body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background-color: #f5f5f5;
}
.navbar { box-shadow: 0 2px 8px rgba(0,0,0,0.15); }
.navbar-brand { font-size: 1.3rem; }
.hero-section {
    background: linear-gradient(135deg, #2c3e50 0%, #3498db 100%);
    border-radius: 1rem;
    padding: 3rem 1rem !important;
}
.hero-section .btn-outline-light { border-radius: 2rem; padding: 0.5rem 1.5rem; }
.section-title {
    font-weight: 700; font-size: 1.5rem;
    padding-bottom: 0.5rem; border-bottom: 3px solid #212529;
    display: inline-block;
}
.stone-card {
    border: none; border-radius: 0.75rem; overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
}
.stone-card:hover { transform: translateY(-4px); box-shadow: 0 8px 25px rgba(0,0,0,0.15) !important; }
.stone-card .card-img-top { height: 200px; object-fit: cover; }
.placeholder-img { height: 200px; background: #e9ecef; }
.category-card {
    border: 2px solid #dee2e6; border-radius: 0.75rem;
    transition: all 0.2s; color: #495057;
}
.category-card:hover { border-color: #212529; color: #212529; transform: translateY(-3px); box-shadow: 0 6px 20px rgba(0,0,0,0.1); }
.category-icon { font-size: 2.5rem; }
.main-stone-image { max-height: 500px; object-fit: contain; background: #f8f9fa; cursor: pointer; }
.thumbnail-img {
    width: 80px; height: 60px; object-fit: cover; cursor: pointer;
    border: 3px solid transparent; transition: border-color 0.2s; opacity: 0.7;
}
.thumbnail-img:hover, .thumbnail-img.active { border-color: #212529; opacity: 1; }
.placeholder-img-large { height: 400px; background: #e9ecef; }
.table td { vertical-align: middle; }

/* ── 手机端优化 ─────────────────────────────────── */
@media (max-width: 768px) {
    .hero-section { padding: 2rem 1rem !important; }
    .hero-section h1 { font-size: 1.8rem; }
    .stone-card .card-img-top { height: 150px; }
    .main-stone-image { max-height: 300px; }
    .thumbnail-img { width: 60px; height: 45px; }
    .btn-sm { padding: 0.4rem 0.8rem; font-size: 0.85rem; }
    .stone-block { padding: 0.75rem !important; }
    .card-body { padding: 0.75rem; }
}

/* 图片选择预览 */
.preview-area { min-height: 1.2em; }