:root {
  --bg: #0f0f10;
  --card: #171718;
  --card-art: #080809;
  --text: #f4f4f5;
  --muted: rgba(244, 244, 245, 0.52);
  --faint: rgba(244, 244, 245, 0.34);
  --line: rgba(255, 255, 255, 0.045);
  --line-strong: rgba(255, 255, 255, 0.1);
  --btn: #f4f4f5;
  --btn-text: #0f0f10;
  --panel: #141414;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'PingFang SC', 'Microsoft YaHei',
    sans-serif;
  line-height: 1.5;
}

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

code,
pre {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, 'Liberation Mono', 'Courier New', monospace;
}

.intro-ambient {
  pointer-events: none;
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 45% at 20% 0%, rgba(255, 255, 255, 0.06), transparent 55%),
    radial-gradient(ellipse 50% 40% at 90% 10%, rgba(255, 255, 255, 0.035), transparent 50%);
  z-index: 0;
}

main,
.intro-footer {
  position: relative;
  z-index: 1;
}

.intro-header {
  position: sticky;
  top: 0;
  z-index: 50;
  /* 实底，避免滚动时正文穿透与品牌字叠在一起 */
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}

.intro-header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.intro-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.35rem;
  font-weight: 900;
  letter-spacing: -0.03em;
}

.intro-brand img {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 1rem;
  object-fit: cover;
}

.intro-nav {
  display: flex;
  gap: 0.35rem;
  padding: 0.25rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--line);
}

.intro-nav a {
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--muted);
  transition: color 0.15s ease, background 0.15s ease;
}

.intro-nav a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.06);
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

.intro-hero {
  padding: 2.5rem 0 3.5rem;
}

.intro-kicker {
  margin: 0 0 0.85rem;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--faint);
}

.intro-hero h1 {
  margin: 0;
  max-width: 14ch;
  font-size: clamp(2.4rem, 6vw, 4.6rem);
  font-weight: 950;
  letter-spacing: -0.05em;
  line-height: 1.05;
}

.intro-lead {
  margin: 1.25rem 0 0;
  max-width: 36rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--muted);
}

.intro-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.intro-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.7rem 1.25rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 0.875rem;
  font-weight: 800;
  transition: transform 0.15s ease, background 0.15s ease, opacity 0.15s ease;
}

.intro-btn-primary {
  background: var(--btn);
  color: var(--btn-text);
}

.intro-btn-primary:hover:not(.is-disabled) {
  transform: translateY(-2px);
}

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

.intro-btn-ghost:hover {
  background: rgba(255, 255, 255, 0.04);
}

.intro-btn-block {
  width: 100%;
}

.intro-btn.is-disabled,
.intro-btn[aria-disabled='true'] {
  opacity: 0.42;
  pointer-events: none;
  cursor: not-allowed;
  transform: none;
}

.intro-section {
  margin-top: 1rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--line);
}

.intro-section-head {
  margin-bottom: 1.5rem;
}

.intro-section-head h2 {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 900;
  letter-spacing: -0.03em;
}

.intro-section-head p {
  margin: 0.5rem 0 0;
  color: var(--muted);
  font-weight: 600;
  max-width: 40rem;
}

.intro-card-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.85rem;
}

.intro-card,
.intro-download-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 1.35rem;
  padding: 1.1rem;
}

.intro-card-art {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 0.9rem;
  background: var(--card-art);
  display: grid;
  place-items: center;
  margin-bottom: 1rem;
  border: 1px solid var(--line);
  color: var(--text);
}

.intro-card-art svg {
  width: 1.35rem;
  height: 1.35rem;
  display: block;
}

.intro-card h3,
.intro-download-card h3 {
  margin: 0;
  font-size: 1rem;
  font-weight: 900;
  letter-spacing: -0.02em;
}

.intro-card p,
.intro-download-card > p {
  margin: 0.45rem 0 0;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--muted);
  line-height: 1.55;
}

.intro-download-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.intro-download-card {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  padding: 1.35rem;
}

.intro-tips {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--faint);
  font-size: 0.75rem;
  font-weight: 600;
}

.intro-tips li + li {
  margin-top: 0.25rem;
}

.intro-tips code {
  font-size: 0.72rem;
  color: var(--muted);
}

.intro-download-card .intro-btn {
  align-self: flex-start;
  margin-top: 0.25rem;
}

.intro-meta {
  margin: 0;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--faint);
}

.intro-help-link {
  align-self: flex-start;
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  color: var(--muted);
  font: inherit;
  font-size: 0.75rem;
  font-weight: 800;
  text-align: left;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

.intro-help-link:hover {
  color: var(--text);
}

.intro-footer {
  border-top: 1px solid var(--line);
  padding: 1.5rem;
  text-align: center;
  color: var(--faint);
  font-size: 0.75rem;
  font-weight: 700;
}

.intro-footer p {
  margin: 0.25rem 0;
}

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

.intro-footer a:hover {
  color: var(--text);
}

.intro-modal[hidden] {
  display: none !important;
}

.intro-modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: grid;
  place-items: center;
  padding: 1.25rem;
}

.intro-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.72);
  backdrop-filter: blur(8px);
}

.intro-modal-panel {
  position: relative;
  width: min(100%, 420px);
  border-radius: 1.65rem;
  border: 1px solid var(--line-strong);
  background: var(--panel);
  box-shadow: 0 40px 120px rgba(0, 0, 0, 0.72);
  padding: 1.5rem 1.35rem 1.25rem;
}

.intro-modal-close {
  position: absolute;
  top: 0.85rem;
  right: 0.85rem;
  width: 2rem;
  height: 2rem;
  border-radius: 999px;
  border: 0;
  background: rgba(255, 255, 255, 0.05);
  color: var(--muted);
  display: grid;
  place-items: center;
  cursor: pointer;
}

.intro-modal-close:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text);
}

.intro-modal-kicker {
  margin: 0;
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--faint);
}

.intro-modal-panel h2 {
  margin: 0.55rem 0 0;
  font-size: 1.45rem;
  font-weight: 950;
  letter-spacing: -0.03em;
}

.intro-modal-body {
  margin: 0.85rem 0 0;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--muted);
  line-height: 1.6;
}

.intro-command {
  margin: 1rem 0;
  padding: 0.9rem 1rem;
  border-radius: 0.9rem;
  background: #0b0b0c;
  border: 1px solid var(--line-strong);
  color: #e4e4e7;
  font-size: 0.78rem;
  line-height: 1.45;
  white-space: pre-wrap;
  word-break: break-all;
}

.intro-modal-foot {
  margin: 0.85rem 0 0;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--faint);
  text-align: center;
}

@media (max-width: 960px) {
  .intro-card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 720px) {
  .intro-header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .intro-download-grid,
  .intro-card-grid {
    grid-template-columns: 1fr;
  }

  .intro-hero {
    padding-top: 1.5rem;
  }
}