header {
    background: rgba(17, 24, 39, 0.95);
    backdrop-filter: blur(8px);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    padding: 0.75rem 2rem;
    box-shadow: 0 2px 10px rgba(45, 212, 191, 0.3);
    height: 4rem;
}
.btn-primary {
    background: linear-gradient(45deg, #2dd4bf, #8b5cf6);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    font-size: 0.9rem;
    touch-action: manipulation;
}
.btn-primary::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: all 0.4s ease;
}
.btn-primary:hover::after {
    width: 200%;
    height: 200%;
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(45, 212, 191, 0.5);
}
.btn-auth-off {
    background: linear-gradient(45deg, #4b5563, #6b7280);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    touch-action: manipulation;
}
.btn-auth-on {
    background: linear-gradient(45deg, #2dd4bf, #8b5cf6);
    box-shadow: 0 0 15px rgba(45, 212, 191, 0.5);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}
.btn-auth-off:hover, .btn-auth-on:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(45, 212, 191, 0.5);
}
.btn-auth-off::after, .btn-auth-on::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: all 0.4s ease;
}
.btn-auth-off:hover::after, .btn-auth-on:hover::after {
    width: 200%;
    height: 200%;
}
@media (max-width: 640px) {
    header {
        padding: 0.5rem 1rem;
    }
}