/* 本样式文件实现“私人AI助理”落地页的清爽工具手册视觉、响应式布局与无障碍状态。 */

:root {
  --color-ink: #15283c;
  --color-accent: #1683a0;
  --color-background: #f7fafb;
  --color-footer: #13283a;
  --color-surface: #ffffff;
  --color-copy: #526979;
  --color-muted: #718390;
  --color-border: #d8e4e9;
  --color-soft: #e7f3f6;
  --shadow-card: 0 24px 70px rgba(33, 67, 85, 0.11);
  --container-width: 1120px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--color-ink);
  background: var(--color-background);
  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    "PingFang SC",
    "Microsoft YaHei",
    sans-serif;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.24em;
}

a:focus-visible {
  outline: 3px solid #f4b942;
  outline-offset: 4px;
  border-radius: 0.25rem;
}

.container {
  width: min(calc(100% - 3rem), var(--container-width));
  margin-inline: auto;
}

.site-header {
  position: relative;
  z-index: 10;
  border-bottom: 1px solid rgba(216, 228, 233, 0.8);
  background: rgba(247, 250, 251, 0.96);
}

.header-inner,
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.header-inner {
  min-height: 4.75rem;
}

.brand {
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: -0.025em;
}

.site-nav {
  display: flex;
  gap: clamp(1.25rem, 3vw, 2.75rem);
  color: var(--color-copy);
  font-size: 0.9rem;
  font-weight: 650;
}

.site-nav a {
  text-decoration: none;
}

.site-nav a:hover {
  color: var(--color-accent);
}

.hero {
  position: relative;
  overflow: hidden;
}

.hero::before {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 78% 18%, rgba(22, 131, 160, 0.11), transparent 24rem),
    linear-gradient(rgba(21, 40, 60, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(21, 40, 60, 0.025) 1px, transparent 1px);
  background-size: auto, 42px 42px, 42px 42px;
  content: "";
  pointer-events: none;
  mask-image: linear-gradient(to bottom, black, transparent 88%);
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(18rem, 0.75fr);
  gap: clamp(3rem, 8vw, 7rem);
  align-items: center;
  min-height: 42rem;
  padding-block: clamp(5rem, 10vw, 8.5rem);
}

.hero-copy,
.method-card,
.note-card {
  min-width: 0;
}

.eyebrow,
.section-label,
.card-label,
.note-number {
  margin: 0;
  color: var(--color-accent);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 12ch;
  margin: 1.25rem 0 0;
  font-size: clamp(3.25rem, 7vw, 6.75rem);
  line-height: 0.99;
  letter-spacing: -0.065em;
}

.hero h1::after {
  display: inline-block;
  width: 0.19em;
  height: 0.19em;
  margin-left: 0.1em;
  border-radius: 50%;
  background: var(--color-accent);
  content: "";
}

.hero-lead {
  max-width: 41rem;
  margin: 1.75rem 0 0;
  color: var(--color-copy);
  font-size: clamp(1rem, 1.6vw, 1.18rem);
  line-height: 1.85;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-top: 1.75rem;
}

.hero-meta span {
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 0.35rem 0.75rem;
  color: var(--color-muted);
  background: rgba(255, 255, 255, 0.64);
  font-size: 0.78rem;
  font-weight: 650;
}

.primary-link {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  margin-top: 2rem;
  border-radius: 999px;
  padding: 0.8rem 1.15rem;
  color: #ffffff;
  background: var(--color-ink);
  font-size: 0.9rem;
  font-weight: 750;
  text-decoration: none;
  transition: background-color 160ms ease, transform 160ms ease;
}

.primary-link:hover {
  background: var(--color-accent);
  transform: translateY(-2px);
}

.method-card {
  border: 1px solid rgba(216, 228, 233, 0.95);
  border-radius: 1.5rem;
  padding: clamp(1.5rem, 3vw, 2.25rem);
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow-card);
}

.method-card h2 {
  margin: 0.9rem 0 0;
  font-size: clamp(1.5rem, 2.5vw, 2rem);
  line-height: 1.25;
  letter-spacing: -0.035em;
}

.method-summary {
  margin: 0.8rem 0 0;
  color: var(--color-copy);
}

.method-steps {
  display: grid;
  gap: 1rem;
  margin: 2rem 0 0;
  padding: 0;
  list-style: none;
}

.method-steps li {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0 0.8rem;
  align-items: center;
}

