/**
 * utility.css - 站点自托管极简工具类
 * 仅覆盖全站页面实际用到的 Bootstrap 4.6 子集，替代 161KB 的完整框架
 */
.container-fluid { width: 100%; padding: 0 0; margin: 0 auto; }

/* 栅格（Bootstrap 4.6：gutter 15px） */
.row { display: flex; flex-wrap: wrap; margin-left: -15px; margin-right: -15px; }
.row > * { padding-left: 15px; padding-right: 15px; }
.col-12 { flex: 0 0 100%; max-width: 100%; }
@media (min-width: 992px) {
    .col-lg-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
    .col-lg-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
}

/* 显示与间距 */
.d-none { display: none !important; }
.d-flex { display: flex !important; }
.align-items-center { align-items: center !important; }
.justify-content-between { justify-content: space-between !important; }
.w-100 { width: 100% !important; }
.px-0 { padding-left: 0 !important; padding-right: 0 !important; }
.px-3 { padding-left: 1rem !important; padding-right: 1rem !important; }
.pt-3 { padding-top: 1rem !important; }
.mt-1 { margin-top: .25rem !important; }
.mt-3 { margin-top: 1rem !important; }
.mb-3 { margin-bottom: 1rem !important; }
.mb-4 { margin-bottom: 1.5rem !important; }
.ml-auto { margin-left: auto !important; }
.gap-2 { gap: .5rem !important; }
.gap-3 { gap: 1rem !important; }

/* 表单与按钮（qrcode.html 等页面自带细节样式，这里只补基线） */
.form-control { display: block; width: 100%; background-color: #fff; color: #1e293b; background-clip: padding-box; }
select.form-control { appearance: auto; }
.form-text { display: block; margin-top: .25rem; }
.btn { display: inline-block; text-align: center; cursor: pointer; border: 1px solid transparent; padding: 6px 12px; border-radius: 8px; font-size: .875rem; }
.btn-sm { padding: .25rem .5rem; font-size: .875rem; }
.btn-outline-secondary { border-color: #64748b; color: #64748b; background: #fff; }
.btn-outline-secondary:hover { color: #fff; background: #64748b; }
.input-group { display: flex; width: 100%; }
.input-group .form-control { border-radius: 8px 0 0 8px; }
.input-group-append { display: flex; }

/* 相关工具内链区 */
.related-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 10px; }
.related-card { display: flex; align-items: center; gap: 10px; padding: 12px; border: 1px solid #e2e8f0; border-radius: 10px; background: #fff; text-decoration: none; color: #1e293b; transition: all .2s; }
.related-card:hover { border-color: #4361ee; box-shadow: 0 2px 8px rgba(67,97,238,.12); transform: translateY(-1px); }
.related-icon { width: 34px; height: 34px; border-radius: 8px; display: flex; align-items: center; justify-content: center; color: #fff; font-size: .72rem; font-weight: 700; flex-shrink: 0; }
.related-name { font-size: .85rem; font-weight: 600; margin: 0; }
.related-desc { font-size: .72rem; color: #64748b; margin: 0; }

/* 使用指南/FAQ 内容区（工具页底部） */
.guide-section { margin-top: 24px; }
.guide-section h2 { font-size: .95rem; font-weight: 600; margin: 0 0 10px; color: #1e293b; }
.guide-text { font-size: .82rem; color: #64748b; line-height: 1.8; margin: 0 0 8px; }