* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; color: #333; line-height: 1.6; background: #f5f7fa; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
a { color: #1a73e8; text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header */
.site-header { background: #fff; border-bottom: 1px solid #e0e0e0; padding: 15px 0; position: sticky; top: 0; z-index: 100; }
.site-header .container { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; }
.logo { font-size: 24px; font-weight: bold; }
.logo a { color: #1a73e8; }
.main-nav { display: flex; flex-wrap: wrap; gap: 15px; }
.main-nav a { color: #555; padding: 5px 10px; border-radius: 4px; }
.main-nav a:hover, .main-nav a.active { background: #e8f0fe; color: #1a73e8; text-decoration: none; }

/* Main */
main { padding: 30px 0; min-height: calc(100vh - 200px); }

/* Breadcrumb */
.breadcrumb { margin-bottom: 20px; font-size: 14px; color: #666; }
.breadcrumb span { margin: 0 5px; color: #999; }

/* Hero */
.hero { text-align: center; padding: 40px 0; background: #fff; border-radius: 8px; margin-bottom: 30px; }
.hero h1 { font-size: 32px; margin-bottom: 10px; color: #1a73e8; }
.hero p { font-size: 16px; color: #666; }

/* Category Grid */
.category-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px; margin-bottom: 30px; }
.category-card { background: #fff; border-radius: 8px; padding: 20px; border: 1px solid #e0e0e0; transition: box-shadow 0.2s; }
.category-card:hover { box-shadow: 0 4px 12px rgba(0,0,0,0.1); }
.category-card h3 { font-size: 18px; margin-bottom: 10px; color: #1a73e8; }
.category-card p { font-size: 14px; color: #666; margin-bottom: 10px; }
.category-card .tool-count { font-size: 12px; color: #999; }

/* Tool Grid */
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 15px; margin-bottom: 30px; }
.tool-card { background: #fff; border-radius: 6px; padding: 15px; border: 1px solid #e0e0e0; transition: all 0.2s; }
.tool-card:hover { border-color: #1a73e8; box-shadow: 0 2px 8px rgba(26,115,232,0.15); }
.tool-card h4 { font-size: 15px; margin-bottom: 5px; }
.tool-card h4 a { color: #333; }
.tool-card h4 a:hover { color: #1a73e8; }
.tool-card p { font-size: 12px; color: #999; }

/* Tool Page */
.tool-page { background: #fff; border-radius: 8px; padding: 30px; margin-bottom: 30px; }
.tool-page h1 { font-size: 28px; margin-bottom: 15px; color: #1a73e8; }
.tool-desc { font-size: 15px; color: #666; margin-bottom: 25px; }

/* Tool Box */
.tool-box { background: #f8f9fa; border: 1px solid #e0e0e0; border-radius: 6px; padding: 25px; margin-bottom: 30px; }
.tool-box textarea, .tool-box input[type="text"], .tool-box input[type="number"], .tool-box select { width: 100%; padding: 10px; border: 1px solid #ddd; border-radius: 4px; font-size: 14px; margin-bottom: 10px; font-family: inherit; }
.tool-box textarea { min-height: 120px; resize: vertical; }
.tool-box button { background: #1a73e8; color: #fff; border: none; padding: 10px 25px; border-radius: 4px; cursor: pointer; font-size: 14px; margin-right: 10px; margin-bottom: 10px; }
.tool-box button:hover { background: #1557b0; }
.tool-box button.secondary { background: #6c757d; }
.tool-box button.secondary:hover { background: #5a6268; }
.tool-box .result { background: #fff; border: 1px solid #e0e0e0; border-radius: 4px; padding: 15px; margin-top: 15px; min-height: 50px; word-break: break-all; }
.tool-box .result-label { font-size: 13px; color: #666; margin-bottom: 5px; font-weight: bold; }
.tool-box .file-input { margin-bottom: 15px; }
.tool-box .file-input input[type="file"] { width: 100%; padding: 10px; border: 1px dashed #ddd; border-radius: 4px; }
.tool-box .batch-info { font-size: 13px; color: #666; margin-bottom: 10px; }

/* Content Sections */
.content-section { margin-bottom: 30px; }
.content-section h2 { font-size: 22px; margin-bottom: 15px; color: #333; border-left: 4px solid #1a73e8; padding-left: 10px; }
.content-section h3 { font-size: 18px; margin: 20px 0 10px; color: #444; }
.content-section p { margin-bottom: 12px; font-size: 15px; }
.content-section ul, .content-section ol { margin-left: 25px; margin-bottom: 15px; }
.content-section li { margin-bottom: 8px; font-size: 15px; }

/* Table */
.data-table { width: 100%; border-collapse: collapse; margin-bottom: 20px; }
.data-table th, .data-table td { border: 1px solid #e0e0e0; padding: 10px 12px; text-align: left; font-size: 14px; }
.data-table th { background: #f8f9fa; font-weight: bold; color: #333; }
.data-table tr:nth-child(even) { background: #fafbfc; }

/* FAQ */
.faq-item { margin-bottom: 15px; border: 1px solid #e0e0e0; border-radius: 4px; overflow: hidden; }
.faq-question { background: #f8f9fa; padding: 12px 15px; font-weight: bold; cursor: pointer; }
.faq-answer { padding: 15px; font-size: 14px; color: #555; }

/* Usage Notice */
.usage-notice { background: #e8f5e9; border-left: 4px solid #4caf50; padding: 15px; margin-bottom: 20px; border-radius: 4px; }
.usage-notice h4 { color: #2e7d32; margin-bottom: 8px; }
.usage-notice p { font-size: 14px; color: #388e3c; margin-bottom: 5px; }

/* Footer */
.site-footer { background: #fff; border-top: 1px solid #e0e0e0; padding: 30px 0; text-align: center; color: #666; font-size: 14px; }
.site-footer p { margin-bottom: 8px; }

/* Responsive */
@media (max-width: 768px) {
    .main-nav { gap: 8px; }
    .main-nav a { padding: 4px 8px; font-size: 13px; }
    .hero h1 { font-size: 24px; }
    .tool-page { padding: 20px; }
    .tool-page h1 { font-size: 22px; }
    .category-grid { grid-template-columns: 1fr; }
    .tool-grid { grid-template-columns: repeat(2, 1fr); }
}