:root {
    --bg-color: #f0f2f5;
    --container-bg: #fff;
    --text-color: #333;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --btn-shadow: rgba(76, 175, 80, 0.4);
    --btn-shadow-hover: rgba(76, 175, 80, 0.6);
}

[data-theme="dark"] {
    --bg-color: #1a1a2e;
    --container-bg: #16213e;
    --text-color: #eee;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --btn-shadow: rgba(76, 175, 80, 0.6);
    --btn-shadow-hover: rgba(76, 175, 80, 0.8);
}

body {
    font-family: 'Arial', 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;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    background-color: var(--container-bg);
    box-shadow: 0 4px 10px var(--shadow-color);
    cursor: pointer;
    font-size: 24px;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
}

#theme-toggle:hover {
    transform: scale(1.1);
}

#theme-toggle .icon-sun {
    display: block;
    color: #f39c12;
}

#theme-toggle .icon-moon {
    display: none;
    color: #9b59b6;
}

[data-theme="dark"] #theme-toggle .icon-sun {
    display: none;
}

[data-theme="dark"] #theme-toggle .icon-moon {
    display: block;
}

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 20px var(--shadow-color);
    transition: all 0.3s ease;
}

h1 {
    color: var(--text-color);
    margin-bottom: 30px;
    transition: color 0.3s ease;
}

.numbers-container {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
}

.number {
    width: 60px;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    color: #fff;
    border-radius: 50%;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

#generate-btn {
    background-color: #4CAF50;
    color: white;
    padding: 15px 30px;
    font-size: 18px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s;
    box-shadow: 0 4px 15px var(--btn-shadow);
}

#generate-btn:hover {
    background-color: #45a049;
    box-shadow: 0 6px 20px var(--btn-shadow-hover);
}