:root {
    --primary-color: #4a90e2;
    --background-color: #f0f4f8;
    --text-color: #333;
    --white: #fff;
    --container-bg: #fff;
    --shadow: rgba(0, 0, 0, 0.1);
    --toggle-bg: #e2e8f0;
    --toggle-color: #333;
}

[data-theme="dark"] {
    --primary-color: #60a5fa;
    --background-color: #0f172a;
    --text-color: #e2e8f0;
    --white: #1e293b;
    --container-bg: #1e293b;
    --shadow: rgba(0, 0, 0, 0.4);
    --toggle-bg: #334155;
    --toggle-color: #e2e8f0;
}

* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    background-color: var(--toggle-bg);
    color: var(--toggle-color);
    border: none;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 8px var(--shadow);
    z-index: 100;
}

#theme-toggle:hover {
    transform: scale(1.1);
    background-color: var(--toggle-bg);
}

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 10px 20px var(--shadow);
}

h1 {
    margin-top: 0;
    color: var(--primary-color);
}

button#generate {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    padding: 12px 24px;
    font-size: 16px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.1s ease;
}

button#generate:hover {
    background-color: #357abd;
}

[data-theme="dark"] button#generate:hover {
    background-color: #3b82f6;
}

#numbers {
    margin-top: 30px;
    font-size: 24px;
    font-weight: bold;
    display: flex;
    justify-content: center;
    gap: 10px;
}

.number-circle {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--background-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    border: 2px solid var(--primary-color);
}

.contact-link {
    display: inline-block;
    margin-top: 24px;
    font-size: 14px;
    color: var(--primary-color);
    text-decoration: none;
    opacity: 0.8;
}

.contact-link:hover {
    opacity: 1;
    text-decoration: underline;
}