:root {
    --background-color: #f4f6f9;
    --container-background: #ffffff;
    --text-color: #333333;
    --subtle-text-color: #555555;
    --button-background: #007bff;
    --button-hover: #0056b3;
    --number-background: #4CAF50;
    --number-color: white;
    --border-color: #e0e0e0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: var(--background-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
    line-height: 1.6;
}

body.dark-mode {
    --background-color: #121212;
    --container-background: #1e1e1e;
    --text-color: #e0e0e0;
    --subtle-text-color: #aaaaaa;
    --button-background: #bb86fc;
    --button-hover: #a063f5;
    --number-background: #6200ee;
    --border-color: #333333;
}

header {
    width: 100%;
    text-align: center;
    padding: 20px 0;
    position: relative;
    border-bottom: 1px solid var(--border-color);
}

#theme-toggle {
    position: absolute;
    top: 50%;
    right: 20px;
    transform: translateY(-50%);
    background-color: var(--button-background);
    color: var(--number-color);
    border: none;
    padding: 10px 15px;
    font-size: 14px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

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

.container {
    text-align: center;
    background: var(--container-background);
    padding: 30px 40px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    width: 100%;
    max-width: 700px;
    margin: 30px 20px;
}

h1, h2, h3 {
    color: var(--text-color);
    margin-bottom: 0.5em;
}

.content-section {
    text-align: left;
    margin-bottom: 30px;
    color: var(--subtle-text-color);
}

.content-section h2, .content-section h3 {
    border-bottom: 2px solid var(--button-background);
    padding-bottom: 5px;
    margin-bottom: 15px;
    display: inline-block;
}

.content-section p {
    margin-bottom: 10px;
}

.generator-section {
    margin: 30px 0;
}

.numbers {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
}

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--number-background);
    color: var(--number-color);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
}

#generate {
    background-color: var(--button-background);
    color: var(--number-color);
    border: none;
    padding: 15px 30px;
    font-size: 18px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    font-weight: bold;
}

#generate:hover {
    background-color: var(--button-hover);
}

footer {
    width: 100%;
    text-align: center;
    padding: 20px 0;
    margin-top: auto;
    background-color: var(--container-background);
    color: var(--subtle-text-color);
    border-top: 1px solid var(--border-color);
    font-size: 14px;
}