:root {
    --bg-gradient-start: #fbc2eb;
    --bg-gradient-end: #a6c1ee;
    --container-bg: #ffffff;
    --text-color: #333;
    --number-bg: #f0f2f5;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

.dark-mode {
    --bg-gradient-start: #2c3e50;
    --bg-gradient-end: #000000;
    --container-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --number-bg: #333;
    --shadow-color: rgba(0, 0, 0, 0.5);
}

body {
    font-family: 'Helvetica Neue', sans-serif;
    background-color: #f0f2f5;
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-image: linear-gradient(to top, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    transition: background-image 0.3s ease, color 0.3s ease;
}

.container {
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 10px 30px var(--shadow-color);
    text-align: center;
    max-width: 500px;
    width: 90%;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
    position: relative;
}

h1 {
    font-size: 2.5rem;
    color: var(--text-color);
    margin-bottom: 30px;
}

.lotto-numbers {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
}

.number {
    background-color: var(--number-bg);
    color: var(--text-color);
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: bold;
    box-shadow: 0 4px 10px var(--shadow-color);
    transition: all 0.3s ease;
}

#generate-btn {
    background-color: #4CAF50;
    color: white;
    padding: 15px 30px;
    border: none;
    border-radius: 10px;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
    box-shadow: 0 4px 15px rgba(76, 175, 80, 0.4);
}

#generate-btn:hover {
    background-color: #45a049;
    box-shadow: 0 6px 20px rgba(76, 175, 80, 0.5);
}

#theme-toggle {
    position: absolute;
    top: 15px;
    right: 15px;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    transition: background-color 0.3s ease;
}

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