:root {
  --bg: #0f0f11;
  --card: #17171a;
  --text: #e8e8ea;
  --muted: #a5a7ac;
  --accent: #FFD700;
  --accent-2: #22c55e;
  --border: #222228;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-family: Inter, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial; background: var(--bg); color: var(--text); }
a { color: var(--accent); text-decoration: none; transition: opacity .2s ease, transform .2s ease; }
a:hover { opacity: .9; }
.container { max-width: 1100px; margin: 0 auto; padding: 1.25rem; }
header { position: sticky; top: 0; z-index: 10; backdrop-filter: blur(8px); background: rgba(15,15,17,.65); border-bottom: 1px solid rgba(255,255,255,.04); }
.nav { display: flex; align-items: center; justify-content: space-between; padding: .75rem 0; }
.brand { font-weight: 800; letter-spacing: .3px; }
.nav a { margin-left: 1rem; }
.icon-link { display: inline-flex; align-items: center; justify-content: center; width: 36px; height: 36px; border-radius: 10px; background: var(--card); border: 1px solid var(--border); transition: transform .2s ease, box-shadow .2s ease, background .2s ease; }
.icon-link:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,.35); background: #1e1e22; }
.btn { display: inline-block; padding: .8rem 1rem; background: var(--accent); color: white; border-radius: .9rem; font-weight: 700; border: 0; cursor: pointer; transition: transform .15s ease, box-shadow .15s ease; }
.btn:hover { transform: translateY(-1px); box-shadow: 0 10px 22px rgba(139,92,246,.24); }
.btn.secondary { background: var(--accent-2); }
.hero { padding: 5rem 0 3rem; text-align: center; }
.hero h1 { font-size: clamp(2rem, 4vw, 3rem); margin: 0 0 .75rem; }
.hero p { color: var(--muted); margin: 0 0 1.5rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1rem; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 1.1rem; padding: 1.25rem; opacity: 0; transform: translateY(10px); animation: rise .6s ease forwards; }
.card:nth-child(2) { animation-delay: .08s; }
.card:nth-child(3) { animation-delay: .16s; }
@keyframes rise { to { opacity: 1; transform: translateY(0); } }
.footer { margin-top: 3rem; border-top: 1px solid var(--border); padding: 2rem 0; color: var(--muted); }
.footer a { color: var(--muted); }
.product { display: grid; grid-template-columns: 1fr; gap: 1.25rem; }
@media (min-width: 860px) { .product { grid-template-columns: 1fr 1fr; gap: 2rem; } }
.product img { width: 100%; border-radius: 1rem; border: 1px solid var(--border); box-shadow: 0 12px 28px rgba(0,0,0,.35); }
.badge { display: inline-block; padding: .25rem .5rem; background: #1f2937; border-radius: .5rem; color: var(--muted); font-size: .8rem; }
.price { font-size: 1.75rem; font-weight: 800; margin: .5rem 0 1rem; }
.notice { background: #122; color: #b7ebff; border: 1px solid #194b63; padding: .75rem 1rem; border-radius: .75rem; }
.small { font-size: .92rem; color: var(--muted); }
.flex { display: flex; align-items: center; gap: .75rem; }
.right { display: flex; align-items: center; gap: .5rem; }
nav .links { display: none; }
@media (min-width: 720px) { nav .links { display: inline-block; } }

.book-cover {
  position: relative;
  display: inline-block;
  overflow: hidden;
  border-radius: 10px;
}
.book-cover img {
  width: 100%;
  transition: transform 0.4s ease;
}
.book-cover:hover img {
  transform: scale(1.05);
}
.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgba(0, 0, 0, 0.55);
  color: #fff;
  font-size: 1.1rem;
  opacity: 0;
  transition: opacity 0.3s ease;
}
.book-cover:hover .overlay {
  opacity: 1;
}
.secondary-btn {
  background: transparent;
  border: 1px solid var(--accent, #8b5cf6);
  color: var(--accent, #8b5cf6);
  padding: 0.5rem 1.2rem;
  border-radius: 8px;
  font-weight: 500;
  margin-right: 0.5rem;
  transition: all 0.25s ease;
}
.secondary-btn:hover {
  background: var(--accent, #8b5cf6);
  color: #fff;
  transform: scale(1.02);
}