* { box-sizing: border-box; }
body { margin: 0; font-family: Tahoma, Arial, sans-serif; color: #202124; background: #f7f5f0; line-height: 1.8; }
a { color: #0f766e; text-decoration: none; }
button, input, select, textarea { font: inherit; }
input, select, textarea { width: 100%; border: 1px solid #d8d3c8; border-radius: 8px; padding: 10px 12px; background: #fff; color: #202124; }
textarea { min-height: 130px; grid-column: 1 / -1; }
.topbar { display: flex; justify-content: space-between; align-items: center; gap: 20px; padding: 16px 32px; background: #fff; border-bottom: 1px solid #e6e0d5; position: sticky; top: 0; z-index: 10; }
.brand { font-weight: 800; color: #111827; }
.topbar nav { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.topbar form { display: inline; }
.topbar button, .link-button { background: none; border: 0; color: #0f766e; cursor: pointer; padding: 0; }
.container { max-width: 1180px; margin: 0 auto; padding: 28px 20px 56px; }
.hero { min-height: 260px; display: flex; align-items: end; padding: 34px; border-radius: 8px; background: linear-gradient(135deg, #164e63, #166534); color: #fff; margin-bottom: 24px; }
.hero h1 { margin: 0; font-size: 34px; }
.filters, .form-inline { display: grid; grid-template-columns: 1fr 220px auto; gap: 12px; align-items: center; margin: 18px 0; }
.form-inline.compact { flex: 1; margin: 0; grid-template-columns: repeat(4, minmax(120px, 1fr)) auto; }
.book-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 18px; }
.book-card, .auth-card, .summary, .panel, .sidebar, .line-item, .stats div { background: #fff; border: 1px solid #e6e0d5; border-radius: 8px; }
.book-card { padding: 14px; display: grid; gap: 10px; }
.book-card img, .cover-placeholder { width: 100%; aspect-ratio: 3 / 4; object-fit: cover; border-radius: 6px; background: #dbeafe; display: grid; place-items: center; font-size: 54px; font-weight: 800; color: #1e3a8a; }
.book-card h2 { font-size: 18px; margin: 0; }
.detail { display: grid; grid-template-columns: 310px 1fr; gap: 34px; align-items: start; }
.detail-cover { width: 100%; max-width: 310px; border-radius: 8px; }
.btn { display: inline-flex; align-items: center; justify-content: center; border: 0; border-radius: 8px; padding: 10px 16px; background: #0f766e; color: #fff; cursor: pointer; min-height: 42px; }
.btn.secondary { background: #334155; }
.btn.full { width: 100%; }
.alert { padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; background: #fff; border: 1px solid #ddd; }
.alert.success { border-color: #16a34a; color: #166534; }
.alert.error { border-color: #dc2626; color: #991b1b; }
.line-item { display: flex; justify-content: space-between; align-items: center; gap: 14px; padding: 14px 16px; margin: 10px 0; }
.summary { padding: 18px; margin-top: 20px; max-width: 460px; }
.coupon { display: grid; grid-template-columns: 1fr auto; gap: 10px; }
.auth-card { max-width: 430px; margin: 40px auto; padding: 24px; display: grid; gap: 12px; }
.admin-layout { display: grid; grid-template-columns: 220px 1fr; gap: 18px; align-items: start; }
.sidebar { padding: 12px; display: grid; gap: 8px; }
.sidebar a { padding: 9px 10px; border-radius: 6px; }
.sidebar a:hover { background: #ecfdf5; }
.panel { padding: 20px; }
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.stats div { padding: 18px; display: grid; gap: 4px; }
.stats strong { font-size: 28px; }
.page-head, .actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.form-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.empty, .muted { color: #64748b; }
.downloads { display: flex; gap: 8px; flex-wrap: wrap; }
@media (max-width: 760px) {
    .topbar, .line-item, .page-head { align-items: stretch; flex-direction: column; }
    .filters, .form-inline, .form-inline.compact, .detail, .admin-layout, .form-grid, .stats { grid-template-columns: 1fr; }
    .hero h1 { font-size: 26px; }
    .container { padding-inline: 14px; }
}