/* ==========================================================================
   动效集萃 · 导航页样式
   深色底 + 霓虹紫青  |  无构建、无依赖
   ========================================================================== */

:root {
  --bg: #06060c;
  --bg-soft: #0c0c16;
  --surface: rgba(20, 20, 34, 0.62);
  --surface-strong: rgba(26, 26, 44, 0.86);
  --line: rgba(150, 140, 255, 0.16);
  --line-strong: rgba(168, 85, 247, 0.42);
  --text: #eef0ff;
  --text-dim: #a5a7c4;
  --text-faint: #74769a;
  --neon-a: #a855f7;
  --neon-b: #22d3ee;
  --neon-c: #f0abfc;
  --radius-lg: 20px;
  --radius-md: 14px;
  --shadow-card: 0 18px 48px -24px rgba(0, 0, 0, 0.9);
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC",
    system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

/* ---------------------------------------------------------------- 背景层 */

.bg-layer {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 50% -10%, #171034 0%, #08080f 58%, #050509 100%);
}

.bg-grid {
  position: absolute;
  inset: -20%;
  background-image:
    linear-gradient(rgba(140, 130, 255, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(140, 130, 255, 0.07) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(75% 65% at 50% 32%, #000 0%, transparent 78%);
  -webkit-mask-image: radial-gradient(75% 65% at 50% 32%, #000 0%, transparent 78%);
  animation: gridDrift 34s linear infinite;
}

.bg-stars {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(1.6px 1.6px at 12% 22%, rgba(255, 255, 255, 0.5) 50%, transparent 51%),
    radial-gradient(1.4px 1.4px at 78% 14%, rgba(190, 220, 255, 0.45) 50%, transparent 51%),
    radial-gradient(1.2px 1.2px at 34% 74%, rgba(255, 255, 255, 0.35) 50%, transparent 51%),
    radial-gradient(1.6px 1.6px at 62% 58%, rgba(210, 190, 255, 0.4) 50%, transparent 51%),
    radial-gradient(1.2px 1.2px at 88% 82%, rgba(255, 255, 255, 0.3) 50%, transparent 51%),
    radial-gradient(1.4px 1.4px at 22% 90%, rgba(160, 230, 255, 0.34) 50%, transparent 51%);
  opacity: 0.9;
  animation: twinkle 7s ease-in-out infinite alternate;
}

.bg-glow {
  position: absolute;
  width: 46vmax;
  height: 46vmax;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.4;
  animation: floatGlow 22s ease-in-out infinite;
}

.bg-glow--a {
  top: -18vmax;
  left: -12vmax;
  background: radial-gradient(circle, rgba(168, 85, 247, 0.55), transparent 66%);
}

.bg-glow--b {
  right: -16vmax;
  bottom: -20vmax;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.42), transparent 66%);
  animation-delay: -9s;
}

@keyframes gridDrift {
  from { transform: translate3d(0, 0, 0); }
  to { transform: translate3d(0, -64px, 0); }
}

@keyframes twinkle {
  from { opacity: 0.45; }
  to { opacity: 0.95; }
}

@keyframes floatGlow {
  0%, 100% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(3vmax, 4vmax, 0) scale(1.12); }
}

/* ------------------------------------------------------------------ 布局 */

.shell {
  position: relative;
  z-index: 1;
  width: min(1180px, 100% - 3rem);
  margin: 0 auto;
  padding: clamp(3rem, 7vh, 6rem) 0 2.5rem;
  display: flex;
  flex-direction: column;
  gap: clamp(2.2rem, 5vh, 3.6rem);
  min-height: 100vh;
}

/* ------------------------------------------------------------------ 头部 */

.hero { text-align: center; }

.hero-eyebrow {
  margin: 0 0 0.9rem;
  font-size: 0.72rem;
  letter-spacing: 0.42em;
  text-transform: uppercase;
  color: var(--text-faint);
}

.hero-title {
  margin: 0;
  font-size: clamp(2.4rem, 7vw, 4.1rem);
  font-weight: 800;
  letter-spacing: 0.06em;
  line-height: 1.1;
  background: linear-gradient(100deg, var(--neon-c) 0%, var(--neon-a) 28%, var(--neon-b) 58%, var(--neon-c) 100%);
  background-size: 220% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: titleFlow 9s ease-in-out infinite;
  filter: drop-shadow(0 0 28px rgba(168, 85, 247, 0.35));
}

.hero-sub {
  margin: 1rem auto 0;
  max-width: 34rem;
  color: var(--text-dim);
  font-size: clamp(0.92rem, 2.5vw, 1.05rem);
}

.hero-count {
  margin: 1.1rem 0 0;
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  color: var(--text-faint);
}

@keyframes titleFlow {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* ------------------------------------------------------------------ 网格 */

.main {
  flex: 1 1 auto;
  min-width: 0;
}

.grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  min-width: 0;
  gap: clamp(1.1rem, 2.4vw, 1.8rem);
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 340px), 1fr));
}

/* ------------------------------------------------------------------ 卡片 */

.card {
  --accent: #a855f7;
  --accent-alt: #22d3ee;
  --mx: 50%;
  --my: 0%;
  position: relative;
  min-width: 0;
  max-width: 100%;
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(30, 30, 52, 0.72), rgba(12, 12, 22, 0.86));
  border: 1px solid var(--line);
  box-shadow: var(--shadow-card);
  transition: transform 0.5s var(--ease-out), border-color 0.4s ease, box-shadow 0.5s ease;
  isolation: isolate;
}

.card::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(140deg, var(--accent), transparent 38%, transparent 62%, var(--accent-alt));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask-composite: exclude;
  opacity: 0;
  transition: opacity 0.45s ease;
  pointer-events: none;
}

.card::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(320px circle at var(--mx) var(--my), rgba(255, 255, 255, 0.13), transparent 62%);
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
  z-index: 2;
}

.card:hover,
.card:focus-within {
  transform: translateY(-6px);
  border-color: var(--line-strong);
  box-shadow: 0 26px 60px -26px rgba(168, 85, 247, 0.55), 0 0 0 1px rgba(168, 85, 247, 0.16);
}

.card:hover::before,
.card:focus-within::before { opacity: 1; }

.card:hover::after,
.card:focus-within::after { opacity: 1; }

.card-link {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  height: 100%;
  border-radius: inherit;
  overflow: hidden;
}

.card-link:focus-visible {
  outline: 2px solid var(--accent-alt);
  outline-offset: 3px;
}

.card-media {
  position: relative;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: #05050b;
  border-bottom: 1px solid var(--line);
}

.card-img {
  width: 100%;
  max-width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  transform: scale(1.01);
  transition: transform 0.9s var(--ease-out), filter 0.5s ease;
}

.card:hover .card-img,
.card:focus-within .card-img {
  transform: scale(1.06);
  filter: saturate(1.12) brightness(1.06);
}

.card-sheen {
  position: absolute;
  inset: 0;
  background: linear-gradient(115deg, transparent 34%, rgba(255, 255, 255, 0.16) 48%, transparent 62%);
  transform: translateX(-120%);
  pointer-events: none;
}

.card:hover .card-sheen,
.card:focus-within .card-sheen {
  animation: sheen 1.1s var(--ease-out);
}

@keyframes sheen {
  from { transform: translateX(-120%); }
  to { transform: translateX(120%); }
}

.card-body {
  display: flex;
  flex-direction: column;
  min-width: 0;
  gap: 0.5rem;
  padding: 1.15rem 1.25rem 1.35rem;
  flex: 1 1 auto;
}

.card-title {
  margin: 0;
  font-size: 1.22rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.card-sub {
  margin: 0;
  font-size: 0.76rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-alt);
  opacity: 0.85;
}

.card-desc {
  margin: 0.15rem 0 0;
  font-size: 0.9rem;
  color: var(--text-dim);
  overflow-wrap: anywhere;
}

.tags {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.55rem 0 0;
  padding: 0;
}

.tag {
  font-size: 0.72rem;
  padding: 0.18rem 0.62rem;
  border-radius: 999px;
  color: var(--text-dim);
  background: rgba(255, 255, 255, 0.045);
  border: 1px solid var(--line);
}

.card-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.42rem;
  margin-top: auto;
  padding-top: 1rem;
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--accent-alt);
}

.card-cta-arrow {
  display: inline-block;
  transition: transform 0.35s var(--ease-out);
}

.card:hover .card-cta-arrow,
.card:focus-within .card-cta-arrow {
  transform: translateX(6px);
}

.card--enter {
  opacity: 0;
  animation: cardIn 0.75s var(--ease-out) forwards;
  animation-delay: calc(var(--i, 0) * 110ms + 120ms);
}

@keyframes cardIn {
  from { opacity: 0; transform: translateY(26px) scale(0.97); }
  to { opacity: 1; transform: none; }
}

/* ------------------------------------------------------------ 兜底 / 页脚 */

.fallback {
  padding: 2.4rem;
  text-align: center;
  color: var(--text-dim);
  border: 1px dashed var(--line);
  border-radius: var(--radius-lg);
  background: var(--surface);
}

.fallback p { margin: 0; }

.footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem 1.4rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--line);
  font-size: 0.84rem;
  color: var(--text-faint);
}

.footer-copy { margin: 0; }

.footer-links {
  display: flex;
  gap: 1.1rem;
}

.footer-link {
  position: relative;
  color: var(--text-dim);
  transition: color 0.3s ease;
}

.footer-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -3px;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, var(--neon-a), var(--neon-b));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease-out);
}

.footer-link:hover { color: var(--text); }
.footer-link:hover::after { transform: scaleX(1); }

.footer-link:focus-visible {
  outline: 2px solid var(--neon-b);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------------------------------------------------------------- 响应式 */

@media (max-width: 720px) {
  .shell {
    width: min(1180px, 100% - 2rem);
    padding-top: 2.6rem;
    gap: 2rem;
  }

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

  .footer {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .bg-grid,
  .bg-stars,
  .bg-glow,
  .hero-title { animation: none; }

  .card,
  .card-img,
  .card-cta-arrow,
  .footer-link::after { transition: none; }

  .card--enter { animation: none; opacity: 1; }

  .card:hover .card-sheen,
  .card:focus-within .card-sheen { animation: none; }
}