body {
    margin: 0;
    font-family: Georgia, serif;
    line-height: 1.6;
    padding: 30px 10%;
    transition: background-color .3s, color .3s;
}

/* Themes */
.light-theme { background:#faf6ef; color:#222; }
.dark-theme { background:#1a1a1a; color:#eaeaea; }
.sepia-theme { background:#f4ecd8; color:#3e2f14; }

/* Theme Selector */
header { margin-bottom: 20px; }
.theme-select {
    padding: 8px 12px;
    border-radius: 6px;
}

/* Library Cards */
.book-card {
    padding: 15px; margin: 12px 0;
    border-radius: 8px;
    border: 1px solid #999;
    cursor:pointer;
}

/* Buttons */
.view-buttons {
    margin: 20px 0;
}
.view-buttons button {
    margin-right:10px; padding:8px 14px;
    border-radius:6px; border:none; cursor:pointer;
}
.active-view { font-weight:bold; text-decoration:underline; }

/* Text */
pre, article { white-space: pre-wrap; }

/* Side by Side Mode */
.side { display:flex; gap:5%; }
.side article { width:47%; }