:root {
    --bg-color: #f0f2f5;
    --container-bg: white;
    --text-color: #333;
    --btn-bg: #007bff;
    --btn-hover: #0056b3;
    --number-bg: #4CAF50;
    --number-text: white;
    --shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    --nav-bg: #ffffff;
}

.dark-theme {
    --bg-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --btn-bg: #3700b3;
    --btn-hover: #6200ee;
    --number-bg: #03dac6;
    --number-text: #000;
    --shadow: 0 10px 20px rgba(0, 0, 0, 0.5);
    --nav-bg: #1e1e1e;
}

body {
    font-family: 'Noto Sans KR', 'Arial', sans-serif;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.navbar {
    display: flex;
    justify-content: center;
    gap: 20px;
    padding: 15px;
    background-color: var(--nav-bg);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: bold;
    transition: color 0.3s;
}

.navbar a:hover {
    color: var(--btn-bg);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 40px 20px;
}

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 40px;
    border-radius: 15px;
    box-shadow: var(--shadow);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
    width: 100%;
    max-width: 600px;
    margin-bottom: 30px;
}

h1 {
    color: var(--text-color);
    margin-bottom: 30px;
}

.info-section {
    text-align: left;
    margin-top: 40px;
    line-height: 1.8;
}

.info-section h2 {
    border-left: 5px solid var(--btn-bg);
    padding-left: 10px;
    margin-bottom: 15px;
}

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

.number {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--number-bg);
    color: var(--number-text);
    font-size: 24px;
    font-weight: bold;
    transition: background-color 0.3s ease, color 0.3s ease;
}

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

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

.contact-form {
    margin-top: 40px;
    text-align: left;
}

.contact-form hr, #disqus_container hr {
    border: 0;
    border-top: 1px solid var(--text-color);
    opacity: 0.2;
    margin: 30px 0;
}

.contact-form h3 {
    margin-bottom: 15px;
}

.contact-form form {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.contact-form input, 
.contact-form textarea {
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    background-color: var(--container-bg);
    color: var(--text-color);
}

.contact-form textarea {
    height: 100px;
    resize: none;
}

.contact-form button {
    background-color: var(--btn-bg);
    color: white;
    border: none;
    padding: 10px;
    border-radius: 4px;
    cursor: pointer;
}

.contact-form button:hover {
    background-color: var(--btn-hover);
}

#disqus_container {
    margin-top: 40px;
    text-align: left;
}

footer {
    text-align: center;
    padding: 30px;
    background-color: var(--nav-bg);
    border-top: 1px solid rgba(0,0,0,0.05);
}

footer p {
    font-size: 14px;
    opacity: 0.7;
}

.footer-links {
    margin-top: 10px;
}

.footer-links a {
    margin: 0 10px;
    text-decoration: none;
    color: var(--text-color);
    font-size: 13px;
}

#theme-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--btn-bg);
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 50px;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
    z-index: 1000;
}

.back-link {
    display: inline-block;
    margin-top: 20px;
    text-decoration: none;
    color: var(--btn-bg);
}