/* Letter Roller — 官网样式 */
:root {
  --bg-deep: #0a1512;
  --bg-dark: #0f1f1a;
  --bg-card: #122920;
  --bg-card-hover: #16352a;
  --accent: #f2cc33;
  --accent-soft: rgba(242, 204, 51, 0.18);
  --accent-border: #b89a28;
  --text: #e8ebe6;
  --muted: #8fa396;
  --cyan: #7fd8ff;
  --radius: 14px;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, sans-serif;
  background: var(--bg-deep);
  color: var(--text);
  line-height: 1.55;
  min-height: 100vh;
}

/* 背景纹理 + 顶部光晕 */
.bg-mesh {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(46, 120, 90, 0.35), transparent),
    radial-gradient(ellipse 60% 40% at 100% 50%, rgba(242, 204, 51, 0.06), transparent),
    radial-gradient(ellipse 50% 30% at 0% 80%, rgba(127, 216, 255, 0.05), transparent),
    var(--bg-deep);
}

.lr-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.65rem 1.25rem;
  background: rgba(10, 21, 18, 0.88);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(242, 204, 51, 0.12);
}

.lr-nav a.brand {
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  letter-spacing: 0.04em;
}

.lr-nav .links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
}

.lr-nav .links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
}

.lr-nav .links a:hover {
  color: var(--cyan);
}

.wrap {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 1.25rem 3.5rem;
}

/* Hero */
.hero {
  text-align: center;
  padding: 2.5rem 0 2rem;
}

.hero-badge {
  display: inline-block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  border: 1px solid var(--accent-border);
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  background: var(--accent-soft);
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: clamp(2rem, 6vw, 2.75rem);
  font-weight: 800;
  margin: 0 0 0.5rem;
  color: var(--accent);
  text-shadow: 0 0 40px rgba(242, 204, 51, 0.2);
}

.hero .tagline {
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 36rem;
  margin: 0 auto 1.5rem;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  margin-bottom: 1rem;
}

/* Sections */
section.block {
  margin: 2.25rem 0;
}

section.block h2 {
  font-size: 1.35rem;
  color: var(--accent);
  margin: 0 0 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

section.block h2 .icon {
  font-size: 1.25rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid rgba(242, 204, 51, 0.2);
  border-radius: var(--radius);
  padding: 1.35rem 1.5rem;
  box-shadow: var(--shadow);
}

.card + .card {
  margin-top: 1rem;
}

/* Feature grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}

.feature-tile {
  background: var(--bg-card);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius);
  padding: 1.15rem 1.25rem;
  transition: border-color 0.2s, background 0.2s;
}

.feature-tile:hover {
  background: var(--bg-card-hover);
  border-color: rgba(242, 204, 51, 0.25);
}

.feature-tile h3 {
  margin: 0 0 0.4rem;
  font-size: 1rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.feature-tile p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted);
}

/* How to play steps */
.steps {
  display: grid;
  gap: 1rem;
  counter-reset: step;
}

.step {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.step::before {
  counter-increment: step;
  content: counter(step);
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
}

.step strong {
  color: var(--text);
}

.step p {
  margin: 0.25rem 0 0;
  font-size: 0.9rem;
  color: var(--muted);
}

/* Lang pills */
.langs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.75rem;
}

.langs span {
  background: var(--accent-soft);
  color: var(--accent);
  padding: 0.3rem 0.65rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 600;
}

/* Download */
.download-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
  margin: 1.25rem 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 200px;
  padding: 0.9rem 1.4rem;
  border-radius: 12px;
  font-weight: 700;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s, opacity 0.15s;
  border: 2px solid var(--accent-border);
  background: linear-gradient(180deg, #2d6b52 0%, #1a4034 100%);
  color: var(--accent);
}

.btn:hover:not(.btn-soon) {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.4);
  color: #fff;
}

.btn-soon {
  opacity: 0.55;
  cursor: not-allowed;
  pointer-events: auto;
}

.hint {
  font-size: 0.85rem;
  color: var(--muted);
  text-align: center;
  max-width: 520px;
  margin: 0 auto;
}

