:root {
    --bg-color: #f4f4f9;
    --text-color: #333;
    --container-bg: #ffffff;
    --heading-color: #2c3e50;
    --tagline-color: #7f8c8d;
    --feature-bg: #f8f9fa;
    --border-color: #e9ecef;
    --footer-color: #6c757d;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --container-bg: #1e1e1e;
    --heading-color: #ecf0f1;
    --tagline-color: #bdc3c7;
    --feature-bg: #2d2d2d;
    --border-color: #444;
    --footer-color: #95a5a6;
    --shadow-color: rgba(0, 0, 0, 0.5);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
}

.container {
    background-color: var(--container-bg);
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px var(--shadow-color);
    max-width: 500px;
    width: 100%;
    text-align: center;
}

.logo {
    max-width: 150px;
    height: auto;
    margin-bottom: 1rem;
}

.logo-dark {
    display: none;
}

h1 {
    color: var(--heading-color);
    margin-top: 0;
    margin-bottom: 0.5rem;
}

.tagline {
    color: var(--tagline-color);
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

.features {
    text-align: left;
    background: var(--feature-bg);
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    border: 1px solid var(--border-color);
}

footer {
    font-size: 0.9rem;
    color: var(--footer-color);
}

#theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    color: var(--text-color);
}

[data-theme="dark"] .logo-light {
    display: none;
}

[data-theme="dark"] .logo-dark {
    display: inline-block;
}