:root {
    --bg-color: #f0f2f5;
    --container-bg: #fff;
    --text-color: #333;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --number-bg: #eee;
    --btn-bg: #4CAF50;
    --btn-hover: #45a049;
    --toggle-bg: #333;
    --toggle-text: #fff;
}

[data-theme='dark'] {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f2f5;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --number-bg: #444;
    --btn-bg: #2e7d32;
    --btn-hover: #1b5e20;
    --toggle-bg: #f0f2f5;
    --toggle-text: #333;
}

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

.container {
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 8px var(--shadow-color);
    text-align: center;
    transition: background-color 0.3s, box-shadow 0.3s;
    position: relative;
    width: 100%;
    max-width: 400px;
}

.back-link {
    position: absolute;
    top: 10px;
    left: 10px;
    text-decoration: none;
    color: var(--text-color);
    font-size: 0.8rem;
    opacity: 0.7;
    transition: opacity 0.3s;
}

.back-link:hover {
    opacity: 1;
}

.affiliate-form {
    text-align: left;
    margin-top: 1rem;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: bold;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--number-bg);
    border-radius: 5px;
    background-color: var(--container-bg);
    color: var(--text-color);
    font-family: inherit;
    box-sizing: border-box;
}

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

#generate {
    position: absolute;
    top: 10px;
    right: 10px;
    background-color: var(--toggle-bg);
    color: var(--toggle-text);
    border: none;
    border-radius: 5px;
    padding: 5px 10px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: background-color 0.3s, color 0.3s;
}

h1 {
    margin-bottom: 2rem;
}

.numbers {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

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

#generate {
    background-color: var(--btn-bg);
    color: white;
    padding: 1rem 2rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
}

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