/* ==========================================
   BACK TO TOP BUTTON - Square Design
   ========================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 999;
    width: 40px;
    height: 40px;
    border: 2px solid #00FF00;
    border-radius: 8px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 600;
}

body.light-mode .back-to-top {
    background-color: #2A2A2A;
    color: #00FF00;
}

body.dark-mode .back-to-top {
    background-color: #1E1E1E;
    color: #00FF00;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    animation: fadeInUp 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55), subtlePulse 3s infinite;
}

.back-to-top:hover {
    transform: translateY(-8px) scale(1.15);
    box-shadow: 0 12px 35px rgba(0, 255, 0, 0.6);
    background-color: rgba(0, 255, 0, 0.25);
    border-width: 3px;
}

.back-to-top:active {
    transform: translateY(-4px) scale(1.05);
    box-shadow: 0 6px 20px rgba(0, 255, 0, 0.4);
}

/* ==========================================
   ANIMATIONS
   ========================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px) scale(0.8);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes subtlePulse {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(0, 255, 0, 0.4);
    }
    50% {
        box-shadow: 0 0 0 15px rgba(0, 255, 0, 0);
    }
}

/* ==========================================
   RESPONSIVE - BACK TO TOP
   ========================================== */
@media (max-width: 768px) {
    .back-to-top {
        width: 36px;
        height: 36px;
        bottom: 20px;
        right: 20px;
        font-size: 18px;
    }
}

@media (max-width: 480px) {
    .back-to-top {
        width: 32px;
        height: 32px;
        bottom: 15px;
        right: 15px;
        font-size: 16px;
    }
}