:root {
    --bg-color: #f5f5f5;
    --text-color: #333;
    --card-bg: #fff;
    --border-color: #ddd;
    --primary-color: #0070f3;
    --primary-hover: #005bb5;
    --error-color: #e00;
}
[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #f5f5f5;
    --card-bg: #2d2d2d;
    --border-color: #444;
}

* { box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
}
.container { max-width: 1000px; margin: 0 auto; padding: 20px; }
header { background: var(--card-bg); border-bottom: 1px solid var(--border-color); padding: 10px 0; }
.header-flex { display: flex; justify-content: space-between; align-items: center; }
h1, h2, h3 { margin-top: 0; }
input, select, button { padding: 10px; border: 1px solid var(--border-color); border-radius: 6px; background: var(--bg-color); color: var(--text-color); margin-bottom: 10px; }
button { background: var(--primary-color); color: white; border: none; cursor: pointer; transition: 0.2s; }
button:hover { background: var(--primary-hover); }
.admin-link { color: var(--primary-color); text-decoration: none; padding: 10px; }
#searchInput { width: 300px; }
.card { background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 8px; padding: 20px; margin-bottom: 20px; }

/* Grid for Categories */
.category-section { margin-bottom: 30px; }
.bookmark-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 15px; }
.bookmark-item {
    background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 8px; padding: 15px;
    display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text-color);
    transition: transform 0.2s, box-shadow 0.2s;
}
.bookmark-item:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
.bookmark-icon { width: 24px; height: 24px; border-radius: 4px; }

/* Admin */
.admin-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 768px) { .admin-grid { grid-template-columns: 1fr; } }
form { display: flex; flex-direction: column; }
.admin-list { list-style: none; padding: 0; }
.admin-list li { display: flex; justify-content: space-between; padding: 10px; border-bottom: 1px solid var(--border-color); }
.btn-delete { background: var(--error-color); padding: 5px 10px; font-size: 12px; }
.error { color: var(--error-color); }