/* ==========================================================================
   immersive.css — 萌新教程 · 沉浸式首页
   仅作用于 #/ 首页；内容页沿用 style.css / fx.css
   ========================================================================== */

body.xy-home .layout {
  display: block;
  max-width: none;
}
body.xy-home .sidebar,
body.xy-home .toc {
  display: none;
}
body.xy-home .main {
  padding: 0;
}
body.xy-home .menu-btn {
  display: none;
}
body.xy-home .topbar,
body.xy-home .site-footer {
  display: none;
}
body.xy-home .xy-hero-inner {
  padding-top: 96px;
}
.xy-landing-brand {
  position: absolute;
  top: 26px;
  left: 28px;
  z-index: 3;
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
}
.xy-landing-brand .brand-text {
  font-size: 15px;
}
.xy-landing-foot {
  position: absolute;
  left: 50%;
  bottom: 26px;
  z-index: 3;
  transform: translateX(-50%);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .28em;
  white-space: nowrap;
}
.xy-enter {
  min-width: 150px;
  font-size: 15px;
  font-weight: 600;
}
.xy-enter span {
  display: inline-block;
  margin-left: 6px;
  transition: transform .2s ease;
}
.xy-enter:hover span {
  transform: translateX(3px);
}

.xy-hero {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 100vh;
  min-height: 100svh;
  overflow: hidden;
  isolation: isolate;
  border-bottom: 1px solid var(--border);
  background:
    radial-gradient(1200px 700px at 78% 30%, color-mix(in srgb, var(--green) 14%, transparent), transparent 65%),
    radial-gradient(900px 600px at 10% 80%, color-mix(in srgb, #7c3aed 9%, transparent), transparent 70%),
    var(--bg);
}
.xy-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: linear-gradient(180deg, color-mix(in srgb, var(--bg) 12%, transparent), transparent 30%, transparent 68%, var(--bg));
}
[data-theme="dark"] .xy-hero::after {
  background: linear-gradient(180deg, rgba(5, 10, 7, .18), transparent 30%, transparent 62%, var(--bg));
}
.xy-canvas {
  position: absolute;
  inset: 0;
  z-index: 0;
  display: block;
  width: 100%;
  height: 100%;
}
.xy-hero-inner {
  position: relative;
  z-index: 2;
  width: min(1200px, 100%);
  margin: 0 auto;
  padding: 132px 28px 110px;
}
.xy-eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 22px;
  color: var(--green-dark);
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .26em;
}
[data-theme="dark"] .xy-eyebrow { color: var(--green); }
.xy-eyebrow::before {
  content: "";
  width: 34px;
  height: 1px;
  background: currentColor;
  opacity: .6;
}
.xy-title {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 0;
  font-size: clamp(42px, 7.6vw, 104px);
  font-weight: 800;
  line-height: .98;
  letter-spacing: -.045em;
}
.xy-line { display: block; overflow: hidden; }
.xy-line > span { display: block; }
.xy-line-2 > span {
  background: linear-gradient(100deg, var(--green), #6fd6a0 38%, #7c9cff 72%, #a78bfa);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.xy-lead {
  max-width: 600px;
  margin: 26px 0 0;
  color: var(--text-2);
  font-size: 16px;
  line-height: 1.85;
}
.xy-lead strong { color: var(--text); font-weight: 600; }
.xy-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-top: 30px;
}
.xy-actions .btn { min-height: 44px; padding: 0 20px; }
.xy-link {
  color: var(--text-2);
  font-size: 13.5px;
  padding: 8px 4px;
  border-bottom: 1px solid transparent;
}
.xy-link:hover { color: var(--green); border-bottom-color: var(--green-line); text-decoration: none; }
.xy-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
  max-width: 600px;
  margin-top: 48px;
  padding-top: 20px;
  border-top: 1px dashed var(--border-strong);
}
.xy-stat { display: flex; align-items: baseline; gap: 8px; }
.xy-stat b {
  font-size: 30px;
  line-height: 1;
  letter-spacing: -.03em;
  font-variant-numeric: tabular-nums;
}
.xy-stat span { color: var(--muted); font-size: 12.5px; }
.xy-scroll {
  position: absolute;
  left: 50%;
  bottom: 22px;
  z-index: 3;
  display: flex;
  align-items: center;
  gap: 10px;
  transform: translateX(-50%);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .3em;
  white-space: nowrap;
}
.xy-scroll i {
  display: block;
  width: 1px;
  height: 34px;
  background: linear-gradient(180deg, var(--green), transparent);
  animation: xy-scroll 1.8s ease-in-out infinite;
}
@keyframes xy-scroll {
  0%, 100% { transform: scaleY(.45); opacity: .45; transform-origin: top; }
  50% { transform: scaleY(1); opacity: 1; transform-origin: top; }
}

