.shot {
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: #fff;
  box-shadow: var(--shadow);
}

.shot img {
  width: 100%;
}

.shot figcaption {
  padding: 10px 12px;
  font-size: 0.9rem;
  color: var(--muted);
  background: #fafcfe;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 18px 0 8px;
}

.feature-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.feature-card img {
  width: 100%;
  aspect-ratio: 9 / 16;
  object-fit: cover;
  object-position: top;
  background: #eef3f8;
}

.feature-card .body {
  padding: 14px;
}

.feature-card h3 {
  margin: 0 0 6px;
  font-size: 1.05rem;
}

.feature-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.pill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 12px 0 18px;
}

.pill-list span {
  background: var(--blue-soft);
  color: var(--blue-deep);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 0.9rem;
}

.note {
  background: #fff8e8;
  border-left: 4px solid #f0b429;
  padding: 12px 14px;
  border-radius: 0 10px 10px 0;
  margin: 16px 0;
  color: #6a5316;
}

.site-footer {
  margin-top: 40px;
  padding: 36px 0 28px;
  background: #0d2138;
  color: #c9d7e8;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 24px;
}

.site-footer a {
  color: #dce8f6;
}

.site-footer h3 {
  margin: 0 0 12px;
  color: #fff;
  font-size: 1rem;
}

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-footer li {
  margin-bottom: 8px;
}

.footer-brand {
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.footer-brand img {
  width: 48px;
  height: 48px;
  border-radius: 12px;
}

.copy {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 0.9rem;
  color: #9eb0c4;
}

.page-hero {
  padding: 36px 0 10px;
}

.page-hero h1 {
  margin: 0 0 10px;
  font-family: var(--display);
  font-size: clamp(1.8rem, 3vw, 2.3rem);
}

.page-hero p {
  margin: 0;
  color: var(--muted);
  max-width: 760px;
}

.error-page {
  min-height: 70vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 48px 16px;
}

.error-page h1 {
  font-family: var(--display);
  font-size: clamp(2.4rem, 6vw, 4rem);
  margin: 0 0 10px;
  color: var(--blue-deep);
}

.breadcrumb {
  font-size: 0.92rem;
  color: var(--muted);
  margin-bottom: 14px;
}

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

@media (max-width: 960px) {
  .hero-grid,
  .media-block,
  .media-block.reverse,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .media-block.reverse .shot {
    order: 0;
  }

  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 720px) {
  .menu-toggle {
    display: inline-flex;
    flex-direction: column;
  }

  .nav {
    display: none;
  }

  .nav.open {
    display: flex;
    position: absolute;
    top: calc(100% + 1px);
    left: 0;
    right: 0;
    z-index: 120;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 12px;
    background: rgba(255, 255, 255, 0.98);
    border: 1px solid var(--line);
    border-radius: 14px;
    box-shadow: var(--shadow);
  }

  .nav.open a {
    padding: 12px 14px;
    border-radius: 10px;
  }

  .nav-wrap {
    flex-wrap: nowrap;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .prose {
    padding: 20px 16px;
  }

  .hero {
    padding-top: 28px;
  }

  .feature-card img {
    aspect-ratio: 3 / 4;
  }
}