:root {
    --bg-color: #f0f2f5;
    --container-bg-color: #ffffff;
    --text-color: #333;
    --button-bg-color: #4CAF50;
    --button-hover-bg-color: #45a049;
    --button-shadow-color: rgba(76, 175, 80, 0.4);
    --button-hover-shadow-color: rgba(76, 175, 80, 0.5);
    --circle-bg-color: #f8f9fa;
    --circle-border-color: #dee2e6;
    --circle-text-color: #495057;
    --circle-shadow-color: rgba(0, 0, 0, 0.05);
}

.dark-mode {
    --bg-color: #2c2c2c;
    --container-bg-color: #3c3c3c;
    --text-color: #f0f2f5;
    --button-bg-color: #6a1b9a;
    --button-hover-bg-color: #4a148c;
    --button-shadow-color: rgba(106, 27, 154, 0.4);
    --button-hover-shadow-color: rgba(106, 27, 154, 0.5);
    --circle-bg-color: #495057;
    --circle-border-color: #6c757d;
    --circle-text-color: #f8f9fa;
    --circle-shadow-color: rgba(255, 255, 255, 0.1);
}

@layer base, components;

@layer base {
    body {
        font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
        display: flex;
        flex-direction: column; /* Changed to column to accommodate theme switch */
        justify-content: center;
        align-items: center;
        min-height: 100vh;
        background-color: var(--bg-color);
        transition: background-color 0.3s ease;
    }

    .container {
        text-align: center;
        padding: 2rem;
        background-color: var(--container-bg-color);
        border-radius: 1rem;
        box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
        width: 90%;
        max-width: 400px;
        container-type: inline-size;
        transition: background-color 0.3s ease, color 0.3s ease;
    }

    h1 {
        font-size: 2rem;
        color: var(--text-color);
        margin-bottom: 1.5rem;
        transition: color 0.3s ease;
    }
}

.theme-switch-wrapper {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
}

.theme-switch {
    display: inline-block;
    height: 34px;
    position: relative;
    width: 60px;
}

.theme-switch input {
    display: none;
}

.slider {
    background-color: #ccc;
    bottom: 0;
    cursor: pointer;
    left: 0;
    position: absolute;
    right: 0;
    top: 0;
    transition: .4s;
}

.slider:before {
    background-color: #fff;
    bottom: 4px;
    content: "";
    height: 26px;
    left: 4px;
    position: absolute;
    transition: .4s;
    width: 26px;
}

input:checked + .slider {
    background-color: #66bb6a;
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

@layer components {
    #generate-btn {
        background-color: var(--button-bg-color);
        color: white;
        padding: 1rem 2rem;
        border: none;
        border-radius: 0.5rem;
        font-size: 1rem;
        cursor: pointer;
        transition: all 0.3s ease;
        box-shadow: 0 4px 15px var(--button-shadow-color);
    }

    #generate-btn:hover {
        background-color: var(--button-hover-bg-color);
        transform: translateY(-2px);
        box-shadow: 0 6px 20px var(--button-hover-shadow-color);
    }

    #numbers-container {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
        margin-top: 2rem;
    }

    .number-circle {
        width: 50px;
        height: 50px;
        background-color: var(--circle-bg-color);
        border: 2px solid var(--circle-border-color);
        border-radius: 50%;
        display: flex;
        justify-content: center;
        align-items: center;
        font-size: 1.5rem;
        font-weight: bold;
        color: var(--circle-text-color);
        box-shadow: 0 2px 5px var(--circle-shadow-color);
        transition: background-color 0.3s ease, border-color 0.3s ease, color 0.3s ease, box-shadow 0.3s ease;
    }
}

@container (max-width: 350px) {
    h1 {
        font-size: 1.5rem;
    }

    #generate-btn {
        padding: 0.8rem 1.5rem;
        font-size: 0.9rem;
    }

    .number-circle {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
}