:root {
    --bg-color: #f0f4f8;
    --text-color: #0b132b;
    --card-bg: #ffffff;
    --ball-text: #000;
    --battery-border: #aaa;
    --btn-bg: #22c55e;
    --btn-hover: #16a34a;
    --toggle-bg: #fff;
    --toggle-text: #333;
}

[data-theme="dark"] {
    --bg-color: #0b132b;
    --text-color: #ffffff;
    --card-bg: #1c2541;
    --ball-text: #000;
    --battery-border: #aaa;
    --btn-bg: #22c55e;
    --btn-hover: #16a34a;
    --toggle-bg: #333;
    --toggle-text: #f0f0f0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: 'Pretendard', 'Apple SD Gothic Neo', Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding-top: 100px;
    padding-bottom: 60px;
    transition: background-color 0.3s, color 0.3s;
    gap: 80px;
}

/* Header & Nav */
.main-header {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--card-bg);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 1000;
}

.nav-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo { font-size: 22px; font-weight: 800; margin: 0; color: var(--btn-bg); }

.nav-links {
    list-style: none;
    display: flex;
    gap: 25px;
    margin: 0;
    padding: 0;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 600;
    font-size: 15px;
    transition: color 0.3s;
}

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

/* Sections */
.content-wrapper { width: 100%; display: flex; flex-direction: column; align-items: center; gap: 80px; }

.section-desc { max-width: 430px; margin: 10px auto 30px; opacity: 0.8; line-height: 1.6; }

.info-section {
    width: 100%;
    padding: 80px 20px;
    background: var(--card-bg);
    text-align: center;
}

.info-section.alternate { background: var(--bg-color); }

.container { max-width: 1000px; margin: 0 auto; }

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.info-card {
    padding: 30px;
    border-radius: 15px;
    background: var(--bg-color);
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

.info-card h3 { margin-top: 0; color: var(--btn-bg); }
.note { font-size: 13px; opacity: 0.6; margin-top: 20px; }

/* Footer */
.site-footer {
    width: 100%;
    padding: 40px 20px;
    background: var(--card-bg);
    text-align: center;
    border-top: 1px solid rgba(0,0,0,0.1);
}

.footer-links { margin-bottom: 10px; }
.footer-links a { color: var(--text-color); text-decoration: none; font-size: 14px; margin: 0 10px; }
.site-footer p { font-size: 13px; opacity: 0.6; }

@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-container { justify-content: center; }
}

@media (max-width: 480px) {
    .headerRow, .set, .contact-container, .disqus-container, .wrapper { width: 90vw; }
}