:root {
    --bg-color: #f0f2f5;
    --text-color: #333;
    --container-bg: #ffffff;
    --container-shadow: rgba(0, 0, 0, 0.1);
    --grid-color: #f9f9f9;
    --btn-bg: #007bff;
    --btn-hover: #0056b3;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --container-bg: #1e1e1e;
    --container-shadow: rgba(0, 0, 0, 0.5);
    --grid-color: #1a1a1a;
    --btn-bg: #3b82f6;
    --btn-hover: #2563eb;
}

body {
    font-family: 'Helvetica Neue', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    background-image: linear-gradient(45deg, var(--grid-color) 25%, transparent 25%),
                      linear-gradient(-45deg, var(--grid-color) 25%, transparent 25%),
                      linear-gradient(45deg, transparent 75%, var(--grid-color) 75%),
                      linear-gradient(-45deg, transparent 75%, var(--grid-color) 75%);
    background-size: 20px 20px;
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

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

.theme-toggle {
    position: absolute;
    top: 15px;
    right: 15px;
    background: none;
    border: 2px solid var(--text-color);
    color: var(--text-color);
    padding: 5px 12px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.theme-toggle:hover {
    background-color: var(--text-color);
    color: var(--container-bg);
}

h1 {
    margin-bottom: 30px;
}

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

.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 15px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease;
    cursor: default;
}

#generate-btn {
    background-color: var(--btn-bg);
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 18px;
    border-radius: 50px;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s, transform 0.3s;
    box-shadow: 0 4px 15px rgba(0, 123, 255, 0.4);
}

#generate-btn:hover {
    background-color: var(--btn-hover);
    box-shadow: 0 6px 20px rgba(0, 123, 255, 0.5);
    transform: translateY(-2px);
}

#generate-btn:active {
    transform: translateY(1px);
    box-shadow: 0 2px 10px rgba(0, 123, 255, 0.4);
}