*, *::before, *::after {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    padding: 0;
}

main {
    /* Vibrant gradient background */
    background: #667eea;
    background: -webkit-linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    
    background-repeat: no-repeat;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    font-family: "Oxygen", sans-serif;
    padding: 20px;
    transition: background 0.8s ease;
}

.card {
    background: rgba(255, 255, 255, 0.15);
    -webkit-backdrop-filter: blur(10px); /* Safari 9+, iOS 9+ */
    backdrop-filter: blur(10px);
    border-radius: 24px;
    padding: 48px 40px;
    box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37),
                0 0 0 1px rgba(255, 255, 255, 0.18) inset;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
    max-width: 500px;
    width: 100%;
    animation: fadeIn 0.6s ease-out;
    margin-top: 3em;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#title {
    margin: 0;
    font-size: 2.5rem;
    font-weight: 300;
    color: white;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease;
}

#activity {
    margin: 0;
    font-size: 1.25rem;
    color: white;
    text-align: center;
    min-height: 60px;
    display: flex;
    align-items: center;
    line-height: 1.6;
    transition: all 0.3s ease;
    font-weight: 700;
    text-decoration: underline;
}

button {
    position: relative;
    height: 140px;
    width: 140px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: none;
    cursor: pointer;
    outline: none;
    box-shadow: 0 8px 24px rgba(102, 126, 234, 0.5);
    transition: all 0.3s ease;
    animation: pulse 2s infinite;
    overflow: hidden;
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 8px 24px rgba(102, 126, 234, 0.5);
    }
    50% {
        box-shadow: 0 8px 32px rgba(102, 126, 234, 0.8),
                    0 0 20px rgba(102, 126, 234, 0.4);
    }
}

button::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, 
        transparent 30%, 
        rgba(255, 255, 255, 0.3) 50%, 
        transparent 70%);
    animation: shine 3s infinite;
}

@keyframes shine {
    0% {
        transform: translateX(-100%) translateY(-100%);
    }
    100% {
        transform: translateX(100%) translateY(100%);
    }
}

button:hover {
    transform: scale(1.1);
    box-shadow: 0 12px 32px rgba(102, 126, 234, 0.7);
}

button:active {
    transform: scale(0.95);
}

.button-text {
    position: relative;
    z-index: 1;
    color: white;
    font-weight: bold;
    font-size: 1.1rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.fun {
    /* Energetic gradient */
    background: linear-gradient(135deg, #ce0526 0%, #5f0986 100%);
}

.fun .card {
    animation: celebrate 0.6s ease-out;
}

@keyframes celebrate {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.fun button {
    background: linear-gradient(135deg, #f5576c 0%, #f093fb 100%);
    animation: pulseActive 2s infinite;
}

@keyframes pulseActive {
    0%, 100% {
        box-shadow: 0 8px 24px rgba(245, 87, 108, 0.5);
    }
    50% {
        box-shadow: 0 8px 32px rgba(245, 87, 108, 0.8),
                    0 0 20px rgba(245, 87, 108, 0.4);
    }
}