.method-steps li > span {
  display: grid;
  grid-row: 1 / span 2;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border-radius: 0.65rem;
  color: var(--color-accent);
  background: var(--color-soft);
  font-size: 0.78rem;
  font-weight: 800;
}

.method-steps strong {
  font-size: 0.92rem;
}

.method-steps small {
  color: var(--color-muted);
  font-size: 0.78rem;
}

.notes-section {
  border-block: 1px solid var(--color-border);
  padding-block: clamp(4.5rem, 8vw, 7rem);
  background: rgba(255, 255, 255, 0.5);
}

.section-heading {
  display: flex;
  justify-content: space-between;
  gap: 3rem;
  align-items: end;
  margin-bottom: 2.5rem;
}

.section-heading h2,
.about-section h2 {
  margin: 0.8rem 0 0;
  font-size: clamp(2rem, 4vw, 3.3rem);
  line-height: 1.12;
  letter-spacing: -0.05em;
}

.section-heading > p {
  max-width: 19rem;
  margin: 0;
  color: var(--color-muted);
  text-align: right;
}

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

.note-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-border);
  border-radius: 1.25rem;
  padding: clamp(1.35rem, 2.5vw, 2rem);
  background: var(--color-surface);
}

.note-card h3 {
  min-height: 3.2em;
  margin: 1.65rem 0 0;
  font-size: 1.35rem;
  line-height: 1.3;
  letter-spacing: -0.025em;
}

.note-card > p:not(.note-example) {
  margin: 1rem 0 0;
  color: var(--color-copy);
}

.note-card ul {
  display: grid;
  gap: 0.75rem;
  margin: 1.5rem 0 0;
  padding: 0;
  color: var(--color-copy);
  list-style: none;
}

.note-card li {
  position: relative;
  padding-left: 1.05rem;
}

.note-card li::before {
  position: absolute;
  top: 0.68em;
  left: 0;
  width: 0.35rem;
  height: 0.35rem;
  border-radius: 50%;
  background: var(--color-accent);
  content: "";
}

.note-example {
  margin: auto 0 0;
  padding-top: 1.75rem;
  color: var(--color-ink);
  font-size: 0.9rem;
  font-weight: 650;
}

.about-section {
  padding-block: clamp(4.5rem, 9vw, 8rem);
}

.about-grid {
  display: grid;
  grid-template-columns: minmax(14rem, 0.65fr) minmax(0, 1.35fr);
  gap: clamp(3rem, 10vw, 9rem);
}

.about-copy {
  color: var(--color-copy);
  font-size: clamp(1rem, 1.6vw, 1.15rem);
  line-height: 1.9;
}

.about-copy p {
  margin: 0;
}

.about-copy p + p {
  margin-top: 1.25rem;
}

.site-footer {
  color: #c8d6df;
  background: var(--color-footer);
}

.footer-inner {
  min-height: 5.5rem;
  padding-top: 1.5rem;
  padding-bottom: calc(1.5rem + env(safe-area-inset-bottom));
  font-size: 0.86rem;
}

.footer-inner a {
  color: #ffffff;
}

@media (max-width: 960px) {
  .hero-grid {
    grid-template-columns: minmax(0, 1fr) minmax(17rem, 0.72fr);
    gap: 2rem;
  }

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

  .note-card h3 {
    min-height: auto;
  }
}

@media (max-width: 767px) {
  .container {
    width: min(calc(100% - 2rem), var(--container-width));
  }

  .header-inner {
    min-height: 4.25rem;
  }

  .site-nav {
    gap: 1rem;
    font-size: 0.82rem;
  }

  .hero-grid,
  .about-grid {
    grid-template-columns: 1fr;
  }

  .hero-grid {
    gap: 2.5rem;
    min-height: auto;
    padding-block: 4.5rem;
  }

  .hero h1 {
    max-width: 10ch;
    font-size: clamp(3rem, 15vw, 4.4rem);
  }

  .method-card {
    border-radius: 1.25rem;
  }

  .section-heading {
    display: block;
  }

  .section-heading > p {
    margin-top: 0.8rem;
    text-align: left;
  }

  .about-grid {
    gap: 2rem;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: 0.6rem;
  }
}

@media (max-width: 420px) {
  .header-inner {
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    gap: 0.15rem;
    padding-block: 0.7rem;
  }

  .hero-meta {
    gap: 0.45rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}