:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f8fafc;
    --text-muted: #94a3b8;
    --accent: #38bdf8;
    --accent-hover: #0284c7;
    --success: #22c55e;
    --danger: #ef4444;
    --border: #334155;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--accent);
}

.nav {
    display: flex;
    gap: 1rem;
}

.nav-link {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    transition: all 0.2s;
}

.nav-link.active, .nav-link:hover {
    color: var(--text-color);
    background-color: var(--border);
}

.badge {
    background-color: var(--accent);
    color: #000;
    font-size: 0.75rem;
    padding: 2px 6px;
    border-radius: 10px;
    font-weight: bold;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 1.5rem;
}

.search-box {
    margin-bottom: 2rem;
}

.search-form {
    display: flex;
    gap: 0.5rem;
}

.search-input {
    flex: 1;
    padding: 0.8rem 1rem;
    border-radius: 8px;
    border: 1px solid var(--border);
    background-color: var(--card-bg);
    color: var(--text-color);
    font-size: 1rem;
}

.search-input:focus {
    outline: 2px solid var(--accent);
}

.btn {
    padding: 0.7rem 1.2rem;
    border-radius: 8px;
    border: none;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.btn-primary { background-color: var(--accent); color: #0f172a; }
.btn-primary:hover { background-color: var(--accent-hover); color: #fff; }

.btn-success { background-color: var(--success); color: #fff; }
.btn-danger { background-color: var(--danger); color: #fff; }
.btn-outline { background-color: transparent; border: 1px solid var(--border); color: var(--text-color); }
.btn-outline:hover { background-color: var(--border); }
.btn-lg { padding: 1rem 1.5rem; font-size: 1.1rem; width: 100%; }
.btn-block { width: 100%; }

.result-card.featured {
    background: linear-gradient(145deg, #1e293b, #0f172a);
    border: 2px solid var(--accent);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
}

.tag {
    display: inline-block;
    background-color: var(--accent);
    color: #0f172a;
    font-weight: bold;
    font-size: 0.8rem;
    padding: 4px 8px;
    border-radius: 4px;
    margin-bottom: 0.8rem;
}

.book-title { font-size: 1.8rem; margin-bottom: 0.3rem; }
.book-author { font-size: 1.2rem; color: var(--accent); margin-bottom: 0.8rem; }
.book-meta { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 1.2rem; }

.ai-box {
    background-color: rgba(15, 23, 42, 0.7);
    border-left: 4px solid var(--accent);
    padding: 1.2rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
}

.ai-box h3 { margin-bottom: 0.5rem; color: var(--accent); }
.reason-note { font-size: 0.95rem; margin-bottom: 0.8rem; color: #e2e8f0; }
.ai-text { font-size: 1rem; color: #cbd5e1; white-space: pre-wrap; line-height: 1.6; }

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.card {
    background-color: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem;
}

.card h4 { font-size: 1.1rem; margin-bottom: 0.3rem; }
.card .author { color: var(--accent); font-size: 0.9rem; margin-bottom: 0.4rem; }
.card .meta { color: var(--text-muted); font-size: 0.8rem; margin-bottom: 0.8rem; }

.shelf-grid {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-top: 1rem;
}

.shelf-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 1.2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.shelf-info { flex: 1; }
.shelf-title { font-size: 1.3rem; margin-bottom: 0.2rem; }
.shelf-author { color: var(--accent); font-size: 1rem; margin-bottom: 0.6rem; }
.shelf-progress-bar { height: 6px; background-color: var(--border); border-radius: 3px; overflow: hidden; margin-bottom: 0.4rem; }
.shelf-progress-bar .fill { height: 100%; background-color: var(--success); }
.shelf-meta { font-size: 0.85rem; color: var(--text-muted); }

.shelf-actions { display: flex; flex-direction: column; gap: 0.5rem; width: 120px; }