:root {
    --bg-gradient: linear-gradient(to right, #ff7e5f, #feb47b);
    --container-bg: white;
    --text-color: #333;
    --shadow-color: rgba(0,0,0,0.1);
    --btn-bg: #4CAF50;
    --btn-color: white;
}

.dark-mode {
    --bg-gradient: linear-gradient(to right, #2c3e50, #000000);
    --container-bg: #1e1e1e;
    --text-color: #f1f1f1;
    --shadow-color: rgba(255,255,255,0.05);
    --btn-bg: #388E3C;
}

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

.container {
    text-align: center;
    background-color: var(--container-bg);
    color: var(--text-color);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 0 20px var(--shadow-color);
    transition: background-color 0.3s ease, color 0.3s ease;
    position: relative;
}

.theme-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    padding: 5px 10px;
    font-size: 14px;
    background-color: transparent;
    border: 1px solid var(--text-color);
    color: var(--text-color);
    border-radius: 5px;
    margin-bottom: 0;
}

button#generate {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    margin-bottom: 20px;
    border: none;
    border-radius: 5px;
    background-color: var(--btn-bg);
    color: var(--btn-color);
}

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

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}