.nav-button{position:fixed;bottom:24px;right:24px;width:56px;height:56px;border-radius:50%;border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;z-index:200;box-shadow:0 4px 20px rgba(0,0,0,.3),0 0 40px rgba(0,0,0,.2);transition:all .3s cubic-bezier(.4,0,.2,1);color:oklch(.96 .012 35);opacity:1;transform:scale(1);will-change:transform,opacity;-webkit-backface-visibility:hidden;backface-visibility:hidden}.nav-button.nav-up{background:linear-gradient(135deg,oklch(.51 .18 20) 0%,oklch(.32 .13 22) 100%);box-shadow:0 4px 18px rgba(80,10,24,.46),0 0 24px rgba(150,18,45,.18)}.nav-button.nav-down{background:linear-gradient(135deg,oklch(.68 .13 68) 0%,oklch(.48 .14 42) 100%);box-shadow:0 4px 18px rgba(83,44,8,.42),0 0 24px rgba(191,115,31,.18)}.nav-button:hover{transform:scale(1.04);box-shadow:0 6px 24px rgba(0,0,0,.36),0 0 28px rgba(0,0,0,.2)}.nav-button.nav-up:hover{box-shadow:0 6px 24px rgba(80,10,24,.55),0 0 30px rgba(150,18,45,.24)}.nav-button.nav-down:hover{box-shadow:0 6px 24px rgba(83,44,8,.52),0 0 30px rgba(191,115,31,.24)}.nav-button:active{transform:scale(.95)}.nav-button.hidden{opacity:0;transform:scale(0);pointer-events:none}.nav-button svg{width:24px;height:24px;stroke-width:2.5}@media (max-width:640px){.nav-button{width:52px;height:52px;bottom:20px;right:20px;touch-action:manipulation}.nav-button svg{width:22px;height:22px}.nav-button::before{content:'';position:absolute;top:-8px;left:-8px;right:-8px;bottom:-8px;border-radius:50%}}@media (min-width:641px) and (max-width:1024px){.nav-button{width:54px;height:54px}}.nav-button{-webkit-tap-highlight-color:transparent;-webkit-user-select:none;user-select:none;touch-action:manipulation}.nav-button{animation:fadeScaleIn .3s cubic-bezier(.4,0,.2,1)}@keyframes fadeScaleIn{from{opacity:0;transform:scale(0)}to{opacity:1;transform:scale(1)}}