:root {
    --bg-color: #f0f0f0;
    --container-bg: transparent;
    --text-color: #333;
    --button-bg: #4CAF50;
    --button-text: white;
    --number-bg: #fff;
    --number-text: #333;
    --shadow: rgba(0,0,0,0.2);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --text-color: #f0f0f0;
    --button-bg: #2e7d32;
    --button-text: #e0e0e0;
    --number-bg: #333;
    --number-text: #fff;
    --shadow: rgba(255,255,255,0.1);
}

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

.container {
    text-align: center;
    padding: 2rem;
    background-color: var(--container-bg);
    border-radius: 15px;
}

.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
}

#toggle-btn {
    background: none;
    border: 2px solid var(--button-bg);
    color: var(--text-color);
    padding: 8px 16px;
    cursor: pointer;
    border-radius: 20px;
    font-weight: bold;
    transition: all 0.3s;
}

#toggle-btn:hover {
    background-color: var(--button-bg);
    color: var(--button-text);
}

button#generate {
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 15px 32px;
    font-size: 18px;
    margin: 20px 0;
    cursor: pointer;
    border-radius: 30px;
    border: none;
    box-shadow: 0 4px 15px var(--shadow);
    transition: transform 0.1s, box-shadow 0.3s;
}

button#generate:active {
    transform: scale(0.95);
}

.numbers-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 30px;
}

.number {
    width: 60px;
    height: 60px;
    background-color: var(--number-bg);
    color: var(--number-text);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    box-shadow: 0 4px 8px var(--shadow);
    transition: all 0.3s;
}

.contact-section {
    margin-top: 50px;
    text-align: left;
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
}

.contact-section hr {
    border: 0;
    border-top: 1px solid var(--shadow);
    margin-bottom: 30px;
}

.contact-section h3 {
    text-align: center;
    margin-bottom: 20px;
}

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

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

.form-group textarea {
    height: 100px;
    resize: vertical;
}

#submit-btn {
    width: 100%;
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 12px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: bold;
    transition: opacity 0.3s;
}

#submit-btn:hover {
    opacity: 0.9;
}