body { font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }
.font-serif { font-family: ui-serif, Georgia, Cambria, "Times New Roman", Times, serif; }
.mask-bottom-soft { -webkit-mask-image: linear-gradient(to bottom, black 50%, transparent 100%); mask-image: linear-gradient(to bottom, black 50%, transparent 100%); }
.scrollbar-hide::-webkit-scrollbar { display: none; }
.scrollbar-hide { -ms-overflow-style: none; scrollbar-width: none; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { transform: translateY(20px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }
.animate-in { animation: fadeIn 0.3s cubic-bezier(0.16, 1, 0.3, 1) forwards; }
.slide-in-from-bottom { animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1) forwards; }
button { user-select: none; -webkit-tap-highlight-color: transparent; }
.book-shadow { box-shadow: 5px 5px 15px rgba(75, 63, 53, 0.15), inset 3px 0 5px rgba(255,255,255,0.4), inset -1px 0 2px rgba(0,0,0,0.1); }
.book-spine { border-left: 4px solid rgba(255,255,255,0.7); }
.upload-loader { border: 2px solid #F1E6D2; border-top: 2px solid #FF8000; border-radius: 50%; width: 16px; height: 16px; animation: spin 1s linear infinite; display: inline-block; }
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }