:root {
    --bg-color: #f0f2f5;
    --bg-gradient: linear-gradient(45deg, #d2f7d2, #a8e6cf, #81cfe0, #5ac8d8, #32c3d0);
    --container-bg: white;
    --text-color: #333;
    --heading-color: #2c3e50;
    --btn-bg: #3498db;
    --btn-hover: #2980b9;
    --number-bg: #ecf0f1;
    --number-text: #34495e;
    --shadow: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --bg-gradient: linear-gradient(45deg, #2c3e50, #000000);
    --container-bg: #2d2d2d;
    --text-color: #f0f2f5;
    --heading-color: #ecf0f1;
    --btn-bg: #e67e22;
    --btn-hover: #d35400;
    --number-bg: #3e3e3e;
    --number-text: #ecf0f1;
    --shadow: rgba(0, 0, 0, 0.5);
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-image: var(--bg-gradient);
    transition: background 0.3s ease, color 0.3s ease;
}

.container {
    text-align: center;
    background: var(--container-bg);
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--shadow);
    width: 90%;
    max-width: 500px;
    position: relative;
    transition: background 0.3s ease, box-shadow 0.3s ease;
}

#theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
    padding: 5px;
    border-radius: 50%;
    transition: transform 0.3s ease;
}

#theme-toggle:hover {
    transform: rotate(20deg);
}

h1 {
    font-size: 2.5em;
    margin-bottom: 20px;
    color: var(--heading-color);
}

#generate-btn {
    background-color: var(--btn-bg);
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.2em;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s, transform 0.1s;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

#generate-btn:active {
    transform: scale(0.98);
}

#generate-btn:hover {
    background-color: var(--btn-hover);
}

#numbers-container {
    margin-top: 30px;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
}

.divider {
    margin: 40px 0;
    border: none;
    border-top: 1px solid var(--shadow);
}

.contact-section {
    margin-top: 20px;
    text-align: left;
}

.contact-section h2 {
    font-size: 1.5rem;
    color: var(--heading-color);
    margin-bottom: 20px;
    text-align: center;
}

.form-group {
    margin-bottom: 15px;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--number-bg);
    border-radius: 8px;
    background-color: var(--number-bg);
    color: var(--text-color);
    font-family: inherit;
    box-sizing: border-box;
    transition: border-color 0.3s;
}

.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--btn-bg);
}

.form-group textarea {
    height: 100px;
    resize: none;
}

#submit-btn {
    width: 100%;
    background-color: #2ecc71;
    color: white;
    border: none;
    padding: 12px;
    border-radius: 8px;
    font-size: 1.1em;
    cursor: pointer;
    transition: background-color 0.3s;
}

#submit-btn:hover {
    background-color: #27ae60;
}

.form-note {
    font-size: 0.8rem;
    color: #888;
    margin-top: 10px;
    text-align: center;
}


@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(0.8);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}