body {
    background: linear-gradient(-45deg, #ffffff, #f5f5f7, #e8e8ed, #ffffff);
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
}

@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}
:root {
    --glass-bg: rgba(255, 255, 255, 0.4);
    --glass-border: rgba(255, 255, 255, 0.2);
    --apple-blue: #0071e3;
}

/* Der Glas-Effekt für Karten */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(15px) saturate(180%);
    -webkit-backdrop-filter: blur(15px) saturate(180%);
    border: 1px solid var(--glass-border);
    border-radius: 30px;
    box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.07);
}

/* Scroll Reveal Initialzustand */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s cubic-bezier(0.2, 0, 0.2, 1);
}

/* Zustand wenn sichtbar */
.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Bubble Hover Animation */
.bubble-btn {
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.bubble-btn:hover {
    transform: scale(1.08) translateY(-2px);
}

/* Back to Top Button im Glas-Look */
#backToTop {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    opacity: 0; /* Standardmäßig unsichtbar */
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 1001;
    color: var(--apple-black);
    font-size: 20px;
}

/* Erscheinen-Zustand */
#backToTop.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* Bubble-Hover-Effekt */
#backToTop:hover {
    transform: scale(1.15) translateY(-5px);
    background: rgba(255, 255, 255, 0.8);
    color: var(--apple-blue);
}