:root {
    --bg-color: #ffffff;
    --secondary-bg: #f5f5f7;
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --border-color: #e8e8ed;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --max-width: 980px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    background: var(--bg-color);
    font-family: var(--font-sans);
    color: var(--text-primary);
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}

/* ---------------- CONTAINER ---------------- */

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 40px;
}

/* ---------------- NAVBAR ---------------- */

.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    height: 48px;
    background: rgba(255,255,255,0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 40px;
}

.nav-logo {
    font-size: 14px;
    text-decoration: none;
    color: var(--text-primary);
}

.nav-links a {
    font-size: 12px;
    color: var(--text-secondary);
    text-decoration: none;
}

/* ---------------- SECTION ---------------- */

.overview-section {
    padding-top: 140px;
    padding-bottom: 100px;
}

.welcome-title {
    font-size: 44px;
    margin-bottom: 40px;
}

/* ---------------- LIST STYLE (APPLE STRIPES) ---------------- */

.book-grid {
    border-top: 1px solid var(--border-color);
}

.book-card {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 28px 0;
    border-bottom: 1px solid var(--border-color);
}

.book-title {
    font-size: 20px;
    font-weight: 400;
}

/* Audio rechts */
.book-card audio {
    width: 280px;
}

/* ---------------- FOOTER ---------------- */

.footer {
    padding: 60px 0;
    font-size: 12px;
    color: var(--text-secondary);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-right {
    display: flex;
    gap: 24px;
    align-items: center;
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s var(--transition-smooth);
}

.footer-link:hover {
    color: var(--text-primary);
}

/* ---------------- MOBILE ---------------- */

@media (max-width: 768px) {

    .container,
    .nav-container {
        padding: 0 24px;
    }

    .welcome-title {
        font-size: 32px;
    }

    .book-card {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }

    .book-card audio {
        width: 100%;
    }

    .footer-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
}