:root {
            --primary: #2563eb;
            --primary-dark: #1d4ed8;
            --secondary: #64748b;
            --bg: #f8fafc;
            --surface: #ffffff;
            --text: #0f172a;
            --text-muted: #475569;
            --border: #e2e8f0;
            --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
            --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
            --radius: 12px;
            --radius-sm: 8px;
            --max-width: 1280px;
            --gap: 24px;
        }

        * { margin: 0; padding: 0; box-sizing: border-box; }
        html { scroll-behavior: smooth; scroll-padding-top: 20px; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            background: var(--bg); color: var(--text); line-height: 1.6; -webkit-font-smoothing: antialiased;
        }

        .breadcrumb { max-width: var(--max-width); margin: 0 auto; padding: 12px var(--gap); font-size: 13px; color: var(--text-muted); }
        .breadcrumb a { color: var(--text-muted); text-decoration: none; }
        .breadcrumb a:hover { color: var(--primary); }
        .breadcrumb span { color: var(--text); }

        .site-header { background: var(--surface); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 50; }
        .header-inner { max-width: var(--max-width); margin: 0 auto; padding: 16px var(--gap); display: flex; align-items: center; justify-content: space-between; }
        .brand { display: flex; align-items: center; gap: 12px; text-decoration: none; color: var(--text); }
        .brand-text h1 { font-size: 20px; font-weight: 700; line-height: 1.2; }
        .brand-text p { font-size: 13px; color: var(--text-muted); margin: 0; }

        .tool-layout { max-width: var(--max-width); margin: 0 auto; padding: var(--gap); display: flex; gap: var(--gap); align-items: flex-start; }
        .tool-main { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 20px; }
        .tool-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow); }
        .tool-card h1 { font-size: 24px; font-weight: 700; margin-bottom: 6px; }
        .tool-card .subtitle { color: var(--text-muted); font-size: 14px; margin-bottom: 24px; }

        .qr-tabs { display: flex; gap: 4px; margin-bottom: 20px; border-bottom: 1px solid var(--border); overflow-x: auto; }
        .qr-tab {
            padding: 10px 18px; font-size: 14px; font-weight: 600; cursor: pointer;
            border-bottom: 2px solid transparent; color: var(--text-muted); background: none; border: none;
            border-bottom: 2px solid transparent; transition: all 0.2s; font-family: inherit; white-space: nowrap; flex-shrink: 0;
        }
        .qr-tab.active { color: var(--primary); border-bottom-color: var(--primary); }
        .qr-tab:hover { color: var(--primary); }

        .qr-panel { display: none; }
        .qr-panel.active { display: block; }

        .form-group { margin-bottom: 16px; }
        .form-group label { display: block; font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 6px; }
        .form-group .hint { font-size: 12px; color: var(--text-muted); font-weight: 400; margin-left: 4px; }
        .form-group input[type="text"], .form-group input[type="url"], .form-group input[type="tel"], .form-group input[type="number"], .form-group input[type="file"], .form-group textarea, .form-group select {
            width: 100%; padding: 10px 14px; border: 1px solid var(--border); border-radius: var(--radius-sm);
            font-size: 14px; background: var(--bg); color: var(--text); transition: border-color 0.2s; font-family: inherit;
        }
        .form-group input:focus, .form-group textarea:focus, .form-group select:focus { outline: none; border-color: var(--primary); background: var(--surface); }
        .form-group textarea { resize: vertical; min-height: 80px; }
        .form-group input[type="color"] { width: 52px; height: 40px; border: 1px solid var(--border); border-radius: var(--radius-sm); background: none; cursor: pointer; padding: 2px; }
        .form-group input[type="range"] { width: 100%; accent-color: var(--primary); }
        .form-group input[type="file"] { padding: 8px 14px; font-size: 13px; }
        .form-group input[type="checkbox"] { width: auto; margin-right: 6px; accent-color: var(--primary); }
        .slider-val { font-size: 13px; font-weight: 700; color: var(--primary); font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace; margin-top: 4px; }
        .input-row { display: flex; gap: 10px; align-items: center; }
        .input-row input { flex: 1; }
        .input-row input[type="color"] { flex: 0; }
        .checkbox-row { display: flex; align-items: center; gap: 8px; margin-top: 6px; }
        .checkbox-row label { font-weight: 400; font-size: 13px; margin: 0; cursor: pointer; }

        .style-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
        .style-card { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 16px; }
        .style-card h4 { font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 10px; }

        .preset-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
        .preset-btn {
            padding: 10px 6px; font-size: 12px; font-weight: 600; background: var(--bg); color: var(--text-muted);
            border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; transition: all 0.2s; font-family: inherit; text-align: center;
        }
        .preset-btn:hover { border-color: var(--primary); color: var(--primary); background: #eff6ff; }
        .preset-btn.active { border-color: var(--primary); background: var(--primary); color: #fff; }

        .btn-primary {
            display: inline-flex; align-items: center; justify-content: center; gap: 8px;
            padding: 12px 32px; background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: #fff; border: none; border-radius: var(--radius-sm); font-size: 15px; font-weight: 600;
            cursor: pointer; transition: all 0.2s; font-family: inherit;
        }
        .btn-primary:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3); }
        .btn-secondary {
            display: inline-flex; align-items: center; justify-content: center; gap: 8px;
            padding: 12px 24px; background: var(--bg); color: var(--text); border: 1px solid var(--border);
            border-radius: var(--radius-sm); font-size: 14px; font-weight: 600; cursor: pointer;
            transition: all 0.2s; font-family: inherit;
        }
        .btn-secondary:hover { border-color: var(--primary); color: var(--primary); background: #eff6ff; }
        .btn-wrap { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 16px; }

