:root {
    --bg-color: #f0f2f5;
    --container-bg: white;
    --text-color: #333;
    --number-bg: #eee;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --button-bg: #007bff;
    --button-hover-bg: #0056b3;
    --button-text-color: white;
}

body.dark-mode {
    --bg-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #f0f2f5;
    --number-bg: #333;
    --shadow-color: rgba(0, 0, 0, 0.3);
}

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

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 25px var(--shadow-color);
    transition: background-color 0.3s ease;
}

h1 {
    color: var(--text-color);
    margin-bottom: 20px;
}

#theme-toggle {
    background-color: var(--number-bg);
    color: var(--text-color);
    border: 1px solid var(--text-color);
    padding: 8px 15px;
    font-size: 14px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease, color 0.3s ease;
    margin-bottom: 20px;
}

#theme-toggle:hover {
    background-color: var(--text-color);
    color: var(--container-bg);
}

.numbers {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
}

.number {
    display: inline-block;
    width: 50px;
    height: 50px;
    line-height: 50px;
    border-radius: 50%;
    background-color: var(--number-bg);
    margin: 0 10px;
    font-size: 24px;
    font-weight: bold;
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

#generate {
    background-color: var(--button-bg);
    color: var(--button-text-color);
    border: none;
    padding: 15px 30px;
    font-size: 18px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

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

.nav-link, .back-link {
    display: inline-block;
    background-color: var(--button-bg);
    color: var(--button-text-color);
    border: none;
    padding: 10px 20px;
    font-size: 16px;
    border-radius: 8px;
    cursor: pointer;
    text-decoration: none; /* Remove underline from links */
    transition: background-color 0.3s ease;
    margin-top: 20px; /* Space from other elements */
    margin-bottom: 20px;
}

.nav-link:hover, .back-link:hover {
    background-color: var(--button-hover-bg);
}

form {
    margin-top: 30px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

form label {
    color: var(--text-color);
    margin-bottom: 8px;
    font-weight: bold;
    align-self: flex-start; /* Align labels to the left */
}

form input[type="text"],
form input[type="email"],
form textarea {
    width: 100%;
    padding: 12px;
    margin-bottom: 20px;
    border: 1px solid var(--number-bg);
    border-radius: 8px;
    font-size: 16px;
    background-color: var(--number-bg);
    color: var(--text-color);
    transition: border-color 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

form input[type="text"]:focus,
form input[type="email"]:focus,
form textarea:focus {
    border-color: var(--button-bg);
    outline: none;
}

#form-submit {
    background-color: var(--button-bg);
    color: var(--button-text-color);
    border: none;
    padding: 15px 30px;
    font-size: 18px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    width: auto; /* Allow button to size naturally */
    margin-top: 10px;
}

#form-submit:hover {
    background-color: var(--button-hover-bg);
}