/* Footer */
footer.site-footer {
  text-align: center;
  padding: 2rem 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--muted);
  font-size: 0.85rem;
}

footer.site-footer a {
  color: var(--cyan);
}

footer.site-footer code {
  background: rgba(0, 0, 0, 0.35);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.8em;
}

/* --- Inclusive / autism-friendly --- */
.inclusive-section .inclusive-lead {
  color: var(--text);
  font-size: 1.02rem;
  max-width: 52rem;
  margin: 0 0 1rem;
  line-height: 1.65;
}

.inclusive-card {
  border-left: 4px solid rgba(127, 216, 255, 0.45);
}

.inclusive-list {
  margin: 0;
  padding-left: 1.35rem;
  color: var(--muted);
}

.inclusive-list li {
  margin-bottom: 0.75rem;
}

.inclusive-list li strong {
  color: var(--accent);
}

.inclusive-note {
  margin: 1.15rem 0 0;
  padding-top: 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  font-size: 0.88rem;
  color: var(--muted);
}

.inclusive-note a {
  color: var(--cyan);
}

/* --- Screenshots: horizontal scroll + carousel --- */
.screenshot-intro {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0 0 1rem;
  max-width: 52rem;
}

.screenshot-intro code {
  background: rgba(0, 0, 0, 0.35);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
  font-size: 0.85em;
}

.shot-carousel {
  position: relative;
  padding: 0.5rem 2.75rem 1rem;
  overflow: hidden;
}

.shot-carousel-viewport {
  display: flex;
  gap: 1.25rem;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  padding: 0.5rem 0 0.75rem;
  scrollbar-color: var(--accent-border) transparent;
  scrollbar-width: thin;
}

.shot-carousel-viewport:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 4px;
}

.shot-carousel-slide {
  flex: 0 0 min(78vw, 300px);
  scroll-snap-align: center;
  margin: 0;
}

.shot-frame {
  border: 2px solid var(--accent-border);
  border-radius: 16px;
  overflow: hidden;
  background: linear-gradient(180deg, #0a1814 0%, #050a08 100%);
  aspect-ratio: 9 / 16;
  max-height: 460px;
  margin: 0 auto;
  box-shadow: 0 10px 36px rgba(0, 0, 0, 0.5);
}

.shot-frame img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center top;
  display: block;
}

.shot-carousel-slide figcaption {
  text-align: center;
  margin-top: 0.65rem;
  font-size: 0.88rem;
  color: var(--muted);
}

.shot-carousel-prev,
.shot-carousel-next {
  position: absolute;
  top: 40%;
  transform: translateY(-50%);
  z-index: 2;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 2px solid var(--accent-border);
  background: rgba(10, 21, 18, 0.94);
  color: var(--accent);
  font-size: 1.6rem;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  transition: background 0.15s, color 0.15s;
}

.shot-carousel-prev:hover,
.shot-carousel-next:hover {
  background: rgba(30, 64, 52, 0.95);
  color: #fff;
}

.shot-carousel-prev {
  left: 0.35rem;
}

.shot-carousel-next {
  right: 0.35rem;
}

.shot-carousel-dots {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  padding-top: 0.35rem;
}

.shot-carousel-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 1px solid var(--accent-border);
  background: transparent;
  padding: 0;
  cursor: pointer;
  transition: background 0.15s, transform 0.15s;
}

.shot-carousel-dot.is-active {
  background: var(--accent);
  border-color: var(--accent);
  transform: scale(1.15);
}

@media (max-width: 520px) {
  .lr-nav {
    flex-direction: column;
    align-items: flex-start;
  }

  .shot-carousel {
    padding-left: 2.25rem;
    padding-right: 2.25rem;
  }

  .shot-carousel-prev,
  .shot-carousel-next {
    width: 38px;
    height: 38px;
    font-size: 1.35rem;
  }

  .shot-carousel-slide {
    flex-basis: min(82vw, 280px);
  }
}