/* ---------- 内容区 ---------- */
.xy-section {
  position: relative;
  z-index: 1;
  width: min(1200px, 100%);
  margin: 0 auto;
  padding: 92px 28px;
  background: var(--bg);
}
.xy-section-head { margin-bottom: 30px; }
.xy-kicker {
  margin: 0 0 10px;
  color: var(--green-dark);
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .22em;
}
[data-theme="dark"] .xy-kicker { color: var(--green); }
.xy-section-head h2 {
  margin: 0 0 8px;
  font-size: clamp(28px, 3.4vw, 42px);
  letter-spacing: -.035em;
  line-height: 1.1;
}
.xy-section-head p:not(.xy-kicker) { margin: 0; color: var(--muted); font-size: 14px; }
.xy-section .tutorial-grid,
.xy-section .feature-grid { margin-top: 8px; }
.xy-outro {
  position: relative;
  z-index: 1;
  width: min(1200px, calc(100% - 40px));
  margin: 24px auto 72px;
  padding: 64px 28px;
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 24px;
  background:
    radial-gradient(700px 320px at 20% 0%, color-mix(in srgb, var(--green) 20%, transparent), transparent 70%),
    radial-gradient(600px 320px at 90% 100%, color-mix(in srgb, #7c3aed 14%, transparent), transparent 70%),
    var(--surface);
  text-align: center;
}
.xy-outro h2 {
  margin: 0 auto 10px;
  max-width: 720px;
  font-size: clamp(26px, 3.6vw, 44px);
  letter-spacing: -.04em;
  line-height: 1.15;
}
.xy-outro p:not(.xy-kicker) { margin: 0 auto; max-width: 520px; color: var(--muted); font-size: 14px; }
.xy-outro .xy-actions { justify-content: center; }

/* 没有 WebGL 时的静态氛围背景 */
.xy-no-webgl .xy-hero {
  background:
    radial-gradient(900px 560px at 76% 26%, color-mix(in srgb, var(--green) 24%, transparent), transparent 66%),
    radial-gradient(700px 480px at 14% 82%, color-mix(in srgb, #7c3aed 16%, transparent), transparent 70%),
    var(--bg);
}
.xy-no-webgl .xy-canvas { display: none; }

@media (max-width: 900px) {
  body.xy-home .xy-hero-inner { padding-top: 82px; }
  .xy-landing-brand { top: 18px; left: 18px; }
  .xy-landing-brand .brand-mark { width: 30px; height: 30px; font-size: 15px; }
  .xy-landing-brand .brand-text { font-size: 14px; }
  .xy-landing-foot { bottom: 18px; font-size: 9px; letter-spacing: .2em; }
  .xy-hero-inner { padding: 108px 20px 96px; }
  .xy-title { font-size: clamp(38px, 11vw, 68px); }
  .xy-lead { font-size: 14.5px; margin-top: 20px; }
  .xy-actions { gap: 10px; }
  .xy-actions .btn { flex: 1 1 auto; justify-content: center; }
  .xy-stats { gap: 18px; margin-top: 36px; }
  .xy-stat b { font-size: 24px; }
  .xy-section { padding: 68px 20px; }
  .xy-outro { width: calc(100% - 28px); margin-bottom: 48px; padding: 46px 20px; border-radius: 18px; }
  .xy-scroll { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  .xy-scroll i { animation: none; }
  .xy-line > span, .xy-eyebrow, .xy-lead, .xy-actions, .xy-stats { opacity: 1 !important; transform: none !important; }
}