        .result-panel {
            width: 420px; flex-shrink: 0; background: var(--surface); border: 1px solid var(--border);
            border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow);
            position: sticky; top: 90px; max-height: calc(100vh - 110px); overflow-y: auto;
        }
        .result-panel h2 { font-size: 18px; font-weight: 700; margin-bottom: 16px; display: flex; align-items: center; gap: 8px; }
        .result-panel h2 svg { color: var(--primary); }

        .qr-preview-wrap { text-align: center; margin-bottom: 20px; }
        .qr-preview-box {
            display: inline-block; padding: 20px; background: var(--bg); border: 1px solid var(--border);
            border-radius: var(--radius-sm); position: relative; min-width: 200px;
        }
        .qr-preview-box #qrcode { display: inline-block; }
        .qr-preview-box canvas, .qr-preview-box svg {
            display: block;
            max-width: 100%;
            height: auto;
        }
        .qr-info { font-size: 12px; color: var(--text-muted); margin-top: 10px; font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace; }

        .panel-card { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 16px; margin-bottom: 12px; }
        .panel-card h3 { font-size: 14px; font-weight: 600; color: var(--text); margin-bottom: 10px; }
        .panel-row { display: flex; justify-content: space-between; font-size: 13px; padding: 5px 0; border-bottom: 1px dashed var(--border); }
        .panel-row:last-child { border-bottom: none; }
        .panel-row .k { color: var(--text-muted); }
        .panel-row .v { font-weight: 600; }

        .info-section { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--gap) var(--gap); }
        .info-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; margin-bottom: 20px; }
        .info-card h2 { font-size: 20px; font-weight: 700; margin-bottom: 16px; }
        .info-card p { color: var(--text-muted); font-size: 15px; line-height: 1.7; margin-bottom: 12px; }
        .info-card ul { margin-left: 20px; color: var(--text-muted); font-size: 15px; line-height: 1.8; }
        .info-card li { margin-bottom: 6px; }
        .info-card table { width: 100%; border-collapse: collapse; font-size: 14px; margin: 12px 0; }
        .info-card th, .info-card td { padding: 10px 12px; text-align: left; border: 1px solid var(--border); }
        .info-card th { background: var(--bg); font-weight: 600; color: var(--text); }
        .info-card td { color: var(--text-muted); }
        .info-card td code { background: #e0e7ff; color: var(--primary-dark); padding: 2px 6px; border-radius: 4px; font-size: 13px; }

        .site-footer { background: var(--text); color: #94a3b8; padding: 40px 0 24px; font-size: 14px; margin-top: 20px; }
        .footer-inner { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--gap); display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; }
        .footer-brand p { line-height: 1.7; max-width: 300px; }
        .footer-col h4 { color: #f1f5f9; font-size: 14px; font-weight: 600; margin-bottom: 16px; text-transform: uppercase; letter-spacing: 0.05em; }
        .footer-col ul { list-style: none; }
        .footer-col li { margin-bottom: 10px; }
        .footer-col a { color: #94a3b8; text-decoration: none; transition: color 0.2s; }
        .footer-col a:hover { color: #fff; }
        .footer-bottom { max-width: var(--max-width); margin: 32px auto 0; padding: 24px var(--gap) 0; border-top: 1px solid #334155; display: flex; justify-content: space-between; align-items: center; font-size: 13px; }
        .footer-links { display: flex; gap: 20px; }
        .footer-links a { color: #94a3b8; text-decoration: none; }
        .footer-links a:hover { color: #fff; }

        .empty-state { text-align: center; padding: 40px 16px; color: var(--text-muted); font-size: 14px; }
        .empty-state svg { margin-bottom: 12px; opacity: 0.4; }

        /* 折叠面板 */
        details.settings-group { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 16px; overflow: hidden; }
        details.settings-group summary {
            padding: 14px 20px; font-size: 15px; font-weight: 600; color: var(--text);
            cursor: pointer; list-style: none; display: flex; align-items: center; justify-content: space-between;
            user-select: none; background: var(--bg);
        }
        details.settings-group summary::after {
            content: "▸"; font-size: 18px; color: var(--text-muted); transition: transform 0.2s;
        }
        details.settings-group[open] summary::after { transform: rotate(90deg); }
        details.settings-group .group-body { padding: 20px; }
        details.settings-group[open] summary { border-bottom: 1px solid var(--border); }

        .two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
        .file-preview { max-width: 80px; max-height: 80px; border-radius: 6px; border: 1px solid var(--border); margin-top: 8px; display: none; }
        .file-preview.show { display: block; }

        @media (max-width: 768px) {
            .header-inner { padding: 12px 16px; }
            .tool-layout { flex-direction: column; padding: 16px; }
            .tool-card { padding: 20px; }
            .style-grid { grid-template-columns: 1fr; }
            .preset-grid { grid-template-columns: repeat(3, 1fr); }
            .result-panel { width: 100%; position: relative; top: 0; max-height: none; }
            .qr-tabs { padding-bottom: 4px; }
            .footer-inner { grid-template-columns: 1fr 1fr; gap: 24px; }
            .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
            .two-col { grid-template-columns: 1fr; }
        }


.faq-item { margin-bottom: 12px; border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden; }
.faq-item summary { padding: 14px 16px; font-weight: 600; font-size: 15px; cursor: pointer; background: var(--bg); color: var(--text); list-style: none; display: flex; justify-content: space-between; align-items: center; }
.faq-item summary::after { content: "+"; font-size: 20px; color: var(--text-muted); transition: transform 0.2s; }
.faq-item[open] summary::after { content: "−"; }
.faq-item p { padding: 12px 16px 16px; font-size: 14px; color: var(--text-muted); line-height: 1.7; margin: 0; }