:root {
    --purple-blue-gradient: linear-gradient(45deg, #6a11cb 0%, #2575fc 100%);
    --shadow-color: rgba(106, 17, 203, 0.5);
    --font-family: 'Poppins', sans-serif;
    
    /* Light Mode (Default) */
    --background-color: #f0f2f5;
    --card-background: rgba(255, 255, 255, 0.9);
    --text-color: #333333;
    --card-border: rgba(0, 0, 0, 0.1);
    --ball-text-color: #ffffff;
}

[data-theme="dark"] {
    /* Dark Mode */
    --background-color: #121212;
    --card-background: rgba(255, 255, 255, 0.05);
    --text-color: #ffffff;
    --card-border: rgba(255, 255, 255, 0.1);
    --ball-text-color: #ffffff;
}

body {
    font-family: var(--font-family);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: var(--background-color);
    background-image: radial-gradient(circle at 10% 20%, rgba(129, 39, 210, 0.1), transparent 30%),
                      radial-gradient(circle at 80% 90%, rgba(37, 117, 252, 0.1), transparent 30%);
    color: var(--text-color);
    padding: 20px;
    box-sizing: border-box;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.card {
    background: var(--card-background);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 20px;
    border: 1px solid var(--card-border);
    padding: 40px;
    text-align: center;
    max-width: 600px;
    width: 100%;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.2);
    transition: background 0.3s ease, border 0.3s ease;
    position: relative;
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.5rem;
    color: var(--text-color);
    padding: 5px;
    border-radius: 50%;
    transition: background-color 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background-color: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .theme-toggle:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.title {
    font-size: 3rem;
    font-weight: 700;
    background: var(--purple-blue-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 16px;
}

.description {
    font-size: 1.1rem;
    margin-bottom: 30px;
    opacity: 0.8;
}

.generator-btn {
    font-family: var(--font-family);
    font-size: 1.2rem;
    font-weight: 600;
    padding: 15px 35px;
    cursor: pointer;
    background: var(--purple-blue-gradient);
    color: white;
    border: none;
    border-radius: 50px;
    transition: all 0.3s ease;
    box-shadow: 0 0 15px 0 var(--shadow-color), 0 0 20px 0 var(--shadow-color);
    margin-top: 30px;
}

.generator-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 0 25px 0 var(--shadow-color), 0 0 40px 0 var(--shadow-color);
}

.numbers-container {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
    min-height: 80px;
}

.number-ball {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--text-color);
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.5), 0 2px 5px rgba(0, 0, 0, 0.3);
    animation: pop-in 0.5s cubic-bezier(0.68, -0.55, 0.27, 1.55);
    animation-fill-mode: forwards;
    transform: scale(0);
}

@keyframes pop-in {
    to {
        transform: scale(1);
    }
}

/* Color styles for number balls */
.ball-color-1 { background-color: #fbc02d; } /* Yellow */
.ball-color-2 { background-color: #1e88e5; } /* Blue */
.ball-color-3 { background-color: #d81b60; } /* Red */
.ball-color-4 { background-color: #8e8e8e; } /* Gray */
.ball-color-5 { background-color: #388e3c; } /* Green */

@media (max-width: 600px) {
    .card {
        padding: 30px;
    }
    .title {
        font-size: 2.5rem;
    }
    .number-ball {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }
    .generator-btn {
        padding: 12px 30px;
        font-size: 1.1rem;
    }
}